1	//===- ValueTracking.cpp - Walk computations to compute properties --------===//
2	//
3	// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4	// See https://llvm.org/LICENSE.txt for license information.
5	// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6	//
7	//===----------------------------------------------------------------------===//
8	//
9	// This file contains routines that help analyze properties that chains of
10	// computations have.
11	//
12	//===----------------------------------------------------------------------===//
13
14	#include "llvm/Analysis/ValueTracking.h"
15	#include "llvm/ADT/APFloat.h"
16	#include "llvm/ADT/APInt.h"
17	#include "llvm/ADT/ArrayRef.h"
18	#include "llvm/ADT/STLExtras.h"
19	#include "llvm/ADT/ScopeExit.h"
20	#include "llvm/ADT/SmallPtrSet.h"
21	#include "llvm/ADT/SmallSet.h"
22	#include "llvm/ADT/SmallVector.h"
23	#include "llvm/ADT/StringRef.h"
24	#include "llvm/ADT/iterator_range.h"
25	#include "llvm/Analysis/AliasAnalysis.h"
26	#include "llvm/Analysis/AssumeBundleQueries.h"
27	#include "llvm/Analysis/AssumptionCache.h"
28	#include "llvm/Analysis/ConstantFolding.h"
29	#include "llvm/Analysis/DomConditionCache.h"
30	#include "llvm/Analysis/GuardUtils.h"
31	#include "llvm/Analysis/InstructionSimplify.h"
32	#include "llvm/Analysis/Loads.h"
33	#include "llvm/Analysis/LoopInfo.h"
34	#include "llvm/Analysis/OptimizationRemarkEmitter.h"
35	#include "llvm/Analysis/TargetLibraryInfo.h"
36	#include "llvm/Analysis/VectorUtils.h"
37	#include "llvm/Analysis/WithCache.h"
38	#include "llvm/IR/Argument.h"
39	#include "llvm/IR/Attributes.h"
40	#include "llvm/IR/BasicBlock.h"
41	#include "llvm/IR/Constant.h"
42	#include "llvm/IR/ConstantRange.h"
43	#include "llvm/IR/Constants.h"
44	#include "llvm/IR/DerivedTypes.h"
45	#include "llvm/IR/DiagnosticInfo.h"
46	#include "llvm/IR/Dominators.h"
47	#include "llvm/IR/EHPersonalities.h"
48	#include "llvm/IR/Function.h"
49	#include "llvm/IR/GetElementPtrTypeIterator.h"
50	#include "llvm/IR/GlobalAlias.h"
51	#include "llvm/IR/GlobalValue.h"
52	#include "llvm/IR/GlobalVariable.h"
53	#include "llvm/IR/InstrTypes.h"
54	#include "llvm/IR/Instruction.h"
55	#include "llvm/IR/Instructions.h"
56	#include "llvm/IR/IntrinsicInst.h"
57	#include "llvm/IR/Intrinsics.h"
58	#include "llvm/IR/IntrinsicsAArch64.h"
59	#include "llvm/IR/IntrinsicsAMDGPU.h"
60	#include "llvm/IR/IntrinsicsRISCV.h"
61	#include "llvm/IR/IntrinsicsX86.h"
62	#include "llvm/IR/LLVMContext.h"
63	#include "llvm/IR/Metadata.h"
64	#include "llvm/IR/Module.h"
65	#include "llvm/IR/Operator.h"
66	#include "llvm/IR/PatternMatch.h"
67	#include "llvm/IR/Type.h"
68	#include "llvm/IR/User.h"
69	#include "llvm/IR/Value.h"
70	#include "llvm/Support/Casting.h"
71	#include "llvm/Support/CommandLine.h"
72	#include "llvm/Support/Compiler.h"
73	#include "llvm/Support/ErrorHandling.h"
74	#include "llvm/Support/KnownBits.h"
75	#include "llvm/Support/MathExtras.h"
76	#include "llvm/TargetParser/RISCVTargetParser.h"
77	#include <algorithm>
78	#include <cassert>
79	#include <cstdint>
80	#include <optional>
81	#include <utility>
82
83	using namespace llvm;
84	using namespace llvm::PatternMatch;
85
86	// Controls the number of uses of the value searched for possible
87	// dominating comparisons.
88	static cl::opt<unsigned> DomConditionsMaxUses("dom-conditions-max-uses",
89	cl::Hidden, cl::init(Val: 20));
90
91
92	/// Returns the bitwidth of the given scalar or pointer type. For vector types,
93	/// returns the element type's bitwidth.
94	static unsigned getBitWidth(Type *Ty, const DataLayout &DL) {
95	if (unsigned BitWidth = Ty->getScalarSizeInBits())
96	return BitWidth;
97
98	return DL.getPointerTypeSizeInBits(Ty);
99	}
100
101	// Given the provided Value and, potentially, a context instruction, return
102	// the preferred context instruction (if any).
103	static const Instruction *safeCxtI(const Value *V, const Instruction *CxtI) {
104	// If we've been provided with a context instruction, then use that (provided
105	// it has been inserted).
106	if (CxtI && CxtI->getParent())
107	return CxtI;
108
109	// If the value is really an already-inserted instruction, then use that.
110	CxtI = dyn_cast<Instruction>(Val: V);
111	if (CxtI && CxtI->getParent())
112	return CxtI;
113
114	return nullptr;
115	}
116
117	static const Instruction *safeCxtI(const Value *V1, const Value *V2, const Instruction *CxtI) {
118	// If we've been provided with a context instruction, then use that (provided
119	// it has been inserted).
120	if (CxtI && CxtI->getParent())
121	return CxtI;
122
123	// If the value is really an already-inserted instruction, then use that.
124	CxtI = dyn_cast<Instruction>(Val: V1);
125	if (CxtI && CxtI->getParent())
126	return CxtI;
127
128	CxtI = dyn_cast<Instruction>(Val: V2);
129	if (CxtI && CxtI->getParent())
130	return CxtI;
131
132	return nullptr;
133	}
134
135	static bool getShuffleDemandedElts(const ShuffleVectorInst *Shuf,
136	const APInt &DemandedElts,
137	APInt &DemandedLHS, APInt &DemandedRHS) {
138	if (isa<ScalableVectorType>(Val: Shuf->getType())) {
139	assert(DemandedElts == APInt(1,1));
140	DemandedLHS = DemandedRHS = DemandedElts;
141	return true;
142	}
143
144	int NumElts =
145	cast<FixedVectorType>(Val: Shuf->getOperand(i_nocapture: 0)->getType())->getNumElements();
146	return llvm::getShuffleDemandedElts(SrcWidth: NumElts, Mask: Shuf->getShuffleMask(),
147	DemandedElts, DemandedLHS, DemandedRHS);
148	}
149
150	static void computeKnownBits(const Value *V, const APInt &DemandedElts,
151	KnownBits &Known, unsigned Depth,
152	const SimplifyQuery &Q);
153
154	void llvm::computeKnownBits(const Value *V, KnownBits &Known, unsigned Depth,
155	const SimplifyQuery &Q) {
156	// Since the number of lanes in a scalable vector is unknown at compile time,
157	// we track one bit which is implicitly broadcast to all lanes. This means
158	// that all lanes in a scalable vector are considered demanded.
159	auto *FVTy = dyn_cast<FixedVectorType>(Val: V->getType());
160	APInt DemandedElts =
161	FVTy ? APInt::getAllOnes(numBits: FVTy->getNumElements()) : APInt(1, 1);
162	::computeKnownBits(V, DemandedElts, Known, Depth, Q);
163	}
164
165	void llvm::computeKnownBits(const Value *V, KnownBits &Known,
166	const DataLayout &DL, unsigned Depth,
167	AssumptionCache *AC, const Instruction *CxtI,
168	const DominatorTree *DT, bool UseInstrInfo) {
169	computeKnownBits(
170	V, Known, Depth,
171	Q: SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
172	}
173
174	KnownBits llvm::computeKnownBits(const Value *V, const DataLayout &DL,
175	unsigned Depth, AssumptionCache *AC,
176	const Instruction *CxtI,
177	const DominatorTree *DT, bool UseInstrInfo) {
178	return computeKnownBits(
179	V, Depth, Q: SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
180	}
181
182	KnownBits llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
183	const DataLayout &DL, unsigned Depth,
184	AssumptionCache *AC, const Instruction *CxtI,
185	const DominatorTree *DT, bool UseInstrInfo) {
186	return computeKnownBits(
187	V, DemandedElts, Depth,
188	Q: SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
189	}
190
191	static bool haveNoCommonBitsSetSpecialCases(const Value *LHS, const Value *RHS,
192	const SimplifyQuery &SQ) {
193	// Look for an inverted mask: (X & ~M) op (Y & M).
194	{
195	Value *M;
196	if (match(V: LHS, P: m_c_And(L: m_Not(V: m_Value(V&: M)), R: m_Value())) &&
197	match(V: RHS, P: m_c_And(L: m_Specific(V: M), R: m_Value())) &&
198	isGuaranteedNotToBeUndef(V: M, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
199	return true;
200	}
201
202	// X op (Y & ~X)
203	if (match(V: RHS, P: m_c_And(L: m_Not(V: m_Specific(V: LHS)), R: m_Value())) &&
204	isGuaranteedNotToBeUndef(V: LHS, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
205	return true;
206
207	// X op ((X & Y) ^ Y) -- this is the canonical form of the previous pattern
208	// for constant Y.
209	Value *Y;
210	if (match(V: RHS,
211	P: m_c_Xor(L: m_c_And(L: m_Specific(V: LHS), R: m_Value(V&: Y)), R: m_Deferred(V: Y))) &&
212	isGuaranteedNotToBeUndef(V: LHS, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT) &&
213	isGuaranteedNotToBeUndef(V: Y, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
214	return true;
215
216	// Peek through extends to find a 'not' of the other side:
217	// (ext Y) op ext(~Y)
218	if (match(V: LHS, P: m_ZExtOrSExt(Op: m_Value(V&: Y))) &&
219	match(V: RHS, P: m_ZExtOrSExt(Op: m_Not(V: m_Specific(V: Y)))) &&
220	isGuaranteedNotToBeUndef(V: Y, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
221	return true;
222
223	// Look for: (A & B) op ~(A | B)
224	{
225	Value *A, *B;
226	if (match(V: LHS, P: m_And(L: m_Value(V&: A), R: m_Value(V&: B))) &&
227	match(V: RHS, P: m_Not(V: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B)))) &&
228	isGuaranteedNotToBeUndef(V: A, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT) &&
229	isGuaranteedNotToBeUndef(V: B, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
230	return true;
231	}
232
233	return false;
234	}
235
236	bool llvm::haveNoCommonBitsSet(const WithCache<const Value *> &LHSCache,
237	const WithCache<const Value *> &RHSCache,
238	const SimplifyQuery &SQ) {
239	const Value *LHS = LHSCache.getValue();
240	const Value *RHS = RHSCache.getValue();
241
242	assert(LHS->getType() == RHS->getType() &&
243	"LHS and RHS should have the same type");
244	assert(LHS->getType()->isIntOrIntVectorTy() &&
245	"LHS and RHS should be integers");
246
247	if (haveNoCommonBitsSetSpecialCases(LHS, RHS, SQ) ||
248	haveNoCommonBitsSetSpecialCases(LHS: RHS, RHS: LHS, SQ))
249	return true;
250
251	return KnownBits::haveNoCommonBitsSet(LHS: LHSCache.getKnownBits(Q: SQ),
252	RHS: RHSCache.getKnownBits(Q: SQ));
253	}
254
255	bool llvm::isOnlyUsedInZeroEqualityComparison(const Instruction *I) {
256	return !I->user_empty() && all_of(Range: I->users(), P: [](const User *U) {
257	ICmpInst::Predicate P;
258	return match(V: U, P: m_ICmp(Pred&: P, L: m_Value(), R: m_Zero())) && ICmpInst::isEquality(P);
259	});
260	}
261
262	static bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
263	const SimplifyQuery &Q);
264
265	bool llvm::isKnownToBeAPowerOfTwo(const Value *V, const DataLayout &DL,
266	bool OrZero, unsigned Depth,
267	AssumptionCache *AC, const Instruction *CxtI,
268	const DominatorTree *DT, bool UseInstrInfo) {
269	return ::isKnownToBeAPowerOfTwo(
270	V, OrZero, Depth,
271	Q: SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
272	}
273
274	static bool isKnownNonZero(const Value *V, const APInt &DemandedElts,
275	const SimplifyQuery &Q, unsigned Depth);
276
277	bool llvm::isKnownNonNegative(const Value *V, const SimplifyQuery &SQ,
278	unsigned Depth) {
279	return computeKnownBits(V, Depth, Q: SQ).isNonNegative();
280	}
281
282	bool llvm::isKnownPositive(const Value *V, const SimplifyQuery &SQ,
283	unsigned Depth) {
284	if (auto *CI = dyn_cast<ConstantInt>(Val: V))
285	return CI->getValue().isStrictlyPositive();
286
287	// If `isKnownNonNegative` ever becomes more sophisticated, make sure to keep
288	// this updated.
289	KnownBits Known = computeKnownBits(V, Depth, Q: SQ);
290	return Known.isNonNegative() &&
291	(Known.isNonZero() || isKnownNonZero(V, Q: SQ, Depth));
292	}
293
294	bool llvm::isKnownNegative(const Value *V, const SimplifyQuery &SQ,
295	unsigned Depth) {
296	return computeKnownBits(V, Depth, Q: SQ).isNegative();
297	}
298
299	static bool isKnownNonEqual(const Value *V1, const Value *V2, unsigned Depth,
300	const SimplifyQuery &Q);
301
302	bool llvm::isKnownNonEqual(const Value *V1, const Value *V2,
303	const DataLayout &DL, AssumptionCache *AC,
304	const Instruction *CxtI, const DominatorTree *DT,
305	bool UseInstrInfo) {
306	return ::isKnownNonEqual(
307	V1, V2, Depth: 0,
308	Q: SimplifyQuery(DL, DT, AC, safeCxtI(V1: V2, V2: V1, CxtI), UseInstrInfo));
309	}
310
311	bool llvm::MaskedValueIsZero(const Value *V, const APInt &Mask,
312	const SimplifyQuery &SQ, unsigned Depth) {
313	KnownBits Known(Mask.getBitWidth());
314	computeKnownBits(V, Known, Depth, Q: SQ);
315	return Mask.isSubsetOf(RHS: Known.Zero);
316	}
317
318	static unsigned ComputeNumSignBits(const Value *V, const APInt &DemandedElts,
319	unsigned Depth, const SimplifyQuery &Q);
320
321	static unsigned ComputeNumSignBits(const Value *V, unsigned Depth,
322	const SimplifyQuery &Q) {
323	auto *FVTy = dyn_cast<FixedVectorType>(Val: V->getType());
324	APInt DemandedElts =
325	FVTy ? APInt::getAllOnes(numBits: FVTy->getNumElements()) : APInt(1, 1);
326	return ComputeNumSignBits(V, DemandedElts, Depth, Q);
327	}
328
329	unsigned llvm::ComputeNumSignBits(const Value *V, const DataLayout &DL,
330	unsigned Depth, AssumptionCache *AC,
331	const Instruction *CxtI,
332	const DominatorTree *DT, bool UseInstrInfo) {
333	return ::ComputeNumSignBits(
334	V, Depth, Q: SimplifyQuery(DL, DT, AC, safeCxtI(V, CxtI), UseInstrInfo));
335	}
336
337	unsigned llvm::ComputeMaxSignificantBits(const Value *V, const DataLayout &DL,
338	unsigned Depth, AssumptionCache *AC,
339	const Instruction *CxtI,
340	const DominatorTree *DT) {
341	unsigned SignBits = ComputeNumSignBits(V, DL, Depth, AC, CxtI, DT);
342	return V->getType()->getScalarSizeInBits() - SignBits + 1;
343	}
344
345	static void computeKnownBitsAddSub(bool Add, const Value *Op0, const Value *Op1,
346	bool NSW, bool NUW,
347	const APInt &DemandedElts,
348	KnownBits &KnownOut, KnownBits &Known2,
349	unsigned Depth, const SimplifyQuery &Q) {
350	computeKnownBits(V: Op1, DemandedElts, Known&: KnownOut, Depth: Depth + 1, Q);
351
352	// If one operand is unknown and we have no nowrap information,
353	// the result will be unknown independently of the second operand.
354	if (KnownOut.isUnknown() && !NSW && !NUW)
355	return;
356
357	computeKnownBits(V: Op0, DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
358	KnownOut = KnownBits::computeForAddSub(Add, NSW, NUW, LHS: Known2, RHS: KnownOut);
359	}
360
361	static void computeKnownBitsMul(const Value *Op0, const Value *Op1, bool NSW,
362	const APInt &DemandedElts, KnownBits &Known,
363	KnownBits &Known2, unsigned Depth,
364	const SimplifyQuery &Q) {
365	computeKnownBits(V: Op1, DemandedElts, Known, Depth: Depth + 1, Q);
366	computeKnownBits(V: Op0, DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
367
368	bool isKnownNegative = false;
369	bool isKnownNonNegative = false;
370	// If the multiplication is known not to overflow, compute the sign bit.
371	if (NSW) {
372	if (Op0 == Op1) {
373	// The product of a number with itself is non-negative.
374	isKnownNonNegative = true;
375	} else {
376	bool isKnownNonNegativeOp1 = Known.isNonNegative();
377	bool isKnownNonNegativeOp0 = Known2.isNonNegative();
378	bool isKnownNegativeOp1 = Known.isNegative();
379	bool isKnownNegativeOp0 = Known2.isNegative();
380	// The product of two numbers with the same sign is non-negative.
381	isKnownNonNegative = (isKnownNegativeOp1 && isKnownNegativeOp0) ||
382	(isKnownNonNegativeOp1 && isKnownNonNegativeOp0);
383	// The product of a negative number and a non-negative number is either
384	// negative or zero.
385	if (!isKnownNonNegative)
386	isKnownNegative =
387	(isKnownNegativeOp1 && isKnownNonNegativeOp0 &&
388	Known2.isNonZero()) ||
389	(isKnownNegativeOp0 && isKnownNonNegativeOp1 && Known.isNonZero());
390	}
391	}
392
393	bool SelfMultiply = Op0 == Op1;
394	if (SelfMultiply)
395	SelfMultiply &=
396	isGuaranteedNotToBeUndef(V: Op0, AC: Q.AC, CtxI: Q.CxtI, DT: Q.DT, Depth: Depth + 1);
397	Known = KnownBits::mul(LHS: Known, RHS: Known2, NoUndefSelfMultiply: SelfMultiply);
398
399	// Only make use of no-wrap flags if we failed to compute the sign bit
400	// directly. This matters if the multiplication always overflows, in
401	// which case we prefer to follow the result of the direct computation,
402	// though as the program is invoking undefined behaviour we can choose
403	// whatever we like here.
404	if (isKnownNonNegative && !Known.isNegative())
405	Known.makeNonNegative();
406	else if (isKnownNegative && !Known.isNonNegative())
407	Known.makeNegative();
408	}
409
410	void llvm::computeKnownBitsFromRangeMetadata(const MDNode &Ranges,
411	KnownBits &Known) {
412	unsigned BitWidth = Known.getBitWidth();
413	unsigned NumRanges = Ranges.getNumOperands() / 2;
414	assert(NumRanges >= 1);
415
416	Known.Zero.setAllBits();
417	Known.One.setAllBits();
418
419	for (unsigned i = 0; i < NumRanges; ++i) {
420	ConstantInt *Lower =
421	mdconst::extract<ConstantInt>(MD: Ranges.getOperand(I: 2 * i + 0));
422	ConstantInt *Upper =
423	mdconst::extract<ConstantInt>(MD: Ranges.getOperand(I: 2 * i + 1));
424	ConstantRange Range(Lower->getValue(), Upper->getValue());
425
426	// The first CommonPrefixBits of all values in Range are equal.
427	unsigned CommonPrefixBits =
428	(Range.getUnsignedMax() ^ Range.getUnsignedMin()).countl_zero();
429	APInt Mask = APInt::getHighBitsSet(numBits: BitWidth, hiBitsSet: CommonPrefixBits);
430	APInt UnsignedMax = Range.getUnsignedMax().zextOrTrunc(width: BitWidth);
431	Known.One &= UnsignedMax & Mask;
432	Known.Zero &= ~UnsignedMax & Mask;
433	}
434	}
435
436	static bool isEphemeralValueOf(const Instruction *I, const Value *E) {
437	SmallVector<const Value *, 16> WorkSet(1, I);
438	SmallPtrSet<const Value *, 32> Visited;
439	SmallPtrSet<const Value *, 16> EphValues;
440
441	// The instruction defining an assumption's condition itself is always
442	// considered ephemeral to that assumption (even if it has other
443	// non-ephemeral users). See r246696's test case for an example.
444	if (is_contained(Range: I->operands(), Element: E))
445	return true;
446
447	while (!WorkSet.empty()) {
448	const Value *V = WorkSet.pop_back_val();
449	if (!Visited.insert(Ptr: V).second)
450	continue;
451
452	// If all uses of this value are ephemeral, then so is this value.
453	if (llvm::all_of(Range: V->users(), P: [&](const User *U) {
454	return EphValues.count(Ptr: U);
455	})) {
456	if (V == E)
457	return true;
458
459	if (V == I || (isa<Instruction>(Val: V) &&
460	!cast<Instruction>(Val: V)->mayHaveSideEffects() &&
461	!cast<Instruction>(Val: V)->isTerminator())) {
462	EphValues.insert(Ptr: V);
463	if (const User *U = dyn_cast<User>(Val: V))
464	append_range(C&: WorkSet, R: U->operands());
465	}
466	}
467	}
468
469	return false;
470	}
471
472	// Is this an intrinsic that cannot be speculated but also cannot trap?
473	bool llvm::isAssumeLikeIntrinsic(const Instruction *I) {
474	if (const IntrinsicInst *CI = dyn_cast<IntrinsicInst>(Val: I))
475	return CI->isAssumeLikeIntrinsic();
476
477	return false;
478	}
479
480	bool llvm::isValidAssumeForContext(const Instruction *Inv,
481	const Instruction *CxtI,
482	const DominatorTree *DT,
483	bool AllowEphemerals) {
484	// There are two restrictions on the use of an assume:
485	// 1. The assume must dominate the context (or the control flow must
486	// reach the assume whenever it reaches the context).
487	// 2. The context must not be in the assume's set of ephemeral values
488	// (otherwise we will use the assume to prove that the condition
489	// feeding the assume is trivially true, thus causing the removal of
490	// the assume).
491
492	if (Inv->getParent() == CxtI->getParent()) {
493	// If Inv and CtxI are in the same block, check if the assume (Inv) is first
494	// in the BB.
495	if (Inv->comesBefore(Other: CxtI))
496	return true;
497
498	// Don't let an assume affect itself - this would cause the problems
499	// `isEphemeralValueOf` is trying to prevent, and it would also make
500	// the loop below go out of bounds.
501	if (!AllowEphemerals && Inv == CxtI)
502	return false;
503
504	// The context comes first, but they're both in the same block.
505	// Make sure there is nothing in between that might interrupt
506	// the control flow, not even CxtI itself.
507	// We limit the scan distance between the assume and its context instruction
508	// to avoid a compile-time explosion. This limit is chosen arbitrarily, so
509	// it can be adjusted if needed (could be turned into a cl::opt).
510	auto Range = make_range(x: CxtI->getIterator(), y: Inv->getIterator());
511	if (!isGuaranteedToTransferExecutionToSuccessor(Range, ScanLimit: 15))
512	return false;
513
514	return AllowEphemerals || !isEphemeralValueOf(I: Inv, E: CxtI);
515	}
516
517	// Inv and CxtI are in different blocks.
518	if (DT) {
519	if (DT->dominates(Def: Inv, User: CxtI))
520	return true;
521	} else if (Inv->getParent() == CxtI->getParent()->getSinglePredecessor()) {
522	// We don't have a DT, but this trivially dominates.
523	return true;
524	}
525
526	return false;
527	}
528
529	// TODO: cmpExcludesZero misses many cases where `RHS` is non-constant but
530	// we still have enough information about `RHS` to conclude non-zero. For
531	// example Pred=EQ, RHS=isKnownNonZero. cmpExcludesZero is called in loops
532	// so the extra compile time may not be worth it, but possibly a second API
533	// should be created for use outside of loops.
534	static bool cmpExcludesZero(CmpInst::Predicate Pred, const Value *RHS) {
535	// v u> y implies v != 0.
536	if (Pred == ICmpInst::ICMP_UGT)
537	return true;
538
539	// Special-case v != 0 to also handle v != null.
540	if (Pred == ICmpInst::ICMP_NE)
541	return match(V: RHS, P: m_Zero());
542
543	// All other predicates - rely on generic ConstantRange handling.
544	const APInt *C;
545	auto Zero = APInt::getZero(numBits: RHS->getType()->getScalarSizeInBits());
546	if (match(V: RHS, P: m_APInt(Res&: C))) {
547	ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(Pred, Other: *C);
548	return !TrueValues.contains(Val: Zero);
549	}
550
551	auto *VC = dyn_cast<ConstantDataVector>(Val: RHS);
552	if (VC == nullptr)
553	return false;
554
555	for (unsigned ElemIdx = 0, NElem = VC->getNumElements(); ElemIdx < NElem;
556	++ElemIdx) {
557	ConstantRange TrueValues = ConstantRange::makeExactICmpRegion(
558	Pred, Other: VC->getElementAsAPInt(i: ElemIdx));
559	if (TrueValues.contains(Val: Zero))
560	return false;
561	}
562	return true;
563	}
564
565	static bool isKnownNonZeroFromAssume(const Value *V, const SimplifyQuery &Q) {
566	// Use of assumptions is context-sensitive. If we don't have a context, we
567	// cannot use them!
568	if (!Q.AC || !Q.CxtI)
569	return false;
570
571	for (AssumptionCache::ResultElem &Elem : Q.AC->assumptionsFor(V)) {
572	if (!Elem.Assume)
573	continue;
574
575	AssumeInst *I = cast<AssumeInst>(Val&: Elem.Assume);
576	assert(I->getFunction() == Q.CxtI->getFunction() &&
577	"Got assumption for the wrong function!");
578
579	if (Elem.Index != AssumptionCache::ExprResultIdx) {
580	if (!V->getType()->isPointerTy())
581	continue;
582	if (RetainedKnowledge RK = getKnowledgeFromBundle(
583	Assume&: *I, BOI: I->bundle_op_info_begin()[Elem.Index])) {
584	if (RK.WasOn == V &&
585	(RK.AttrKind == Attribute::NonNull ||
586	(RK.AttrKind == Attribute::Dereferenceable &&
587	!NullPointerIsDefined(F: Q.CxtI->getFunction(),
588	AS: V->getType()->getPointerAddressSpace()))) &&
589	isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT))
590	return true;
591	}
592	continue;
593	}
594
595	// Warning: This loop can end up being somewhat performance sensitive.
596	// We're running this loop for once for each value queried resulting in a
597	// runtime of ~O(#assumes * #values).
598
599	Value *RHS;
600	CmpInst::Predicate Pred;
601	auto m_V = m_CombineOr(L: m_Specific(V), R: m_PtrToInt(Op: m_Specific(V)));
602	if (!match(V: I->getArgOperand(i: 0), P: m_c_ICmp(Pred, L: m_V, R: m_Value(V&: RHS))))
603	return false;
604
605	if (cmpExcludesZero(Pred, RHS) && isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT))
606	return true;
607	}
608
609	return false;
610	}
611
612	static void computeKnownBitsFromCmp(const Value *V, CmpInst::Predicate Pred,
613	Value *LHS, Value *RHS, KnownBits &Known,
614	const SimplifyQuery &Q) {
615	if (RHS->getType()->isPointerTy()) {
616	// Handle comparison of pointer to null explicitly, as it will not be
617	// covered by the m_APInt() logic below.
618	if (LHS == V && match(V: RHS, P: m_Zero())) {
619	switch (Pred) {
620	case ICmpInst::ICMP_EQ:
621	Known.setAllZero();
622	break;
623	case ICmpInst::ICMP_SGE:
624	case ICmpInst::ICMP_SGT:
625	Known.makeNonNegative();
626	break;
627	case ICmpInst::ICMP_SLT:
628	Known.makeNegative();
629	break;
630	default:
631	break;
632	}
633	}
634	return;
635	}
636
637	unsigned BitWidth = Known.getBitWidth();
638	auto m_V =
639	m_CombineOr(L: m_Specific(V), R: m_PtrToIntSameSize(DL: Q.DL, Op: m_Specific(V)));
640
641	Value *Y;
642	const APInt *Mask, *C;
643	uint64_t ShAmt;
644	switch (Pred) {
645	case ICmpInst::ICMP_EQ:
646	// assume(V = C)
647	if (match(V: LHS, P: m_V) && match(V: RHS, P: m_APInt(Res&: C))) {
648	Known = Known.unionWith(RHS: KnownBits::makeConstant(C: *C));
649	// assume(V & Mask = C)
650	} else if (match(V: LHS, P: m_c_And(L: m_V, R: m_Value(V&: Y))) &&
651	match(V: RHS, P: m_APInt(Res&: C))) {
652	// For one bits in Mask, we can propagate bits from C to V.
653	Known.One |= *C;
654	if (match(V: Y, P: m_APInt(Res&: Mask)))
655	Known.Zero |= ~*C & *Mask;
656	// assume(V | Mask = C)
657	} else if (match(V: LHS, P: m_c_Or(L: m_V, R: m_Value(V&: Y))) && match(V: RHS, P: m_APInt(Res&: C))) {
658	// For zero bits in Mask, we can propagate bits from C to V.
659	Known.Zero |= ~*C;
660	if (match(V: Y, P: m_APInt(Res&: Mask)))
661	Known.One |= *C & ~*Mask;
662	// assume(V ^ Mask = C)
663	} else if (match(V: LHS, P: m_Xor(L: m_V, R: m_APInt(Res&: Mask))) &&
664	match(V: RHS, P: m_APInt(Res&: C))) {
665	// Equivalent to assume(V == Mask ^ C)
666	Known = Known.unionWith(RHS: KnownBits::makeConstant(C: *C ^ *Mask));
667	// assume(V << ShAmt = C)
668	} else if (match(V: LHS, P: m_Shl(L: m_V, R: m_ConstantInt(V&: ShAmt))) &&
669	match(V: RHS, P: m_APInt(Res&: C)) && ShAmt < BitWidth) {
670	// For those bits in C that are known, we can propagate them to known
671	// bits in V shifted to the right by ShAmt.
672	KnownBits RHSKnown = KnownBits::makeConstant(C: *C);
673	RHSKnown.Zero.lshrInPlace(ShiftAmt: ShAmt);
674	RHSKnown.One.lshrInPlace(ShiftAmt: ShAmt);
675	Known = Known.unionWith(RHS: RHSKnown);
676	// assume(V >> ShAmt = C)
677	} else if (match(V: LHS, P: m_Shr(L: m_V, R: m_ConstantInt(V&: ShAmt))) &&
678	match(V: RHS, P: m_APInt(Res&: C)) && ShAmt < BitWidth) {
679	KnownBits RHSKnown = KnownBits::makeConstant(C: *C);
680	// For those bits in RHS that are known, we can propagate them to known
681	// bits in V shifted to the right by C.
682	Known.Zero |= RHSKnown.Zero << ShAmt;
683	Known.One |= RHSKnown.One << ShAmt;
684	}
685	break;
686	case ICmpInst::ICMP_NE: {
687	// assume (V & B != 0) where B is a power of 2
688	const APInt *BPow2;
689	if (match(V: LHS, P: m_And(L: m_V, R: m_Power2(V&: BPow2))) && match(V: RHS, P: m_Zero()))
690	Known.One |= *BPow2;
691	break;
692	}
693	default:
694	if (match(V: RHS, P: m_APInt(Res&: C))) {
695	const APInt *Offset = nullptr;
696	if (match(V: LHS, P: m_CombineOr(L: m_V, R: m_AddLike(L: m_V, R: m_APInt(Res&: Offset))))) {
697	ConstantRange LHSRange = ConstantRange::makeAllowedICmpRegion(Pred, Other: *C);
698	if (Offset)
699	LHSRange = LHSRange.sub(Other: *Offset);
700	Known = Known.unionWith(RHS: LHSRange.toKnownBits());
701	}
702	// X & Y u> C -> X u> C && Y u> C
703	if ((Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE) &&
704	match(V: LHS, P: m_c_And(L: m_V, R: m_Value()))) {
705	Known.One.setHighBits(
706	(*C + (Pred == ICmpInst::ICMP_UGT)).countLeadingOnes());
707	}
708	// X | Y u< C -> X u< C && Y u< C
709	if ((Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) &&
710	match(V: LHS, P: m_c_Or(L: m_V, R: m_Value()))) {
711	Known.Zero.setHighBits(
712	(*C - (Pred == ICmpInst::ICMP_ULT)).countLeadingZeros());
713	}
714	}
715	break;
716	}
717	}
718
719	static void computeKnownBitsFromICmpCond(const Value *V, ICmpInst *Cmp,
720	KnownBits &Known,
721	const SimplifyQuery &SQ, bool Invert) {
722	ICmpInst::Predicate Pred =
723	Invert ? Cmp->getInversePredicate() : Cmp->getPredicate();
724	Value *LHS = Cmp->getOperand(i_nocapture: 0);
725	Value *RHS = Cmp->getOperand(i_nocapture: 1);
726
727	// Handle icmp pred (trunc V), C
728	if (match(V: LHS, P: m_Trunc(Op: m_Specific(V)))) {
729	KnownBits DstKnown(LHS->getType()->getScalarSizeInBits());
730	computeKnownBitsFromCmp(V: LHS, Pred, LHS, RHS, Known&: DstKnown, Q: SQ);
731	Known = Known.unionWith(RHS: DstKnown.anyext(BitWidth: Known.getBitWidth()));
732	return;
733	}
734
735	computeKnownBitsFromCmp(V, Pred, LHS, RHS, Known, Q: SQ);
736	}
737
738	static void computeKnownBitsFromCond(const Value *V, Value *Cond,
739	KnownBits &Known, unsigned Depth,
740	const SimplifyQuery &SQ, bool Invert) {
741	Value *A, *B;
742	if (Depth < MaxAnalysisRecursionDepth &&
743	match(V: Cond, P: m_LogicalOp(L: m_Value(V&: A), R: m_Value(V&: B)))) {
744	KnownBits Known2(Known.getBitWidth());
745	KnownBits Known3(Known.getBitWidth());
746	computeKnownBitsFromCond(V, Cond: A, Known&: Known2, Depth: Depth + 1, SQ, Invert);
747	computeKnownBitsFromCond(V, Cond: B, Known&: Known3, Depth: Depth + 1, SQ, Invert);
748	if (Invert ? match(V: Cond, P: m_LogicalOr(L: m_Value(), R: m_Value()))
749	: match(V: Cond, P: m_LogicalAnd(L: m_Value(), R: m_Value())))
750	Known2 = Known2.unionWith(RHS: Known3);
751	else
752	Known2 = Known2.intersectWith(RHS: Known3);
753	Known = Known.unionWith(RHS: Known2);
754	}
755
756	if (auto *Cmp = dyn_cast<ICmpInst>(Val: Cond))
757	computeKnownBitsFromICmpCond(V, Cmp, Known, SQ, Invert);
758	}
759
760	void llvm::computeKnownBitsFromContext(const Value *V, KnownBits &Known,
761	unsigned Depth, const SimplifyQuery &Q) {
762	if (!Q.CxtI)
763	return;
764
765	if (Q.DC && Q.DT) {
766	// Handle dominating conditions.
767	for (BranchInst *BI : Q.DC->conditionsFor(V)) {
768	BasicBlockEdge Edge0(BI->getParent(), BI->getSuccessor(i: 0));
769	if (Q.DT->dominates(BBE: Edge0, BB: Q.CxtI->getParent()))
770	computeKnownBitsFromCond(V, Cond: BI->getCondition(), Known, Depth, SQ: Q,
771	/*Invert*/ false);
772
773	BasicBlockEdge Edge1(BI->getParent(), BI->getSuccessor(i: 1));
774	if (Q.DT->dominates(BBE: Edge1, BB: Q.CxtI->getParent()))
775	computeKnownBitsFromCond(V, Cond: BI->getCondition(), Known, Depth, SQ: Q,
776	/*Invert*/ true);
777	}
778
779	if (Known.hasConflict())
780	Known.resetAll();
781	}
782
783	if (!Q.AC)
784	return;
785
786	unsigned BitWidth = Known.getBitWidth();
787
788	// Note that the patterns below need to be kept in sync with the code
789	// in AssumptionCache::updateAffectedValues.
790
791	for (AssumptionCache::ResultElem &Elem : Q.AC->assumptionsFor(V)) {
792	if (!Elem.Assume)
793	continue;
794
795	AssumeInst *I = cast<AssumeInst>(Val&: Elem.Assume);
796	assert(I->getParent()->getParent() == Q.CxtI->getParent()->getParent() &&
797	"Got assumption for the wrong function!");
798
799	if (Elem.Index != AssumptionCache::ExprResultIdx) {
800	if (!V->getType()->isPointerTy())
801	continue;
802	if (RetainedKnowledge RK = getKnowledgeFromBundle(
803	Assume&: *I, BOI: I->bundle_op_info_begin()[Elem.Index])) {
804	if (RK.WasOn == V && RK.AttrKind == Attribute::Alignment &&
805	isPowerOf2_64(Value: RK.ArgValue) &&
806	isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT))
807	Known.Zero.setLowBits(Log2_64(Value: RK.ArgValue));
808	}
809	continue;
810	}
811
812	// Warning: This loop can end up being somewhat performance sensitive.
813	// We're running this loop for once for each value queried resulting in a
814	// runtime of ~O(#assumes * #values).
815
816	Value *Arg = I->getArgOperand(i: 0);
817
818	if (Arg == V && isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT)) {
819	assert(BitWidth == 1 && "assume operand is not i1?");
820	(void)BitWidth;
821	Known.setAllOnes();
822	return;
823	}
824	if (match(V: Arg, P: m_Not(V: m_Specific(V))) &&
825	isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT)) {
826	assert(BitWidth == 1 && "assume operand is not i1?");
827	(void)BitWidth;
828	Known.setAllZero();
829	return;
830	}
831
832	// The remaining tests are all recursive, so bail out if we hit the limit.
833	if (Depth == MaxAnalysisRecursionDepth)
834	continue;
835
836	ICmpInst *Cmp = dyn_cast<ICmpInst>(Val: Arg);
837	if (!Cmp)
838	continue;
839
840	if (!isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT))
841	continue;
842
843	computeKnownBitsFromICmpCond(V, Cmp, Known, SQ: Q, /*Invert=*/false);
844	}
845
846	// Conflicting assumption: Undefined behavior will occur on this execution
847	// path.
848	if (Known.hasConflict())
849	Known.resetAll();
850	}
851
852	/// Compute known bits from a shift operator, including those with a
853	/// non-constant shift amount. Known is the output of this function. Known2 is a
854	/// pre-allocated temporary with the same bit width as Known and on return
855	/// contains the known bit of the shift value source. KF is an
856	/// operator-specific function that, given the known-bits and a shift amount,
857	/// compute the implied known-bits of the shift operator's result respectively
858	/// for that shift amount. The results from calling KF are conservatively
859	/// combined for all permitted shift amounts.
860	static void computeKnownBitsFromShiftOperator(
861	const Operator *I, const APInt &DemandedElts, KnownBits &Known,
862	KnownBits &Known2, unsigned Depth, const SimplifyQuery &Q,
863	function_ref<KnownBits(const KnownBits &, const KnownBits &, bool)> KF) {
864	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
865	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Known, Depth: Depth + 1, Q);
866	// To limit compile-time impact, only query isKnownNonZero() if we know at
867	// least something about the shift amount.
868	bool ShAmtNonZero =
869	Known.isNonZero() ||
870	(Known.getMaxValue().ult(RHS: Known.getBitWidth()) &&
871	isKnownNonZero(V: I->getOperand(i: 1), DemandedElts, Q, Depth: Depth + 1));
872	Known = KF(Known2, Known, ShAmtNonZero);
873	}
874
875	static KnownBits
876	getKnownBitsFromAndXorOr(const Operator *I, const APInt &DemandedElts,
877	const KnownBits &KnownLHS, const KnownBits &KnownRHS,
878	unsigned Depth, const SimplifyQuery &Q) {
879	unsigned BitWidth = KnownLHS.getBitWidth();
880	KnownBits KnownOut(BitWidth);
881	bool IsAnd = false;
882	bool HasKnownOne = !KnownLHS.One.isZero() || !KnownRHS.One.isZero();
883	Value *X = nullptr, *Y = nullptr;
884
885	switch (I->getOpcode()) {
886	case Instruction::And:
887	KnownOut = KnownLHS & KnownRHS;
888	IsAnd = true;
889	// and(x, -x) is common idioms that will clear all but lowest set
890	// bit. If we have a single known bit in x, we can clear all bits
891	// above it.
892	// TODO: instcombine often reassociates independent `and` which can hide
893	// this pattern. Try to match and(x, and(-x, y)) / and(and(x, y), -x).
894	if (HasKnownOne && match(V: I, P: m_c_And(L: m_Value(V&: X), R: m_Neg(V: m_Deferred(V: X))))) {
895	// -(-x) == x so using whichever (LHS/RHS) gets us a better result.
896	if (KnownLHS.countMaxTrailingZeros() <= KnownRHS.countMaxTrailingZeros())
897	KnownOut = KnownLHS.blsi();
898	else
899	KnownOut = KnownRHS.blsi();
900	}
901	break;
902	case Instruction::Or:
903	KnownOut = KnownLHS | KnownRHS;
904	break;
905	case Instruction::Xor:
906	KnownOut = KnownLHS ^ KnownRHS;
907	// xor(x, x-1) is common idioms that will clear all but lowest set
908	// bit. If we have a single known bit in x, we can clear all bits
909	// above it.
910	// TODO: xor(x, x-1) is often rewritting as xor(x, x-C) where C !=
911	// -1 but for the purpose of demanded bits (xor(x, x-C) &
912	// Demanded) == (xor(x, x-1) & Demanded). Extend the xor pattern
913	// to use arbitrary C if xor(x, x-C) as the same as xor(x, x-1).
914	if (HasKnownOne &&
915	match(V: I, P: m_c_Xor(L: m_Value(V&: X), R: m_c_Add(L: m_Deferred(V: X), R: m_AllOnes())))) {
916	const KnownBits &XBits = I->getOperand(i: 0) == X ? KnownLHS : KnownRHS;
917	KnownOut = XBits.blsmsk();
918	}
919	break;
920	default:
921	llvm_unreachable("Invalid Op used in 'analyzeKnownBitsFromAndXorOr'");
922	}
923
924	// and(x, add (x, -1)) is a common idiom that always clears the low bit;
925	// xor/or(x, add (x, -1)) is an idiom that will always set the low bit.
926	// here we handle the more general case of adding any odd number by
927	// matching the form and/xor/or(x, add(x, y)) where y is odd.
928	// TODO: This could be generalized to clearing any bit set in y where the
929	// following bit is known to be unset in y.
930	if (!KnownOut.Zero[0] && !KnownOut.One[0] &&
931	(match(V: I, P: m_c_BinOp(L: m_Value(V&: X), R: m_c_Add(L: m_Deferred(V: X), R: m_Value(V&: Y)))) ||
932	match(V: I, P: m_c_BinOp(L: m_Value(V&: X), R: m_Sub(L: m_Deferred(V: X), R: m_Value(V&: Y)))) ||
933	match(V: I, P: m_c_BinOp(L: m_Value(V&: X), R: m_Sub(L: m_Value(V&: Y), R: m_Deferred(V: X)))))) {
934	KnownBits KnownY(BitWidth);
935	computeKnownBits(V: Y, DemandedElts, Known&: KnownY, Depth: Depth + 1, Q);
936	if (KnownY.countMinTrailingOnes() > 0) {
937	if (IsAnd)
938	KnownOut.Zero.setBit(0);
939	else
940	KnownOut.One.setBit(0);
941	}
942	}
943	return KnownOut;
944	}
945
946	// Public so this can be used in `SimplifyDemandedUseBits`.
947	KnownBits llvm::analyzeKnownBitsFromAndXorOr(const Operator *I,
948	const KnownBits &KnownLHS,
949	const KnownBits &KnownRHS,
950	unsigned Depth,
951	const SimplifyQuery &SQ) {
952	auto *FVTy = dyn_cast<FixedVectorType>(Val: I->getType());
953	APInt DemandedElts =
954	FVTy ? APInt::getAllOnes(numBits: FVTy->getNumElements()) : APInt(1, 1);
955
956	return getKnownBitsFromAndXorOr(I, DemandedElts, KnownLHS, KnownRHS, Depth,
957	Q: SQ);
958	}
959
960	ConstantRange llvm::getVScaleRange(const Function *F, unsigned BitWidth) {
961	Attribute Attr = F->getFnAttribute(Attribute::VScaleRange);
962	// Without vscale_range, we only know that vscale is non-zero.
963	if (!Attr.isValid())
964	return ConstantRange(APInt(BitWidth, 1), APInt::getZero(numBits: BitWidth));
965
966	unsigned AttrMin = Attr.getVScaleRangeMin();
967	// Minimum is larger than vscale width, result is always poison.
968	if ((unsigned)llvm::bit_width(Value: AttrMin) > BitWidth)
969	return ConstantRange::getEmpty(BitWidth);
970
971	APInt Min(BitWidth, AttrMin);
972	std::optional<unsigned> AttrMax = Attr.getVScaleRangeMax();
973	if (!AttrMax || (unsigned)llvm::bit_width(Value: *AttrMax) > BitWidth)
974	return ConstantRange(Min, APInt::getZero(numBits: BitWidth));
975
976	return ConstantRange(Min, APInt(BitWidth, *AttrMax) + 1);
977	}
978
979	static void computeKnownBitsFromOperator(const Operator *I,
980	const APInt &DemandedElts,
981	KnownBits &Known, unsigned Depth,
982	const SimplifyQuery &Q) {
983	unsigned BitWidth = Known.getBitWidth();
984
985	KnownBits Known2(BitWidth);
986	switch (I->getOpcode()) {
987	default: break;
988	case Instruction::Load:
989	if (MDNode *MD =
990	Q.IIQ.getMetadata(I: cast<LoadInst>(Val: I), KindID: LLVMContext::MD_range))
991	computeKnownBitsFromRangeMetadata(Ranges: *MD, Known);
992	break;
993	case Instruction::And:
994	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Known, Depth: Depth + 1, Q);
995	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
996
997	Known = getKnownBitsFromAndXorOr(I, DemandedElts, KnownLHS: Known2, KnownRHS: Known, Depth, Q);
998	break;
999	case Instruction::Or:
1000	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Known, Depth: Depth + 1, Q);
1001	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
1002
1003	Known = getKnownBitsFromAndXorOr(I, DemandedElts, KnownLHS: Known2, KnownRHS: Known, Depth, Q);
1004	break;
1005	case Instruction::Xor:
1006	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Known, Depth: Depth + 1, Q);
1007	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
1008
1009	Known = getKnownBitsFromAndXorOr(I, DemandedElts, KnownLHS: Known2, KnownRHS: Known, Depth, Q);
1010	break;
1011	case Instruction::Mul: {
1012	bool NSW = Q.IIQ.hasNoSignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1013	computeKnownBitsMul(Op0: I->getOperand(i: 0), Op1: I->getOperand(i: 1), NSW, DemandedElts,
1014	Known, Known2, Depth, Q);
1015	break;
1016	}
1017	case Instruction::UDiv: {
1018	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1019	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1020	Known =
1021	KnownBits::udiv(LHS: Known, RHS: Known2, Exact: Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I)));
1022	break;
1023	}
1024	case Instruction::SDiv: {
1025	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1026	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1027	Known =
1028	KnownBits::sdiv(LHS: Known, RHS: Known2, Exact: Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I)));
1029	break;
1030	}
1031	case Instruction::Select: {
1032	auto ComputeForArm = [&](Value *Arm, bool Invert) {
1033	KnownBits Res(Known.getBitWidth());
1034	computeKnownBits(V: Arm, Known&: Res, Depth: Depth + 1, Q);
1035	// If we have a constant arm, we are done.
1036	if (Res.isConstant())
1037	return Res;
1038
1039	// See what condition implies about the bits of the two select arms.
1040	KnownBits CondRes(Res.getBitWidth());
1041	computeKnownBitsFromCond(V: Arm, Cond: I->getOperand(i: 0), Known&: CondRes, Depth: Depth + 1, SQ: Q,
1042	Invert);
1043	// If we don't get any information from the condition, no reason to
1044	// proceed.
1045	if (CondRes.isUnknown())
1046	return Res;
1047
1048	// We can have conflict if the condition is dead. I.e if we have
1049	// (x | 64) < 32 ? (x | 64) : y
1050	// we will have conflict at bit 6 from the condition/the `or`.
1051	// In that case just return. Its not particularly important
1052	// what we do, as this select is going to be simplified soon.
1053	CondRes = CondRes.unionWith(RHS: Res);
1054	if (CondRes.hasConflict())
1055	return Res;
1056
1057	// Finally make sure the information we found is valid. This is relatively
1058	// expensive so it's left for the very end.
1059	if (!isGuaranteedNotToBeUndef(V: Arm, AC: Q.AC, CtxI: Q.CxtI, DT: Q.DT, Depth: Depth + 1))
1060	return Res;
1061
1062	// Finally, we know we get information from the condition and its valid,
1063	// so return it.
1064	return CondRes;
1065	};
1066	// Only known if known in both the LHS and RHS.
1067	Known =
1068	ComputeForArm(I->getOperand(i: 1), /*Invert=*/false)
1069	.intersectWith(RHS: ComputeForArm(I->getOperand(i: 2), /*Invert=*/true));
1070	break;
1071	}
1072	case Instruction::FPTrunc:
1073	case Instruction::FPExt:
1074	case Instruction::FPToUI:
1075	case Instruction::FPToSI:
1076	case Instruction::SIToFP:
1077	case Instruction::UIToFP:
1078	break; // Can't work with floating point.
1079	case Instruction::PtrToInt:
1080	case Instruction::IntToPtr:
1081	// Fall through and handle them the same as zext/trunc.
1082	[[fallthrough]];
1083	case Instruction::ZExt:
1084	case Instruction::Trunc: {
1085	Type *SrcTy = I->getOperand(i: 0)->getType();
1086
1087	unsigned SrcBitWidth;
1088	// Note that we handle pointer operands here because of inttoptr/ptrtoint
1089	// which fall through here.
1090	Type *ScalarTy = SrcTy->getScalarType();
1091	SrcBitWidth = ScalarTy->isPointerTy() ?
1092	Q.DL.getPointerTypeSizeInBits(ScalarTy) :
1093	Q.DL.getTypeSizeInBits(Ty: ScalarTy);
1094
1095	assert(SrcBitWidth && "SrcBitWidth can't be zero");
1096	Known = Known.anyextOrTrunc(BitWidth: SrcBitWidth);
1097	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1098	if (auto *Inst = dyn_cast<PossiblyNonNegInst>(Val: I);
1099	Inst && Inst->hasNonNeg() && !Known.isNegative())
1100	Known.makeNonNegative();
1101	Known = Known.zextOrTrunc(BitWidth);
1102	break;
1103	}
1104	case Instruction::BitCast: {
1105	Type *SrcTy = I->getOperand(i: 0)->getType();
1106	if (SrcTy->isIntOrPtrTy() &&
1107	// TODO: For now, not handling conversions like:
1108	// (bitcast i64 %x to <2 x i32>)
1109	!I->getType()->isVectorTy()) {
1110	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1111	break;
1112	}
1113
1114	// Handle cast from vector integer type to scalar or vector integer.
1115	auto *SrcVecTy = dyn_cast<FixedVectorType>(Val: SrcTy);
1116	if (!SrcVecTy || !SrcVecTy->getElementType()->isIntegerTy() ||
1117	!I->getType()->isIntOrIntVectorTy() ||
1118	isa<ScalableVectorType>(Val: I->getType()))
1119	break;
1120
1121	// Look through a cast from narrow vector elements to wider type.
1122	// Examples: v4i32 -> v2i64, v3i8 -> v24
1123	unsigned SubBitWidth = SrcVecTy->getScalarSizeInBits();
1124	if (BitWidth % SubBitWidth == 0) {
1125	// Known bits are automatically intersected across demanded elements of a
1126	// vector. So for example, if a bit is computed as known zero, it must be
1127	// zero across all demanded elements of the vector.
1128	//
1129	// For this bitcast, each demanded element of the output is sub-divided
1130	// across a set of smaller vector elements in the source vector. To get
1131	// the known bits for an entire element of the output, compute the known
1132	// bits for each sub-element sequentially. This is done by shifting the
1133	// one-set-bit demanded elements parameter across the sub-elements for
1134	// consecutive calls to computeKnownBits. We are using the demanded
1135	// elements parameter as a mask operator.
1136	//
1137	// The known bits of each sub-element are then inserted into place
1138	// (dependent on endian) to form the full result of known bits.
1139	unsigned NumElts = DemandedElts.getBitWidth();
1140	unsigned SubScale = BitWidth / SubBitWidth;
1141	APInt SubDemandedElts = APInt::getZero(numBits: NumElts * SubScale);
1142	for (unsigned i = 0; i != NumElts; ++i) {
1143	if (DemandedElts[i])
1144	SubDemandedElts.setBit(i * SubScale);
1145	}
1146
1147	KnownBits KnownSrc(SubBitWidth);
1148	for (unsigned i = 0; i != SubScale; ++i) {
1149	computeKnownBits(V: I->getOperand(i: 0), DemandedElts: SubDemandedElts.shl(shiftAmt: i), Known&: KnownSrc,
1150	Depth: Depth + 1, Q);
1151	unsigned ShiftElt = Q.DL.isLittleEndian() ? i : SubScale - 1 - i;
1152	Known.insertBits(SubBits: KnownSrc, BitPosition: ShiftElt * SubBitWidth);
1153	}
1154	}
1155	break;
1156	}
1157	case Instruction::SExt: {
1158	// Compute the bits in the result that are not present in the input.
1159	unsigned SrcBitWidth = I->getOperand(i: 0)->getType()->getScalarSizeInBits();
1160
1161	Known = Known.trunc(BitWidth: SrcBitWidth);
1162	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1163	// If the sign bit of the input is known set or clear, then we know the
1164	// top bits of the result.
1165	Known = Known.sext(BitWidth);
1166	break;
1167	}
1168	case Instruction::Shl: {
1169	bool NUW = Q.IIQ.hasNoUnsignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1170	bool NSW = Q.IIQ.hasNoSignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1171	auto KF = [NUW, NSW](const KnownBits &KnownVal, const KnownBits &KnownAmt,
1172	bool ShAmtNonZero) {
1173	return KnownBits::shl(LHS: KnownVal, RHS: KnownAmt, NUW, NSW, ShAmtNonZero);
1174	};
1175	computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
1176	KF);
1177	// Trailing zeros of a right-shifted constant never decrease.
1178	const APInt *C;
1179	if (match(V: I->getOperand(i: 0), P: m_APInt(Res&: C)))
1180	Known.Zero.setLowBits(C->countr_zero());
1181	break;
1182	}
1183	case Instruction::LShr: {
1184	bool Exact = Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I));
1185	auto KF = [Exact](const KnownBits &KnownVal, const KnownBits &KnownAmt,
1186	bool ShAmtNonZero) {
1187	return KnownBits::lshr(LHS: KnownVal, RHS: KnownAmt, ShAmtNonZero, Exact);
1188	};
1189	computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
1190	KF);
1191	// Leading zeros of a left-shifted constant never decrease.
1192	const APInt *C;
1193	if (match(V: I->getOperand(i: 0), P: m_APInt(Res&: C)))
1194	Known.Zero.setHighBits(C->countl_zero());
1195	break;
1196	}
1197	case Instruction::AShr: {
1198	bool Exact = Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I));
1199	auto KF = [Exact](const KnownBits &KnownVal, const KnownBits &KnownAmt,
1200	bool ShAmtNonZero) {
1201	return KnownBits::ashr(LHS: KnownVal, RHS: KnownAmt, ShAmtNonZero, Exact);
1202	};
1203	computeKnownBitsFromShiftOperator(I, DemandedElts, Known, Known2, Depth, Q,
1204	KF);
1205	break;
1206	}
1207	case Instruction::Sub: {
1208	bool NSW = Q.IIQ.hasNoSignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1209	bool NUW = Q.IIQ.hasNoUnsignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1210	computeKnownBitsAddSub(Add: false, Op0: I->getOperand(i: 0), Op1: I->getOperand(i: 1), NSW, NUW,
1211	DemandedElts, KnownOut&: Known, Known2, Depth, Q);
1212	break;
1213	}
1214	case Instruction::Add: {
1215	bool NSW = Q.IIQ.hasNoSignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1216	bool NUW = Q.IIQ.hasNoUnsignedWrap(Op: cast<OverflowingBinaryOperator>(Val: I));
1217	computeKnownBitsAddSub(Add: true, Op0: I->getOperand(i: 0), Op1: I->getOperand(i: 1), NSW, NUW,
1218	DemandedElts, KnownOut&: Known, Known2, Depth, Q);
1219	break;
1220	}
1221	case Instruction::SRem:
1222	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1223	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1224	Known = KnownBits::srem(LHS: Known, RHS: Known2);
1225	break;
1226
1227	case Instruction::URem:
1228	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1229	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1230	Known = KnownBits::urem(LHS: Known, RHS: Known2);
1231	break;
1232	case Instruction::Alloca:
1233	Known.Zero.setLowBits(Log2(A: cast<AllocaInst>(Val: I)->getAlign()));
1234	break;
1235	case Instruction::GetElementPtr: {
1236	// Analyze all of the subscripts of this getelementptr instruction
1237	// to determine if we can prove known low zero bits.
1238	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1239	// Accumulate the constant indices in a separate variable
1240	// to minimize the number of calls to computeForAddSub.
1241	APInt AccConstIndices(BitWidth, 0, /*IsSigned*/ true);
1242
1243	gep_type_iterator GTI = gep_type_begin(GEP: I);
1244	for (unsigned i = 1, e = I->getNumOperands(); i != e; ++i, ++GTI) {
1245	// TrailZ can only become smaller, short-circuit if we hit zero.
1246	if (Known.isUnknown())
1247	break;
1248
1249	Value *Index = I->getOperand(i);
1250
1251	// Handle case when index is zero.
1252	Constant *CIndex = dyn_cast<Constant>(Val: Index);
1253	if (CIndex && CIndex->isZeroValue())
1254	continue;
1255
1256	if (StructType *STy = GTI.getStructTypeOrNull()) {
1257	// Handle struct member offset arithmetic.
1258
1259	assert(CIndex &&
1260	"Access to structure field must be known at compile time");
1261
1262	if (CIndex->getType()->isVectorTy())
1263	Index = CIndex->getSplatValue();
1264
1265	unsigned Idx = cast<ConstantInt>(Val: Index)->getZExtValue();
1266	const StructLayout *SL = Q.DL.getStructLayout(Ty: STy);
1267	uint64_t Offset = SL->getElementOffset(Idx);
1268	AccConstIndices += Offset;
1269	continue;
1270	}
1271
1272	// Handle array index arithmetic.
1273	Type *IndexedTy = GTI.getIndexedType();
1274	if (!IndexedTy->isSized()) {
1275	Known.resetAll();
1276	break;
1277	}
1278
1279	unsigned IndexBitWidth = Index->getType()->getScalarSizeInBits();
1280	KnownBits IndexBits(IndexBitWidth);
1281	computeKnownBits(V: Index, Known&: IndexBits, Depth: Depth + 1, Q);
1282	TypeSize IndexTypeSize = GTI.getSequentialElementStride(DL: Q.DL);
1283	uint64_t TypeSizeInBytes = IndexTypeSize.getKnownMinValue();
1284	KnownBits ScalingFactor(IndexBitWidth);
1285	// Multiply by current sizeof type.
1286	// &A[i] == A + i * sizeof(*A[i]).
1287	if (IndexTypeSize.isScalable()) {
1288	// For scalable types the only thing we know about sizeof is
1289	// that this is a multiple of the minimum size.
1290	ScalingFactor.Zero.setLowBits(llvm::countr_zero(Val: TypeSizeInBytes));
1291	} else if (IndexBits.isConstant()) {
1292	APInt IndexConst = IndexBits.getConstant();
1293	APInt ScalingFactor(IndexBitWidth, TypeSizeInBytes);
1294	IndexConst *= ScalingFactor;
1295	AccConstIndices += IndexConst.sextOrTrunc(width: BitWidth);
1296	continue;
1297	} else {
1298	ScalingFactor =
1299	KnownBits::makeConstant(C: APInt(IndexBitWidth, TypeSizeInBytes));
1300	}
1301	IndexBits = KnownBits::mul(LHS: IndexBits, RHS: ScalingFactor);
1302
1303	// If the offsets have a different width from the pointer, according
1304	// to the language reference we need to sign-extend or truncate them
1305	// to the width of the pointer.
1306	IndexBits = IndexBits.sextOrTrunc(BitWidth);
1307
1308	// Note that inbounds does *not* guarantee nsw for the addition, as only
1309	// the offset is signed, while the base address is unsigned.
1310	Known = KnownBits::computeForAddSub(
1311	/*Add=*/true, /*NSW=*/false, /* NUW=*/false, LHS: Known, RHS: IndexBits);
1312	}
1313	if (!Known.isUnknown() && !AccConstIndices.isZero()) {
1314	KnownBits Index = KnownBits::makeConstant(C: AccConstIndices);
1315	Known = KnownBits::computeForAddSub(
1316	/*Add=*/true, /*NSW=*/false, /* NUW=*/false, LHS: Known, RHS: Index);
1317	}
1318	break;
1319	}
1320	case Instruction::PHI: {
1321	const PHINode *P = cast<PHINode>(Val: I);
1322	BinaryOperator *BO = nullptr;
1323	Value *R = nullptr, *L = nullptr;
1324	if (matchSimpleRecurrence(P, BO, Start&: R, Step&: L)) {
1325	// Handle the case of a simple two-predecessor recurrence PHI.
1326	// There's a lot more that could theoretically be done here, but
1327	// this is sufficient to catch some interesting cases.
1328	unsigned Opcode = BO->getOpcode();
1329
1330	// If this is a shift recurrence, we know the bits being shifted in.
1331	// We can combine that with information about the start value of the
1332	// recurrence to conclude facts about the result.
1333	if ((Opcode == Instruction::LShr || Opcode == Instruction::AShr ||
1334	Opcode == Instruction::Shl) &&
1335	BO->getOperand(i_nocapture: 0) == I) {
1336
1337	// We have matched a recurrence of the form:
1338	// %iv = [R, %entry], [%iv.next, %backedge]
1339	// %iv.next = shift_op %iv, L
1340
1341	// Recurse with the phi context to avoid concern about whether facts
1342	// inferred hold at original context instruction. TODO: It may be
1343	// correct to use the original context. IF warranted, explore and
1344	// add sufficient tests to cover.
1345	SimplifyQuery RecQ = Q;
1346	RecQ.CxtI = P;
1347	computeKnownBits(V: R, DemandedElts, Known&: Known2, Depth: Depth + 1, Q: RecQ);
1348	switch (Opcode) {
1349	case Instruction::Shl:
1350	// A shl recurrence will only increase the tailing zeros
1351	Known.Zero.setLowBits(Known2.countMinTrailingZeros());
1352	break;
1353	case Instruction::LShr:
1354	// A lshr recurrence will preserve the leading zeros of the
1355	// start value
1356	Known.Zero.setHighBits(Known2.countMinLeadingZeros());
1357	break;
1358	case Instruction::AShr:
1359	// An ashr recurrence will extend the initial sign bit
1360	Known.Zero.setHighBits(Known2.countMinLeadingZeros());
1361	Known.One.setHighBits(Known2.countMinLeadingOnes());
1362	break;
1363	};
1364	}
1365
1366	// Check for operations that have the property that if
1367	// both their operands have low zero bits, the result
1368	// will have low zero bits.
1369	if (Opcode == Instruction::Add ||
1370	Opcode == Instruction::Sub ||
1371	Opcode == Instruction::And ||
1372	Opcode == Instruction::Or ||
1373	Opcode == Instruction::Mul) {
1374	// Change the context instruction to the "edge" that flows into the
1375	// phi. This is important because that is where the value is actually
1376	// "evaluated" even though it is used later somewhere else. (see also
1377	// D69571).
1378	SimplifyQuery RecQ = Q;
1379
1380	unsigned OpNum = P->getOperand(i_nocapture: 0) == R ? 0 : 1;
1381	Instruction *RInst = P->getIncomingBlock(i: OpNum)->getTerminator();
1382	Instruction *LInst = P->getIncomingBlock(i: 1-OpNum)->getTerminator();
1383
1384	// Ok, we have a PHI of the form L op= R. Check for low
1385	// zero bits.
1386	RecQ.CxtI = RInst;
1387	computeKnownBits(V: R, Known&: Known2, Depth: Depth + 1, Q: RecQ);
1388
1389	// We need to take the minimum number of known bits
1390	KnownBits Known3(BitWidth);
1391	RecQ.CxtI = LInst;
1392	computeKnownBits(V: L, Known&: Known3, Depth: Depth + 1, Q: RecQ);
1393
1394	Known.Zero.setLowBits(std::min(a: Known2.countMinTrailingZeros(),
1395	b: Known3.countMinTrailingZeros()));
1396
1397	auto *OverflowOp = dyn_cast<OverflowingBinaryOperator>(Val: BO);
1398	if (OverflowOp && Q.IIQ.hasNoSignedWrap(Op: OverflowOp)) {
1399	// If initial value of recurrence is nonnegative, and we are adding
1400	// a nonnegative number with nsw, the result can only be nonnegative
1401	// or poison value regardless of the number of times we execute the
1402	// add in phi recurrence. If initial value is negative and we are
1403	// adding a negative number with nsw, the result can only be
1404	// negative or poison value. Similar arguments apply to sub and mul.
1405	//
1406	// (add non-negative, non-negative) --> non-negative
1407	// (add negative, negative) --> negative
1408	if (Opcode == Instruction::Add) {
1409	if (Known2.isNonNegative() && Known3.isNonNegative())
1410	Known.makeNonNegative();
1411	else if (Known2.isNegative() && Known3.isNegative())
1412	Known.makeNegative();
1413	}
1414
1415	// (sub nsw non-negative, negative) --> non-negative
1416	// (sub nsw negative, non-negative) --> negative
1417	else if (Opcode == Instruction::Sub && BO->getOperand(i_nocapture: 0) == I) {
1418	if (Known2.isNonNegative() && Known3.isNegative())
1419	Known.makeNonNegative();
1420	else if (Known2.isNegative() && Known3.isNonNegative())
1421	Known.makeNegative();
1422	}
1423
1424	// (mul nsw non-negative, non-negative) --> non-negative
1425	else if (Opcode == Instruction::Mul && Known2.isNonNegative() &&
1426	Known3.isNonNegative())
1427	Known.makeNonNegative();
1428	}
1429
1430	break;
1431	}
1432	}
1433
1434	// Unreachable blocks may have zero-operand PHI nodes.
1435	if (P->getNumIncomingValues() == 0)
1436	break;
1437
1438	// Otherwise take the unions of the known bit sets of the operands,
1439	// taking conservative care to avoid excessive recursion.
1440	if (Depth < MaxAnalysisRecursionDepth - 1 && Known.isUnknown()) {
1441	// Skip if every incoming value references to ourself.
1442	if (isa_and_nonnull<UndefValue>(Val: P->hasConstantValue()))
1443	break;
1444
1445	Known.Zero.setAllBits();
1446	Known.One.setAllBits();
1447	for (unsigned u = 0, e = P->getNumIncomingValues(); u < e; ++u) {
1448	Value *IncValue = P->getIncomingValue(i: u);
1449	// Skip direct self references.
1450	if (IncValue == P) continue;
1451
1452	// Change the context instruction to the "edge" that flows into the
1453	// phi. This is important because that is where the value is actually
1454	// "evaluated" even though it is used later somewhere else. (see also
1455	// D69571).
1456	SimplifyQuery RecQ = Q;
1457	RecQ.CxtI = P->getIncomingBlock(i: u)->getTerminator();
1458
1459	Known2 = KnownBits(BitWidth);
1460
1461	// Recurse, but cap the recursion to one level, because we don't
1462	// want to waste time spinning around in loops.
1463	// TODO: See if we can base recursion limiter on number of incoming phi
1464	// edges so we don't overly clamp analysis.
1465	computeKnownBits(V: IncValue, Known&: Known2, Depth: MaxAnalysisRecursionDepth - 1, Q: RecQ);
1466
1467	// See if we can further use a conditional branch into the phi
1468	// to help us determine the range of the value.
1469	if (!Known2.isConstant()) {
1470	ICmpInst::Predicate Pred;
1471	const APInt *RHSC;
1472	BasicBlock *TrueSucc, *FalseSucc;
1473	// TODO: Use RHS Value and compute range from its known bits.
1474	if (match(V: RecQ.CxtI,
1475	P: m_Br(C: m_c_ICmp(Pred, L: m_Specific(V: IncValue), R: m_APInt(Res&: RHSC)),
1476	T: m_BasicBlock(V&: TrueSucc), F: m_BasicBlock(V&: FalseSucc)))) {
1477	// Check for cases of duplicate successors.
1478	if ((TrueSucc == P->getParent()) != (FalseSucc == P->getParent())) {
1479	// If we're using the false successor, invert the predicate.
1480	if (FalseSucc == P->getParent())
1481	Pred = CmpInst::getInversePredicate(pred: Pred);
1482	// Get the knownbits implied by the incoming phi condition.
1483	auto CR = ConstantRange::makeExactICmpRegion(Pred, Other: *RHSC);
1484	KnownBits KnownUnion = Known2.unionWith(RHS: CR.toKnownBits());
1485	// We can have conflicts here if we are analyzing deadcode (its
1486	// impossible for us reach this BB based the icmp).
1487	if (KnownUnion.hasConflict()) {
1488	// No reason to continue analyzing in a known dead region, so
1489	// just resetAll and break. This will cause us to also exit the
1490	// outer loop.
1491	Known.resetAll();
1492	break;
1493	}
1494	Known2 = KnownUnion;
1495	}
1496	}
1497	}
1498
1499	Known = Known.intersectWith(RHS: Known2);
1500	// If all bits have been ruled out, there's no need to check
1501	// more operands.
1502	if (Known.isUnknown())
1503	break;
1504	}
1505	}
1506	break;
1507	}
1508	case Instruction::Call:
1509	case Instruction::Invoke: {
1510	// If range metadata is attached to this call, set known bits from that,
1511	// and then intersect with known bits based on other properties of the
1512	// function.
1513	if (MDNode *MD =
1514	Q.IIQ.getMetadata(I: cast<Instruction>(Val: I), KindID: LLVMContext::MD_range))
1515	computeKnownBitsFromRangeMetadata(Ranges: *MD, Known);
1516
1517	const auto *CB = cast<CallBase>(Val: I);
1518
1519	if (std::optional<ConstantRange> Range = CB->getRange())
1520	Known = Known.unionWith(RHS: Range->toKnownBits());
1521
1522	if (const Value *RV = CB->getReturnedArgOperand()) {
1523	if (RV->getType() == I->getType()) {
1524	computeKnownBits(V: RV, Known&: Known2, Depth: Depth + 1, Q);
1525	Known = Known.unionWith(RHS: Known2);
1526	// If the function doesn't return properly for all input values
1527	// (e.g. unreachable exits) then there might be conflicts between the
1528	// argument value and the range metadata. Simply discard the known bits
1529	// in case of conflicts.
1530	if (Known.hasConflict())
1531	Known.resetAll();
1532	}
1533	}
1534	if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Val: I)) {
1535	switch (II->getIntrinsicID()) {
1536	default: break;
1537	case Intrinsic::abs: {
1538	computeKnownBits(V: I->getOperand(i: 0), Known&: Known2, Depth: Depth + 1, Q);
1539	bool IntMinIsPoison = match(V: II->getArgOperand(i: 1), P: m_One());
1540	Known = Known2.abs(IntMinIsPoison);
1541	break;
1542	}
1543	case Intrinsic::bitreverse:
1544	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
1545	Known.Zero |= Known2.Zero.reverseBits();
1546	Known.One |= Known2.One.reverseBits();
1547	break;
1548	case Intrinsic::bswap:
1549	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known&: Known2, Depth: Depth + 1, Q);
1550	Known.Zero |= Known2.Zero.byteSwap();
1551	Known.One |= Known2.One.byteSwap();
1552	break;
1553	case Intrinsic::ctlz: {
1554	computeKnownBits(V: I->getOperand(i: 0), Known&: Known2, Depth: Depth + 1, Q);
1555	// If we have a known 1, its position is our upper bound.
1556	unsigned PossibleLZ = Known2.countMaxLeadingZeros();
1557	// If this call is poison for 0 input, the result will be less than 2^n.
1558	if (II->getArgOperand(i: 1) == ConstantInt::getTrue(Context&: II->getContext()))
1559	PossibleLZ = std::min(a: PossibleLZ, b: BitWidth - 1);
1560	unsigned LowBits = llvm::bit_width(Value: PossibleLZ);
1561	Known.Zero.setBitsFrom(LowBits);
1562	break;
1563	}
1564	case Intrinsic::cttz: {
1565	computeKnownBits(V: I->getOperand(i: 0), Known&: Known2, Depth: Depth + 1, Q);
1566	// If we have a known 1, its position is our upper bound.
1567	unsigned PossibleTZ = Known2.countMaxTrailingZeros();
1568	// If this call is poison for 0 input, the result will be less than 2^n.
1569	if (II->getArgOperand(i: 1) == ConstantInt::getTrue(Context&: II->getContext()))
1570	PossibleTZ = std::min(a: PossibleTZ, b: BitWidth - 1);
1571	unsigned LowBits = llvm::bit_width(Value: PossibleTZ);
1572	Known.Zero.setBitsFrom(LowBits);
1573	break;
1574	}
1575	case Intrinsic::ctpop: {
1576	computeKnownBits(V: I->getOperand(i: 0), Known&: Known2, Depth: Depth + 1, Q);
1577	// We can bound the space the count needs. Also, bits known to be zero
1578	// can't contribute to the population.
1579	unsigned BitsPossiblySet = Known2.countMaxPopulation();
1580	unsigned LowBits = llvm::bit_width(Value: BitsPossiblySet);
1581	Known.Zero.setBitsFrom(LowBits);
1582	// TODO: we could bound KnownOne using the lower bound on the number
1583	// of bits which might be set provided by popcnt KnownOne2.
1584	break;
1585	}
1586	case Intrinsic::fshr:
1587	case Intrinsic::fshl: {
1588	const APInt *SA;
1589	if (!match(V: I->getOperand(i: 2), P: m_APInt(Res&: SA)))
1590	break;
1591
1592	// Normalize to funnel shift left.
1593	uint64_t ShiftAmt = SA->urem(RHS: BitWidth);
1594	if (II->getIntrinsicID() == Intrinsic::fshr)
1595	ShiftAmt = BitWidth - ShiftAmt;
1596
1597	KnownBits Known3(BitWidth);
1598	computeKnownBits(V: I->getOperand(i: 0), Known&: Known2, Depth: Depth + 1, Q);
1599	computeKnownBits(V: I->getOperand(i: 1), Known&: Known3, Depth: Depth + 1, Q);
1600
1601	Known.Zero =
1602	Known2.Zero.shl(shiftAmt: ShiftAmt) | Known3.Zero.lshr(shiftAmt: BitWidth - ShiftAmt);
1603	Known.One =
1604	Known2.One.shl(shiftAmt: ShiftAmt) | Known3.One.lshr(shiftAmt: BitWidth - ShiftAmt);
1605	break;
1606	}
1607	case Intrinsic::uadd_sat:
1608	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1609	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1610	Known = KnownBits::uadd_sat(LHS: Known, RHS: Known2);
1611	break;
1612	case Intrinsic::usub_sat:
1613	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1614	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1615	Known = KnownBits::usub_sat(LHS: Known, RHS: Known2);
1616	break;
1617	case Intrinsic::sadd_sat:
1618	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1619	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1620	Known = KnownBits::sadd_sat(LHS: Known, RHS: Known2);
1621	break;
1622	case Intrinsic::ssub_sat:
1623	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1624	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1625	Known = KnownBits::ssub_sat(LHS: Known, RHS: Known2);
1626	break;
1627	// for min/max/and/or reduce, any bit common to each element in the
1628	// input vec is set in the output.
1629	case Intrinsic::vector_reduce_and:
1630	case Intrinsic::vector_reduce_or:
1631	case Intrinsic::vector_reduce_umax:
1632	case Intrinsic::vector_reduce_umin:
1633	case Intrinsic::vector_reduce_smax:
1634	case Intrinsic::vector_reduce_smin:
1635	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1636	break;
1637	case Intrinsic::vector_reduce_xor: {
1638	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1639	// The zeros common to all vecs are zero in the output.
1640	// If the number of elements is odd, then the common ones remain. If the
1641	// number of elements is even, then the common ones becomes zeros.
1642	auto *VecTy = cast<VectorType>(Val: I->getOperand(i: 0)->getType());
1643	// Even, so the ones become zeros.
1644	bool EvenCnt = VecTy->getElementCount().isKnownEven();
1645	if (EvenCnt)
1646	Known.Zero |= Known.One;
1647	// Maybe even element count so need to clear ones.
1648	if (VecTy->isScalableTy() || EvenCnt)
1649	Known.One.clearAllBits();
1650	break;
1651	}
1652	case Intrinsic::umin:
1653	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1654	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1655	Known = KnownBits::umin(LHS: Known, RHS: Known2);
1656	break;
1657	case Intrinsic::umax:
1658	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1659	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1660	Known = KnownBits::umax(LHS: Known, RHS: Known2);
1661	break;
1662	case Intrinsic::smin:
1663	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1664	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1665	Known = KnownBits::smin(LHS: Known, RHS: Known2);
1666	break;
1667	case Intrinsic::smax:
1668	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1669	computeKnownBits(V: I->getOperand(i: 1), Known&: Known2, Depth: Depth + 1, Q);
1670	Known = KnownBits::smax(LHS: Known, RHS: Known2);
1671	break;
1672	case Intrinsic::ptrmask: {
1673	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1674
1675	const Value *Mask = I->getOperand(i: 1);
1676	Known2 = KnownBits(Mask->getType()->getScalarSizeInBits());
1677	computeKnownBits(V: Mask, Known&: Known2, Depth: Depth + 1, Q);
1678	// TODO: 1-extend would be more precise.
1679	Known &= Known2.anyextOrTrunc(BitWidth);
1680	break;
1681	}
1682	case Intrinsic::x86_sse42_crc32_64_64:
1683	Known.Zero.setBitsFrom(32);
1684	break;
1685	case Intrinsic::riscv_vsetvli:
1686	case Intrinsic::riscv_vsetvlimax: {
1687	bool HasAVL = II->getIntrinsicID() == Intrinsic::riscv_vsetvli;
1688	const ConstantRange Range = getVScaleRange(F: II->getFunction(), BitWidth);
1689	uint64_t SEW = RISCVVType::decodeVSEW(
1690	VSEW: cast<ConstantInt>(Val: II->getArgOperand(i: HasAVL))->getZExtValue());
1691	RISCVII::VLMUL VLMUL = static_cast<RISCVII::VLMUL>(
1692	cast<ConstantInt>(Val: II->getArgOperand(i: 1 + HasAVL))->getZExtValue());
1693	// The Range is [Lower, Upper), so we need to subtract 1 here to get the
1694	// real upper value.
1695	uint64_t MaxVLEN =
1696	(Range.getUpper().getZExtValue() - 1) * RISCV::RVVBitsPerBlock;
1697	uint64_t MaxVL = MaxVLEN / RISCVVType::getSEWLMULRatio(SEW, VLMul: VLMUL);
1698
1699	// Result of vsetvli must be not larger than AVL.
1700	if (HasAVL)
1701	if (auto *CI = dyn_cast<ConstantInt>(Val: II->getArgOperand(i: 0)))
1702	MaxVL = std::min(a: MaxVL, b: CI->getZExtValue());
1703
1704	unsigned KnownZeroFirstBit = Log2_32(Value: MaxVL) + 1;
1705	if (BitWidth > KnownZeroFirstBit)
1706	Known.Zero.setBitsFrom(KnownZeroFirstBit);
1707	break;
1708	}
1709	case Intrinsic::vscale: {
1710	if (!II->getParent() || !II->getFunction())
1711	break;
1712
1713	Known = getVScaleRange(F: II->getFunction(), BitWidth).toKnownBits();
1714	break;
1715	}
1716	}
1717	}
1718	break;
1719	}
1720	case Instruction::ShuffleVector: {
1721	auto *Shuf = dyn_cast<ShuffleVectorInst>(Val: I);
1722	// FIXME: Do we need to handle ConstantExpr involving shufflevectors?
1723	if (!Shuf) {
1724	Known.resetAll();
1725	return;
1726	}
1727	// For undef elements, we don't know anything about the common state of
1728	// the shuffle result.
1729	APInt DemandedLHS, DemandedRHS;
1730	if (!getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS)) {
1731	Known.resetAll();
1732	return;
1733	}
1734	Known.One.setAllBits();
1735	Known.Zero.setAllBits();
1736	if (!!DemandedLHS) {
1737	const Value *LHS = Shuf->getOperand(i_nocapture: 0);
1738	computeKnownBits(V: LHS, DemandedElts: DemandedLHS, Known, Depth: Depth + 1, Q);
1739	// If we don't know any bits, early out.
1740	if (Known.isUnknown())
1741	break;
1742	}
1743	if (!!DemandedRHS) {
1744	const Value *RHS = Shuf->getOperand(i_nocapture: 1);
1745	computeKnownBits(V: RHS, DemandedElts: DemandedRHS, Known&: Known2, Depth: Depth + 1, Q);
1746	Known = Known.intersectWith(RHS: Known2);
1747	}
1748	break;
1749	}
1750	case Instruction::InsertElement: {
1751	if (isa<ScalableVectorType>(Val: I->getType())) {
1752	Known.resetAll();
1753	return;
1754	}
1755	const Value *Vec = I->getOperand(i: 0);
1756	const Value *Elt = I->getOperand(i: 1);
1757	auto *CIdx = dyn_cast<ConstantInt>(Val: I->getOperand(i: 2));
1758	unsigned NumElts = DemandedElts.getBitWidth();
1759	APInt DemandedVecElts = DemandedElts;
1760	bool NeedsElt = true;
1761	// If we know the index we are inserting too, clear it from Vec check.
1762	if (CIdx && CIdx->getValue().ult(RHS: NumElts)) {
1763	DemandedVecElts.clearBit(BitPosition: CIdx->getZExtValue());
1764	NeedsElt = DemandedElts[CIdx->getZExtValue()];
1765	}
1766
1767	Known.One.setAllBits();
1768	Known.Zero.setAllBits();
1769	if (NeedsElt) {
1770	computeKnownBits(V: Elt, Known, Depth: Depth + 1, Q);
1771	// If we don't know any bits, early out.
1772	if (Known.isUnknown())
1773	break;
1774	}
1775
1776	if (!DemandedVecElts.isZero()) {
1777	computeKnownBits(V: Vec, DemandedElts: DemandedVecElts, Known&: Known2, Depth: Depth + 1, Q);
1778	Known = Known.intersectWith(RHS: Known2);
1779	}
1780	break;
1781	}
1782	case Instruction::ExtractElement: {
1783	// Look through extract element. If the index is non-constant or
1784	// out-of-range demand all elements, otherwise just the extracted element.
1785	const Value *Vec = I->getOperand(i: 0);
1786	const Value *Idx = I->getOperand(i: 1);
1787	auto *CIdx = dyn_cast<ConstantInt>(Val: Idx);
1788	if (isa<ScalableVectorType>(Val: Vec->getType())) {
1789	// FIXME: there's probably *something* we can do with scalable vectors
1790	Known.resetAll();
1791	break;
1792	}
1793	unsigned NumElts = cast<FixedVectorType>(Val: Vec->getType())->getNumElements();
1794	APInt DemandedVecElts = APInt::getAllOnes(numBits: NumElts);
1795	if (CIdx && CIdx->getValue().ult(RHS: NumElts))
1796	DemandedVecElts = APInt::getOneBitSet(numBits: NumElts, BitNo: CIdx->getZExtValue());
1797	computeKnownBits(V: Vec, DemandedElts: DemandedVecElts, Known, Depth: Depth + 1, Q);
1798	break;
1799	}
1800	case Instruction::ExtractValue:
1801	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Val: I->getOperand(i: 0))) {
1802	const ExtractValueInst *EVI = cast<ExtractValueInst>(Val: I);
1803	if (EVI->getNumIndices() != 1) break;
1804	if (EVI->getIndices()[0] == 0) {
1805	switch (II->getIntrinsicID()) {
1806	default: break;
1807	case Intrinsic::uadd_with_overflow:
1808	case Intrinsic::sadd_with_overflow:
1809	computeKnownBitsAddSub(
1810	Add: true, Op0: II->getArgOperand(i: 0), Op1: II->getArgOperand(i: 1), /*NSW=*/false,
1811	/* NUW=*/false, DemandedElts, KnownOut&: Known, Known2, Depth, Q);
1812	break;
1813	case Intrinsic::usub_with_overflow:
1814	case Intrinsic::ssub_with_overflow:
1815	computeKnownBitsAddSub(
1816	Add: false, Op0: II->getArgOperand(i: 0), Op1: II->getArgOperand(i: 1), /*NSW=*/false,
1817	/* NUW=*/false, DemandedElts, KnownOut&: Known, Known2, Depth, Q);
1818	break;
1819	case Intrinsic::umul_with_overflow:
1820	case Intrinsic::smul_with_overflow:
1821	computeKnownBitsMul(Op0: II->getArgOperand(i: 0), Op1: II->getArgOperand(i: 1), NSW: false,
1822	DemandedElts, Known, Known2, Depth, Q);
1823	break;
1824	}
1825	}
1826	}
1827	break;
1828	case Instruction::Freeze:
1829	if (isGuaranteedNotToBePoison(V: I->getOperand(i: 0), AC: Q.AC, CtxI: Q.CxtI, DT: Q.DT,
1830	Depth: Depth + 1))
1831	computeKnownBits(V: I->getOperand(i: 0), Known, Depth: Depth + 1, Q);
1832	break;
1833	}
1834	}
1835
1836	/// Determine which bits of V are known to be either zero or one and return
1837	/// them.
1838	KnownBits llvm::computeKnownBits(const Value *V, const APInt &DemandedElts,
1839	unsigned Depth, const SimplifyQuery &Q) {
1840	KnownBits Known(getBitWidth(Ty: V->getType(), DL: Q.DL));
1841	::computeKnownBits(V, DemandedElts, Known, Depth, Q);
1842	return Known;
1843	}
1844
1845	/// Determine which bits of V are known to be either zero or one and return
1846	/// them.
1847	KnownBits llvm::computeKnownBits(const Value *V, unsigned Depth,
1848	const SimplifyQuery &Q) {
1849	KnownBits Known(getBitWidth(Ty: V->getType(), DL: Q.DL));
1850	computeKnownBits(V, Known, Depth, Q);
1851	return Known;
1852	}
1853
1854	/// Determine which bits of V are known to be either zero or one and return
1855	/// them in the Known bit set.
1856	///
1857	/// NOTE: we cannot consider 'undef' to be "IsZero" here. The problem is that
1858	/// we cannot optimize based on the assumption that it is zero without changing
1859	/// it to be an explicit zero. If we don't change it to zero, other code could
1860	/// optimized based on the contradictory assumption that it is non-zero.
1861	/// Because instcombine aggressively folds operations with undef args anyway,
1862	/// this won't lose us code quality.
1863	///
1864	/// This function is defined on values with integer type, values with pointer
1865	/// type, and vectors of integers. In the case
1866	/// where V is a vector, known zero, and known one values are the
1867	/// same width as the vector element, and the bit is set only if it is true
1868	/// for all of the demanded elements in the vector specified by DemandedElts.
1869	void computeKnownBits(const Value *V, const APInt &DemandedElts,
1870	KnownBits &Known, unsigned Depth,
1871	const SimplifyQuery &Q) {
1872	if (!DemandedElts) {
1873	// No demanded elts, better to assume we don't know anything.
1874	Known.resetAll();
1875	return;
1876	}
1877
1878	assert(V && "No Value?");
1879	assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
1880
1881	#ifndef NDEBUG
1882	Type *Ty = V->getType();
1883	unsigned BitWidth = Known.getBitWidth();
1884
1885	assert((Ty->isIntOrIntVectorTy(BitWidth) || Ty->isPtrOrPtrVectorTy()) &&
1886	"Not integer or pointer type!");
1887
1888	if (auto *FVTy = dyn_cast<FixedVectorType>(Val: Ty)) {
1889	assert(
1890	FVTy->getNumElements() == DemandedElts.getBitWidth() &&
1891	"DemandedElt width should equal the fixed vector number of elements");
1892	} else {
1893	assert(DemandedElts == APInt(1, 1) &&
1894	"DemandedElt width should be 1 for scalars or scalable vectors");
1895	}
1896
1897	Type *ScalarTy = Ty->getScalarType();
1898	if (ScalarTy->isPointerTy()) {
1899	assert(BitWidth == Q.DL.getPointerTypeSizeInBits(ScalarTy) &&
1900	"V and Known should have same BitWidth");
1901	} else {
1902	assert(BitWidth == Q.DL.getTypeSizeInBits(ScalarTy) &&
1903	"V and Known should have same BitWidth");
1904	}
1905	#endif
1906
1907	const APInt *C;
1908	if (match(V, P: m_APInt(Res&: C))) {
1909	// We know all of the bits for a scalar constant or a splat vector constant!
1910	Known = KnownBits::makeConstant(C: *C);
1911	return;
1912	}
1913	// Null and aggregate-zero are all-zeros.
1914	if (isa<ConstantPointerNull>(Val: V) || isa<ConstantAggregateZero>(Val: V)) {
1915	Known.setAllZero();
1916	return;
1917	}
1918	// Handle a constant vector by taking the intersection of the known bits of
1919	// each element.
1920	if (const ConstantDataVector *CDV = dyn_cast<ConstantDataVector>(Val: V)) {
1921	assert(!isa<ScalableVectorType>(V->getType()));
1922	// We know that CDV must be a vector of integers. Take the intersection of
1923	// each element.
1924	Known.Zero.setAllBits(); Known.One.setAllBits();
1925	for (unsigned i = 0, e = CDV->getNumElements(); i != e; ++i) {
1926	if (!DemandedElts[i])
1927	continue;
1928	APInt Elt = CDV->getElementAsAPInt(i);
1929	Known.Zero &= ~Elt;
1930	Known.One &= Elt;
1931	}
1932	if (Known.hasConflict())
1933	Known.resetAll();
1934	return;
1935	}
1936
1937	if (const auto *CV = dyn_cast<ConstantVector>(Val: V)) {
1938	assert(!isa<ScalableVectorType>(V->getType()));
1939	// We know that CV must be a vector of integers. Take the intersection of
1940	// each element.
1941	Known.Zero.setAllBits(); Known.One.setAllBits();
1942	for (unsigned i = 0, e = CV->getNumOperands(); i != e; ++i) {
1943	if (!DemandedElts[i])
1944	continue;
1945	Constant *Element = CV->getAggregateElement(Elt: i);
1946	if (isa<PoisonValue>(Val: Element))
1947	continue;
1948	auto *ElementCI = dyn_cast_or_null<ConstantInt>(Val: Element);
1949	if (!ElementCI) {
1950	Known.resetAll();
1951	return;
1952	}
1953	const APInt &Elt = ElementCI->getValue();
1954	Known.Zero &= ~Elt;
1955	Known.One &= Elt;
1956	}
1957	if (Known.hasConflict())
1958	Known.resetAll();
1959	return;
1960	}
1961
1962	// Start out not knowing anything.
1963	Known.resetAll();
1964
1965	// We can't imply anything about undefs.
1966	if (isa<UndefValue>(Val: V))
1967	return;
1968
1969	// There's no point in looking through other users of ConstantData for
1970	// assumptions. Confirm that we've handled them all.
1971	assert(!isa<ConstantData>(V) && "Unhandled constant data!");
1972
1973	if (const auto *A = dyn_cast<Argument>(Val: V))
1974	if (std::optional<ConstantRange> Range = A->getRange())
1975	Known = Range->toKnownBits();
1976
1977	// All recursive calls that increase depth must come after this.
1978	if (Depth == MaxAnalysisRecursionDepth)
1979	return;
1980
1981	// A weak GlobalAlias is totally unknown. A non-weak GlobalAlias has
1982	// the bits of its aliasee.
1983	if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(Val: V)) {
1984	if (!GA->isInterposable())
1985	computeKnownBits(V: GA->getAliasee(), Known, Depth: Depth + 1, Q);
1986	return;
1987	}
1988
1989	if (const Operator *I = dyn_cast<Operator>(Val: V))
1990	computeKnownBitsFromOperator(I, DemandedElts, Known, Depth, Q);
1991	else if (const GlobalValue *GV = dyn_cast<GlobalValue>(Val: V)) {
1992	if (std::optional<ConstantRange> CR = GV->getAbsoluteSymbolRange())
1993	Known = CR->toKnownBits();
1994	}
1995
1996	// Aligned pointers have trailing zeros - refine Known.Zero set
1997	if (isa<PointerType>(Val: V->getType())) {
1998	Align Alignment = V->getPointerAlignment(DL: Q.DL);
1999	Known.Zero.setLowBits(Log2(A: Alignment));
2000	}
2001
2002	// computeKnownBitsFromContext strictly refines Known.
2003	// Therefore, we run them after computeKnownBitsFromOperator.
2004
2005	// Check whether we can determine known bits from context such as assumes.
2006	computeKnownBitsFromContext(V, Known, Depth, Q);
2007
2008	assert((Known.Zero & Known.One) == 0 && "Bits known to be one AND zero?");
2009	}
2010
2011	/// Try to detect a recurrence that the value of the induction variable is
2012	/// always a power of two (or zero).
2013	static bool isPowerOfTwoRecurrence(const PHINode *PN, bool OrZero,
2014	unsigned Depth, SimplifyQuery &Q) {
2015	BinaryOperator *BO = nullptr;
2016	Value *Start = nullptr, *Step = nullptr;
2017	if (!matchSimpleRecurrence(P: PN, BO, Start, Step))
2018	return false;
2019
2020	// Initial value must be a power of two.
2021	for (const Use &U : PN->operands()) {
2022	if (U.get() == Start) {
2023	// Initial value comes from a different BB, need to adjust context
2024	// instruction for analysis.
2025	Q.CxtI = PN->getIncomingBlock(U)->getTerminator();
2026	if (!isKnownToBeAPowerOfTwo(V: Start, OrZero, Depth, Q))
2027	return false;
2028	}
2029	}
2030
2031	// Except for Mul, the induction variable must be on the left side of the
2032	// increment expression, otherwise its value can be arbitrary.
2033	if (BO->getOpcode() != Instruction::Mul && BO->getOperand(i_nocapture: 1) != Step)
2034	return false;
2035
2036	Q.CxtI = BO->getParent()->getTerminator();
2037	switch (BO->getOpcode()) {
2038	case Instruction::Mul:
2039	// Power of two is closed under multiplication.
2040	return (OrZero || Q.IIQ.hasNoUnsignedWrap(Op: BO) ||
2041	Q.IIQ.hasNoSignedWrap(Op: BO)) &&
2042	isKnownToBeAPowerOfTwo(V: Step, OrZero, Depth, Q);
2043	case Instruction::SDiv:
2044	// Start value must not be signmask for signed division, so simply being a
2045	// power of two is not sufficient, and it has to be a constant.
2046	if (!match(V: Start, P: m_Power2()) || match(V: Start, P: m_SignMask()))
2047	return false;
2048	[[fallthrough]];
2049	case Instruction::UDiv:
2050	// Divisor must be a power of two.
2051	// If OrZero is false, cannot guarantee induction variable is non-zero after
2052	// division, same for Shr, unless it is exact division.
2053	return (OrZero || Q.IIQ.isExact(Op: BO)) &&
2054	isKnownToBeAPowerOfTwo(V: Step, OrZero: false, Depth, Q);
2055	case Instruction::Shl:
2056	return OrZero || Q.IIQ.hasNoUnsignedWrap(Op: BO) || Q.IIQ.hasNoSignedWrap(Op: BO);
2057	case Instruction::AShr:
2058	if (!match(V: Start, P: m_Power2()) || match(V: Start, P: m_SignMask()))
2059	return false;
2060	[[fallthrough]];
2061	case Instruction::LShr:
2062	return OrZero || Q.IIQ.isExact(Op: BO);
2063	default:
2064	return false;
2065	}
2066	}
2067
2068	/// Return true if the given value is known to have exactly one
2069	/// bit set when defined. For vectors return true if every element is known to
2070	/// be a power of two when defined. Supports values with integer or pointer
2071	/// types and vectors of integers.
2072	bool isKnownToBeAPowerOfTwo(const Value *V, bool OrZero, unsigned Depth,
2073	const SimplifyQuery &Q) {
2074	assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
2075
2076	if (isa<Constant>(Val: V))
2077	return OrZero ? match(V, P: m_Power2OrZero()) : match(V, P: m_Power2());
2078
2079	// i1 is by definition a power of 2 or zero.
2080	if (OrZero && V->getType()->getScalarSizeInBits() == 1)
2081	return true;
2082
2083	auto *I = dyn_cast<Instruction>(Val: V);
2084	if (!I)
2085	return false;
2086
2087	if (Q.CxtI && match(V, P: m_VScale())) {
2088	const Function *F = Q.CxtI->getFunction();
2089	// The vscale_range indicates vscale is a power-of-two.
2090	return F->hasFnAttribute(Attribute::VScaleRange);
2091	}
2092
2093	// 1 << X is clearly a power of two if the one is not shifted off the end. If
2094	// it is shifted off the end then the result is undefined.
2095	if (match(V: I, P: m_Shl(L: m_One(), R: m_Value())))
2096	return true;
2097
2098	// (signmask) >>l X is clearly a power of two if the one is not shifted off
2099	// the bottom. If it is shifted off the bottom then the result is undefined.
2100	if (match(V: I, P: m_LShr(L: m_SignMask(), R: m_Value())))
2101	return true;
2102
2103	// The remaining tests are all recursive, so bail out if we hit the limit.
2104	if (Depth++ == MaxAnalysisRecursionDepth)
2105	return false;
2106
2107	switch (I->getOpcode()) {
2108	case Instruction::ZExt:
2109	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q);
2110	case Instruction::Trunc:
2111	return OrZero && isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q);
2112	case Instruction::Shl:
2113	if (OrZero || Q.IIQ.hasNoUnsignedWrap(Op: I) || Q.IIQ.hasNoSignedWrap(Op: I))
2114	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q);
2115	return false;
2116	case Instruction::LShr:
2117	if (OrZero || Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I)))
2118	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q);
2119	return false;
2120	case Instruction::UDiv:
2121	if (Q.IIQ.isExact(Op: cast<BinaryOperator>(Val: I)))
2122	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q);
2123	return false;
2124	case Instruction::Mul:
2125	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 1), OrZero, Depth, Q) &&
2126	isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q) &&
2127	(OrZero || isKnownNonZero(V: I, Q, Depth));
2128	case Instruction::And:
2129	// A power of two and'd with anything is a power of two or zero.
2130	if (OrZero &&
2131	(isKnownToBeAPowerOfTwo(V: I->getOperand(i: 1), /*OrZero*/ true, Depth, Q) ||
2132	isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), /*OrZero*/ true, Depth, Q)))
2133	return true;
2134	// X & (-X) is always a power of two or zero.
2135	if (match(V: I->getOperand(i: 0), P: m_Neg(V: m_Specific(V: I->getOperand(i: 1)))) ||
2136	match(V: I->getOperand(i: 1), P: m_Neg(V: m_Specific(V: I->getOperand(i: 0)))))
2137	return OrZero || isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2138	return false;
2139	case Instruction::Add: {
2140	// Adding a power-of-two or zero to the same power-of-two or zero yields
2141	// either the original power-of-two, a larger power-of-two or zero.
2142	const OverflowingBinaryOperator *VOBO = cast<OverflowingBinaryOperator>(Val: V);
2143	if (OrZero || Q.IIQ.hasNoUnsignedWrap(Op: VOBO) ||
2144	Q.IIQ.hasNoSignedWrap(Op: VOBO)) {
2145	if (match(V: I->getOperand(i: 0),
2146	P: m_c_And(L: m_Specific(V: I->getOperand(i: 1)), R: m_Value())) &&
2147	isKnownToBeAPowerOfTwo(V: I->getOperand(i: 1), OrZero, Depth, Q))
2148	return true;
2149	if (match(V: I->getOperand(i: 1),
2150	P: m_c_And(L: m_Specific(V: I->getOperand(i: 0)), R: m_Value())) &&
2151	isKnownToBeAPowerOfTwo(V: I->getOperand(i: 0), OrZero, Depth, Q))
2152	return true;
2153
2154	unsigned BitWidth = V->getType()->getScalarSizeInBits();
2155	KnownBits LHSBits(BitWidth);
2156	computeKnownBits(V: I->getOperand(i: 0), Known&: LHSBits, Depth, Q);
2157
2158	KnownBits RHSBits(BitWidth);
2159	computeKnownBits(V: I->getOperand(i: 1), Known&: RHSBits, Depth, Q);
2160	// If i8 V is a power of two or zero:
2161	// ZeroBits: 1 1 1 0 1 1 1 1
2162	// ~ZeroBits: 0 0 0 1 0 0 0 0
2163	if ((~(LHSBits.Zero & RHSBits.Zero)).isPowerOf2())
2164	// If OrZero isn't set, we cannot give back a zero result.
2165	// Make sure either the LHS or RHS has a bit set.
2166	if (OrZero || RHSBits.One.getBoolValue() || LHSBits.One.getBoolValue())
2167	return true;
2168	}
2169	return false;
2170	}
2171	case Instruction::Select:
2172	return isKnownToBeAPowerOfTwo(V: I->getOperand(i: 1), OrZero, Depth, Q) &&
2173	isKnownToBeAPowerOfTwo(V: I->getOperand(i: 2), OrZero, Depth, Q);
2174	case Instruction::PHI: {
2175	// A PHI node is power of two if all incoming values are power of two, or if
2176	// it is an induction variable where in each step its value is a power of
2177	// two.
2178	auto *PN = cast<PHINode>(Val: I);
2179	SimplifyQuery RecQ = Q;
2180
2181	// Check if it is an induction variable and always power of two.
2182	if (isPowerOfTwoRecurrence(PN, OrZero, Depth, Q&: RecQ))
2183	return true;
2184
2185	// Recursively check all incoming values. Limit recursion to 2 levels, so
2186	// that search complexity is limited to number of operands^2.
2187	unsigned NewDepth = std::max(a: Depth, b: MaxAnalysisRecursionDepth - 1);
2188	return llvm::all_of(Range: PN->operands(), P: [&](const Use &U) {
2189	// Value is power of 2 if it is coming from PHI node itself by induction.
2190	if (U.get() == PN)
2191	return true;
2192
2193	// Change the context instruction to the incoming block where it is
2194	// evaluated.
2195	RecQ.CxtI = PN->getIncomingBlock(U)->getTerminator();
2196	return isKnownToBeAPowerOfTwo(V: U.get(), OrZero, Depth: NewDepth, Q: RecQ);
2197	});
2198	}
2199	case Instruction::Invoke:
2200	case Instruction::Call: {
2201	if (auto *II = dyn_cast<IntrinsicInst>(Val: I)) {
2202	switch (II->getIntrinsicID()) {
2203	case Intrinsic::umax:
2204	case Intrinsic::smax:
2205	case Intrinsic::umin:
2206	case Intrinsic::smin:
2207	return isKnownToBeAPowerOfTwo(V: II->getArgOperand(i: 1), OrZero, Depth, Q) &&
2208	isKnownToBeAPowerOfTwo(V: II->getArgOperand(i: 0), OrZero, Depth, Q);
2209	// bswap/bitreverse just move around bits, but don't change any 1s/0s
2210	// thus dont change pow2/non-pow2 status.
2211	case Intrinsic::bitreverse:
2212	case Intrinsic::bswap:
2213	return isKnownToBeAPowerOfTwo(V: II->getArgOperand(i: 0), OrZero, Depth, Q);
2214	case Intrinsic::fshr:
2215	case Intrinsic::fshl:
2216	// If Op0 == Op1, this is a rotate. is_pow2(rotate(x, y)) == is_pow2(x)
2217	if (II->getArgOperand(i: 0) == II->getArgOperand(i: 1))
2218	return isKnownToBeAPowerOfTwo(V: II->getArgOperand(i: 0), OrZero, Depth, Q);
2219	break;
2220	default:
2221	break;
2222	}
2223	}
2224	return false;
2225	}
2226	default:
2227	return false;
2228	}
2229	}
2230
2231	/// Test whether a GEP's result is known to be non-null.
2232	///
2233	/// Uses properties inherent in a GEP to try to determine whether it is known
2234	/// to be non-null.
2235	///
2236	/// Currently this routine does not support vector GEPs.
2237	static bool isGEPKnownNonNull(const GEPOperator *GEP, unsigned Depth,
2238	const SimplifyQuery &Q) {
2239	const Function *F = nullptr;
2240	if (const Instruction *I = dyn_cast<Instruction>(Val: GEP))
2241	F = I->getFunction();
2242
2243	if (!GEP->isInBounds() ||
2244	NullPointerIsDefined(F, AS: GEP->getPointerAddressSpace()))
2245	return false;
2246
2247	// FIXME: Support vector-GEPs.
2248	assert(GEP->getType()->isPointerTy() && "We only support plain pointer GEP");
2249
2250	// If the base pointer is non-null, we cannot walk to a null address with an
2251	// inbounds GEP in address space zero.
2252	if (isKnownNonZero(V: GEP->getPointerOperand(), Q, Depth))
2253	return true;
2254
2255	// Walk the GEP operands and see if any operand introduces a non-zero offset.
2256	// If so, then the GEP cannot produce a null pointer, as doing so would
2257	// inherently violate the inbounds contract within address space zero.
2258	for (gep_type_iterator GTI = gep_type_begin(GEP), GTE = gep_type_end(GEP);
2259	GTI != GTE; ++GTI) {
2260	// Struct types are easy -- they must always be indexed by a constant.
2261	if (StructType *STy = GTI.getStructTypeOrNull()) {
2262	ConstantInt *OpC = cast<ConstantInt>(Val: GTI.getOperand());
2263	unsigned ElementIdx = OpC->getZExtValue();
2264	const StructLayout *SL = Q.DL.getStructLayout(Ty: STy);
2265	uint64_t ElementOffset = SL->getElementOffset(Idx: ElementIdx);
2266	if (ElementOffset > 0)
2267	return true;
2268	continue;
2269	}
2270
2271	// If we have a zero-sized type, the index doesn't matter. Keep looping.
2272	if (GTI.getSequentialElementStride(DL: Q.DL).isZero())
2273	continue;
2274
2275	// Fast path the constant operand case both for efficiency and so we don't
2276	// increment Depth when just zipping down an all-constant GEP.
2277	if (ConstantInt *OpC = dyn_cast<ConstantInt>(Val: GTI.getOperand())) {
2278	if (!OpC->isZero())
2279	return true;
2280	continue;
2281	}
2282
2283	// We post-increment Depth here because while isKnownNonZero increments it
2284	// as well, when we pop back up that increment won't persist. We don't want
2285	// to recurse 10k times just because we have 10k GEP operands. We don't
2286	// bail completely out because we want to handle constant GEPs regardless
2287	// of depth.
2288	if (Depth++ >= MaxAnalysisRecursionDepth)
2289	continue;
2290
2291	if (isKnownNonZero(V: GTI.getOperand(), Q, Depth))
2292	return true;
2293	}
2294
2295	return false;
2296	}
2297
2298	static bool isKnownNonNullFromDominatingCondition(const Value *V,
2299	const Instruction *CtxI,
2300	const DominatorTree *DT) {
2301	assert(!isa<Constant>(V) && "Called for constant?");
2302
2303	if (!CtxI || !DT)
2304	return false;
2305
2306	unsigned NumUsesExplored = 0;
2307	for (const auto *U : V->users()) {
2308	// Avoid massive lists
2309	if (NumUsesExplored >= DomConditionsMaxUses)
2310	break;
2311	NumUsesExplored++;
2312
2313	// If the value is used as an argument to a call or invoke, then argument
2314	// attributes may provide an answer about null-ness.
2315	if (const auto *CB = dyn_cast<CallBase>(Val: U))
2316	if (auto *CalledFunc = CB->getCalledFunction())
2317	for (const Argument &Arg : CalledFunc->args())
2318	if (CB->getArgOperand(i: Arg.getArgNo()) == V &&
2319	Arg.hasNonNullAttr(/* AllowUndefOrPoison */ false) &&
2320	DT->dominates(Def: CB, User: CtxI))
2321	return true;
2322
2323	// If the value is used as a load/store, then the pointer must be non null.
2324	if (V == getLoadStorePointerOperand(V: U)) {
2325	const Instruction *I = cast<Instruction>(Val: U);
2326	if (!NullPointerIsDefined(F: I->getFunction(),
2327	AS: V->getType()->getPointerAddressSpace()) &&
2328	DT->dominates(Def: I, User: CtxI))
2329	return true;
2330	}
2331
2332	if ((match(V: U, P: m_IDiv(L: m_Value(), R: m_Specific(V))) ||
2333	match(V: U, P: m_IRem(L: m_Value(), R: m_Specific(V)))) &&
2334	isValidAssumeForContext(Inv: cast<Instruction>(Val: U), CxtI: CtxI, DT))
2335	return true;
2336
2337	// Consider only compare instructions uniquely controlling a branch
2338	Value *RHS;
2339	CmpInst::Predicate Pred;
2340	if (!match(V: U, P: m_c_ICmp(Pred, L: m_Specific(V), R: m_Value(V&: RHS))))
2341	continue;
2342
2343	bool NonNullIfTrue;
2344	if (cmpExcludesZero(Pred, RHS))
2345	NonNullIfTrue = true;
2346	else if (cmpExcludesZero(Pred: CmpInst::getInversePredicate(pred: Pred), RHS))
2347	NonNullIfTrue = false;
2348	else
2349	continue;
2350
2351	SmallVector<const User *, 4> WorkList;
2352	SmallPtrSet<const User *, 4> Visited;
2353	for (const auto *CmpU : U->users()) {
2354	assert(WorkList.empty() && "Should be!");
2355	if (Visited.insert(Ptr: CmpU).second)
2356	WorkList.push_back(Elt: CmpU);
2357
2358	while (!WorkList.empty()) {
2359	auto *Curr = WorkList.pop_back_val();
2360
2361	// If a user is an AND, add all its users to the work list. We only
2362	// propagate "pred != null" condition through AND because it is only
2363	// correct to assume that all conditions of AND are met in true branch.
2364	// TODO: Support similar logic of OR and EQ predicate?
2365	if (NonNullIfTrue)
2366	if (match(V: Curr, P: m_LogicalAnd(L: m_Value(), R: m_Value()))) {
2367	for (const auto *CurrU : Curr->users())
2368	if (Visited.insert(Ptr: CurrU).second)
2369	WorkList.push_back(Elt: CurrU);
2370	continue;
2371	}
2372
2373	if (const BranchInst *BI = dyn_cast<BranchInst>(Val: Curr)) {
2374	assert(BI->isConditional() && "uses a comparison!");
2375
2376	BasicBlock *NonNullSuccessor =
2377	BI->getSuccessor(i: NonNullIfTrue ? 0 : 1);
2378	BasicBlockEdge Edge(BI->getParent(), NonNullSuccessor);
2379	if (Edge.isSingleEdge() && DT->dominates(BBE: Edge, BB: CtxI->getParent()))
2380	return true;
2381	} else if (NonNullIfTrue && isGuard(U: Curr) &&
2382	DT->dominates(Def: cast<Instruction>(Val: Curr), User: CtxI)) {
2383	return true;
2384	}
2385	}
2386	}
2387	}
2388
2389	return false;
2390	}
2391
2392	/// Does the 'Range' metadata (which must be a valid MD_range operand list)
2393	/// ensure that the value it's attached to is never Value? 'RangeType' is
2394	/// is the type of the value described by the range.
2395	static bool rangeMetadataExcludesValue(const MDNode* Ranges, const APInt& Value) {
2396	const unsigned NumRanges = Ranges->getNumOperands() / 2;
2397	assert(NumRanges >= 1);
2398	for (unsigned i = 0; i < NumRanges; ++i) {
2399	ConstantInt *Lower =
2400	mdconst::extract<ConstantInt>(MD: Ranges->getOperand(I: 2 * i + 0));
2401	ConstantInt *Upper =
2402	mdconst::extract<ConstantInt>(MD: Ranges->getOperand(I: 2 * i + 1));
2403	ConstantRange Range(Lower->getValue(), Upper->getValue());
2404	if (Range.contains(Val: Value))
2405	return false;
2406	}
2407	return true;
2408	}
2409
2410	/// Try to detect a recurrence that monotonically increases/decreases from a
2411	/// non-zero starting value. These are common as induction variables.
2412	static bool isNonZeroRecurrence(const PHINode *PN) {
2413	BinaryOperator *BO = nullptr;
2414	Value *Start = nullptr, *Step = nullptr;
2415	const APInt *StartC, *StepC;
2416	if (!matchSimpleRecurrence(P: PN, BO, Start, Step) ||
2417	!match(V: Start, P: m_APInt(Res&: StartC)) || StartC->isZero())
2418	return false;
2419
2420	switch (BO->getOpcode()) {
2421	case Instruction::Add:
2422	// Starting from non-zero and stepping away from zero can never wrap back
2423	// to zero.
2424	return BO->hasNoUnsignedWrap() ||
2425	(BO->hasNoSignedWrap() && match(V: Step, P: m_APInt(Res&: StepC)) &&
2426	StartC->isNegative() == StepC->isNegative());
2427	case Instruction::Mul:
2428	return (BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap()) &&
2429	match(V: Step, P: m_APInt(Res&: StepC)) && !StepC->isZero();
2430	case Instruction::Shl:
2431	return BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap();
2432	case Instruction::AShr:
2433	case Instruction::LShr:
2434	return BO->isExact();
2435	default:
2436	return false;
2437	}
2438	}
2439
2440	static bool isNonZeroAdd(const APInt &DemandedElts, unsigned Depth,
2441	const SimplifyQuery &Q, unsigned BitWidth, Value *X,
2442	Value *Y, bool NSW, bool NUW) {
2443	if (NUW)
2444	return isKnownNonZero(V: Y, DemandedElts, Q, Depth) ||
2445	isKnownNonZero(V: X, DemandedElts, Q, Depth);
2446
2447	KnownBits XKnown = computeKnownBits(V: X, DemandedElts, Depth, Q);
2448	KnownBits YKnown = computeKnownBits(V: Y, DemandedElts, Depth, Q);
2449
2450	// If X and Y are both non-negative (as signed values) then their sum is not
2451	// zero unless both X and Y are zero.
2452	if (XKnown.isNonNegative() && YKnown.isNonNegative())
2453	if (isKnownNonZero(V: Y, DemandedElts, Q, Depth) ||
2454	isKnownNonZero(V: X, DemandedElts, Q, Depth))
2455	return true;
2456
2457	// If X and Y are both negative (as signed values) then their sum is not
2458	// zero unless both X and Y equal INT_MIN.
2459	if (XKnown.isNegative() && YKnown.isNegative()) {
2460	APInt Mask = APInt::getSignedMaxValue(numBits: BitWidth);
2461	// The sign bit of X is set. If some other bit is set then X is not equal
2462	// to INT_MIN.
2463	if (XKnown.One.intersects(RHS: Mask))
2464	return true;
2465	// The sign bit of Y is set. If some other bit is set then Y is not equal
2466	// to INT_MIN.
2467	if (YKnown.One.intersects(RHS: Mask))
2468	return true;
2469	}
2470
2471	// The sum of a non-negative number and a power of two is not zero.
2472	if (XKnown.isNonNegative() &&
2473	isKnownToBeAPowerOfTwo(V: Y, /*OrZero*/ false, Depth, Q))
2474	return true;
2475	if (YKnown.isNonNegative() &&
2476	isKnownToBeAPowerOfTwo(V: X, /*OrZero*/ false, Depth, Q))
2477	return true;
2478
2479	return KnownBits::computeForAddSub(/*Add=*/true, NSW, NUW, LHS: XKnown, RHS: YKnown)
2480	.isNonZero();
2481	}
2482
2483	static bool isNonZeroSub(const APInt &DemandedElts, unsigned Depth,
2484	const SimplifyQuery &Q, unsigned BitWidth, Value *X,
2485	Value *Y) {
2486	// TODO: Move this case into isKnownNonEqual().
2487	if (auto *C = dyn_cast<Constant>(Val: X))
2488	if (C->isNullValue() && isKnownNonZero(V: Y, DemandedElts, Q, Depth))
2489	return true;
2490
2491	return ::isKnownNonEqual(V1: X, V2: Y, Depth, Q);
2492	}
2493
2494	static bool isNonZeroMul(const APInt &DemandedElts, unsigned Depth,
2495	const SimplifyQuery &Q, unsigned BitWidth, Value *X,
2496	Value *Y, bool NSW, bool NUW) {
2497	// If X and Y are non-zero then so is X * Y as long as the multiplication
2498	// does not overflow.
2499	if (NSW || NUW)
2500	return isKnownNonZero(V: X, DemandedElts, Q, Depth) &&
2501	isKnownNonZero(V: Y, DemandedElts, Q, Depth);
2502
2503	// If either X or Y is odd, then if the other is non-zero the result can't
2504	// be zero.
2505	KnownBits XKnown = computeKnownBits(V: X, DemandedElts, Depth, Q);
2506	if (XKnown.One[0])
2507	return isKnownNonZero(V: Y, DemandedElts, Q, Depth);
2508
2509	KnownBits YKnown = computeKnownBits(V: Y, DemandedElts, Depth, Q);
2510	if (YKnown.One[0])
2511	return XKnown.isNonZero() || isKnownNonZero(V: X, DemandedElts, Q, Depth);
2512
2513	// If there exists any subset of X (sX) and subset of Y (sY) s.t sX * sY is
2514	// non-zero, then X * Y is non-zero. We can find sX and sY by just taking
2515	// the lowest known One of X and Y. If they are non-zero, the result
2516	// must be non-zero. We can check if LSB(X) * LSB(Y) != 0 by doing
2517	// X.CountLeadingZeros + Y.CountLeadingZeros < BitWidth.
2518	return (XKnown.countMaxTrailingZeros() + YKnown.countMaxTrailingZeros()) <
2519	BitWidth;
2520	}
2521
2522	static bool isNonZeroShift(const Operator *I, const APInt &DemandedElts,
2523	unsigned Depth, const SimplifyQuery &Q,
2524	const KnownBits &KnownVal) {
2525	auto ShiftOp = [&](const APInt &Lhs, const APInt &Rhs) {
2526	switch (I->getOpcode()) {
2527	case Instruction::Shl:
2528	return Lhs.shl(ShiftAmt: Rhs);
2529	case Instruction::LShr:
2530	return Lhs.lshr(ShiftAmt: Rhs);
2531	case Instruction::AShr:
2532	return Lhs.ashr(ShiftAmt: Rhs);
2533	default:
2534	llvm_unreachable("Unknown Shift Opcode");
2535	}
2536	};
2537
2538	auto InvShiftOp = [&](const APInt &Lhs, const APInt &Rhs) {
2539	switch (I->getOpcode()) {
2540	case Instruction::Shl:
2541	return Lhs.lshr(ShiftAmt: Rhs);
2542	case Instruction::LShr:
2543	case Instruction::AShr:
2544	return Lhs.shl(ShiftAmt: Rhs);
2545	default:
2546	llvm_unreachable("Unknown Shift Opcode");
2547	}
2548	};
2549
2550	if (KnownVal.isUnknown())
2551	return false;
2552
2553	KnownBits KnownCnt =
2554	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Depth, Q);
2555	APInt MaxShift = KnownCnt.getMaxValue();
2556	unsigned NumBits = KnownVal.getBitWidth();
2557	if (MaxShift.uge(RHS: NumBits))
2558	return false;
2559
2560	if (!ShiftOp(KnownVal.One, MaxShift).isZero())
2561	return true;
2562
2563	// If all of the bits shifted out are known to be zero, and Val is known
2564	// non-zero then at least one non-zero bit must remain.
2565	if (InvShiftOp(KnownVal.Zero, NumBits - MaxShift)
2566	.eq(RHS: InvShiftOp(APInt::getAllOnes(numBits: NumBits), NumBits - MaxShift)) &&
2567	isKnownNonZero(V: I->getOperand(i: 0), DemandedElts, Q, Depth))
2568	return true;
2569
2570	return false;
2571	}
2572
2573	static bool isKnownNonZeroFromOperator(const Operator *I,
2574	const APInt &DemandedElts,
2575	unsigned Depth, const SimplifyQuery &Q) {
2576	unsigned BitWidth = getBitWidth(Ty: I->getType()->getScalarType(), DL: Q.DL);
2577	switch (I->getOpcode()) {
2578	case Instruction::Alloca:
2579	// Alloca never returns null, malloc might.
2580	return I->getType()->getPointerAddressSpace() == 0;
2581	case Instruction::GetElementPtr:
2582	if (I->getType()->isPointerTy())
2583	return isGEPKnownNonNull(GEP: cast<GEPOperator>(Val: I), Depth, Q);
2584	break;
2585	case Instruction::BitCast: {
2586	// We need to be a bit careful here. We can only peek through the bitcast
2587	// if the scalar size of elements in the operand are smaller than and a
2588	// multiple of the size they are casting too. Take three cases:
2589	//
2590	// 1) Unsafe:
2591	// bitcast <2 x i16> %NonZero to <4 x i8>
2592	//
2593	// %NonZero can have 2 non-zero i16 elements, but isKnownNonZero on a
2594	// <4 x i8> requires that all 4 i8 elements be non-zero which isn't
2595	// guranteed (imagine just sign bit set in the 2 i16 elements).
2596	//
2597	// 2) Unsafe:
2598	// bitcast <4 x i3> %NonZero to <3 x i4>
2599	//
2600	// Even though the scalar size of the src (`i3`) is smaller than the
2601	// scalar size of the dst `i4`, because `i3` is not a multiple of `i4`
2602	// its possible for the `3 x i4` elements to be zero because there are
2603	// some elements in the destination that don't contain any full src
2604	// element.
2605	//
2606	// 3) Safe:
2607	// bitcast <4 x i8> %NonZero to <2 x i16>
2608	//
2609	// This is always safe as non-zero in the 4 i8 elements implies
2610	// non-zero in the combination of any two adjacent ones. Since i8 is a
2611	// multiple of i16, each i16 is guranteed to have 2 full i8 elements.
2612	// This all implies the 2 i16 elements are non-zero.
2613	Type *FromTy = I->getOperand(i: 0)->getType();
2614	if ((FromTy->isIntOrIntVectorTy() || FromTy->isPtrOrPtrVectorTy()) &&
2615	(BitWidth % getBitWidth(Ty: FromTy->getScalarType(), DL: Q.DL)) == 0)
2616	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2617	} break;
2618	case Instruction::IntToPtr:
2619	// Note that we have to take special care to avoid looking through
2620	// truncating casts, e.g., int2ptr/ptr2int with appropriate sizes, as well
2621	// as casts that can alter the value, e.g., AddrSpaceCasts.
2622	if (!isa<ScalableVectorType>(Val: I->getType()) &&
2623	Q.DL.getTypeSizeInBits(Ty: I->getOperand(i: 0)->getType()).getFixedValue() <=
2624	Q.DL.getTypeSizeInBits(Ty: I->getType()).getFixedValue())
2625	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2626	break;
2627	case Instruction::PtrToInt:
2628	// Similar to int2ptr above, we can look through ptr2int here if the cast
2629	// is a no-op or an extend and not a truncate.
2630	if (!isa<ScalableVectorType>(Val: I->getType()) &&
2631	Q.DL.getTypeSizeInBits(Ty: I->getOperand(i: 0)->getType()).getFixedValue() <=
2632	Q.DL.getTypeSizeInBits(Ty: I->getType()).getFixedValue())
2633	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2634	break;
2635	case Instruction::Trunc:
2636	// nuw/nsw trunc preserves zero/non-zero status of input.
2637	if (auto *TI = dyn_cast<TruncInst>(Val: I))
2638	if (TI->hasNoSignedWrap() || TI->hasNoUnsignedWrap())
2639	return isKnownNonZero(V: TI->getOperand(i_nocapture: 0), Q, Depth);
2640	break;
2641
2642	case Instruction::Sub:
2643	return isNonZeroSub(DemandedElts, Depth, Q, BitWidth, X: I->getOperand(i: 0),
2644	Y: I->getOperand(i: 1));
2645	case Instruction::Or:
2646	// X | Y != 0 if X != 0 or Y != 0.
2647	return isKnownNonZero(V: I->getOperand(i: 1), DemandedElts, Q, Depth) ||
2648	isKnownNonZero(V: I->getOperand(i: 0), DemandedElts, Q, Depth);
2649	case Instruction::SExt:
2650	case Instruction::ZExt:
2651	// ext X != 0 if X != 0.
2652	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2653
2654	case Instruction::Shl: {
2655	// shl nsw/nuw can't remove any non-zero bits.
2656	const OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(Val: I);
2657	if (Q.IIQ.hasNoUnsignedWrap(Op: BO) || Q.IIQ.hasNoSignedWrap(Op: BO))
2658	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2659
2660	// shl X, Y != 0 if X is odd. Note that the value of the shift is undefined
2661	// if the lowest bit is shifted off the end.
2662	KnownBits Known(BitWidth);
2663	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Known, Depth, Q);
2664	if (Known.One[0])
2665	return true;
2666
2667	return isNonZeroShift(I, DemandedElts, Depth, Q, KnownVal: Known);
2668	}
2669	case Instruction::LShr:
2670	case Instruction::AShr: {
2671	// shr exact can only shift out zero bits.
2672	const PossiblyExactOperator *BO = cast<PossiblyExactOperator>(Val: I);
2673	if (BO->isExact())
2674	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2675
2676	// shr X, Y != 0 if X is negative. Note that the value of the shift is not
2677	// defined if the sign bit is shifted off the end.
2678	KnownBits Known =
2679	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Depth, Q);
2680	if (Known.isNegative())
2681	return true;
2682
2683	return isNonZeroShift(I, DemandedElts, Depth, Q, KnownVal: Known);
2684	}
2685	case Instruction::UDiv:
2686	case Instruction::SDiv: {
2687	// X / Y
2688	// div exact can only produce a zero if the dividend is zero.
2689	if (cast<PossiblyExactOperator>(Val: I)->isExact())
2690	return isKnownNonZero(V: I->getOperand(i: 0), DemandedElts, Q, Depth);
2691
2692	KnownBits XKnown =
2693	computeKnownBits(V: I->getOperand(i: 0), DemandedElts, Depth, Q);
2694	// If X is fully unknown we won't be able to figure anything out so don't
2695	// both computing knownbits for Y.
2696	if (XKnown.isUnknown())
2697	return false;
2698
2699	KnownBits YKnown =
2700	computeKnownBits(V: I->getOperand(i: 1), DemandedElts, Depth, Q);
2701	if (I->getOpcode() == Instruction::SDiv) {
2702	// For signed division need to compare abs value of the operands.
2703	XKnown = XKnown.abs(/*IntMinIsPoison*/ false);
2704	YKnown = YKnown.abs(/*IntMinIsPoison*/ false);
2705	}
2706	// If X u>= Y then div is non zero (0/0 is UB).
2707	std::optional<bool> XUgeY = KnownBits::uge(LHS: XKnown, RHS: YKnown);
2708	// If X is total unknown or X u< Y we won't be able to prove non-zero
2709	// with compute known bits so just return early.
2710	return XUgeY && *XUgeY;
2711	}
2712	case Instruction::Add: {
2713	// X + Y.
2714
2715	// If Add has nuw wrap flag, then if either X or Y is non-zero the result is
2716	// non-zero.
2717	auto *BO = cast<OverflowingBinaryOperator>(Val: I);
2718	return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth, X: I->getOperand(i: 0),
2719	Y: I->getOperand(i: 1), NSW: Q.IIQ.hasNoSignedWrap(Op: BO),
2720	NUW: Q.IIQ.hasNoUnsignedWrap(Op: BO));
2721	}
2722	case Instruction::Mul: {
2723	const OverflowingBinaryOperator *BO = cast<OverflowingBinaryOperator>(Val: I);
2724	return isNonZeroMul(DemandedElts, Depth, Q, BitWidth, X: I->getOperand(i: 0),
2725	Y: I->getOperand(i: 1), NSW: Q.IIQ.hasNoSignedWrap(Op: BO),
2726	NUW: Q.IIQ.hasNoUnsignedWrap(Op: BO));
2727	}
2728	case Instruction::Select: {
2729	// (C ? X : Y) != 0 if X != 0 and Y != 0.
2730
2731	// First check if the arm is non-zero using `isKnownNonZero`. If that fails,
2732	// then see if the select condition implies the arm is non-zero. For example
2733	// (X != 0 ? X : Y), we know the true arm is non-zero as the `X` "return" is
2734	// dominated by `X != 0`.
2735	auto SelectArmIsNonZero = [&](bool IsTrueArm) {
2736	Value *Op;
2737	Op = IsTrueArm ? I->getOperand(i: 1) : I->getOperand(i: 2);
2738	// Op is trivially non-zero.
2739	if (isKnownNonZero(V: Op, DemandedElts, Q, Depth))
2740	return true;
2741
2742	// The condition of the select dominates the true/false arm. Check if the
2743	// condition implies that a given arm is non-zero.
2744	Value *X;
2745	CmpInst::Predicate Pred;
2746	if (!match(V: I->getOperand(i: 0), P: m_c_ICmp(Pred, L: m_Specific(V: Op), R: m_Value(V&: X))))
2747	return false;
2748
2749	if (!IsTrueArm)
2750	Pred = ICmpInst::getInversePredicate(pred: Pred);
2751
2752	return cmpExcludesZero(Pred, RHS: X);
2753	};
2754
2755	if (SelectArmIsNonZero(/* IsTrueArm */ true) &&
2756	SelectArmIsNonZero(/* IsTrueArm */ false))
2757	return true;
2758	break;
2759	}
2760	case Instruction::PHI: {
2761	auto *PN = cast<PHINode>(Val: I);
2762	if (Q.IIQ.UseInstrInfo && isNonZeroRecurrence(PN))
2763	return true;
2764
2765	// Check if all incoming values are non-zero using recursion.
2766	SimplifyQuery RecQ = Q;
2767	unsigned NewDepth = std::max(a: Depth, b: MaxAnalysisRecursionDepth - 1);
2768	return llvm::all_of(Range: PN->operands(), P: [&](const Use &U) {
2769	if (U.get() == PN)
2770	return true;
2771	RecQ.CxtI = PN->getIncomingBlock(U)->getTerminator();
2772	// Check if the branch on the phi excludes zero.
2773	ICmpInst::Predicate Pred;
2774	Value *X;
2775	BasicBlock *TrueSucc, *FalseSucc;
2776	if (match(V: RecQ.CxtI,
2777	P: m_Br(C: m_c_ICmp(Pred, L: m_Specific(V: U.get()), R: m_Value(V&: X)),
2778	T: m_BasicBlock(V&: TrueSucc), F: m_BasicBlock(V&: FalseSucc)))) {
2779	// Check for cases of duplicate successors.
2780	if ((TrueSucc == PN->getParent()) != (FalseSucc == PN->getParent())) {
2781	// If we're using the false successor, invert the predicate.
2782	if (FalseSucc == PN->getParent())
2783	Pred = CmpInst::getInversePredicate(pred: Pred);
2784	if (cmpExcludesZero(Pred, RHS: X))
2785	return true;
2786	}
2787	}
2788	// Finally recurse on the edge and check it directly.
2789	return isKnownNonZero(V: U.get(), DemandedElts, Q: RecQ, Depth: NewDepth);
2790	});
2791	}
2792	case Instruction::InsertElement: {
2793	if (isa<ScalableVectorType>(Val: I->getType()))
2794	break;
2795
2796	const Value *Vec = I->getOperand(i: 0);
2797	const Value *Elt = I->getOperand(i: 1);
2798	auto *CIdx = dyn_cast<ConstantInt>(Val: I->getOperand(i: 2));
2799
2800	unsigned NumElts = DemandedElts.getBitWidth();
2801	APInt DemandedVecElts = DemandedElts;
2802	bool SkipElt = false;
2803	// If we know the index we are inserting too, clear it from Vec check.
2804	if (CIdx && CIdx->getValue().ult(RHS: NumElts)) {
2805	DemandedVecElts.clearBit(BitPosition: CIdx->getZExtValue());
2806	SkipElt = !DemandedElts[CIdx->getZExtValue()];
2807	}
2808
2809	// Result is zero if Elt is non-zero and rest of the demanded elts in Vec
2810	// are non-zero.
2811	return (SkipElt || isKnownNonZero(V: Elt, Q, Depth)) &&
2812	(DemandedVecElts.isZero() ||
2813	isKnownNonZero(V: Vec, DemandedElts: DemandedVecElts, Q, Depth));
2814	}
2815	case Instruction::ExtractElement:
2816	if (const auto *EEI = dyn_cast<ExtractElementInst>(Val: I)) {
2817	const Value *Vec = EEI->getVectorOperand();
2818	const Value *Idx = EEI->getIndexOperand();
2819	auto *CIdx = dyn_cast<ConstantInt>(Val: Idx);
2820	if (auto *VecTy = dyn_cast<FixedVectorType>(Val: Vec->getType())) {
2821	unsigned NumElts = VecTy->getNumElements();
2822	APInt DemandedVecElts = APInt::getAllOnes(numBits: NumElts);
2823	if (CIdx && CIdx->getValue().ult(RHS: NumElts))
2824	DemandedVecElts = APInt::getOneBitSet(numBits: NumElts, BitNo: CIdx->getZExtValue());
2825	return isKnownNonZero(V: Vec, DemandedElts: DemandedVecElts, Q, Depth);
2826	}
2827	}
2828	break;
2829	case Instruction::ShuffleVector: {
2830	auto *Shuf = dyn_cast<ShuffleVectorInst>(Val: I);
2831	if (!Shuf)
2832	break;
2833	APInt DemandedLHS, DemandedRHS;
2834	// For undef elements, we don't know anything about the common state of
2835	// the shuffle result.
2836	if (!getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS))
2837	break;
2838	// If demanded elements for both vecs are non-zero, the shuffle is non-zero.
2839	return (DemandedRHS.isZero() ||
2840	isKnownNonZero(V: Shuf->getOperand(i_nocapture: 1), DemandedElts: DemandedRHS, Q, Depth)) &&
2841	(DemandedLHS.isZero() ||
2842	isKnownNonZero(V: Shuf->getOperand(i_nocapture: 0), DemandedElts: DemandedLHS, Q, Depth));
2843	}
2844	case Instruction::Freeze:
2845	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth) &&
2846	isGuaranteedNotToBePoison(V: I->getOperand(i: 0), AC: Q.AC, CtxI: Q.CxtI, DT: Q.DT,
2847	Depth);
2848	case Instruction::Load: {
2849	auto *LI = cast<LoadInst>(Val: I);
2850	// A Load tagged with nonnull or dereferenceable with null pointer undefined
2851	// is never null.
2852	if (auto *PtrT = dyn_cast<PointerType>(Val: I->getType())) {
2853	if (Q.IIQ.getMetadata(I: LI, KindID: LLVMContext::MD_nonnull) ||
2854	(Q.IIQ.getMetadata(I: LI, KindID: LLVMContext::MD_dereferenceable) &&
2855	!NullPointerIsDefined(F: LI->getFunction(), AS: PtrT->getAddressSpace())))
2856	return true;
2857	} else if (MDNode *Ranges = Q.IIQ.getMetadata(I: LI, KindID: LLVMContext::MD_range)) {
2858	return rangeMetadataExcludesValue(Ranges, Value: APInt::getZero(numBits: BitWidth));
2859	}
2860
2861	// No need to fall through to computeKnownBits as range metadata is already
2862	// handled in isKnownNonZero.
2863	return false;
2864	}
2865	case Instruction::ExtractValue: {
2866	const WithOverflowInst *WO;
2867	if (match(V: I, P: m_ExtractValue<0>(V: m_WithOverflowInst(I&: WO)))) {
2868	switch (WO->getBinaryOp()) {
2869	default:
2870	break;
2871	case Instruction::Add:
2872	return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth,
2873	X: WO->getArgOperand(i: 0), Y: WO->getArgOperand(i: 1),
2874	/*NSW=*/false,
2875	/*NUW=*/false);
2876	case Instruction::Sub:
2877	return isNonZeroSub(DemandedElts, Depth, Q, BitWidth,
2878	X: WO->getArgOperand(i: 0), Y: WO->getArgOperand(i: 1));
2879	case Instruction::Mul:
2880	return isNonZeroMul(DemandedElts, Depth, Q, BitWidth,
2881	X: WO->getArgOperand(i: 0), Y: WO->getArgOperand(i: 1),
2882	/*NSW=*/false, /*NUW=*/false);
2883	break;
2884	}
2885	}
2886	break;
2887	}
2888	case Instruction::Call:
2889	case Instruction::Invoke: {
2890	const auto *Call = cast<CallBase>(Val: I);
2891	if (I->getType()->isPointerTy()) {
2892	if (Call->isReturnNonNull())
2893	return true;
2894	if (const auto *RP = getArgumentAliasingToReturnedPointer(Call, MustPreserveNullness: true))
2895	return isKnownNonZero(V: RP, Q, Depth);
2896	} else {
2897	if (MDNode *Ranges = Q.IIQ.getMetadata(I: Call, KindID: LLVMContext::MD_range))
2898	return rangeMetadataExcludesValue(Ranges, Value: APInt::getZero(numBits: BitWidth));
2899	if (std::optional<ConstantRange> Range = Call->getRange()) {
2900	const APInt ZeroValue(Range->getBitWidth(), 0);
2901	if (!Range->contains(Val: ZeroValue))
2902	return true;
2903	}
2904	if (const Value *RV = Call->getReturnedArgOperand())
2905	if (RV->getType() == I->getType() && isKnownNonZero(V: RV, Q, Depth))
2906	return true;
2907	}
2908
2909	if (auto *II = dyn_cast<IntrinsicInst>(Val: I)) {
2910	switch (II->getIntrinsicID()) {
2911	case Intrinsic::sshl_sat:
2912	case Intrinsic::ushl_sat:
2913	case Intrinsic::abs:
2914	case Intrinsic::bitreverse:
2915	case Intrinsic::bswap:
2916	case Intrinsic::ctpop:
2917	return isKnownNonZero(V: II->getArgOperand(i: 0), DemandedElts, Q, Depth);
2918	// NB: We don't do usub_sat here as in any case we can prove its
2919	// non-zero, we will fold it to `sub nuw` in InstCombine.
2920	case Intrinsic::ssub_sat:
2921	return isNonZeroSub(DemandedElts, Depth, Q, BitWidth,
2922	X: II->getArgOperand(i: 0), Y: II->getArgOperand(i: 1));
2923	case Intrinsic::sadd_sat:
2924	return isNonZeroAdd(DemandedElts, Depth, Q, BitWidth,
2925	X: II->getArgOperand(i: 0), Y: II->getArgOperand(i: 1),
2926	/*NSW=*/true, /* NUW=*/false);
2927	// umin/smin/smax/smin/or of all non-zero elements is always non-zero.
2928	case Intrinsic::vector_reduce_or:
2929	case Intrinsic::vector_reduce_umax:
2930	case Intrinsic::vector_reduce_umin:
2931	case Intrinsic::vector_reduce_smax:
2932	case Intrinsic::vector_reduce_smin:
2933	return isKnownNonZero(V: II->getArgOperand(i: 0), Q, Depth);
2934	case Intrinsic::umax:
2935	case Intrinsic::uadd_sat:
2936	return isKnownNonZero(V: II->getArgOperand(i: 1), DemandedElts, Q, Depth) ||
2937	isKnownNonZero(V: II->getArgOperand(i: 0), DemandedElts, Q, Depth);
2938	case Intrinsic::smax: {
2939	// If either arg is strictly positive the result is non-zero. Otherwise
2940	// the result is non-zero if both ops are non-zero.
2941	auto IsNonZero = [&](Value *Op, std::optional<bool> &OpNonZero,
2942	const KnownBits &OpKnown) {
2943	if (!OpNonZero.has_value())
2944	OpNonZero = OpKnown.isNonZero() ||
2945	isKnownNonZero(V: Op, DemandedElts, Q, Depth);
2946	return *OpNonZero;
2947	};
2948	// Avoid re-computing isKnownNonZero.
2949	std::optional<bool> Op0NonZero, Op1NonZero;
2950	KnownBits Op1Known =
2951	computeKnownBits(V: II->getArgOperand(i: 1), DemandedElts, Depth, Q);
2952	if (Op1Known.isNonNegative() &&
2953	IsNonZero(II->getArgOperand(i: 1), Op1NonZero, Op1Known))
2954	return true;
2955	KnownBits Op0Known =
2956	computeKnownBits(V: II->getArgOperand(i: 0), DemandedElts, Depth, Q);
2957	if (Op0Known.isNonNegative() &&
2958	IsNonZero(II->getArgOperand(i: 0), Op0NonZero, Op0Known))
2959	return true;
2960	return IsNonZero(II->getArgOperand(i: 1), Op1NonZero, Op1Known) &&
2961	IsNonZero(II->getArgOperand(i: 0), Op0NonZero, Op0Known);
2962	}
2963	case Intrinsic::smin: {
2964	// If either arg is negative the result is non-zero. Otherwise
2965	// the result is non-zero if both ops are non-zero.
2966	KnownBits Op1Known =
2967	computeKnownBits(V: II->getArgOperand(i: 1), DemandedElts, Depth, Q);
2968	if (Op1Known.isNegative())
2969	return true;
2970	KnownBits Op0Known =
2971	computeKnownBits(V: II->getArgOperand(i: 0), DemandedElts, Depth, Q);
2972	if (Op0Known.isNegative())
2973	return true;
2974
2975	if (Op1Known.isNonZero() && Op0Known.isNonZero())
2976	return true;
2977	}
2978	[[fallthrough]];
2979	case Intrinsic::umin:
2980	return isKnownNonZero(V: II->getArgOperand(i: 0), DemandedElts, Q, Depth) &&
2981	isKnownNonZero(V: II->getArgOperand(i: 1), DemandedElts, Q, Depth);
2982	case Intrinsic::cttz:
2983	return computeKnownBits(V: II->getArgOperand(i: 0), DemandedElts, Depth, Q)
2984	.Zero[0];
2985	case Intrinsic::ctlz:
2986	return computeKnownBits(V: II->getArgOperand(i: 0), DemandedElts, Depth, Q)
2987	.isNonNegative();
2988	case Intrinsic::fshr:
2989	case Intrinsic::fshl:
2990	// If Op0 == Op1, this is a rotate. rotate(x, y) != 0 iff x != 0.
2991	if (II->getArgOperand(i: 0) == II->getArgOperand(i: 1))
2992	return isKnownNonZero(V: II->getArgOperand(i: 0), DemandedElts, Q, Depth);
2993	break;
2994	case Intrinsic::vscale:
2995	return true;
2996	case Intrinsic::experimental_get_vector_length:
2997	return isKnownNonZero(V: I->getOperand(i: 0), Q, Depth);
2998	default:
2999	break;
3000	}
3001	break;
3002	}
3003
3004	return false;
3005	}
3006	}
3007
3008	KnownBits Known(BitWidth);
3009	computeKnownBits(V: I, DemandedElts, Known, Depth, Q);
3010	return Known.One != 0;
3011	}
3012
3013	/// Return true if the given value is known to be non-zero when defined. For
3014	/// vectors, return true if every demanded element is known to be non-zero when
3015	/// defined. For pointers, if the context instruction and dominator tree are
3016	/// specified, perform context-sensitive analysis and return true if the
3017	/// pointer couldn't possibly be null at the specified instruction.
3018	/// Supports values with integer or pointer type and vectors of integers.
3019	bool isKnownNonZero(const Value *V, const APInt &DemandedElts,
3020	const SimplifyQuery &Q, unsigned Depth) {
3021	Type *Ty = V->getType();
3022
3023	#ifndef NDEBUG
3024	assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
3025
3026	if (auto *FVTy = dyn_cast<FixedVectorType>(Val: Ty)) {
3027	assert(
3028	FVTy->getNumElements() == DemandedElts.getBitWidth() &&
3029	"DemandedElt width should equal the fixed vector number of elements");
3030	} else {
3031	assert(DemandedElts == APInt(1, 1) &&
3032	"DemandedElt width should be 1 for scalars");
3033	}
3034	#endif
3035
3036	if (auto *C = dyn_cast<Constant>(Val: V)) {
3037	if (C->isNullValue())
3038	return false;
3039	if (isa<ConstantInt>(Val: C))
3040	// Must be non-zero due to null test above.
3041	return true;
3042
3043	// For constant vectors, check that all elements are poison or known
3044	// non-zero to determine that the whole vector is known non-zero.
3045	if (auto *VecTy = dyn_cast<FixedVectorType>(Val: Ty)) {
3046	for (unsigned i = 0, e = VecTy->getNumElements(); i != e; ++i) {
3047	if (!DemandedElts[i])
3048	continue;
3049	Constant *Elt = C->getAggregateElement(Elt: i);
3050	if (!Elt || Elt->isNullValue())
3051	return false;
3052	if (!isa<PoisonValue>(Val: Elt) && !isa<ConstantInt>(Val: Elt))
3053	return false;
3054	}
3055	return true;
3056	}
3057
3058	// A global variable in address space 0 is non null unless extern weak
3059	// or an absolute symbol reference. Other address spaces may have null as a
3060	// valid address for a global, so we can't assume anything.
3061	if (const GlobalValue *GV = dyn_cast<GlobalValue>(Val: V)) {
3062	if (!GV->isAbsoluteSymbolRef() && !GV->hasExternalWeakLinkage() &&
3063	GV->getType()->getAddressSpace() == 0)
3064	return true;
3065	}
3066
3067	// For constant expressions, fall through to the Operator code below.
3068	if (!isa<ConstantExpr>(Val: V))
3069	return false;
3070	}
3071
3072	if (const auto *A = dyn_cast<Argument>(Val: V))
3073	if (std::optional<ConstantRange> Range = A->getRange()) {
3074	const APInt ZeroValue(Range->getBitWidth(), 0);
3075	if (!Range->contains(Val: ZeroValue))
3076	return true;
3077	}
3078
3079	if (!isa<Constant>(Val: V) && isKnownNonZeroFromAssume(V, Q))
3080	return true;
3081
3082	// Some of the tests below are recursive, so bail out if we hit the limit.
3083	if (Depth++ >= MaxAnalysisRecursionDepth)
3084	return false;
3085
3086	// Check for pointer simplifications.
3087
3088	if (PointerType *PtrTy = dyn_cast<PointerType>(Val: Ty)) {
3089	// A byval, inalloca may not be null in a non-default addres space. A
3090	// nonnull argument is assumed never 0.
3091	if (const Argument *A = dyn_cast<Argument>(Val: V)) {
3092	if (((A->hasPassPointeeByValueCopyAttr() &&
3093	!NullPointerIsDefined(F: A->getParent(), AS: PtrTy->getAddressSpace())) ||
3094	A->hasNonNullAttr()))
3095	return true;
3096	}
3097	}
3098
3099	if (const auto *I = dyn_cast<Operator>(Val: V))
3100	if (isKnownNonZeroFromOperator(I, DemandedElts, Depth, Q))
3101	return true;
3102
3103	if (!isa<Constant>(Val: V) &&
3104	isKnownNonNullFromDominatingCondition(V, CtxI: Q.CxtI, DT: Q.DT))
3105	return true;
3106
3107	return false;
3108	}
3109
3110	bool llvm::isKnownNonZero(const Value *V, const SimplifyQuery &Q,
3111	unsigned Depth) {
3112	auto *FVTy = dyn_cast<FixedVectorType>(Val: V->getType());
3113	APInt DemandedElts =
3114	FVTy ? APInt::getAllOnes(numBits: FVTy->getNumElements()) : APInt(1, 1);
3115	return ::isKnownNonZero(V, DemandedElts, Q, Depth);
3116	}
3117
3118	/// If the pair of operators are the same invertible function, return the
3119	/// the operands of the function corresponding to each input. Otherwise,
3120	/// return std::nullopt. An invertible function is one that is 1-to-1 and maps
3121	/// every input value to exactly one output value. This is equivalent to
3122	/// saying that Op1 and Op2 are equal exactly when the specified pair of
3123	/// operands are equal, (except that Op1 and Op2 may be poison more often.)
3124	static std::optional<std::pair<Value*, Value*>>
3125	getInvertibleOperands(const Operator *Op1,
3126	const Operator *Op2) {
3127	if (Op1->getOpcode() != Op2->getOpcode())
3128	return std::nullopt;
3129
3130	auto getOperands = [&](unsigned OpNum) -> auto {
3131	return std::make_pair(x: Op1->getOperand(i: OpNum), y: Op2->getOperand(i: OpNum));
3132	};
3133
3134	switch (Op1->getOpcode()) {
3135	default:
3136	break;
3137	case Instruction::Or:
3138	if (!cast<PossiblyDisjointInst>(Val: Op1)->isDisjoint() ||
3139	!cast<PossiblyDisjointInst>(Val: Op2)->isDisjoint())
3140	break;
3141	[[fallthrough]];
3142	case Instruction::Xor:
3143	case Instruction::Add: {
3144	Value *Other;
3145	if (match(V: Op2, P: m_c_BinOp(L: m_Specific(V: Op1->getOperand(i: 0)), R: m_Value(V&: Other))))
3146	return std::make_pair(x: Op1->getOperand(i: 1), y&: Other);
3147	if (match(V: Op2, P: m_c_BinOp(L: m_Specific(V: Op1->getOperand(i: 1)), R: m_Value(V&: Other))))
3148	return std::make_pair(x: Op1->getOperand(i: 0), y&: Other);
3149	break;
3150	}
3151	case Instruction::Sub:
3152	if (Op1->getOperand(i: 0) == Op2->getOperand(i: 0))
3153	return getOperands(1);
3154	if (Op1->getOperand(i: 1) == Op2->getOperand(i: 1))
3155	return getOperands(0);
3156	break;
3157	case Instruction::Mul: {
3158	// invertible if A * B == (A * B) mod 2^N where A, and B are integers
3159	// and N is the bitwdith. The nsw case is non-obvious, but proven by
3160	// alive2: https://alive2.llvm.org/ce/z/Z6D5qK
3161	auto *OBO1 = cast<OverflowingBinaryOperator>(Val: Op1);
3162	auto *OBO2 = cast<OverflowingBinaryOperator>(Val: Op2);
3163	if ((!OBO1->hasNoUnsignedWrap() || !OBO2->hasNoUnsignedWrap()) &&
3164	(!OBO1->hasNoSignedWrap() || !OBO2->hasNoSignedWrap()))
3165	break;
3166
3167	// Assume operand order has been canonicalized
3168	if (Op1->getOperand(i: 1) == Op2->getOperand(i: 1) &&
3169	isa<ConstantInt>(Val: Op1->getOperand(i: 1)) &&
3170	!cast<ConstantInt>(Val: Op1->getOperand(i: 1))->isZero())
3171	return getOperands(0);
3172	break;
3173	}
3174	case Instruction::Shl: {
3175	// Same as multiplies, with the difference that we don't need to check
3176	// for a non-zero multiply. Shifts always multiply by non-zero.
3177	auto *OBO1 = cast<OverflowingBinaryOperator>(Val: Op1);
3178	auto *OBO2 = cast<OverflowingBinaryOperator>(Val: Op2);
3179	if ((!OBO1->hasNoUnsignedWrap() || !OBO2->hasNoUnsignedWrap()) &&
3180	(!OBO1->hasNoSignedWrap() || !OBO2->hasNoSignedWrap()))
3181	break;
3182
3183	if (Op1->getOperand(i: 1) == Op2->getOperand(i: 1))
3184	return getOperands(0);
3185	break;
3186	}
3187	case Instruction::AShr:
3188	case Instruction::LShr: {
3189	auto *PEO1 = cast<PossiblyExactOperator>(Val: Op1);
3190	auto *PEO2 = cast<PossiblyExactOperator>(Val: Op2);
3191	if (!PEO1->isExact() || !PEO2->isExact())
3192	break;
3193
3194	if (Op1->getOperand(i: 1) == Op2->getOperand(i: 1))
3195	return getOperands(0);
3196	break;
3197	}
3198	case Instruction::SExt:
3199	case Instruction::ZExt:
3200	if (Op1->getOperand(i: 0)->getType() == Op2->getOperand(i: 0)->getType())
3201	return getOperands(0);
3202	break;
3203	case Instruction::PHI: {
3204	const PHINode *PN1 = cast<PHINode>(Val: Op1);
3205	const PHINode *PN2 = cast<PHINode>(Val: Op2);
3206
3207	// If PN1 and PN2 are both recurrences, can we prove the entire recurrences
3208	// are a single invertible function of the start values? Note that repeated
3209	// application of an invertible function is also invertible
3210	BinaryOperator *BO1 = nullptr;
3211	Value *Start1 = nullptr, *Step1 = nullptr;
3212	BinaryOperator *BO2 = nullptr;
3213	Value *Start2 = nullptr, *Step2 = nullptr;
3214	if (PN1->getParent() != PN2->getParent() ||
3215	!matchSimpleRecurrence(P: PN1, BO&: BO1, Start&: Start1, Step&: Step1) ||
3216	!matchSimpleRecurrence(P: PN2, BO&: BO2, Start&: Start2, Step&: Step2))
3217	break;
3218
3219	auto Values = getInvertibleOperands(Op1: cast<Operator>(Val: BO1),
3220	Op2: cast<Operator>(Val: BO2));
3221	if (!Values)
3222	break;
3223
3224	// We have to be careful of mutually defined recurrences here. Ex:
3225	// * X_i = X_(i-1) OP Y_(i-1), and Y_i = X_(i-1) OP V
3226	// * X_i = Y_i = X_(i-1) OP Y_(i-1)
3227	// The invertibility of these is complicated, and not worth reasoning
3228	// about (yet?).
3229	if (Values->first != PN1 || Values->second != PN2)
3230	break;
3231
3232	return std::make_pair(x&: Start1, y&: Start2);
3233	}
3234	}
3235	return std::nullopt;
3236	}
3237
3238	/// Return true if V1 == (binop V2, X), where X is known non-zero.
3239	/// Only handle a small subset of binops where (binop V2, X) with non-zero X
3240	/// implies V2 != V1.
3241	static bool isModifyingBinopOfNonZero(const Value *V1, const Value *V2,
3242	unsigned Depth, const SimplifyQuery &Q) {
3243	const BinaryOperator *BO = dyn_cast<BinaryOperator>(Val: V1);
3244	if (!BO)
3245	return false;
3246	switch (BO->getOpcode()) {
3247	default:
3248	break;
3249	case Instruction::Or:
3250	if (!cast<PossiblyDisjointInst>(Val: V1)->isDisjoint())
3251	break;
3252	[[fallthrough]];
3253	case Instruction::Xor:
3254	case Instruction::Add:
3255	Value *Op = nullptr;
3256	if (V2 == BO->getOperand(i_nocapture: 0))
3257	Op = BO->getOperand(i_nocapture: 1);
3258	else if (V2 == BO->getOperand(i_nocapture: 1))
3259	Op = BO->getOperand(i_nocapture: 0);
3260	else
3261	return false;
3262	return isKnownNonZero(V: Op, Q, Depth: Depth + 1);
3263	}
3264	return false;
3265	}
3266
3267	/// Return true if V2 == V1 * C, where V1 is known non-zero, C is not 0/1 and
3268	/// the multiplication is nuw or nsw.
3269	static bool isNonEqualMul(const Value *V1, const Value *V2, unsigned Depth,
3270	const SimplifyQuery &Q) {
3271	if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Val: V2)) {
3272	const APInt *C;
3273	return match(V: OBO, P: m_Mul(L: m_Specific(V: V1), R: m_APInt(Res&: C))) &&
3274	(OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap()) &&
3275	!C->isZero() && !C->isOne() && isKnownNonZero(V: V1, Q, Depth: Depth + 1);
3276	}
3277	return false;
3278	}
3279
3280	/// Return true if V2 == V1 << C, where V1 is known non-zero, C is not 0 and
3281	/// the shift is nuw or nsw.
3282	static bool isNonEqualShl(const Value *V1, const Value *V2, unsigned Depth,
3283	const SimplifyQuery &Q) {
3284	if (auto *OBO = dyn_cast<OverflowingBinaryOperator>(Val: V2)) {
3285	const APInt *C;
3286	return match(V: OBO, P: m_Shl(L: m_Specific(V: V1), R: m_APInt(Res&: C))) &&
3287	(OBO->hasNoUnsignedWrap() || OBO->hasNoSignedWrap()) &&
3288	!C->isZero() && isKnownNonZero(V: V1, Q, Depth: Depth + 1);
3289	}
3290	return false;
3291	}
3292
3293	static bool isNonEqualPHIs(const PHINode *PN1, const PHINode *PN2,
3294	unsigned Depth, const SimplifyQuery &Q) {
3295	// Check two PHIs are in same block.
3296	if (PN1->getParent() != PN2->getParent())
3297	return false;
3298
3299	SmallPtrSet<const BasicBlock *, 8> VisitedBBs;
3300	bool UsedFullRecursion = false;
3301	for (const BasicBlock *IncomBB : PN1->blocks()) {
3302	if (!VisitedBBs.insert(Ptr: IncomBB).second)
3303	continue; // Don't reprocess blocks that we have dealt with already.
3304	const Value *IV1 = PN1->getIncomingValueForBlock(BB: IncomBB);
3305	const Value *IV2 = PN2->getIncomingValueForBlock(BB: IncomBB);
3306	const APInt *C1, *C2;
3307	if (match(V: IV1, P: m_APInt(Res&: C1)) && match(V: IV2, P: m_APInt(Res&: C2)) && *C1 != *C2)
3308	continue;
3309
3310	// Only one pair of phi operands is allowed for full recursion.
3311	if (UsedFullRecursion)
3312	return false;
3313
3314	SimplifyQuery RecQ = Q;
3315	RecQ.CxtI = IncomBB->getTerminator();
3316	if (!isKnownNonEqual(V1: IV1, V2: IV2, Depth: Depth + 1, Q: RecQ))
3317	return false;
3318	UsedFullRecursion = true;
3319	}
3320	return true;
3321	}
3322
3323	static bool isNonEqualSelect(const Value *V1, const Value *V2, unsigned Depth,
3324	const SimplifyQuery &Q) {
3325	const SelectInst *SI1 = dyn_cast<SelectInst>(Val: V1);
3326	if (!SI1)
3327	return false;
3328
3329	if (const SelectInst *SI2 = dyn_cast<SelectInst>(Val: V2)) {
3330	const Value *Cond1 = SI1->getCondition();
3331	const Value *Cond2 = SI2->getCondition();
3332	if (Cond1 == Cond2)
3333	return isKnownNonEqual(V1: SI1->getTrueValue(), V2: SI2->getTrueValue(),
3334	Depth: Depth + 1, Q) &&
3335	isKnownNonEqual(V1: SI1->getFalseValue(), V2: SI2->getFalseValue(),
3336	Depth: Depth + 1, Q);
3337	}
3338	return isKnownNonEqual(V1: SI1->getTrueValue(), V2, Depth: Depth + 1, Q) &&
3339	isKnownNonEqual(V1: SI1->getFalseValue(), V2, Depth: Depth + 1, Q);
3340	}
3341
3342	// Check to see if A is both a GEP and is the incoming value for a PHI in the
3343	// loop, and B is either a ptr or another GEP. If the PHI has 2 incoming values,
3344	// one of them being the recursive GEP A and the other a ptr at same base and at
3345	// the same/higher offset than B we are only incrementing the pointer further in
3346	// loop if offset of recursive GEP is greater than 0.
3347	static bool isNonEqualPointersWithRecursiveGEP(const Value *A, const Value *B,
3348	const SimplifyQuery &Q) {
3349	if (!A->getType()->isPointerTy() || !B->getType()->isPointerTy())
3350	return false;
3351
3352	auto *GEPA = dyn_cast<GEPOperator>(Val: A);
3353	if (!GEPA || GEPA->getNumIndices() != 1 || !isa<Constant>(Val: GEPA->idx_begin()))
3354	return false;
3355
3356	// Handle 2 incoming PHI values with one being a recursive GEP.
3357	auto *PN = dyn_cast<PHINode>(Val: GEPA->getPointerOperand());
3358	if (!PN || PN->getNumIncomingValues() != 2)
3359	return false;
3360
3361	// Search for the recursive GEP as an incoming operand, and record that as
3362	// Step.
3363	Value *Start = nullptr;
3364	Value *Step = const_cast<Value *>(A);
3365	if (PN->getIncomingValue(i: 0) == Step)
3366	Start = PN->getIncomingValue(i: 1);
3367	else if (PN->getIncomingValue(i: 1) == Step)
3368	Start = PN->getIncomingValue(i: 0);
3369	else
3370	return false;
3371
3372	// Other incoming node base should match the B base.
3373	// StartOffset >= OffsetB && StepOffset > 0?
3374	// StartOffset <= OffsetB && StepOffset < 0?
3375	// Is non-equal if above are true.
3376	// We use stripAndAccumulateInBoundsConstantOffsets to restrict the
3377	// optimisation to inbounds GEPs only.
3378	unsigned IndexWidth = Q.DL.getIndexTypeSizeInBits(Ty: Start->getType());
3379	APInt StartOffset(IndexWidth, 0);
3380	Start = Start->stripAndAccumulateInBoundsConstantOffsets(DL: Q.DL, Offset&: StartOffset);
3381	APInt StepOffset(IndexWidth, 0);
3382	Step = Step->stripAndAccumulateInBoundsConstantOffsets(DL: Q.DL, Offset&: StepOffset);
3383
3384	// Check if Base Pointer of Step matches the PHI.
3385	if (Step != PN)
3386	return false;
3387	APInt OffsetB(IndexWidth, 0);
3388	B = B->stripAndAccumulateInBoundsConstantOffsets(DL: Q.DL, Offset&: OffsetB);
3389	return Start == B &&
3390	((StartOffset.sge(RHS: OffsetB) && StepOffset.isStrictlyPositive()) ||
3391	(StartOffset.sle(RHS: OffsetB) && StepOffset.isNegative()));
3392	}
3393
3394	/// Return true if it is known that V1 != V2.
3395	static bool isKnownNonEqual(const Value *V1, const Value *V2, unsigned Depth,
3396	const SimplifyQuery &Q) {
3397	if (V1 == V2)
3398	return false;
3399	if (V1->getType() != V2->getType())
3400	// We can't look through casts yet.
3401	return false;
3402
3403	if (Depth >= MaxAnalysisRecursionDepth)
3404	return false;
3405
3406	// See if we can recurse through (exactly one of) our operands. This
3407	// requires our operation be 1-to-1 and map every input value to exactly
3408	// one output value. Such an operation is invertible.
3409	auto *O1 = dyn_cast<Operator>(Val: V1);
3410	auto *O2 = dyn_cast<Operator>(Val: V2);
3411	if (O1 && O2 && O1->getOpcode() == O2->getOpcode()) {
3412	if (auto Values = getInvertibleOperands(Op1: O1, Op2: O2))
3413	return isKnownNonEqual(V1: Values->first, V2: Values->second, Depth: Depth + 1, Q);
3414
3415	if (const PHINode *PN1 = dyn_cast<PHINode>(Val: V1)) {
3416	const PHINode *PN2 = cast<PHINode>(Val: V2);
3417	// FIXME: This is missing a generalization to handle the case where one is
3418	// a PHI and another one isn't.
3419	if (isNonEqualPHIs(PN1, PN2, Depth, Q))
3420	return true;
3421	};
3422	}
3423
3424	if (isModifyingBinopOfNonZero(V1, V2, Depth, Q) ||
3425	isModifyingBinopOfNonZero(V1: V2, V2: V1, Depth, Q))
3426	return true;
3427
3428	if (isNonEqualMul(V1, V2, Depth, Q) || isNonEqualMul(V1: V2, V2: V1, Depth, Q))
3429	return true;
3430
3431	if (isNonEqualShl(V1, V2, Depth, Q) || isNonEqualShl(V1: V2, V2: V1, Depth, Q))
3432	return true;
3433
3434	if (V1->getType()->isIntOrIntVectorTy()) {
3435	// Are any known bits in V1 contradictory to known bits in V2? If V1
3436	// has a known zero where V2 has a known one, they must not be equal.
3437	KnownBits Known1 = computeKnownBits(V: V1, Depth, Q);
3438	if (!Known1.isUnknown()) {
3439	KnownBits Known2 = computeKnownBits(V: V2, Depth, Q);
3440	if (Known1.Zero.intersects(RHS: Known2.One) ||
3441	Known2.Zero.intersects(RHS: Known1.One))
3442	return true;
3443	}
3444	}
3445
3446	if (isNonEqualSelect(V1, V2, Depth, Q) || isNonEqualSelect(V1: V2, V2: V1, Depth, Q))
3447	return true;
3448
3449	if (isNonEqualPointersWithRecursiveGEP(A: V1, B: V2, Q) ||
3450	isNonEqualPointersWithRecursiveGEP(A: V2, B: V1, Q))
3451	return true;
3452
3453	Value *A, *B;
3454	// PtrToInts are NonEqual if their Ptrs are NonEqual.
3455	// Check PtrToInt type matches the pointer size.
3456	if (match(V: V1, P: m_PtrToIntSameSize(DL: Q.DL, Op: m_Value(V&: A))) &&
3457	match(V: V2, P: m_PtrToIntSameSize(DL: Q.DL, Op: m_Value(V&: B))))
3458	return isKnownNonEqual(V1: A, V2: B, Depth: Depth + 1, Q);
3459
3460	return false;
3461	}
3462
3463	// Match a signed min+max clamp pattern like smax(smin(In, CHigh), CLow).
3464	// Returns the input and lower/upper bounds.
3465	static bool isSignedMinMaxClamp(const Value *Select, const Value *&In,
3466	const APInt *&CLow, const APInt *&CHigh) {
3467	assert(isa<Operator>(Select) &&
3468	cast<Operator>(Select)->getOpcode() == Instruction::Select &&
3469	"Input should be a Select!");
3470
3471	const Value *LHS = nullptr, *RHS = nullptr;
3472	SelectPatternFlavor SPF = matchSelectPattern(V: Select, LHS, RHS).Flavor;
3473	if (SPF != SPF_SMAX && SPF != SPF_SMIN)
3474	return false;
3475
3476	if (!match(V: RHS, P: m_APInt(Res&: CLow)))
3477	return false;
3478
3479	const Value *LHS2 = nullptr, *RHS2 = nullptr;
3480	SelectPatternFlavor SPF2 = matchSelectPattern(V: LHS, LHS&: LHS2, RHS&: RHS2).Flavor;
3481	if (getInverseMinMaxFlavor(SPF) != SPF2)
3482	return false;
3483
3484	if (!match(V: RHS2, P: m_APInt(Res&: CHigh)))
3485	return false;
3486
3487	if (SPF == SPF_SMIN)
3488	std::swap(a&: CLow, b&: CHigh);
3489
3490	In = LHS2;
3491	return CLow->sle(RHS: *CHigh);
3492	}
3493
3494	static bool isSignedMinMaxIntrinsicClamp(const IntrinsicInst *II,
3495	const APInt *&CLow,
3496	const APInt *&CHigh) {
3497	assert((II->getIntrinsicID() == Intrinsic::smin ||
3498	II->getIntrinsicID() == Intrinsic::smax) && "Must be smin/smax");
3499
3500	Intrinsic::ID InverseID = getInverseMinMaxIntrinsic(MinMaxID: II->getIntrinsicID());
3501	auto *InnerII = dyn_cast<IntrinsicInst>(Val: II->getArgOperand(i: 0));
3502	if (!InnerII || InnerII->getIntrinsicID() != InverseID ||
3503	!match(V: II->getArgOperand(i: 1), P: m_APInt(Res&: CLow)) ||
3504	!match(V: InnerII->getArgOperand(i: 1), P: m_APInt(Res&: CHigh)))
3505	return false;
3506
3507	if (II->getIntrinsicID() == Intrinsic::smin)
3508	std::swap(a&: CLow, b&: CHigh);
3509	return CLow->sle(RHS: *CHigh);
3510	}
3511
3512	/// For vector constants, loop over the elements and find the constant with the
3513	/// minimum number of sign bits. Return 0 if the value is not a vector constant
3514	/// or if any element was not analyzed; otherwise, return the count for the
3515	/// element with the minimum number of sign bits.
3516	static unsigned computeNumSignBitsVectorConstant(const Value *V,
3517	const APInt &DemandedElts,
3518	unsigned TyBits) {
3519	const auto *CV = dyn_cast<Constant>(Val: V);
3520	if (!CV || !isa<FixedVectorType>(Val: CV->getType()))
3521	return 0;
3522
3523	unsigned MinSignBits = TyBits;
3524	unsigned NumElts = cast<FixedVectorType>(Val: CV->getType())->getNumElements();
3525	for (unsigned i = 0; i != NumElts; ++i) {
3526	if (!DemandedElts[i])
3527	continue;
3528	// If we find a non-ConstantInt, bail out.
3529	auto *Elt = dyn_cast_or_null<ConstantInt>(Val: CV->getAggregateElement(Elt: i));
3530	if (!Elt)
3531	return 0;
3532
3533	MinSignBits = std::min(a: MinSignBits, b: Elt->getValue().getNumSignBits());
3534	}
3535
3536	return MinSignBits;
3537	}
3538
3539	static unsigned ComputeNumSignBitsImpl(const Value *V,
3540	const APInt &DemandedElts,
3541	unsigned Depth, const SimplifyQuery &Q);
3542
3543	static unsigned ComputeNumSignBits(const Value *V, const APInt &DemandedElts,
3544	unsigned Depth, const SimplifyQuery &Q) {
3545	unsigned Result = ComputeNumSignBitsImpl(V, DemandedElts, Depth, Q);
3546	assert(Result > 0 && "At least one sign bit needs to be present!");
3547	return Result;
3548	}
3549
3550	/// Return the number of times the sign bit of the register is replicated into
3551	/// the other bits. We know that at least 1 bit is always equal to the sign bit
3552	/// (itself), but other cases can give us information. For example, immediately
3553	/// after an "ashr X, 2", we know that the top 3 bits are all equal to each
3554	/// other, so we return 3. For vectors, return the number of sign bits for the
3555	/// vector element with the minimum number of known sign bits of the demanded
3556	/// elements in the vector specified by DemandedElts.
3557	static unsigned ComputeNumSignBitsImpl(const Value *V,
3558	const APInt &DemandedElts,
3559	unsigned Depth, const SimplifyQuery &Q) {
3560	Type *Ty = V->getType();
3561	#ifndef NDEBUG
3562	assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
3563
3564	if (auto *FVTy = dyn_cast<FixedVectorType>(Val: Ty)) {
3565	assert(
3566	FVTy->getNumElements() == DemandedElts.getBitWidth() &&
3567	"DemandedElt width should equal the fixed vector number of elements");
3568	} else {
3569	assert(DemandedElts == APInt(1, 1) &&
3570	"DemandedElt width should be 1 for scalars");
3571	}
3572	#endif
3573
3574	// We return the minimum number of sign bits that are guaranteed to be present
3575	// in V, so for undef we have to conservatively return 1. We don't have the
3576	// same behavior for poison though -- that's a FIXME today.
3577
3578	Type *ScalarTy = Ty->getScalarType();
3579	unsigned TyBits = ScalarTy->isPointerTy() ?
3580	Q.DL.getPointerTypeSizeInBits(ScalarTy) :
3581	Q.DL.getTypeSizeInBits(Ty: ScalarTy);
3582
3583	unsigned Tmp, Tmp2;
3584	unsigned FirstAnswer = 1;
3585
3586	// Note that ConstantInt is handled by the general computeKnownBits case
3587	// below.
3588
3589	if (Depth == MaxAnalysisRecursionDepth)
3590	return 1;
3591
3592	if (auto *U = dyn_cast<Operator>(Val: V)) {
3593	switch (Operator::getOpcode(V)) {
3594	default: break;
3595	case Instruction::SExt:
3596	Tmp = TyBits - U->getOperand(i: 0)->getType()->getScalarSizeInBits();
3597	return ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q) + Tmp;
3598
3599	case Instruction::SDiv: {
3600	const APInt *Denominator;
3601	// sdiv X, C -> adds log(C) sign bits.
3602	if (match(V: U->getOperand(i: 1), P: m_APInt(Res&: Denominator))) {
3603
3604	// Ignore non-positive denominator.
3605	if (!Denominator->isStrictlyPositive())
3606	break;
3607
3608	// Calculate the incoming numerator bits.
3609	unsigned NumBits = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3610
3611	// Add floor(log(C)) bits to the numerator bits.
3612	return std::min(a: TyBits, b: NumBits + Denominator->logBase2());
3613	}
3614	break;
3615	}
3616
3617	case Instruction::SRem: {
3618	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3619
3620	const APInt *Denominator;
3621	// srem X, C -> we know that the result is within [-C+1,C) when C is a
3622	// positive constant. This let us put a lower bound on the number of sign
3623	// bits.
3624	if (match(V: U->getOperand(i: 1), P: m_APInt(Res&: Denominator))) {
3625
3626	// Ignore non-positive denominator.
3627	if (Denominator->isStrictlyPositive()) {
3628	// Calculate the leading sign bit constraints by examining the
3629	// denominator. Given that the denominator is positive, there are two
3630	// cases:
3631	//
3632	// 1. The numerator is positive. The result range is [0,C) and
3633	// [0,C) u< (1 << ceilLogBase2(C)).
3634	//
3635	// 2. The numerator is negative. Then the result range is (-C,0] and
3636	// integers in (-C,0] are either 0 or >u (-1 << ceilLogBase2(C)).
3637	//
3638	// Thus a lower bound on the number of sign bits is `TyBits -
3639	// ceilLogBase2(C)`.
3640
3641	unsigned ResBits = TyBits - Denominator->ceilLogBase2();
3642	Tmp = std::max(a: Tmp, b: ResBits);
3643	}
3644	}
3645	return Tmp;
3646	}
3647
3648	case Instruction::AShr: {
3649	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3650	// ashr X, C -> adds C sign bits. Vectors too.
3651	const APInt *ShAmt;
3652	if (match(V: U->getOperand(i: 1), P: m_APInt(Res&: ShAmt))) {
3653	if (ShAmt->uge(RHS: TyBits))
3654	break; // Bad shift.
3655	unsigned ShAmtLimited = ShAmt->getZExtValue();
3656	Tmp += ShAmtLimited;
3657	if (Tmp > TyBits) Tmp = TyBits;
3658	}
3659	return Tmp;
3660	}
3661	case Instruction::Shl: {
3662	const APInt *ShAmt;
3663	if (match(V: U->getOperand(i: 1), P: m_APInt(Res&: ShAmt))) {
3664	// shl destroys sign bits.
3665	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3666	if (ShAmt->uge(RHS: TyBits) || // Bad shift.
3667	ShAmt->uge(RHS: Tmp)) break; // Shifted all sign bits out.
3668	Tmp2 = ShAmt->getZExtValue();
3669	return Tmp - Tmp2;
3670	}
3671	break;
3672	}
3673	case Instruction::And:
3674	case Instruction::Or:
3675	case Instruction::Xor: // NOT is handled here.
3676	// Logical binary ops preserve the number of sign bits at the worst.
3677	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3678	if (Tmp != 1) {
3679	Tmp2 = ComputeNumSignBits(V: U->getOperand(i: 1), Depth: Depth + 1, Q);
3680	FirstAnswer = std::min(a: Tmp, b: Tmp2);
3681	// We computed what we know about the sign bits as our first
3682	// answer. Now proceed to the generic code that uses
3683	// computeKnownBits, and pick whichever answer is better.
3684	}
3685	break;
3686
3687	case Instruction::Select: {
3688	// If we have a clamp pattern, we know that the number of sign bits will
3689	// be the minimum of the clamp min/max range.
3690	const Value *X;
3691	const APInt *CLow, *CHigh;
3692	if (isSignedMinMaxClamp(Select: U, In&: X, CLow, CHigh))
3693	return std::min(a: CLow->getNumSignBits(), b: CHigh->getNumSignBits());
3694
3695	Tmp = ComputeNumSignBits(V: U->getOperand(i: 1), Depth: Depth + 1, Q);
3696	if (Tmp == 1) break;
3697	Tmp2 = ComputeNumSignBits(V: U->getOperand(i: 2), Depth: Depth + 1, Q);
3698	return std::min(a: Tmp, b: Tmp2);
3699	}
3700
3701	case Instruction::Add:
3702	// Add can have at most one carry bit. Thus we know that the output
3703	// is, at worst, one more bit than the inputs.
3704	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3705	if (Tmp == 1) break;
3706
3707	// Special case decrementing a value (ADD X, -1):
3708	if (const auto *CRHS = dyn_cast<Constant>(Val: U->getOperand(i: 1)))
3709	if (CRHS->isAllOnesValue()) {
3710	KnownBits Known(TyBits);
3711	computeKnownBits(V: U->getOperand(i: 0), Known, Depth: Depth + 1, Q);
3712
3713	// If the input is known to be 0 or 1, the output is 0/-1, which is
3714	// all sign bits set.
3715	if ((Known.Zero | 1).isAllOnes())
3716	return TyBits;
3717
3718	// If we are subtracting one from a positive number, there is no carry
3719	// out of the result.
3720	if (Known.isNonNegative())
3721	return Tmp;
3722	}
3723
3724	Tmp2 = ComputeNumSignBits(V: U->getOperand(i: 1), Depth: Depth + 1, Q);
3725	if (Tmp2 == 1) break;
3726	return std::min(a: Tmp, b: Tmp2) - 1;
3727
3728	case Instruction::Sub:
3729	Tmp2 = ComputeNumSignBits(V: U->getOperand(i: 1), Depth: Depth + 1, Q);
3730	if (Tmp2 == 1) break;
3731
3732	// Handle NEG.
3733	if (const auto *CLHS = dyn_cast<Constant>(Val: U->getOperand(i: 0)))
3734	if (CLHS->isNullValue()) {
3735	KnownBits Known(TyBits);
3736	computeKnownBits(V: U->getOperand(i: 1), Known, Depth: Depth + 1, Q);
3737	// If the input is known to be 0 or 1, the output is 0/-1, which is
3738	// all sign bits set.
3739	if ((Known.Zero | 1).isAllOnes())
3740	return TyBits;
3741
3742	// If the input is known to be positive (the sign bit is known clear),
3743	// the output of the NEG has the same number of sign bits as the
3744	// input.
3745	if (Known.isNonNegative())
3746	return Tmp2;
3747
3748	// Otherwise, we treat this like a SUB.
3749	}
3750
3751	// Sub can have at most one carry bit. Thus we know that the output
3752	// is, at worst, one more bit than the inputs.
3753	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3754	if (Tmp == 1) break;
3755	return std::min(a: Tmp, b: Tmp2) - 1;
3756
3757	case Instruction::Mul: {
3758	// The output of the Mul can be at most twice the valid bits in the
3759	// inputs.
3760	unsigned SignBitsOp0 = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3761	if (SignBitsOp0 == 1) break;
3762	unsigned SignBitsOp1 = ComputeNumSignBits(V: U->getOperand(i: 1), Depth: Depth + 1, Q);
3763	if (SignBitsOp1 == 1) break;
3764	unsigned OutValidBits =
3765	(TyBits - SignBitsOp0 + 1) + (TyBits - SignBitsOp1 + 1);
3766	return OutValidBits > TyBits ? 1 : TyBits - OutValidBits + 1;
3767	}
3768
3769	case Instruction::PHI: {
3770	const PHINode *PN = cast<PHINode>(Val: U);
3771	unsigned NumIncomingValues = PN->getNumIncomingValues();
3772	// Don't analyze large in-degree PHIs.
3773	if (NumIncomingValues > 4) break;
3774	// Unreachable blocks may have zero-operand PHI nodes.
3775	if (NumIncomingValues == 0) break;
3776
3777	// Take the minimum of all incoming values. This can't infinitely loop
3778	// because of our depth threshold.
3779	SimplifyQuery RecQ = Q;
3780	Tmp = TyBits;
3781	for (unsigned i = 0, e = NumIncomingValues; i != e; ++i) {
3782	if (Tmp == 1) return Tmp;
3783	RecQ.CxtI = PN->getIncomingBlock(i)->getTerminator();
3784	Tmp = std::min(
3785	a: Tmp, b: ComputeNumSignBits(V: PN->getIncomingValue(i), Depth: Depth + 1, Q: RecQ));
3786	}
3787	return Tmp;
3788	}
3789
3790	case Instruction::Trunc: {
3791	// If the input contained enough sign bits that some remain after the
3792	// truncation, then we can make use of that. Otherwise we don't know
3793	// anything.
3794	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3795	unsigned OperandTyBits = U->getOperand(i: 0)->getType()->getScalarSizeInBits();
3796	if (Tmp > (OperandTyBits - TyBits))
3797	return Tmp - (OperandTyBits - TyBits);
3798
3799	return 1;
3800	}
3801
3802	case Instruction::ExtractElement:
3803	// Look through extract element. At the moment we keep this simple and
3804	// skip tracking the specific element. But at least we might find
3805	// information valid for all elements of the vector (for example if vector
3806	// is sign extended, shifted, etc).
3807	return ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3808
3809	case Instruction::ShuffleVector: {
3810	// Collect the minimum number of sign bits that are shared by every vector
3811	// element referenced by the shuffle.
3812	auto *Shuf = dyn_cast<ShuffleVectorInst>(Val: U);
3813	if (!Shuf) {
3814	// FIXME: Add support for shufflevector constant expressions.
3815	return 1;
3816	}
3817	APInt DemandedLHS, DemandedRHS;
3818	// For undef elements, we don't know anything about the common state of
3819	// the shuffle result.
3820	if (!getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS))
3821	return 1;
3822	Tmp = std::numeric_limits<unsigned>::max();
3823	if (!!DemandedLHS) {
3824	const Value *LHS = Shuf->getOperand(i_nocapture: 0);
3825	Tmp = ComputeNumSignBits(V: LHS, DemandedElts: DemandedLHS, Depth: Depth + 1, Q);
3826	}
3827	// If we don't know anything, early out and try computeKnownBits
3828	// fall-back.
3829	if (Tmp == 1)
3830	break;
3831	if (!!DemandedRHS) {
3832	const Value *RHS = Shuf->getOperand(i_nocapture: 1);
3833	Tmp2 = ComputeNumSignBits(V: RHS, DemandedElts: DemandedRHS, Depth: Depth + 1, Q);
3834	Tmp = std::min(a: Tmp, b: Tmp2);
3835	}
3836	// If we don't know anything, early out and try computeKnownBits
3837	// fall-back.
3838	if (Tmp == 1)
3839	break;
3840	assert(Tmp <= TyBits && "Failed to determine minimum sign bits");
3841	return Tmp;
3842	}
3843	case Instruction::Call: {
3844	if (const auto *II = dyn_cast<IntrinsicInst>(Val: U)) {
3845	switch (II->getIntrinsicID()) {
3846	default: break;
3847	case Intrinsic::abs:
3848	Tmp = ComputeNumSignBits(V: U->getOperand(i: 0), Depth: Depth + 1, Q);
3849	if (Tmp == 1) break;
3850
3851	// Absolute value reduces number of sign bits by at most 1.
3852	return Tmp - 1;
3853	case Intrinsic::smin:
3854	case Intrinsic::smax: {
3855	const APInt *CLow, *CHigh;
3856	if (isSignedMinMaxIntrinsicClamp(II, CLow, CHigh))
3857	return std::min(a: CLow->getNumSignBits(), b: CHigh->getNumSignBits());
3858	}
3859	}
3860	}
3861	}
3862	}
3863	}
3864
3865	// Finally, if we can prove that the top bits of the result are 0's or 1's,
3866	// use this information.
3867
3868	// If we can examine all elements of a vector constant successfully, we're
3869	// done (we can't do any better than that). If not, keep trying.
3870	if (unsigned VecSignBits =
3871	computeNumSignBitsVectorConstant(V, DemandedElts, TyBits))
3872	return VecSignBits;
3873
3874	KnownBits Known(TyBits);
3875	computeKnownBits(V, DemandedElts, Known, Depth, Q);
3876
3877	// If we know that the sign bit is either zero or one, determine the number of
3878	// identical bits in the top of the input value.
3879	return std::max(a: FirstAnswer, b: Known.countMinSignBits());
3880	}
3881
3882	Intrinsic::ID llvm::getIntrinsicForCallSite(const CallBase &CB,
3883	const TargetLibraryInfo *TLI) {
3884	const Function *F = CB.getCalledFunction();
3885	if (!F)
3886	return Intrinsic::not_intrinsic;
3887
3888	if (F->isIntrinsic())
3889	return F->getIntrinsicID();
3890
3891	// We are going to infer semantics of a library function based on mapping it
3892	// to an LLVM intrinsic. Check that the library function is available from
3893	// this callbase and in this environment.
3894	LibFunc Func;
3895	if (F->hasLocalLinkage() || !TLI || !TLI->getLibFunc(CB, F&: Func) ||
3896	!CB.onlyReadsMemory())
3897	return Intrinsic::not_intrinsic;
3898
3899	switch (Func) {
3900	default:
3901	break;
3902	case LibFunc_sin:
3903	case LibFunc_sinf:
3904	case LibFunc_sinl:
3905	return Intrinsic::sin;
3906	case LibFunc_cos:
3907	case LibFunc_cosf:
3908	case LibFunc_cosl:
3909	return Intrinsic::cos;
3910	case LibFunc_exp:
3911	case LibFunc_expf:
3912	case LibFunc_expl:
3913	return Intrinsic::exp;
3914	case LibFunc_exp2:
3915	case LibFunc_exp2f:
3916	case LibFunc_exp2l:
3917	return Intrinsic::exp2;
3918	case LibFunc_log:
3919	case LibFunc_logf:
3920	case LibFunc_logl:
3921	return Intrinsic::log;
3922	case LibFunc_log10:
3923	case LibFunc_log10f:
3924	case LibFunc_log10l:
3925	return Intrinsic::log10;
3926	case LibFunc_log2:
3927	case LibFunc_log2f:
3928	case LibFunc_log2l:
3929	return Intrinsic::log2;
3930	case LibFunc_fabs:
3931	case LibFunc_fabsf:
3932	case LibFunc_fabsl:
3933	return Intrinsic::fabs;
3934	case LibFunc_fmin:
3935	case LibFunc_fminf:
3936	case LibFunc_fminl:
3937	return Intrinsic::minnum;
3938	case LibFunc_fmax:
3939	case LibFunc_fmaxf:
3940	case LibFunc_fmaxl:
3941	return Intrinsic::maxnum;
3942	case LibFunc_copysign:
3943	case LibFunc_copysignf:
3944	case LibFunc_copysignl:
3945	return Intrinsic::copysign;
3946	case LibFunc_floor:
3947	case LibFunc_floorf:
3948	case LibFunc_floorl:
3949	return Intrinsic::floor;
3950	case LibFunc_ceil:
3951	case LibFunc_ceilf:
3952	case LibFunc_ceill:
3953	return Intrinsic::ceil;
3954	case LibFunc_trunc:
3955	case LibFunc_truncf:
3956	case LibFunc_truncl:
3957	return Intrinsic::trunc;
3958	case LibFunc_rint:
3959	case LibFunc_rintf:
3960	case LibFunc_rintl:
3961	return Intrinsic::rint;
3962	case LibFunc_nearbyint:
3963	case LibFunc_nearbyintf:
3964	case LibFunc_nearbyintl:
3965	return Intrinsic::nearbyint;
3966	case LibFunc_round:
3967	case LibFunc_roundf:
3968	case LibFunc_roundl:
3969	return Intrinsic::round;
3970	case LibFunc_roundeven:
3971	case LibFunc_roundevenf:
3972	case LibFunc_roundevenl:
3973	return Intrinsic::roundeven;
3974	case LibFunc_pow:
3975	case LibFunc_powf:
3976	case LibFunc_powl:
3977	return Intrinsic::pow;
3978	case LibFunc_sqrt:
3979	case LibFunc_sqrtf:
3980	case LibFunc_sqrtl:
3981	return Intrinsic::sqrt;
3982	}
3983
3984	return Intrinsic::not_intrinsic;
3985	}
3986
3987	/// Return true if it's possible to assume IEEE treatment of input denormals in
3988	/// \p F for \p Val.
3989	static bool inputDenormalIsIEEE(const Function &F, const Type *Ty) {
3990	Ty = Ty->getScalarType();
3991	return F.getDenormalMode(FPType: Ty->getFltSemantics()).Input == DenormalMode::IEEE;
3992	}
3993
3994	static bool inputDenormalIsIEEEOrPosZero(const Function &F, const Type *Ty) {
3995	Ty = Ty->getScalarType();
3996	DenormalMode Mode = F.getDenormalMode(FPType: Ty->getFltSemantics());
3997	return Mode.Input == DenormalMode::IEEE ||
3998	Mode.Input == DenormalMode::PositiveZero;
3999	}
4000
4001	static bool outputDenormalIsIEEEOrPosZero(const Function &F, const Type *Ty) {
4002	Ty = Ty->getScalarType();
4003	DenormalMode Mode = F.getDenormalMode(FPType: Ty->getFltSemantics());
4004	return Mode.Output == DenormalMode::IEEE ||
4005	Mode.Output == DenormalMode::PositiveZero;
4006	}
4007
4008	bool KnownFPClass::isKnownNeverLogicalZero(const Function &F, Type *Ty) const {
4009	return isKnownNeverZero() &&
4010	(isKnownNeverSubnormal() || inputDenormalIsIEEE(F, Ty));
4011	}
4012
4013	bool KnownFPClass::isKnownNeverLogicalNegZero(const Function &F,
4014	Type *Ty) const {
4015	return isKnownNeverNegZero() &&
4016	(isKnownNeverNegSubnormal() || inputDenormalIsIEEEOrPosZero(F, Ty));
4017	}
4018
4019	bool KnownFPClass::isKnownNeverLogicalPosZero(const Function &F,
4020	Type *Ty) const {
4021	if (!isKnownNeverPosZero())
4022	return false;
4023
4024	// If we know there are no denormals, nothing can be flushed to zero.
4025	if (isKnownNeverSubnormal())
4026	return true;
4027
4028	DenormalMode Mode = F.getDenormalMode(FPType: Ty->getScalarType()->getFltSemantics());
4029	switch (Mode.Input) {
4030	case DenormalMode::IEEE:
4031	return true;
4032	case DenormalMode::PreserveSign:
4033	// Negative subnormal won't flush to +0
4034	return isKnownNeverPosSubnormal();
4035	case DenormalMode::PositiveZero:
4036	default:
4037	// Both positive and negative subnormal could flush to +0
4038	return false;
4039	}
4040
4041	llvm_unreachable("covered switch over denormal mode");
4042	}
4043
4044	void KnownFPClass::propagateDenormal(const KnownFPClass &Src, const Function &F,
4045	Type *Ty) {
4046	KnownFPClasses = Src.KnownFPClasses;
4047	// If we aren't assuming the source can't be a zero, we don't have to check if
4048	// a denormal input could be flushed.
4049	if (!Src.isKnownNeverPosZero() && !Src.isKnownNeverNegZero())
4050	return;
4051
4052	// If we know the input can't be a denormal, it can't be flushed to 0.
4053	if (Src.isKnownNeverSubnormal())
4054	return;
4055
4056	DenormalMode Mode = F.getDenormalMode(FPType: Ty->getScalarType()->getFltSemantics());
4057
4058	if (!Src.isKnownNeverPosSubnormal() && Mode != DenormalMode::getIEEE())
4059	KnownFPClasses |= fcPosZero;
4060
4061	if (!Src.isKnownNeverNegSubnormal() && Mode != DenormalMode::getIEEE()) {
4062	if (Mode != DenormalMode::getPositiveZero())
4063	KnownFPClasses |= fcNegZero;
4064
4065	if (Mode.Input == DenormalMode::PositiveZero ||
4066	Mode.Output == DenormalMode::PositiveZero ||
4067	Mode.Input == DenormalMode::Dynamic ||
4068	Mode.Output == DenormalMode::Dynamic)
4069	KnownFPClasses |= fcPosZero;
4070	}
4071	}
4072
4073	void KnownFPClass::propagateCanonicalizingSrc(const KnownFPClass &Src,
4074	const Function &F, Type *Ty) {
4075	propagateDenormal(Src, F, Ty);
4076	propagateNaN(Src, /*PreserveSign=*/true);
4077	}
4078
4079	/// Given an exploded icmp instruction, return true if the comparison only
4080	/// checks the sign bit. If it only checks the sign bit, set TrueIfSigned if
4081	/// the result of the comparison is true when the input value is signed.
4082	bool llvm::isSignBitCheck(ICmpInst::Predicate Pred, const APInt &RHS,
4083	bool &TrueIfSigned) {
4084	switch (Pred) {
4085	case ICmpInst::ICMP_SLT: // True if LHS s< 0
4086	TrueIfSigned = true;
4087	return RHS.isZero();
4088	case ICmpInst::ICMP_SLE: // True if LHS s<= -1
4089	TrueIfSigned = true;
4090	return RHS.isAllOnes();
4091	case ICmpInst::ICMP_SGT: // True if LHS s> -1
4092	TrueIfSigned = false;
4093	return RHS.isAllOnes();
4094	case ICmpInst::ICMP_SGE: // True if LHS s>= 0
4095	TrueIfSigned = false;
4096	return RHS.isZero();
4097	case ICmpInst::ICMP_UGT:
4098	// True if LHS u> RHS and RHS == sign-bit-mask - 1
4099	TrueIfSigned = true;
4100	return RHS.isMaxSignedValue();
4101	case ICmpInst::ICMP_UGE:
4102	// True if LHS u>= RHS and RHS == sign-bit-mask (2^7, 2^15, 2^31, etc)
4103	TrueIfSigned = true;
4104	return RHS.isMinSignedValue();
4105	case ICmpInst::ICMP_ULT:
4106	// True if LHS u< RHS and RHS == sign-bit-mask (2^7, 2^15, 2^31, etc)
4107	TrueIfSigned = false;
4108	return RHS.isMinSignedValue();
4109	case ICmpInst::ICMP_ULE:
4110	// True if LHS u<= RHS and RHS == sign-bit-mask - 1
4111	TrueIfSigned = false;
4112	return RHS.isMaxSignedValue();
4113	default:
4114	return false;
4115	}
4116	}
4117
4118	/// Returns a pair of values, which if passed to llvm.is.fpclass, returns the
4119	/// same result as an fcmp with the given operands.
4120	std::pair<Value *, FPClassTest> llvm::fcmpToClassTest(FCmpInst::Predicate Pred,
4121	const Function &F,
4122	Value *LHS, Value *RHS,
4123	bool LookThroughSrc) {
4124	const APFloat *ConstRHS;
4125	if (!match(V: RHS, P: m_APFloatAllowPoison(Res&: ConstRHS)))
4126	return {nullptr, fcAllFlags};
4127
4128	return fcmpToClassTest(Pred, F, LHS, ConstRHS, LookThroughSrc);
4129	}
4130
4131	std::pair<Value *, FPClassTest>
4132	llvm::fcmpToClassTest(FCmpInst::Predicate Pred, const Function &F, Value *LHS,
4133	const APFloat *ConstRHS, bool LookThroughSrc) {
4134
4135	auto [Src, ClassIfTrue, ClassIfFalse] =
4136	fcmpImpliesClass(Pred, F, LHS, RHS: *ConstRHS, LookThroughSrc);
4137	if (Src && ClassIfTrue == ~ClassIfFalse)
4138	return {Src, ClassIfTrue};
4139	return {nullptr, fcAllFlags};
4140	}
4141
4142	/// Return the return value for fcmpImpliesClass for a compare that produces an
4143	/// exact class test.
4144	static std::tuple<Value *, FPClassTest, FPClassTest> exactClass(Value *V,
4145	FPClassTest M) {
4146	return {V, M, ~M};
4147	}
4148
4149	std::tuple<Value *, FPClassTest, FPClassTest>
4150	llvm::fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
4151	FPClassTest RHSClass, bool LookThroughSrc) {
4152	assert(RHSClass != fcNone);
4153	Value *Src = LHS;
4154
4155	if (Pred == FCmpInst::FCMP_TRUE)
4156	return exactClass(V: Src, M: fcAllFlags);
4157
4158	if (Pred == FCmpInst::FCMP_FALSE)
4159	return exactClass(V: Src, M: fcNone);
4160
4161	const FPClassTest OrigClass = RHSClass;
4162
4163	const bool IsNegativeRHS = (RHSClass & fcNegative) == RHSClass;
4164	const bool IsPositiveRHS = (RHSClass & fcPositive) == RHSClass;
4165	const bool IsNaN = (RHSClass & ~fcNan) == fcNone;
4166
4167	if (IsNaN) {
4168	// fcmp o__ x, nan -> false
4169	// fcmp u__ x, nan -> true
4170	return exactClass(V: Src, M: CmpInst::isOrdered(predicate: Pred) ? fcNone : fcAllFlags);
4171	}
4172
4173	// fcmp ord x, zero|normal|subnormal|inf -> ~fcNan
4174	if (Pred == FCmpInst::FCMP_ORD)
4175	return exactClass(V: Src, M: ~fcNan);
4176
4177	// fcmp uno x, zero|normal|subnormal|inf -> fcNan
4178	if (Pred == FCmpInst::FCMP_UNO)
4179	return exactClass(V: Src, M: fcNan);
4180
4181	const bool IsFabs = LookThroughSrc && match(V: LHS, P: m_FAbs(Op0: m_Value(V&: Src)));
4182	if (IsFabs)
4183	RHSClass = llvm::inverse_fabs(Mask: RHSClass);
4184
4185	const bool IsZero = (OrigClass & fcZero) == OrigClass;
4186	if (IsZero) {
4187	assert(Pred != FCmpInst::FCMP_ORD && Pred != FCmpInst::FCMP_UNO);
4188	// Compares with fcNone are only exactly equal to fcZero if input denormals
4189	// are not flushed.
4190	// TODO: Handle DAZ by expanding masks to cover subnormal cases.
4191	if (!inputDenormalIsIEEE(F, Ty: LHS->getType()))
4192	return {nullptr, fcAllFlags, fcAllFlags};
4193
4194	switch (Pred) {
4195	case FCmpInst::FCMP_OEQ: // Match x == 0.0
4196	return exactClass(V: Src, M: fcZero);
4197	case FCmpInst::FCMP_UEQ: // Match isnan(x) || (x == 0.0)
4198	return exactClass(V: Src, M: fcZero | fcNan);
4199	case FCmpInst::FCMP_UNE: // Match (x != 0.0)
4200	return exactClass(V: Src, M: ~fcZero);
4201	case FCmpInst::FCMP_ONE: // Match !isnan(x) && x != 0.0
4202	return exactClass(V: Src, M: ~fcNan & ~fcZero);
4203	case FCmpInst::FCMP_ORD:
4204	// Canonical form of ord/uno is with a zero. We could also handle
4205	// non-canonical other non-NaN constants or LHS == RHS.
4206	return exactClass(V: Src, M: ~fcNan);
4207	case FCmpInst::FCMP_UNO:
4208	return exactClass(V: Src, M: fcNan);
4209	case FCmpInst::FCMP_OGT: // x > 0
4210	return exactClass(V: Src, M: fcPosSubnormal | fcPosNormal | fcPosInf);
4211	case FCmpInst::FCMP_UGT: // isnan(x) || x > 0
4212	return exactClass(V: Src, M: fcPosSubnormal | fcPosNormal | fcPosInf | fcNan);
4213	case FCmpInst::FCMP_OGE: // x >= 0
4214	return exactClass(V: Src, M: fcPositive | fcNegZero);
4215	case FCmpInst::FCMP_UGE: // isnan(x) || x >= 0
4216	return exactClass(V: Src, M: fcPositive | fcNegZero | fcNan);
4217	case FCmpInst::FCMP_OLT: // x < 0
4218	return exactClass(V: Src, M: fcNegSubnormal | fcNegNormal | fcNegInf);
4219	case FCmpInst::FCMP_ULT: // isnan(x) || x < 0
4220	return exactClass(V: Src, M: fcNegSubnormal | fcNegNormal | fcNegInf | fcNan);
4221	case FCmpInst::FCMP_OLE: // x <= 0
4222	return exactClass(V: Src, M: fcNegative | fcPosZero);
4223	case FCmpInst::FCMP_ULE: // isnan(x) || x <= 0
4224	return exactClass(V: Src, M: fcNegative | fcPosZero | fcNan);
4225	default:
4226	llvm_unreachable("all compare types are handled");
4227	}
4228
4229	return {nullptr, fcAllFlags, fcAllFlags};
4230	}
4231
4232	const bool IsDenormalRHS = (OrigClass & fcSubnormal) == OrigClass;
4233
4234	const bool IsInf = (OrigClass & fcInf) == OrigClass;
4235	if (IsInf) {
4236	FPClassTest Mask = fcAllFlags;
4237
4238	switch (Pred) {
4239	case FCmpInst::FCMP_OEQ:
4240	case FCmpInst::FCMP_UNE: {
4241	// Match __builtin_isinf patterns
4242	//
4243	// fcmp oeq x, +inf -> is_fpclass x, fcPosInf
4244	// fcmp oeq fabs(x), +inf -> is_fpclass x, fcInf
4245	// fcmp oeq x, -inf -> is_fpclass x, fcNegInf
4246	// fcmp oeq fabs(x), -inf -> is_fpclass x, 0 -> false
4247	//
4248	// fcmp une x, +inf -> is_fpclass x, ~fcPosInf
4249	// fcmp une fabs(x), +inf -> is_fpclass x, ~fcInf
4250	// fcmp une x, -inf -> is_fpclass x, ~fcNegInf
4251	// fcmp une fabs(x), -inf -> is_fpclass x, fcAllFlags -> true
4252	if (IsNegativeRHS) {
4253	Mask = fcNegInf;
4254	if (IsFabs)
4255	Mask = fcNone;
4256	} else {
4257	Mask = fcPosInf;
4258	if (IsFabs)
4259	Mask |= fcNegInf;
4260	}
4261	break;
4262	}
4263	case FCmpInst::FCMP_ONE:
4264	case FCmpInst::FCMP_UEQ: {
4265	// Match __builtin_isinf patterns
4266	// fcmp one x, -inf -> is_fpclass x, fcNegInf
4267	// fcmp one fabs(x), -inf -> is_fpclass x, ~fcNegInf & ~fcNan
4268	// fcmp one x, +inf -> is_fpclass x, ~fcNegInf & ~fcNan
4269	// fcmp one fabs(x), +inf -> is_fpclass x, ~fcInf & fcNan
4270	//
4271	// fcmp ueq x, +inf -> is_fpclass x, fcPosInf|fcNan
4272	// fcmp ueq (fabs x), +inf -> is_fpclass x, fcInf|fcNan
4273	// fcmp ueq x, -inf -> is_fpclass x, fcNegInf|fcNan
4274	// fcmp ueq fabs(x), -inf -> is_fpclass x, fcNan
4275	if (IsNegativeRHS) {
4276	Mask = ~fcNegInf & ~fcNan;
4277	if (IsFabs)
4278	Mask = ~fcNan;
4279	} else {
4280	Mask = ~fcPosInf & ~fcNan;
4281	if (IsFabs)
4282	Mask &= ~fcNegInf;
4283	}
4284
4285	break;
4286	}
4287	case FCmpInst::FCMP_OLT:
4288	case FCmpInst::FCMP_UGE: {
4289	if (IsNegativeRHS) {
4290	// No value is ordered and less than negative infinity.
4291	// All values are unordered with or at least negative infinity.
4292	// fcmp olt x, -inf -> false
4293	// fcmp uge x, -inf -> true
4294	Mask = fcNone;
4295	break;
4296	}
4297
4298	// fcmp olt fabs(x), +inf -> fcFinite
4299	// fcmp uge fabs(x), +inf -> ~fcFinite
4300	// fcmp olt x, +inf -> fcFinite|fcNegInf
4301	// fcmp uge x, +inf -> ~(fcFinite|fcNegInf)
4302	Mask = fcFinite;
4303	if (!IsFabs)
4304	Mask |= fcNegInf;
4305	break;
4306	}
4307	case FCmpInst::FCMP_OGE:
4308	case FCmpInst::FCMP_ULT: {
4309	if (IsNegativeRHS) {
4310	// fcmp oge x, -inf -> ~fcNan
4311	// fcmp oge fabs(x), -inf -> ~fcNan
4312	// fcmp ult x, -inf -> fcNan
4313	// fcmp ult fabs(x), -inf -> fcNan
4314	Mask = ~fcNan;
4315	break;
4316	}
4317
4318	// fcmp oge fabs(x), +inf -> fcInf
4319	// fcmp oge x, +inf -> fcPosInf
4320	// fcmp ult fabs(x), +inf -> ~fcInf
4321	// fcmp ult x, +inf -> ~fcPosInf
4322	Mask = fcPosInf;
4323	if (IsFabs)
4324	Mask |= fcNegInf;
4325	break;
4326	}
4327	case FCmpInst::FCMP_OGT:
4328	case FCmpInst::FCMP_ULE: {
4329	if (IsNegativeRHS) {
4330	// fcmp ogt x, -inf -> fcmp one x, -inf
4331	// fcmp ogt fabs(x), -inf -> fcmp ord x, x
4332	// fcmp ule x, -inf -> fcmp ueq x, -inf
4333	// fcmp ule fabs(x), -inf -> fcmp uno x, x
4334	Mask = IsFabs ? ~fcNan : ~(fcNegInf | fcNan);
4335	break;
4336	}
4337
4338	// No value is ordered and greater than infinity.
4339	Mask = fcNone;
4340	break;
4341	}
4342	case FCmpInst::FCMP_OLE:
4343	case FCmpInst::FCMP_UGT: {
4344	if (IsNegativeRHS) {
4345	Mask = IsFabs ? fcNone : fcNegInf;
4346	break;
4347	}
4348
4349	// fcmp ole x, +inf -> fcmp ord x, x
4350	// fcmp ole fabs(x), +inf -> fcmp ord x, x
4351	// fcmp ole x, -inf -> fcmp oeq x, -inf
4352	// fcmp ole fabs(x), -inf -> false
4353	Mask = ~fcNan;
4354	break;
4355	}
4356	default:
4357	llvm_unreachable("all compare types are handled");
4358	}
4359
4360	// Invert the comparison for the unordered cases.
4361	if (FCmpInst::isUnordered(predicate: Pred))
4362	Mask = ~Mask;
4363
4364	return exactClass(V: Src, M: Mask);
4365	}
4366
4367	if (Pred == FCmpInst::FCMP_OEQ)
4368	return {Src, RHSClass, fcAllFlags};
4369
4370	if (Pred == FCmpInst::FCMP_UEQ) {
4371	FPClassTest Class = RHSClass | fcNan;
4372	return {Src, Class, ~fcNan};
4373	}
4374
4375	if (Pred == FCmpInst::FCMP_ONE)
4376	return {Src, ~fcNan, RHSClass | fcNan};
4377
4378	if (Pred == FCmpInst::FCMP_UNE)
4379	return {Src, fcAllFlags, RHSClass};
4380
4381	assert((RHSClass == fcNone || RHSClass == fcPosNormal ||
4382	RHSClass == fcNegNormal || RHSClass == fcNormal ||
4383	RHSClass == fcPosSubnormal || RHSClass == fcNegSubnormal ||
4384	RHSClass == fcSubnormal) &&
4385	"should have been recognized as an exact class test");
4386
4387	if (IsNegativeRHS) {
4388	// TODO: Handle fneg(fabs)
4389	if (IsFabs) {
4390	// fabs(x) o> -k -> fcmp ord x, x
4391	// fabs(x) u> -k -> true
4392	// fabs(x) o< -k -> false
4393	// fabs(x) u< -k -> fcmp uno x, x
4394	switch (Pred) {
4395	case FCmpInst::FCMP_OGT:
4396	case FCmpInst::FCMP_OGE:
4397	return {Src, ~fcNan, fcNan};
4398	case FCmpInst::FCMP_UGT:
4399	case FCmpInst::FCMP_UGE:
4400	return {Src, fcAllFlags, fcNone};
4401	case FCmpInst::FCMP_OLT:
4402	case FCmpInst::FCMP_OLE:
4403	return {Src, fcNone, fcAllFlags};
4404	case FCmpInst::FCMP_ULT:
4405	case FCmpInst::FCMP_ULE:
4406	return {Src, fcNan, ~fcNan};
4407	default:
4408	break;
4409	}
4410
4411	return {nullptr, fcAllFlags, fcAllFlags};
4412	}
4413
4414	FPClassTest ClassesLE = fcNegInf | fcNegNormal;
4415	FPClassTest ClassesGE = fcPositive | fcNegZero | fcNegSubnormal;
4416
4417	if (IsDenormalRHS)
4418	ClassesLE |= fcNegSubnormal;
4419	else
4420	ClassesGE |= fcNegNormal;
4421
4422	switch (Pred) {
4423	case FCmpInst::FCMP_OGT:
4424	case FCmpInst::FCMP_OGE:
4425	return {Src, ClassesGE, ~ClassesGE | RHSClass};
4426	case FCmpInst::FCMP_UGT:
4427	case FCmpInst::FCMP_UGE:
4428	return {Src, ClassesGE | fcNan, ~(ClassesGE | fcNan) | RHSClass};
4429	case FCmpInst::FCMP_OLT:
4430	case FCmpInst::FCMP_OLE:
4431	return {Src, ClassesLE, ~ClassesLE | RHSClass};
4432	case FCmpInst::FCMP_ULT:
4433	case FCmpInst::FCMP_ULE:
4434	return {Src, ClassesLE | fcNan, ~(ClassesLE | fcNan) | RHSClass};
4435	default:
4436	break;
4437	}
4438	} else if (IsPositiveRHS) {
4439	FPClassTest ClassesGE = fcPosNormal | fcPosInf;
4440	FPClassTest ClassesLE = fcNegative | fcPosZero | fcPosSubnormal;
4441	if (IsDenormalRHS)
4442	ClassesGE |= fcPosSubnormal;
4443	else
4444	ClassesLE |= fcPosNormal;
4445
4446	if (IsFabs) {
4447	ClassesGE = llvm::inverse_fabs(Mask: ClassesGE);
4448	ClassesLE = llvm::inverse_fabs(Mask: ClassesLE);
4449	}
4450
4451	switch (Pred) {
4452	case FCmpInst::FCMP_OGT:
4453	case FCmpInst::FCMP_OGE:
4454	return {Src, ClassesGE, ~ClassesGE | RHSClass};
4455	case FCmpInst::FCMP_UGT:
4456	case FCmpInst::FCMP_UGE:
4457	return {Src, ClassesGE | fcNan, ~(ClassesGE | fcNan) | RHSClass};
4458	case FCmpInst::FCMP_OLT:
4459	case FCmpInst::FCMP_OLE:
4460	return {Src, ClassesLE, ~ClassesLE | RHSClass};
4461	case FCmpInst::FCMP_ULT:
4462	case FCmpInst::FCMP_ULE:
4463	return {Src, ClassesLE | fcNan, ~(ClassesLE | fcNan) | RHSClass};
4464	default:
4465	break;
4466	}
4467	}
4468
4469	return {nullptr, fcAllFlags, fcAllFlags};
4470	}
4471
4472	std::tuple<Value *, FPClassTest, FPClassTest>
4473	llvm::fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
4474	const APFloat &ConstRHS, bool LookThroughSrc) {
4475	// We can refine checks against smallest normal / largest denormal to an
4476	// exact class test.
4477	if (!ConstRHS.isNegative() && ConstRHS.isSmallestNormalized()) {
4478	Value *Src = LHS;
4479	const bool IsFabs = LookThroughSrc && match(V: LHS, P: m_FAbs(Op0: m_Value(V&: Src)));
4480
4481	FPClassTest Mask;
4482	// Match pattern that's used in __builtin_isnormal.
4483	switch (Pred) {
4484	case FCmpInst::FCMP_OLT:
4485	case FCmpInst::FCMP_UGE: {
4486	// fcmp olt x, smallest_normal -> fcNegInf|fcNegNormal|fcSubnormal|fcZero
4487	// fcmp olt fabs(x), smallest_normal -> fcSubnormal|fcZero
4488	// fcmp uge x, smallest_normal -> fcNan|fcPosNormal|fcPosInf
4489	// fcmp uge fabs(x), smallest_normal -> ~(fcSubnormal|fcZero)
4490	Mask = fcZero | fcSubnormal;
4491	if (!IsFabs)
4492	Mask |= fcNegNormal | fcNegInf;
4493
4494	break;
4495	}
4496	case FCmpInst::FCMP_OGE:
4497	case FCmpInst::FCMP_ULT: {
4498	// fcmp oge x, smallest_normal -> fcPosNormal | fcPosInf
4499	// fcmp oge fabs(x), smallest_normal -> fcInf | fcNormal
4500	// fcmp ult x, smallest_normal -> ~(fcPosNormal | fcPosInf)
4501	// fcmp ult fabs(x), smallest_normal -> ~(fcInf | fcNormal)
4502	Mask = fcPosInf | fcPosNormal;
4503	if (IsFabs)
4504	Mask |= fcNegInf | fcNegNormal;
4505	break;
4506	}
4507	default:
4508	return fcmpImpliesClass(Pred, F, LHS, RHSClass: ConstRHS.classify(),
4509	LookThroughSrc);
4510	}
4511
4512	// Invert the comparison for the unordered cases.
4513	if (FCmpInst::isUnordered(predicate: Pred))
4514	Mask = ~Mask;
4515
4516	return exactClass(V: Src, M: Mask);
4517	}
4518
4519	return fcmpImpliesClass(Pred, F, LHS, RHSClass: ConstRHS.classify(), LookThroughSrc);
4520	}
4521
4522	std::tuple<Value *, FPClassTest, FPClassTest>
4523	llvm::fcmpImpliesClass(CmpInst::Predicate Pred, const Function &F, Value *LHS,
4524	Value *RHS, bool LookThroughSrc) {
4525	const APFloat *ConstRHS;
4526	if (!match(V: RHS, P: m_APFloatAllowPoison(Res&: ConstRHS)))
4527	return {nullptr, fcAllFlags, fcAllFlags};
4528
4529	// TODO: Just call computeKnownFPClass for RHS to handle non-constants.
4530	return fcmpImpliesClass(Pred, F, LHS, ConstRHS: *ConstRHS, LookThroughSrc);
4531	}
4532
4533	static void computeKnownFPClassFromCond(const Value *V, Value *Cond,
4534	bool CondIsTrue,
4535	const Instruction *CxtI,
4536	KnownFPClass &KnownFromContext) {
4537	CmpInst::Predicate Pred;
4538	Value *LHS;
4539	uint64_t ClassVal = 0;
4540	const APFloat *CRHS;
4541	const APInt *RHS;
4542	if (match(V: Cond, P: m_FCmp(Pred, L: m_Value(V&: LHS), R: m_APFloat(Res&: CRHS)))) {
4543	auto [CmpVal, MaskIfTrue, MaskIfFalse] = fcmpImpliesClass(
4544	Pred, F: *CxtI->getParent()->getParent(), LHS, ConstRHS: *CRHS, LookThroughSrc: LHS != V);
4545	if (CmpVal == V)
4546	KnownFromContext.knownNot(RuleOut: ~(CondIsTrue ? MaskIfTrue : MaskIfFalse));
4547	} else if (match(Cond, m_Intrinsic<Intrinsic::is_fpclass>(
4548	m_Value(LHS), m_ConstantInt(ClassVal)))) {
4549	FPClassTest Mask = static_cast<FPClassTest>(ClassVal);
4550	KnownFromContext.knownNot(RuleOut: CondIsTrue ? ~Mask : Mask);
4551	} else if (match(V: Cond, P: m_ICmp(Pred, L: m_ElementWiseBitCast(Op: m_Value(V&: LHS)),
4552	R: m_APInt(Res&: RHS)))) {
4553	bool TrueIfSigned;
4554	if (!isSignBitCheck(Pred, RHS: *RHS, TrueIfSigned))
4555	return;
4556	if (TrueIfSigned == CondIsTrue)
4557	KnownFromContext.signBitMustBeOne();
4558	else
4559	KnownFromContext.signBitMustBeZero();
4560	}
4561	}
4562
4563	static KnownFPClass computeKnownFPClassFromContext(const Value *V,
4564	const SimplifyQuery &Q) {
4565	KnownFPClass KnownFromContext;
4566
4567	if (!Q.CxtI)
4568	return KnownFromContext;
4569
4570	if (Q.DC && Q.DT) {
4571	// Handle dominating conditions.
4572	for (BranchInst *BI : Q.DC->conditionsFor(V)) {
4573	Value *Cond = BI->getCondition();
4574
4575	BasicBlockEdge Edge0(BI->getParent(), BI->getSuccessor(i: 0));
4576	if (Q.DT->dominates(BBE: Edge0, BB: Q.CxtI->getParent()))
4577	computeKnownFPClassFromCond(V, Cond, /*CondIsTrue=*/true, CxtI: Q.CxtI,
4578	KnownFromContext);
4579
4580	BasicBlockEdge Edge1(BI->getParent(), BI->getSuccessor(i: 1));
4581	if (Q.DT->dominates(BBE: Edge1, BB: Q.CxtI->getParent()))
4582	computeKnownFPClassFromCond(V, Cond, /*CondIsTrue=*/false, CxtI: Q.CxtI,
4583	KnownFromContext);
4584	}
4585	}
4586
4587	if (!Q.AC)
4588	return KnownFromContext;
4589
4590	// Try to restrict the floating-point classes based on information from
4591	// assumptions.
4592	for (auto &AssumeVH : Q.AC->assumptionsFor(V)) {
4593	if (!AssumeVH)
4594	continue;
4595	CallInst *I = cast<CallInst>(Val&: AssumeVH);
4596
4597	assert(I->getFunction() == Q.CxtI->getParent()->getParent() &&
4598	"Got assumption for the wrong function!");
4599	assert(I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume &&
4600	"must be an assume intrinsic");
4601
4602	if (!isValidAssumeForContext(Inv: I, CxtI: Q.CxtI, DT: Q.DT))
4603	continue;
4604
4605	computeKnownFPClassFromCond(V, Cond: I->getArgOperand(i: 0), /*CondIsTrue=*/true,
4606	CxtI: Q.CxtI, KnownFromContext);
4607	}
4608
4609	return KnownFromContext;
4610	}
4611
4612	void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
4613	FPClassTest InterestedClasses, KnownFPClass &Known,
4614	unsigned Depth, const SimplifyQuery &Q);
4615
4616	static void computeKnownFPClass(const Value *V, KnownFPClass &Known,
4617	FPClassTest InterestedClasses, unsigned Depth,
4618	const SimplifyQuery &Q) {
4619	auto *FVTy = dyn_cast<FixedVectorType>(Val: V->getType());
4620	APInt DemandedElts =
4621	FVTy ? APInt::getAllOnes(numBits: FVTy->getNumElements()) : APInt(1, 1);
4622	computeKnownFPClass(V, DemandedElts, InterestedClasses, Known, Depth, Q);
4623	}
4624
4625	static void computeKnownFPClassForFPTrunc(const Operator *Op,
4626	const APInt &DemandedElts,
4627	FPClassTest InterestedClasses,
4628	KnownFPClass &Known, unsigned Depth,
4629	const SimplifyQuery &Q) {
4630	if ((InterestedClasses &
4631	(KnownFPClass::OrderedLessThanZeroMask | fcNan)) == fcNone)
4632	return;
4633
4634	KnownFPClass KnownSrc;
4635	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts, InterestedClasses,
4636	Known&: KnownSrc, Depth: Depth + 1, Q);
4637
4638	// Sign should be preserved
4639	// TODO: Handle cannot be ordered greater than zero
4640	if (KnownSrc.cannotBeOrderedLessThanZero())
4641	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
4642
4643	Known.propagateNaN(Src: KnownSrc, PreserveSign: true);
4644
4645	// Infinity needs a range check.
4646	}
4647
4648	void computeKnownFPClass(const Value *V, const APInt &DemandedElts,
4649	FPClassTest InterestedClasses, KnownFPClass &Known,
4650	unsigned Depth, const SimplifyQuery &Q) {
4651	assert(Known.isUnknown() && "should not be called with known information");
4652
4653	if (!DemandedElts) {
4654	// No demanded elts, better to assume we don't know anything.
4655	Known.resetAll();
4656	return;
4657	}
4658
4659	assert(Depth <= MaxAnalysisRecursionDepth && "Limit Search Depth");
4660
4661	if (auto *CFP = dyn_cast<ConstantFP>(Val: V)) {
4662	Known.KnownFPClasses = CFP->getValueAPF().classify();
4663	Known.SignBit = CFP->isNegative();
4664	return;
4665	}
4666
4667	if (isa<ConstantAggregateZero>(Val: V)) {
4668	Known.KnownFPClasses = fcPosZero;
4669	Known.SignBit = false;
4670	return;
4671	}
4672
4673	if (isa<PoisonValue>(Val: V)) {
4674	Known.KnownFPClasses = fcNone;
4675	Known.SignBit = false;
4676	return;
4677	}
4678
4679	// Try to handle fixed width vector constants
4680	auto *VFVTy = dyn_cast<FixedVectorType>(Val: V->getType());
4681	const Constant *CV = dyn_cast<Constant>(Val: V);
4682	if (VFVTy && CV) {
4683	Known.KnownFPClasses = fcNone;
4684	bool SignBitAllZero = true;
4685	bool SignBitAllOne = true;
4686
4687	// For vectors, verify that each element is not NaN.
4688	unsigned NumElts = VFVTy->getNumElements();
4689	for (unsigned i = 0; i != NumElts; ++i) {
4690	if (!DemandedElts[i])
4691	continue;
4692
4693	Constant *Elt = CV->getAggregateElement(Elt: i);
4694	if (!Elt) {
4695	Known = KnownFPClass();
4696	return;
4697	}
4698	if (isa<UndefValue>(Val: Elt))
4699	continue;
4700	auto *CElt = dyn_cast<ConstantFP>(Val: Elt);
4701	if (!CElt) {
4702	Known = KnownFPClass();
4703	return;
4704	}
4705
4706	const APFloat &C = CElt->getValueAPF();
4707	Known.KnownFPClasses |= C.classify();
4708	if (C.isNegative())
4709	SignBitAllZero = false;
4710	else
4711	SignBitAllOne = false;
4712	}
4713	if (SignBitAllOne != SignBitAllZero)
4714	Known.SignBit = SignBitAllOne;
4715	return;
4716	}
4717
4718	FPClassTest KnownNotFromFlags = fcNone;
4719	if (const auto *CB = dyn_cast<CallBase>(Val: V))
4720	KnownNotFromFlags |= CB->getRetNoFPClass();
4721	else if (const auto *Arg = dyn_cast<Argument>(Val: V))
4722	KnownNotFromFlags |= Arg->getNoFPClass();
4723
4724	const Operator *Op = dyn_cast<Operator>(Val: V);
4725	if (const FPMathOperator *FPOp = dyn_cast_or_null<FPMathOperator>(Val: Op)) {
4726	if (FPOp->hasNoNaNs())
4727	KnownNotFromFlags |= fcNan;
4728	if (FPOp->hasNoInfs())
4729	KnownNotFromFlags |= fcInf;
4730	}
4731
4732	KnownFPClass AssumedClasses = computeKnownFPClassFromContext(V, Q);
4733	KnownNotFromFlags |= ~AssumedClasses.KnownFPClasses;
4734
4735	// We no longer need to find out about these bits from inputs if we can
4736	// assume this from flags/attributes.
4737	InterestedClasses &= ~KnownNotFromFlags;
4738
4739	auto ClearClassesFromFlags = make_scope_exit(F: [=, &Known] {
4740	Known.knownNot(RuleOut: KnownNotFromFlags);
4741	if (!Known.SignBit && AssumedClasses.SignBit) {
4742	if (*AssumedClasses.SignBit)
4743	Known.signBitMustBeOne();
4744	else
4745	Known.signBitMustBeZero();
4746	}
4747	});
4748
4749	if (!Op)
4750	return;
4751
4752	// All recursive calls that increase depth must come after this.
4753	if (Depth == MaxAnalysisRecursionDepth)
4754	return;
4755
4756	const unsigned Opc = Op->getOpcode();
4757	switch (Opc) {
4758	case Instruction::FNeg: {
4759	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts, InterestedClasses,
4760	Known, Depth: Depth + 1, Q);
4761	Known.fneg();
4762	break;
4763	}
4764	case Instruction::Select: {
4765	Value *Cond = Op->getOperand(i: 0);
4766	Value *LHS = Op->getOperand(i: 1);
4767	Value *RHS = Op->getOperand(i: 2);
4768
4769	FPClassTest FilterLHS = fcAllFlags;
4770	FPClassTest FilterRHS = fcAllFlags;
4771
4772	Value *TestedValue = nullptr;
4773	FPClassTest MaskIfTrue = fcAllFlags;
4774	FPClassTest MaskIfFalse = fcAllFlags;
4775	uint64_t ClassVal = 0;
4776	const Function *F = cast<Instruction>(Val: Op)->getFunction();
4777	CmpInst::Predicate Pred;
4778	Value *CmpLHS, *CmpRHS;
4779	if (F && match(V: Cond, P: m_FCmp(Pred, L: m_Value(V&: CmpLHS), R: m_Value(V&: CmpRHS)))) {
4780	// If the select filters out a value based on the class, it no longer
4781	// participates in the class of the result
4782
4783	// TODO: In some degenerate cases we can infer something if we try again
4784	// without looking through sign operations.
4785	bool LookThroughFAbsFNeg = CmpLHS != LHS && CmpLHS != RHS;
4786	std::tie(args&: TestedValue, args&: MaskIfTrue, args&: MaskIfFalse) =
4787	fcmpImpliesClass(Pred, F: *F, LHS: CmpLHS, RHS: CmpRHS, LookThroughSrc: LookThroughFAbsFNeg);
4788	} else if (match(Cond,
4789	m_Intrinsic<Intrinsic::is_fpclass>(
4790	m_Value(TestedValue), m_ConstantInt(ClassVal)))) {
4791	FPClassTest TestedMask = static_cast<FPClassTest>(ClassVal);
4792	MaskIfTrue = TestedMask;
4793	MaskIfFalse = ~TestedMask;
4794	}
4795
4796	if (TestedValue == LHS) {
4797	// match !isnan(x) ? x : y
4798	FilterLHS = MaskIfTrue;
4799	} else if (TestedValue == RHS) { // && IsExactClass
4800	// match !isnan(x) ? y : x
4801	FilterRHS = MaskIfFalse;
4802	}
4803
4804	KnownFPClass Known2;
4805	computeKnownFPClass(V: LHS, DemandedElts, InterestedClasses: InterestedClasses & FilterLHS, Known,
4806	Depth: Depth + 1, Q);
4807	Known.KnownFPClasses &= FilterLHS;
4808
4809	computeKnownFPClass(V: RHS, DemandedElts, InterestedClasses: InterestedClasses & FilterRHS,
4810	Known&: Known2, Depth: Depth + 1, Q);
4811	Known2.KnownFPClasses &= FilterRHS;
4812
4813	Known |= Known2;
4814	break;
4815	}
4816	case Instruction::Call: {
4817	const CallInst *II = cast<CallInst>(Val: Op);
4818	const Intrinsic::ID IID = II->getIntrinsicID();
4819	switch (IID) {
4820	case Intrinsic::fabs: {
4821	if ((InterestedClasses & (fcNan | fcPositive)) != fcNone) {
4822	// If we only care about the sign bit we don't need to inspect the
4823	// operand.
4824	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts,
4825	InterestedClasses, Known, Depth: Depth + 1, Q);
4826	}
4827
4828	Known.fabs();
4829	break;
4830	}
4831	case Intrinsic::copysign: {
4832	KnownFPClass KnownSign;
4833
4834	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
4835	Known, Depth: Depth + 1, Q);
4836	computeKnownFPClass(V: II->getArgOperand(i: 1), DemandedElts, InterestedClasses,
4837	Known&: KnownSign, Depth: Depth + 1, Q);
4838	Known.copysign(Sign: KnownSign);
4839	break;
4840	}
4841	case Intrinsic::fma:
4842	case Intrinsic::fmuladd: {
4843	if ((InterestedClasses & fcNegative) == fcNone)
4844	break;
4845
4846	if (II->getArgOperand(i: 0) != II->getArgOperand(i: 1))
4847	break;
4848
4849	// The multiply cannot be -0 and therefore the add can't be -0
4850	Known.knownNot(RuleOut: fcNegZero);
4851
4852	// x * x + y is non-negative if y is non-negative.
4853	KnownFPClass KnownAddend;
4854	computeKnownFPClass(V: II->getArgOperand(i: 2), DemandedElts, InterestedClasses,
4855	Known&: KnownAddend, Depth: Depth + 1, Q);
4856
4857	if (KnownAddend.cannotBeOrderedLessThanZero())
4858	Known.knownNot(RuleOut: fcNegative);
4859	break;
4860	}
4861	case Intrinsic::sqrt:
4862	case Intrinsic::experimental_constrained_sqrt: {
4863	KnownFPClass KnownSrc;
4864	FPClassTest InterestedSrcs = InterestedClasses;
4865	if (InterestedClasses & fcNan)
4866	InterestedSrcs |= KnownFPClass::OrderedLessThanZeroMask;
4867
4868	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses: InterestedSrcs,
4869	Known&: KnownSrc, Depth: Depth + 1, Q);
4870
4871	if (KnownSrc.isKnownNeverPosInfinity())
4872	Known.knownNot(RuleOut: fcPosInf);
4873	if (KnownSrc.isKnownNever(Mask: fcSNan))
4874	Known.knownNot(RuleOut: fcSNan);
4875
4876	// Any negative value besides -0 returns a nan.
4877	if (KnownSrc.isKnownNeverNaN() && KnownSrc.cannotBeOrderedLessThanZero())
4878	Known.knownNot(RuleOut: fcNan);
4879
4880	// The only negative value that can be returned is -0 for -0 inputs.
4881	Known.knownNot(RuleOut: fcNegInf | fcNegSubnormal | fcNegNormal);
4882
4883	// If the input denormal mode could be PreserveSign, a negative
4884	// subnormal input could produce a negative zero output.
4885	const Function *F = II->getFunction();
4886	if (Q.IIQ.hasNoSignedZeros(Op: II) ||
4887	(F && KnownSrc.isKnownNeverLogicalNegZero(F: *F, Ty: II->getType()))) {
4888	Known.knownNot(RuleOut: fcNegZero);
4889	if (KnownSrc.isKnownNeverNaN())
4890	Known.signBitMustBeZero();
4891	}
4892
4893	break;
4894	}
4895	case Intrinsic::sin:
4896	case Intrinsic::cos: {
4897	// Return NaN on infinite inputs.
4898	KnownFPClass KnownSrc;
4899	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
4900	Known&: KnownSrc, Depth: Depth + 1, Q);
4901	Known.knownNot(RuleOut: fcInf);
4902	if (KnownSrc.isKnownNeverNaN() && KnownSrc.isKnownNeverInfinity())
4903	Known.knownNot(RuleOut: fcNan);
4904	break;
4905	}
4906	case Intrinsic::maxnum:
4907	case Intrinsic::minnum:
4908	case Intrinsic::minimum:
4909	case Intrinsic::maximum: {
4910	KnownFPClass KnownLHS, KnownRHS;
4911	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
4912	Known&: KnownLHS, Depth: Depth + 1, Q);
4913	computeKnownFPClass(V: II->getArgOperand(i: 1), DemandedElts, InterestedClasses,
4914	Known&: KnownRHS, Depth: Depth + 1, Q);
4915
4916	bool NeverNaN = KnownLHS.isKnownNeverNaN() || KnownRHS.isKnownNeverNaN();
4917	Known = KnownLHS | KnownRHS;
4918
4919	// If either operand is not NaN, the result is not NaN.
4920	if (NeverNaN && (IID == Intrinsic::minnum || IID == Intrinsic::maxnum))
4921	Known.knownNot(RuleOut: fcNan);
4922
4923	if (IID == Intrinsic::maxnum) {
4924	// If at least one operand is known to be positive, the result must be
4925	// positive.
4926	if ((KnownLHS.cannotBeOrderedLessThanZero() &&
4927	KnownLHS.isKnownNeverNaN()) ||
4928	(KnownRHS.cannotBeOrderedLessThanZero() &&
4929	KnownRHS.isKnownNeverNaN()))
4930	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
4931	} else if (IID == Intrinsic::maximum) {
4932	// If at least one operand is known to be positive, the result must be
4933	// positive.
4934	if (KnownLHS.cannotBeOrderedLessThanZero() ||
4935	KnownRHS.cannotBeOrderedLessThanZero())
4936	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
4937	} else if (IID == Intrinsic::minnum) {
4938	// If at least one operand is known to be negative, the result must be
4939	// negative.
4940	if ((KnownLHS.cannotBeOrderedGreaterThanZero() &&
4941	KnownLHS.isKnownNeverNaN()) ||
4942	(KnownRHS.cannotBeOrderedGreaterThanZero() &&
4943	KnownRHS.isKnownNeverNaN()))
4944	Known.knownNot(RuleOut: KnownFPClass::OrderedGreaterThanZeroMask);
4945	} else {
4946	// If at least one operand is known to be negative, the result must be
4947	// negative.
4948	if (KnownLHS.cannotBeOrderedGreaterThanZero() ||
4949	KnownRHS.cannotBeOrderedGreaterThanZero())
4950	Known.knownNot(RuleOut: KnownFPClass::OrderedGreaterThanZeroMask);
4951	}
4952
4953	// Fixup zero handling if denormals could be returned as a zero.
4954	//
4955	// As there's no spec for denormal flushing, be conservative with the
4956	// treatment of denormals that could be flushed to zero. For older
4957	// subtargets on AMDGPU the min/max instructions would not flush the
4958	// output and return the original value.
4959	//
4960	if ((Known.KnownFPClasses & fcZero) != fcNone &&
4961	!Known.isKnownNeverSubnormal()) {
4962	const Function *Parent = II->getFunction();
4963	if (!Parent)
4964	break;
4965
4966	DenormalMode Mode = Parent->getDenormalMode(
4967	FPType: II->getType()->getScalarType()->getFltSemantics());
4968	if (Mode != DenormalMode::getIEEE())
4969	Known.KnownFPClasses |= fcZero;
4970	}
4971
4972	if (Known.isKnownNeverNaN()) {
4973	if (KnownLHS.SignBit && KnownRHS.SignBit &&
4974	*KnownLHS.SignBit == *KnownRHS.SignBit) {
4975	if (*KnownLHS.SignBit)
4976	Known.signBitMustBeOne();
4977	else
4978	Known.signBitMustBeZero();
4979	} else if ((IID == Intrinsic::maximum || IID == Intrinsic::minimum) ||
4980	((KnownLHS.isKnownNeverNegZero() ||
4981	KnownRHS.isKnownNeverPosZero()) &&
4982	(KnownLHS.isKnownNeverPosZero() ||
4983	KnownRHS.isKnownNeverNegZero()))) {
4984	if ((IID == Intrinsic::maximum || IID == Intrinsic::maxnum) &&
4985	(KnownLHS.SignBit == false || KnownRHS.SignBit == false))
4986	Known.signBitMustBeZero();
4987	else if ((IID == Intrinsic::minimum || IID == Intrinsic::minnum) &&
4988	(KnownLHS.SignBit == true || KnownRHS.SignBit == true))
4989	Known.signBitMustBeOne();
4990	}
4991	}
4992	break;
4993	}
4994	case Intrinsic::canonicalize: {
4995	KnownFPClass KnownSrc;
4996	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
4997	Known&: KnownSrc, Depth: Depth + 1, Q);
4998
4999	// This is essentially a stronger form of
5000	// propagateCanonicalizingSrc. Other "canonicalizing" operations don't
5001	// actually have an IR canonicalization guarantee.
5002
5003	// Canonicalize may flush denormals to zero, so we have to consider the
5004	// denormal mode to preserve known-not-0 knowledge.
5005	Known.KnownFPClasses = KnownSrc.KnownFPClasses | fcZero | fcQNan;
5006
5007	// Stronger version of propagateNaN
5008	// Canonicalize is guaranteed to quiet signaling nans.
5009	if (KnownSrc.isKnownNeverNaN())
5010	Known.knownNot(RuleOut: fcNan);
5011	else
5012	Known.knownNot(RuleOut: fcSNan);
5013
5014	const Function *F = II->getFunction();
5015	if (!F)
5016	break;
5017
5018	// If the parent function flushes denormals, the canonical output cannot
5019	// be a denormal.
5020	const fltSemantics &FPType =
5021	II->getType()->getScalarType()->getFltSemantics();
5022	DenormalMode DenormMode = F->getDenormalMode(FPType);
5023	if (DenormMode == DenormalMode::getIEEE()) {
5024	if (KnownSrc.isKnownNever(Mask: fcPosZero))
5025	Known.knownNot(RuleOut: fcPosZero);
5026	if (KnownSrc.isKnownNever(Mask: fcNegZero))
5027	Known.knownNot(RuleOut: fcNegZero);
5028	break;
5029	}
5030
5031	if (DenormMode.inputsAreZero() || DenormMode.outputsAreZero())
5032	Known.knownNot(RuleOut: fcSubnormal);
5033
5034	if (DenormMode.Input == DenormalMode::PositiveZero ||
5035	(DenormMode.Output == DenormalMode::PositiveZero &&
5036	DenormMode.Input == DenormalMode::IEEE))
5037	Known.knownNot(RuleOut: fcNegZero);
5038
5039	break;
5040	}
5041	case Intrinsic::vector_reduce_fmax:
5042	case Intrinsic::vector_reduce_fmin:
5043	case Intrinsic::vector_reduce_fmaximum:
5044	case Intrinsic::vector_reduce_fminimum: {
5045	// reduce min/max will choose an element from one of the vector elements,
5046	// so we can infer and class information that is common to all elements.
5047	Known = computeKnownFPClass(V: II->getArgOperand(i: 0), FMF: II->getFastMathFlags(),
5048	InterestedClasses, Depth: Depth + 1, SQ: Q);
5049	// Can only propagate sign if output is never NaN.
5050	if (!Known.isKnownNeverNaN())
5051	Known.SignBit.reset();
5052	break;
5053	}
5054	case Intrinsic::trunc:
5055	case Intrinsic::floor:
5056	case Intrinsic::ceil:
5057	case Intrinsic::rint:
5058	case Intrinsic::nearbyint:
5059	case Intrinsic::round:
5060	case Intrinsic::roundeven: {
5061	KnownFPClass KnownSrc;
5062	FPClassTest InterestedSrcs = InterestedClasses;
5063	if (InterestedSrcs & fcPosFinite)
5064	InterestedSrcs |= fcPosFinite;
5065	if (InterestedSrcs & fcNegFinite)
5066	InterestedSrcs |= fcNegFinite;
5067	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses: InterestedSrcs,
5068	Known&: KnownSrc, Depth: Depth + 1, Q);
5069
5070	// Integer results cannot be subnormal.
5071	Known.knownNot(RuleOut: fcSubnormal);
5072
5073	Known.propagateNaN(Src: KnownSrc, PreserveSign: true);
5074
5075	// Pass through infinities, except PPC_FP128 is a special case for
5076	// intrinsics other than trunc.
5077	if (IID == Intrinsic::trunc || !V->getType()->isMultiUnitFPType()) {
5078	if (KnownSrc.isKnownNeverPosInfinity())
5079	Known.knownNot(RuleOut: fcPosInf);
5080	if (KnownSrc.isKnownNeverNegInfinity())
5081	Known.knownNot(RuleOut: fcNegInf);
5082	}
5083
5084	// Negative round ups to 0 produce -0
5085	if (KnownSrc.isKnownNever(Mask: fcPosFinite))
5086	Known.knownNot(RuleOut: fcPosFinite);
5087	if (KnownSrc.isKnownNever(Mask: fcNegFinite))
5088	Known.knownNot(RuleOut: fcNegFinite);
5089
5090	break;
5091	}
5092	case Intrinsic::exp:
5093	case Intrinsic::exp2:
5094	case Intrinsic::exp10: {
5095	Known.knownNot(RuleOut: fcNegative);
5096	if ((InterestedClasses & fcNan) == fcNone)
5097	break;
5098
5099	KnownFPClass KnownSrc;
5100	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
5101	Known&: KnownSrc, Depth: Depth + 1, Q);
5102	if (KnownSrc.isKnownNeverNaN()) {
5103	Known.knownNot(RuleOut: fcNan);
5104	Known.signBitMustBeZero();
5105	}
5106
5107	break;
5108	}
5109	case Intrinsic::fptrunc_round: {
5110	computeKnownFPClassForFPTrunc(Op, DemandedElts, InterestedClasses, Known,
5111	Depth, Q);
5112	break;
5113	}
5114	case Intrinsic::log:
5115	case Intrinsic::log10:
5116	case Intrinsic::log2:
5117	case Intrinsic::experimental_constrained_log:
5118	case Intrinsic::experimental_constrained_log10:
5119	case Intrinsic::experimental_constrained_log2: {
5120	// log(+inf) -> +inf
5121	// log([+-]0.0) -> -inf
5122	// log(-inf) -> nan
5123	// log(-x) -> nan
5124	if ((InterestedClasses & (fcNan | fcInf)) == fcNone)
5125	break;
5126
5127	FPClassTest InterestedSrcs = InterestedClasses;
5128	if ((InterestedClasses & fcNegInf) != fcNone)
5129	InterestedSrcs |= fcZero | fcSubnormal;
5130	if ((InterestedClasses & fcNan) != fcNone)
5131	InterestedSrcs |= fcNan | (fcNegative & ~fcNan);
5132
5133	KnownFPClass KnownSrc;
5134	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses: InterestedSrcs,
5135	Known&: KnownSrc, Depth: Depth + 1, Q);
5136
5137	if (KnownSrc.isKnownNeverPosInfinity())
5138	Known.knownNot(RuleOut: fcPosInf);
5139
5140	if (KnownSrc.isKnownNeverNaN() && KnownSrc.cannotBeOrderedLessThanZero())
5141	Known.knownNot(RuleOut: fcNan);
5142
5143	const Function *F = II->getFunction();
5144	if (F && KnownSrc.isKnownNeverLogicalZero(F: *F, Ty: II->getType()))
5145	Known.knownNot(RuleOut: fcNegInf);
5146
5147	break;
5148	}
5149	case Intrinsic::powi: {
5150	if ((InterestedClasses & fcNegative) == fcNone)
5151	break;
5152
5153	const Value *Exp = II->getArgOperand(i: 1);
5154	Type *ExpTy = Exp->getType();
5155	unsigned BitWidth = ExpTy->getScalarType()->getIntegerBitWidth();
5156	KnownBits ExponentKnownBits(BitWidth);
5157	computeKnownBits(V: Exp, DemandedElts: isa<VectorType>(Val: ExpTy) ? DemandedElts : APInt(1, 1),
5158	Known&: ExponentKnownBits, Depth: Depth + 1, Q);
5159
5160	if (ExponentKnownBits.Zero[0]) { // Is even
5161	Known.knownNot(RuleOut: fcNegative);
5162	break;
5163	}
5164
5165	// Given that exp is an integer, here are the
5166	// ways that pow can return a negative value:
5167	//
5168	// pow(-x, exp) --> negative if exp is odd and x is negative.
5169	// pow(-0, exp) --> -inf if exp is negative odd.
5170	// pow(-0, exp) --> -0 if exp is positive odd.
5171	// pow(-inf, exp) --> -0 if exp is negative odd.
5172	// pow(-inf, exp) --> -inf if exp is positive odd.
5173	KnownFPClass KnownSrc;
5174	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses: fcNegative,
5175	Known&: KnownSrc, Depth: Depth + 1, Q);
5176	if (KnownSrc.isKnownNever(Mask: fcNegative))
5177	Known.knownNot(RuleOut: fcNegative);
5178	break;
5179	}
5180	case Intrinsic::ldexp: {
5181	KnownFPClass KnownSrc;
5182	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
5183	Known&: KnownSrc, Depth: Depth + 1, Q);
5184	Known.propagateNaN(Src: KnownSrc, /*PropagateSign=*/PreserveSign: true);
5185
5186	// Sign is preserved, but underflows may produce zeroes.
5187	if (KnownSrc.isKnownNever(Mask: fcNegative))
5188	Known.knownNot(RuleOut: fcNegative);
5189	else if (KnownSrc.cannotBeOrderedLessThanZero())
5190	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
5191
5192	if (KnownSrc.isKnownNever(Mask: fcPositive))
5193	Known.knownNot(RuleOut: fcPositive);
5194	else if (KnownSrc.cannotBeOrderedGreaterThanZero())
5195	Known.knownNot(RuleOut: KnownFPClass::OrderedGreaterThanZeroMask);
5196
5197	// Can refine inf/zero handling based on the exponent operand.
5198	const FPClassTest ExpInfoMask = fcZero | fcSubnormal | fcInf;
5199	if ((InterestedClasses & ExpInfoMask) == fcNone)
5200	break;
5201	if ((KnownSrc.KnownFPClasses & ExpInfoMask) == fcNone)
5202	break;
5203
5204	const fltSemantics &Flt =
5205	II->getType()->getScalarType()->getFltSemantics();
5206	unsigned Precision = APFloat::semanticsPrecision(Flt);
5207	const Value *ExpArg = II->getArgOperand(i: 1);
5208	ConstantRange ExpRange = computeConstantRange(
5209	V: ExpArg, ForSigned: true, UseInstrInfo: Q.IIQ.UseInstrInfo, AC: Q.AC, CtxI: Q.CxtI, DT: Q.DT, Depth: Depth + 1);
5210
5211	const int MantissaBits = Precision - 1;
5212	if (ExpRange.getSignedMin().sge(RHS: static_cast<int64_t>(MantissaBits)))
5213	Known.knownNot(RuleOut: fcSubnormal);
5214
5215	const Function *F = II->getFunction();
5216	const APInt *ConstVal = ExpRange.getSingleElement();
5217	if (ConstVal && ConstVal->isZero()) {
5218	// ldexp(x, 0) -> x, so propagate everything.
5219	Known.propagateCanonicalizingSrc(Src: KnownSrc, F: *F, Ty: II->getType());
5220	} else if (ExpRange.isAllNegative()) {
5221	// If we know the power is <= 0, can't introduce inf
5222	if (KnownSrc.isKnownNeverPosInfinity())
5223	Known.knownNot(RuleOut: fcPosInf);
5224	if (KnownSrc.isKnownNeverNegInfinity())
5225	Known.knownNot(RuleOut: fcNegInf);
5226	} else if (ExpRange.isAllNonNegative()) {
5227	// If we know the power is >= 0, can't introduce subnormal or zero
5228	if (KnownSrc.isKnownNeverPosSubnormal())
5229	Known.knownNot(RuleOut: fcPosSubnormal);
5230	if (KnownSrc.isKnownNeverNegSubnormal())
5231	Known.knownNot(RuleOut: fcNegSubnormal);
5232	if (F && KnownSrc.isKnownNeverLogicalPosZero(F: *F, Ty: II->getType()))
5233	Known.knownNot(RuleOut: fcPosZero);
5234	if (F && KnownSrc.isKnownNeverLogicalNegZero(F: *F, Ty: II->getType()))
5235	Known.knownNot(RuleOut: fcNegZero);
5236	}
5237
5238	break;
5239	}
5240	case Intrinsic::arithmetic_fence: {
5241	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts, InterestedClasses,
5242	Known, Depth: Depth + 1, Q);
5243	break;
5244	}
5245	case Intrinsic::experimental_constrained_sitofp:
5246	case Intrinsic::experimental_constrained_uitofp:
5247	// Cannot produce nan
5248	Known.knownNot(RuleOut: fcNan);
5249
5250	// sitofp and uitofp turn into +0.0 for zero.
5251	Known.knownNot(RuleOut: fcNegZero);
5252
5253	// Integers cannot be subnormal
5254	Known.knownNot(RuleOut: fcSubnormal);
5255
5256	if (IID == Intrinsic::experimental_constrained_uitofp)
5257	Known.signBitMustBeZero();
5258
5259	// TODO: Copy inf handling from instructions
5260	break;
5261	default:
5262	break;
5263	}
5264
5265	break;
5266	}
5267	case Instruction::FAdd:
5268	case Instruction::FSub: {
5269	KnownFPClass KnownLHS, KnownRHS;
5270	bool WantNegative =
5271	Op->getOpcode() == Instruction::FAdd &&
5272	(InterestedClasses & KnownFPClass::OrderedLessThanZeroMask) != fcNone;
5273	bool WantNaN = (InterestedClasses & fcNan) != fcNone;
5274	bool WantNegZero = (InterestedClasses & fcNegZero) != fcNone;
5275
5276	if (!WantNaN && !WantNegative && !WantNegZero)
5277	break;
5278
5279	FPClassTest InterestedSrcs = InterestedClasses;
5280	if (WantNegative)
5281	InterestedSrcs |= KnownFPClass::OrderedLessThanZeroMask;
5282	if (InterestedClasses & fcNan)
5283	InterestedSrcs |= fcInf;
5284	computeKnownFPClass(V: Op->getOperand(i: 1), DemandedElts, InterestedClasses: InterestedSrcs,
5285	Known&: KnownRHS, Depth: Depth + 1, Q);
5286
5287	if ((WantNaN && KnownRHS.isKnownNeverNaN()) ||
5288	(WantNegative && KnownRHS.cannotBeOrderedLessThanZero()) ||
5289	WantNegZero || Opc == Instruction::FSub) {
5290
5291	// RHS is canonically cheaper to compute. Skip inspecting the LHS if
5292	// there's no point.
5293	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts, InterestedClasses: InterestedSrcs,
5294	Known&: KnownLHS, Depth: Depth + 1, Q);
5295	// Adding positive and negative infinity produces NaN.
5296	// TODO: Check sign of infinities.
5297	if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
5298	(KnownLHS.isKnownNeverInfinity() || KnownRHS.isKnownNeverInfinity()))
5299	Known.knownNot(RuleOut: fcNan);
5300
5301	// FIXME: Context function should always be passed in separately
5302	const Function *F = cast<Instruction>(Val: Op)->getFunction();
5303
5304	if (Op->getOpcode() == Instruction::FAdd) {
5305	if (KnownLHS.cannotBeOrderedLessThanZero() &&
5306	KnownRHS.cannotBeOrderedLessThanZero())
5307	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
5308	if (!F)
5309	break;
5310
5311	// (fadd x, 0.0) is guaranteed to return +0.0, not -0.0.
5312	if ((KnownLHS.isKnownNeverLogicalNegZero(F: *F, Ty: Op->getType()) ||
5313	KnownRHS.isKnownNeverLogicalNegZero(F: *F, Ty: Op->getType())) &&
5314	// Make sure output negative denormal can't flush to -0
5315	outputDenormalIsIEEEOrPosZero(F: *F, Ty: Op->getType()))
5316	Known.knownNot(RuleOut: fcNegZero);
5317	} else {
5318	if (!F)
5319	break;
5320
5321	// Only fsub -0, +0 can return -0
5322	if ((KnownLHS.isKnownNeverLogicalNegZero(F: *F, Ty: Op->getType()) ||
5323	KnownRHS.isKnownNeverLogicalPosZero(F: *F, Ty: Op->getType())) &&
5324	// Make sure output negative denormal can't flush to -0
5325	outputDenormalIsIEEEOrPosZero(F: *F, Ty: Op->getType()))
5326	Known.knownNot(RuleOut: fcNegZero);
5327	}
5328	}
5329
5330	break;
5331	}
5332	case Instruction::FMul: {
5333	// X * X is always non-negative or a NaN.
5334	if (Op->getOperand(i: 0) == Op->getOperand(i: 1))
5335	Known.knownNot(RuleOut: fcNegative);
5336
5337	if ((InterestedClasses & fcNan) != fcNan)
5338	break;
5339
5340	// fcSubnormal is only needed in case of DAZ.
5341	const FPClassTest NeedForNan = fcNan | fcInf | fcZero | fcSubnormal;
5342
5343	KnownFPClass KnownLHS, KnownRHS;
5344	computeKnownFPClass(V: Op->getOperand(i: 1), DemandedElts, InterestedClasses: NeedForNan, Known&: KnownRHS,
5345	Depth: Depth + 1, Q);
5346	if (!KnownRHS.isKnownNeverNaN())
5347	break;
5348
5349	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts, InterestedClasses: NeedForNan, Known&: KnownLHS,
5350	Depth: Depth + 1, Q);
5351	if (!KnownLHS.isKnownNeverNaN())
5352	break;
5353
5354	if (KnownLHS.SignBit && KnownRHS.SignBit) {
5355	if (*KnownLHS.SignBit == *KnownRHS.SignBit)
5356	Known.signBitMustBeZero();
5357	else
5358	Known.signBitMustBeOne();
5359	}
5360
5361	// If 0 * +/-inf produces NaN.
5362	if (KnownLHS.isKnownNeverInfinity() && KnownRHS.isKnownNeverInfinity()) {
5363	Known.knownNot(RuleOut: fcNan);
5364	break;
5365	}
5366
5367	const Function *F = cast<Instruction>(Val: Op)->getFunction();
5368	if (!F)
5369	break;
5370
5371	if ((KnownRHS.isKnownNeverInfinity() ||
5372	KnownLHS.isKnownNeverLogicalZero(F: *F, Ty: Op->getType())) &&
5373	(KnownLHS.isKnownNeverInfinity() ||
5374	KnownRHS.isKnownNeverLogicalZero(F: *F, Ty: Op->getType())))
5375	Known.knownNot(RuleOut: fcNan);
5376
5377	break;
5378	}
5379	case Instruction::FDiv:
5380	case Instruction::FRem: {
5381	if (Op->getOperand(i: 0) == Op->getOperand(i: 1)) {
5382	// TODO: Could filter out snan if we inspect the operand
5383	if (Op->getOpcode() == Instruction::FDiv) {
5384	// X / X is always exactly 1.0 or a NaN.
5385	Known.KnownFPClasses = fcNan | fcPosNormal;
5386	} else {
5387	// X % X is always exactly [+-]0.0 or a NaN.
5388	Known.KnownFPClasses = fcNan | fcZero;
5389	}
5390
5391	break;
5392	}
5393
5394	const bool WantNan = (InterestedClasses & fcNan) != fcNone;
5395	const bool WantNegative = (InterestedClasses & fcNegative) != fcNone;
5396	const bool WantPositive =
5397	Opc == Instruction::FRem && (InterestedClasses & fcPositive) != fcNone;
5398	if (!WantNan && !WantNegative && !WantPositive)
5399	break;
5400
5401	KnownFPClass KnownLHS, KnownRHS;
5402
5403	computeKnownFPClass(V: Op->getOperand(i: 1), DemandedElts,
5404	InterestedClasses: fcNan | fcInf | fcZero | fcNegative, Known&: KnownRHS,
5405	Depth: Depth + 1, Q);
5406
5407	bool KnowSomethingUseful =
5408	KnownRHS.isKnownNeverNaN() || KnownRHS.isKnownNever(Mask: fcNegative);
5409
5410	if (KnowSomethingUseful || WantPositive) {
5411	const FPClassTest InterestedLHS =
5412	WantPositive ? fcAllFlags
5413	: fcNan | fcInf | fcZero | fcSubnormal | fcNegative;
5414
5415	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts,
5416	InterestedClasses: InterestedClasses & InterestedLHS, Known&: KnownLHS,
5417	Depth: Depth + 1, Q);
5418	}
5419
5420	const Function *F = cast<Instruction>(Val: Op)->getFunction();
5421
5422	if (Op->getOpcode() == Instruction::FDiv) {
5423	// Only 0/0, Inf/Inf produce NaN.
5424	if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
5425	(KnownLHS.isKnownNeverInfinity() ||
5426	KnownRHS.isKnownNeverInfinity()) &&
5427	((F && KnownLHS.isKnownNeverLogicalZero(F: *F, Ty: Op->getType())) ||
5428	(F && KnownRHS.isKnownNeverLogicalZero(F: *F, Ty: Op->getType())))) {
5429	Known.knownNot(RuleOut: fcNan);
5430	}
5431
5432	// X / -0.0 is -Inf (or NaN).
5433	// +X / +X is +X
5434	if (KnownLHS.isKnownNever(Mask: fcNegative) && KnownRHS.isKnownNever(Mask: fcNegative))
5435	Known.knownNot(RuleOut: fcNegative);
5436	} else {
5437	// Inf REM x and x REM 0 produce NaN.
5438	if (KnownLHS.isKnownNeverNaN() && KnownRHS.isKnownNeverNaN() &&
5439	KnownLHS.isKnownNeverInfinity() && F &&
5440	KnownRHS.isKnownNeverLogicalZero(F: *F, Ty: Op->getType())) {
5441	Known.knownNot(RuleOut: fcNan);
5442	}
5443
5444	// The sign for frem is the same as the first operand.
5445	if (KnownLHS.cannotBeOrderedLessThanZero())
5446	Known.knownNot(RuleOut: KnownFPClass::OrderedLessThanZeroMask);
5447	if (KnownLHS.cannotBeOrderedGreaterThanZero())
5448	Known.knownNot(RuleOut: KnownFPClass::OrderedGreaterThanZeroMask);
5449
5450	// See if we can be more aggressive about the sign of 0.
5451	if (KnownLHS.isKnownNever(Mask: fcNegative))
5452	Known.knownNot(RuleOut: fcNegative);
5453	if (KnownLHS.isKnownNever(Mask: fcPositive))
5454	Known.knownNot(RuleOut: fcPositive);
5455	}
5456
5457	break;
5458	}
5459	case Instruction::FPExt: {
5460	// Infinity, nan and zero propagate from source.
5461	computeKnownFPClass(V: Op->getOperand(i: 0), DemandedElts, InterestedClasses,
5462	Known, Depth: Depth + 1, Q);
5463
5464	const fltSemantics &DstTy =
5465	Op->getType()->getScalarType()->getFltSemantics();
5466	const fltSemantics &SrcTy =
5467	Op->getOperand(i: 0)->getType()->getScalarType()->getFltSemantics();
5468
5469	// All subnormal inputs should be in the normal range in the result type.
5470	if (APFloat::isRepresentableAsNormalIn(Src: SrcTy, Dst: DstTy)) {
5471	if (Known.KnownFPClasses & fcPosSubnormal)
5472	Known.KnownFPClasses |= fcPosNormal;
5473	if (Known.KnownFPClasses & fcNegSubnormal)
5474	Known.KnownFPClasses |= fcNegNormal;
5475	Known.knownNot(RuleOut: fcSubnormal);
5476	}
5477
5478	// Sign bit of a nan isn't guaranteed.
5479	if (!Known.isKnownNeverNaN())
5480	Known.SignBit = std::nullopt;
5481	break;
5482	}
5483	case Instruction::FPTrunc: {
5484	computeKnownFPClassForFPTrunc(Op, DemandedElts, InterestedClasses, Known,
5485	Depth, Q);
5486	break;
5487	}
5488	case Instruction::SIToFP:
5489	case Instruction::UIToFP: {
5490	// Cannot produce nan
5491	Known.knownNot(RuleOut: fcNan);
5492
5493	// Integers cannot be subnormal
5494	Known.knownNot(RuleOut: fcSubnormal);
5495
5496	// sitofp and uitofp turn into +0.0 for zero.
5497	Known.knownNot(RuleOut: fcNegZero);
5498	if (Op->getOpcode() == Instruction::UIToFP)
5499	Known.signBitMustBeZero();
5500
5501	if (InterestedClasses & fcInf) {
5502	// Get width of largest magnitude integer (remove a bit if signed).
5503	// This still works for a signed minimum value because the largest FP
5504	// value is scaled by some fraction close to 2.0 (1.0 + 0.xxxx).
5505	int IntSize = Op->getOperand(i: 0)->getType()->getScalarSizeInBits();
5506	if (Op->getOpcode() == Instruction::SIToFP)
5507	--IntSize;
5508
5509	// If the exponent of the largest finite FP value can hold the largest
5510	// integer, the result of the cast must be finite.
5511	Type *FPTy = Op->getType()->getScalarType();
5512	if (ilogb(Arg: APFloat::getLargest(Sem: FPTy->getFltSemantics())) >= IntSize)
5513	Known.knownNot(RuleOut: fcInf);
5514	}
5515
5516	break;
5517	}
5518	case Instruction::ExtractElement: {
5519	// Look through extract element. If the index is non-constant or
5520	// out-of-range demand all elements, otherwise just the extracted element.
5521	const Value *Vec = Op->getOperand(i: 0);
5522	const Value *Idx = Op->getOperand(i: 1);
5523	auto *CIdx = dyn_cast<ConstantInt>(Val: Idx);
5524
5525	if (auto *VecTy = dyn_cast<FixedVectorType>(Val: Vec->getType())) {
5526	unsigned NumElts = VecTy->getNumElements();
5527	APInt DemandedVecElts = APInt::getAllOnes(numBits: NumElts);
5528	if (CIdx && CIdx->getValue().ult(RHS: NumElts))
5529	DemandedVecElts = APInt::getOneBitSet(numBits: NumElts, BitNo: CIdx->getZExtValue());
5530	return computeKnownFPClass(V: Vec, DemandedElts: DemandedVecElts, InterestedClasses, Known,
5531	Depth: Depth + 1, Q);
5532	}
5533
5534	break;
5535	}
5536	case Instruction::InsertElement: {
5537	if (isa<ScalableVectorType>(Val: Op->getType()))
5538	return;
5539
5540	const Value *Vec = Op->getOperand(i: 0);
5541	const Value *Elt = Op->getOperand(i: 1);
5542	auto *CIdx = dyn_cast<ConstantInt>(Val: Op->getOperand(i: 2));
5543	unsigned NumElts = DemandedElts.getBitWidth();
5544	APInt DemandedVecElts = DemandedElts;
5545	bool NeedsElt = true;
5546	// If we know the index we are inserting to, clear it from Vec check.
5547	if (CIdx && CIdx->getValue().ult(RHS: NumElts)) {
5548	DemandedVecElts.clearBit(BitPosition: CIdx->getZExtValue());
5549	NeedsElt = DemandedElts[CIdx->getZExtValue()];
5550	}
5551
5552	// Do we demand the inserted element?
5553	if (NeedsElt) {
5554	computeKnownFPClass(V: Elt, Known, InterestedClasses, Depth: Depth + 1, Q);
5555	// If we don't know any bits, early out.
5556	if (Known.isUnknown())
5557	break;
5558	} else {
5559	Known.KnownFPClasses = fcNone;
5560	}
5561
5562	// Do we need anymore elements from Vec?
5563	if (!DemandedVecElts.isZero()) {
5564	KnownFPClass Known2;
5565	computeKnownFPClass(V: Vec, DemandedElts: DemandedVecElts, InterestedClasses, Known&: Known2,
5566	Depth: Depth + 1, Q);
5567	Known |= Known2;
5568	}
5569
5570	break;
5571	}
5572	case Instruction::ShuffleVector: {
5573	// For undef elements, we don't know anything about the common state of
5574	// the shuffle result.
5575	APInt DemandedLHS, DemandedRHS;
5576	auto *Shuf = dyn_cast<ShuffleVectorInst>(Val: Op);
5577	if (!Shuf || !getShuffleDemandedElts(Shuf, DemandedElts, DemandedLHS, DemandedRHS))
5578	return;
5579
5580	if (!!DemandedLHS) {
5581	const Value *LHS = Shuf->getOperand(i_nocapture: 0);
5582	computeKnownFPClass(V: LHS, DemandedElts: DemandedLHS, InterestedClasses, Known,
5583	Depth: Depth + 1, Q);
5584
5585	// If we don't know any bits, early out.
5586	if (Known.isUnknown())
5587	break;
5588	} else {
5589	Known.KnownFPClasses = fcNone;
5590	}
5591
5592	if (!!DemandedRHS) {
5593	KnownFPClass Known2;
5594	const Value *RHS = Shuf->getOperand(i_nocapture: 1);
5595	computeKnownFPClass(V: RHS, DemandedElts: DemandedRHS, InterestedClasses, Known&: Known2,
5596	Depth: Depth + 1, Q);
5597	Known |= Known2;
5598	}
5599
5600	break;
5601	}
5602	case Instruction::ExtractValue: {
5603	const ExtractValueInst *Extract = cast<ExtractValueInst>(Val: Op);
5604	ArrayRef<unsigned> Indices = Extract->getIndices();
5605	const Value *Src = Extract->getAggregateOperand();
5606	if (isa<StructType>(Val: Src->getType()) && Indices.size() == 1 &&
5607	Indices[0] == 0) {
5608	if (const auto *II = dyn_cast<IntrinsicInst>(Val: Src)) {
5609	switch (II->getIntrinsicID()) {
5610	case Intrinsic::frexp: {
5611	Known.knownNot(RuleOut: fcSubnormal);
5612
5613	KnownFPClass KnownSrc;
5614	computeKnownFPClass(V: II->getArgOperand(i: 0), DemandedElts,
5615	InterestedClasses, Known&: KnownSrc, Depth: Depth + 1, Q);
5616
5617	const Function *F = cast<Instruction>(Val: Op)->getFunction();
5618
5619	if (KnownSrc.isKnownNever(Mask: fcNegative))
5620	Known.knownNot(RuleOut: fcNegative);
5621	else {
5622	if (F && KnownSrc.isKnownNeverLogicalNegZero(F: *F, Ty: Op->getType()))
5623	Known.knownNot(RuleOut: fcNegZero);
5624	if (KnownSrc.isKnownNever(Mask: fcNegInf))
5625	Known.knownNot(RuleOut: fcNegInf);
5626	}
5627
5628	if (KnownSrc.isKnownNever(Mask: fcPositive))
5629	Known.knownNot(RuleOut: fcPositive);
5630	else {
5631	if (F && KnownSrc.isKnownNeverLogicalPosZero(F: *F, Ty: Op->getType()))
5632	Known.knownNot(RuleOut: fcPosZero);
5633	if (KnownSrc.isKnownNever(Mask: fcPosInf))
5634	Known.knownNot(RuleOut: fcPosInf);
5635	}
5636
5637	Known.propagateNaN(Src: KnownSrc);
5638	return;
5639	}
5640	default:
5641	break;
5642	}
5643	}
5644	}
5645
5646	computeKnownFPClass(V: Src, DemandedElts, InterestedClasses, Known, Depth: Depth + 1,
5647	Q);
5648	break;
5649	}
5650	case Instruction::PHI: {
5651	const PHINode *P = cast<PHINode>(Val: Op);
5652	// Unreachable blocks may have zero-operand PHI nodes.
5653	if (P->getNumIncomingValues() == 0)
5654	break;
5655
5656	// Otherwise take the unions of the known bit sets of the operands,
5657	// taking conservative care to avoid excessive recursion.
5658	const unsigned PhiRecursionLimit = MaxAnalysisRecursionDepth - 2;
5659
5660	if (Depth < PhiRecursionLimit) {
5661	// Skip if every incoming value references to ourself.
5662	if (isa_and_nonnull<UndefValue>(Val: P->hasConstantValue()))
5663	break;
5664
5665	bool First = true;
5666
5667	for (const Use &U : P->operands()) {
5668	Value *IncValue = U.get();
5669	// Skip direct self references.
5670	if (IncValue == P)
5671	continue;
5672
5673	KnownFPClass KnownSrc;
5674	// Recurse, but cap the recursion to two levels, because we don't want
5675	// to waste time spinning around in loops. We need at least depth 2 to
5676	// detect known sign bits.
5677	computeKnownFPClass(
5678	V: IncValue, DemandedElts, InterestedClasses, Known&: KnownSrc,
5679	Depth: PhiRecursionLimit,
5680	Q: Q.getWithInstruction(I: P->getIncomingBlock(U)->getTerminator()));
5681
5682	if (First) {
5683	Known = KnownSrc;
5684	First = false;
5685	} else {
5686	Known |= KnownSrc;
5687	}
5688
5689	if (Known.KnownFPClasses == fcAllFlags)
5690	break;
5691	}
5692	}
5693
5694	break;
5695	}
5696	default:
5697	break;
5698	}
5699	}
5700
5701	KnownFPClass llvm::computeKnownFPClass(const Value *V,
5702	const APInt &DemandedElts,
5703	FPClassTest InterestedClasses,
5704	unsigned Depth,
5705	const SimplifyQuery &SQ) {
5706	KnownFPClass KnownClasses;
5707	::computeKnownFPClass(V, DemandedElts, InterestedClasses, Known&: KnownClasses, Depth,
5708	Q: SQ);
5709	return KnownClasses;
5710	}
5711
5712	KnownFPClass llvm::computeKnownFPClass(const Value *V,
5713	FPClassTest InterestedClasses,
5714	unsigned Depth,
5715	const SimplifyQuery &SQ) {
5716	KnownFPClass Known;
5717	::computeKnownFPClass(V, Known, InterestedClasses, Depth, Q: SQ);
5718	return Known;
5719	}
5720
5721	Value *llvm::isBytewiseValue(Value *V, const DataLayout &DL) {
5722
5723	// All byte-wide stores are splatable, even of arbitrary variables.
5724	if (V->getType()->isIntegerTy(Bitwidth: 8))
5725	return V;
5726
5727	LLVMContext &Ctx = V->getContext();
5728
5729	// Undef don't care.
5730	auto *UndefInt8 = UndefValue::get(T: Type::getInt8Ty(C&: Ctx));
5731	if (isa<UndefValue>(Val: V))
5732	return UndefInt8;
5733
5734	// Return Undef for zero-sized type.
5735	if (DL.getTypeStoreSize(Ty: V->getType()).isZero())
5736	return UndefInt8;
5737
5738	Constant *C = dyn_cast<Constant>(Val: V);
5739	if (!C) {
5740	// Conceptually, we could handle things like:
5741	// %a = zext i8 %X to i16
5742	// %b = shl i16 %a, 8
5743	// %c = or i16 %a, %b
5744	// but until there is an example that actually needs this, it doesn't seem
5745	// worth worrying about.
5746	return nullptr;
5747	}
5748
5749	// Handle 'null' ConstantArrayZero etc.
5750	if (C->isNullValue())
5751	return Constant::getNullValue(Ty: Type::getInt8Ty(C&: Ctx));
5752
5753	// Constant floating-point values can be handled as integer values if the
5754	// corresponding integer value is "byteable". An important case is 0.0.
5755	if (ConstantFP *CFP = dyn_cast<ConstantFP>(Val: C)) {
5756	Type *Ty = nullptr;
5757	if (CFP->getType()->isHalfTy())
5758	Ty = Type::getInt16Ty(C&: Ctx);
5759	else if (CFP->getType()->isFloatTy())
5760	Ty = Type::getInt32Ty(C&: Ctx);
5761	else if (CFP->getType()->isDoubleTy())
5762	Ty = Type::getInt64Ty(C&: Ctx);
5763	// Don't handle long double formats, which have strange constraints.
5764	return Ty ? isBytewiseValue(V: ConstantExpr::getBitCast(C: CFP, Ty), DL)
5765	: nullptr;
5766	}
5767
5768	// We can handle constant integers that are multiple of 8 bits.
5769	if (ConstantInt *CI = dyn_cast<ConstantInt>(Val: C)) {
5770	if (CI->getBitWidth() % 8 == 0) {
5771	assert(CI->getBitWidth() > 8 && "8 bits should be handled above!");
5772	if (!CI->getValue().isSplat(SplatSizeInBits: 8))
5773	return nullptr;
5774	return ConstantInt::get(Context&: Ctx, V: CI->getValue().trunc(width: 8));
5775	}
5776	}
5777
5778	if (auto *CE = dyn_cast<ConstantExpr>(Val: C)) {
5779	if (CE->getOpcode() == Instruction::IntToPtr) {
5780	if (auto *PtrTy = dyn_cast<PointerType>(Val: CE->getType())) {
5781	unsigned BitWidth = DL.getPointerSizeInBits(AS: PtrTy->getAddressSpace());
5782	if (Constant *Op = ConstantFoldIntegerCast(
5783	C: CE->getOperand(i_nocapture: 0), DestTy: Type::getIntNTy(C&: Ctx, N: BitWidth), IsSigned: false, DL))
5784	return isBytewiseValue(V: Op, DL);
5785	}
5786	}
5787	}
5788
5789	auto Merge = [&](Value *LHS, Value *RHS) -> Value * {
5790	if (LHS == RHS)
5791	return LHS;
5792	if (!LHS || !RHS)
5793	return nullptr;
5794	if (LHS == UndefInt8)
5795	return RHS;
5796	if (RHS == UndefInt8)
5797	return LHS;
5798	return nullptr;
5799	};
5800
5801	if (ConstantDataSequential *CA = dyn_cast<ConstantDataSequential>(Val: C)) {
5802	Value *Val = UndefInt8;
5803	for (unsigned I = 0, E = CA->getNumElements(); I != E; ++I)
5804	if (!(Val = Merge(Val, isBytewiseValue(V: CA->getElementAsConstant(i: I), DL))))
5805	return nullptr;
5806	return Val;
5807	}
5808
5809	if (isa<ConstantAggregate>(Val: C)) {
5810	Value *Val = UndefInt8;
5811	for (unsigned I = 0, E = C->getNumOperands(); I != E; ++I)
5812	if (!(Val = Merge(Val, isBytewiseValue(V: C->getOperand(i: I), DL))))
5813	return nullptr;
5814	return Val;
5815	}
5816
5817	// Don't try to handle the handful of other constants.
5818	return nullptr;
5819	}
5820
5821	// This is the recursive version of BuildSubAggregate. It takes a few different
5822	// arguments. Idxs is the index within the nested struct From that we are
5823	// looking at now (which is of type IndexedType). IdxSkip is the number of
5824	// indices from Idxs that should be left out when inserting into the resulting
5825	// struct. To is the result struct built so far, new insertvalue instructions
5826	// build on that.
5827	static Value *BuildSubAggregate(Value *From, Value *To, Type *IndexedType,
5828	SmallVectorImpl<unsigned> &Idxs,
5829	unsigned IdxSkip,
5830	BasicBlock::iterator InsertBefore) {
5831	StructType *STy = dyn_cast<StructType>(Val: IndexedType);
5832	if (STy) {
5833	// Save the original To argument so we can modify it
5834	Value *OrigTo = To;
5835	// General case, the type indexed by Idxs is a struct
5836	for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
5837	// Process each struct element recursively
5838	Idxs.push_back(Elt: i);
5839	Value *PrevTo = To;
5840	To = BuildSubAggregate(From, To, IndexedType: STy->getElementType(N: i), Idxs, IdxSkip,
5841	InsertBefore);
5842	Idxs.pop_back();
5843	if (!To) {
5844	// Couldn't find any inserted value for this index? Cleanup
5845	while (PrevTo != OrigTo) {
5846	InsertValueInst* Del = cast<InsertValueInst>(Val: PrevTo);
5847	PrevTo = Del->getAggregateOperand();
5848	Del->eraseFromParent();
5849	}
5850	// Stop processing elements
5851	break;
5852	}
5853	}
5854	// If we successfully found a value for each of our subaggregates
5855	if (To)
5856	return To;
5857	}
5858	// Base case, the type indexed by SourceIdxs is not a struct, or not all of
5859	// the struct's elements had a value that was inserted directly. In the latter
5860	// case, perhaps we can't determine each of the subelements individually, but
5861	// we might be able to find the complete struct somewhere.
5862
5863	// Find the value that is at that particular spot
5864	Value *V = FindInsertedValue(V: From, idx_range: Idxs);
5865
5866	if (!V)
5867	return nullptr;
5868
5869	// Insert the value in the new (sub) aggregate
5870	return InsertValueInst::Create(Agg: To, Val: V, Idxs: ArrayRef(Idxs).slice(N: IdxSkip), NameStr: "tmp",
5871	InsertBefore);
5872	}
5873
5874	// This helper takes a nested struct and extracts a part of it (which is again a
5875	// struct) into a new value. For example, given the struct:
5876	// { a, { b, { c, d }, e } }
5877	// and the indices "1, 1" this returns
5878	// { c, d }.
5879	//
5880	// It does this by inserting an insertvalue for each element in the resulting
5881	// struct, as opposed to just inserting a single struct. This will only work if
5882	// each of the elements of the substruct are known (ie, inserted into From by an
5883	// insertvalue instruction somewhere).
5884	//
5885	// All inserted insertvalue instructions are inserted before InsertBefore
5886	static Value *BuildSubAggregate(Value *From, ArrayRef<unsigned> idx_range,
5887	BasicBlock::iterator InsertBefore) {
5888	Type *IndexedType = ExtractValueInst::getIndexedType(Agg: From->getType(),
5889	Idxs: idx_range);
5890	Value *To = PoisonValue::get(T: IndexedType);
5891	SmallVector<unsigned, 10> Idxs(idx_range.begin(), idx_range.end());
5892	unsigned IdxSkip = Idxs.size();
5893
5894	return BuildSubAggregate(From, To, IndexedType, Idxs, IdxSkip, InsertBefore);
5895	}
5896
5897	/// Given an aggregate and a sequence of indices, see if the scalar value
5898	/// indexed is already around as a register, for example if it was inserted
5899	/// directly into the aggregate.
5900	///
5901	/// If InsertBefore is not null, this function will duplicate (modified)
5902	/// insertvalues when a part of a nested struct is extracted.
5903	Value *
5904	llvm::FindInsertedValue(Value *V, ArrayRef<unsigned> idx_range,
5905	std::optional<BasicBlock::iterator> InsertBefore) {
5906	// Nothing to index? Just return V then (this is useful at the end of our
5907	// recursion).
5908	if (idx_range.empty())
5909	return V;
5910	// We have indices, so V should have an indexable type.
5911	assert((V->getType()->isStructTy() || V->getType()->isArrayTy()) &&
5912	"Not looking at a struct or array?");
5913	assert(ExtractValueInst::getIndexedType(V->getType(), idx_range) &&
5914	"Invalid indices for type?");
5915
5916	if (Constant *C = dyn_cast<Constant>(Val: V)) {
5917	C = C->getAggregateElement(Elt: idx_range[0]);
5918	if (!C) return nullptr;
5919	return FindInsertedValue(V: C, idx_range: idx_range.slice(N: 1), InsertBefore);
5920	}
5921
5922	if (InsertValueInst *I = dyn_cast<InsertValueInst>(Val: V)) {
5923	// Loop the indices for the insertvalue instruction in parallel with the
5924	// requested indices
5925	const unsigned *req_idx = idx_range.begin();
5926	for (const unsigned *i = I->idx_begin(), *e = I->idx_end();
5927	i != e; ++i, ++req_idx) {
5928	if (req_idx == idx_range.end()) {
5929	// We can't handle this without inserting insertvalues
5930	if (!InsertBefore)
5931	return nullptr;
5932
5933	// The requested index identifies a part of a nested aggregate. Handle
5934	// this specially. For example,
5935	// %A = insertvalue { i32, {i32, i32 } } undef, i32 10, 1, 0
5936	// %B = insertvalue { i32, {i32, i32 } } %A, i32 11, 1, 1
5937	// %C = extractvalue {i32, { i32, i32 } } %B, 1
5938	// This can be changed into
5939	// %A = insertvalue {i32, i32 } undef, i32 10, 0
5940	// %C = insertvalue {i32, i32 } %A, i32 11, 1
5941	// which allows the unused 0,0 element from the nested struct to be
5942	// removed.
5943	return BuildSubAggregate(From: V, idx_range: ArrayRef(idx_range.begin(), req_idx),
5944	InsertBefore: *InsertBefore);
5945	}
5946
5947	// This insert value inserts something else than what we are looking for.
5948	// See if the (aggregate) value inserted into has the value we are
5949	// looking for, then.
5950	if (*req_idx != *i)
5951	return FindInsertedValue(V: I->getAggregateOperand(), idx_range,
5952	InsertBefore);
5953	}
5954	// If we end up here, the indices of the insertvalue match with those
5955	// requested (though possibly only partially). Now we recursively look at
5956	// the inserted value, passing any remaining indices.
5957	return FindInsertedValue(V: I->getInsertedValueOperand(),
5958	idx_range: ArrayRef(req_idx, idx_range.end()), InsertBefore);
5959	}
5960
5961	if (ExtractValueInst *I = dyn_cast<ExtractValueInst>(Val: V)) {
5962	// If we're extracting a value from an aggregate that was extracted from
5963	// something else, we can extract from that something else directly instead.
5964	// However, we will need to chain I's indices with the requested indices.
5965
5966	// Calculate the number of indices required
5967	unsigned size = I->getNumIndices() + idx_range.size();
5968	// Allocate some space to put the new indices in
5969	SmallVector<unsigned, 5> Idxs;
5970	Idxs.reserve(N: size);
5971	// Add indices from the extract value instruction
5972	Idxs.append(in_start: I->idx_begin(), in_end: I->idx_end());
5973
5974	// Add requested indices
5975	Idxs.append(in_start: idx_range.begin(), in_end: idx_range.end());
5976
5977	assert(Idxs.size() == size
5978	&& "Number of indices added not correct?");
5979
5980	return FindInsertedValue(V: I->getAggregateOperand(), idx_range: Idxs, InsertBefore);
5981	}
5982	// Otherwise, we don't know (such as, extracting from a function return value
5983	// or load instruction)
5984	return nullptr;
5985	}
5986
5987	bool llvm::isGEPBasedOnPointerToString(const GEPOperator *GEP,
5988	unsigned CharSize) {
5989	// Make sure the GEP has exactly three arguments.
5990	if (GEP->getNumOperands() != 3)
5991	return false;
5992
5993	// Make sure the index-ee is a pointer to array of \p CharSize integers.
5994	// CharSize.
5995	ArrayType *AT = dyn_cast<ArrayType>(Val: GEP->getSourceElementType());
5996	if (!AT || !AT->getElementType()->isIntegerTy(Bitwidth: CharSize))
5997	return false;
5998
5999	// Check to make sure that the first operand of the GEP is an integer and
6000	// has value 0 so that we are sure we're indexing into the initializer.
6001	const ConstantInt *FirstIdx = dyn_cast<ConstantInt>(Val: GEP->getOperand(i_nocapture: 1));
6002	if (!FirstIdx || !FirstIdx->isZero())
6003	return false;
6004
6005	return true;
6006	}
6007
6008	// If V refers to an initialized global constant, set Slice either to
6009	// its initializer if the size of its elements equals ElementSize, or,
6010	// for ElementSize == 8, to its representation as an array of unsiged
6011	// char. Return true on success.
6012	// Offset is in the unit "nr of ElementSize sized elements".
6013	bool llvm::getConstantDataArrayInfo(const Value *V,
6014	ConstantDataArraySlice &Slice,
6015	unsigned ElementSize, uint64_t Offset) {
6016	assert(V && "V should not be null.");
6017	assert((ElementSize % 8) == 0 &&
6018	"ElementSize expected to be a multiple of the size of a byte.");
6019	unsigned ElementSizeInBytes = ElementSize / 8;
6020
6021	// Drill down into the pointer expression V, ignoring any intervening
6022	// casts, and determine the identity of the object it references along
6023	// with the cumulative byte offset into it.
6024	const GlobalVariable *GV =
6025	dyn_cast<GlobalVariable>(Val: getUnderlyingObject(V));
6026	if (!GV || !GV->isConstant() || !GV->hasDefinitiveInitializer())
6027	// Fail if V is not based on constant global object.
6028	return false;
6029
6030	const DataLayout &DL = GV->getParent()->getDataLayout();
6031	APInt Off(DL.getIndexTypeSizeInBits(Ty: V->getType()), 0);
6032
6033	if (GV != V->stripAndAccumulateConstantOffsets(DL, Offset&: Off,
6034	/*AllowNonInbounds*/ true))
6035	// Fail if a constant offset could not be determined.
6036	return false;
6037
6038	uint64_t StartIdx = Off.getLimitedValue();
6039	if (StartIdx == UINT64_MAX)
6040	// Fail if the constant offset is excessive.
6041	return false;
6042
6043	// Off/StartIdx is in the unit of bytes. So we need to convert to number of
6044	// elements. Simply bail out if that isn't possible.
6045	if ((StartIdx % ElementSizeInBytes) != 0)
6046	return false;
6047
6048	Offset += StartIdx / ElementSizeInBytes;
6049	ConstantDataArray *Array = nullptr;
6050	ArrayType *ArrayTy = nullptr;
6051
6052	if (GV->getInitializer()->isNullValue()) {
6053	Type *GVTy = GV->getValueType();
6054	uint64_t SizeInBytes = DL.getTypeStoreSize(Ty: GVTy).getFixedValue();
6055	uint64_t Length = SizeInBytes / ElementSizeInBytes;
6056
6057	Slice.Array = nullptr;
6058	Slice.Offset = 0;
6059	// Return an empty Slice for undersized constants to let callers
6060	// transform even undefined library calls into simpler, well-defined
6061	// expressions. This is preferable to making the calls although it
6062	// prevents sanitizers from detecting such calls.
6063	Slice.Length = Length < Offset ? 0 : Length - Offset;
6064	return true;
6065	}
6066
6067	auto *Init = const_cast<Constant *>(GV->getInitializer());
6068	if (auto *ArrayInit = dyn_cast<ConstantDataArray>(Val: Init)) {
6069	Type *InitElTy = ArrayInit->getElementType();
6070	if (InitElTy->isIntegerTy(Bitwidth: ElementSize)) {
6071	// If Init is an initializer for an array of the expected type
6072	// and size, use it as is.
6073	Array = ArrayInit;
6074	ArrayTy = ArrayInit->getType();
6075	}
6076	}
6077
6078	if (!Array) {
6079	if (ElementSize != 8)
6080	// TODO: Handle conversions to larger integral types.
6081	return false;
6082
6083	// Otherwise extract the portion of the initializer starting
6084	// at Offset as an array of bytes, and reset Offset.
6085	Init = ReadByteArrayFromGlobal(GV, Offset);
6086	if (!Init)
6087	return false;
6088
6089	Offset = 0;
6090	Array = dyn_cast<ConstantDataArray>(Val: Init);
6091	ArrayTy = dyn_cast<ArrayType>(Val: Init->getType());
6092	}
6093
6094	uint64_t NumElts = ArrayTy->getArrayNumElements();
6095	if (Offset > NumElts)
6096	return false;
6097
6098	Slice.Array = Array;
6099	Slice.Offset = Offset;
6100	Slice.Length = NumElts - Offset;
6101	return true;
6102	}
6103
6104	/// Extract bytes from the initializer of the constant array V, which need
6105	/// not be a nul-terminated string. On success, store the bytes in Str and
6106	/// return true. When TrimAtNul is set, Str will contain only the bytes up
6107	/// to but not including the first nul. Return false on failure.
6108	bool llvm::getConstantStringInfo(const Value *V, StringRef &Str,
6109	bool TrimAtNul) {
6110	ConstantDataArraySlice Slice;
6111	if (!getConstantDataArrayInfo(V, Slice, ElementSize: 8))
6112	return false;
6113
6114	if (Slice.Array == nullptr) {
6115	if (TrimAtNul) {
6116	// Return a nul-terminated string even for an empty Slice. This is
6117	// safe because all existing SimplifyLibcalls callers require string
6118	// arguments and the behavior of the functions they fold is undefined
6119	// otherwise. Folding the calls this way is preferable to making
6120	// the undefined library calls, even though it prevents sanitizers
6121	// from reporting such calls.
6122	Str = StringRef();
6123	return true;
6124	}
6125	if (Slice.Length == 1) {
6126	Str = StringRef("", 1);
6127	return true;
6128	}
6129	// We cannot instantiate a StringRef as we do not have an appropriate string
6130	// of 0s at hand.
6131	return false;
6132	}
6133
6134	// Start out with the entire array in the StringRef.
6135	Str = Slice.Array->getAsString();
6136	// Skip over 'offset' bytes.
6137	Str = Str.substr(Start: Slice.Offset);
6138
6139	if (TrimAtNul) {
6140	// Trim off the \0 and anything after it. If the array is not nul
6141	// terminated, we just return the whole end of string. The client may know
6142	// some other way that the string is length-bound.
6143	Str = Str.substr(Start: 0, N: Str.find(C: '\0'));
6144	}
6145	return true;
6146	}
6147
6148	// These next two are very similar to the above, but also look through PHI
6149	// nodes.
6150	// TODO: See if we can integrate these two together.
6151
6152	/// If we can compute the length of the string pointed to by
6153	/// the specified pointer, return 'len+1'. If we can't, return 0.
6154	static uint64_t GetStringLengthH(const Value *V,
6155	SmallPtrSetImpl<const PHINode*> &PHIs,
6156	unsigned CharSize) {
6157	// Look through noop bitcast instructions.
6158	V = V->stripPointerCasts();
6159
6160	// If this is a PHI node, there are two cases: either we have already seen it
6161	// or we haven't.
6162	if (const PHINode *PN = dyn_cast<PHINode>(Val: V)) {
6163	if (!PHIs.insert(Ptr: PN).second)
6164	return ~0ULL; // already in the set.
6165
6166	// If it was new, see if all the input strings are the same length.
6167	uint64_t LenSoFar = ~0ULL;
6168	for (Value *IncValue : PN->incoming_values()) {
6169	uint64_t Len = GetStringLengthH(V: IncValue, PHIs, CharSize);
6170	if (Len == 0) return 0; // Unknown length -> unknown.
6171
6172	if (Len == ~0ULL) continue;
6173
6174	if (Len != LenSoFar && LenSoFar != ~0ULL)
6175	return 0; // Disagree -> unknown.
6176	LenSoFar = Len;
6177	}
6178
6179	// Success, all agree.
6180	return LenSoFar;
6181	}
6182
6183	// strlen(select(c,x,y)) -> strlen(x) ^ strlen(y)
6184	if (const SelectInst *SI = dyn_cast<SelectInst>(Val: V)) {
6185	uint64_t Len1 = GetStringLengthH(V: SI->getTrueValue(), PHIs, CharSize);
6186	if (Len1 == 0) return 0;
6187	uint64_t Len2 = GetStringLengthH(V: SI->getFalseValue(), PHIs, CharSize);
6188	if (Len2 == 0) return 0;
6189	if (Len1 == ~0ULL) return Len2;
6190	if (Len2 == ~0ULL) return Len1;
6191	if (Len1 != Len2) return 0;
6192	return Len1;
6193	}
6194
6195	// Otherwise, see if we can read the string.
6196	ConstantDataArraySlice Slice;
6197	if (!getConstantDataArrayInfo(V, Slice, ElementSize: CharSize))
6198	return 0;
6199
6200	if (Slice.Array == nullptr)
6201	// Zeroinitializer (including an empty one).
6202	return 1;
6203
6204	// Search for the first nul character. Return a conservative result even
6205	// when there is no nul. This is safe since otherwise the string function
6206	// being folded such as strlen is undefined, and can be preferable to
6207	// making the undefined library call.
6208	unsigned NullIndex = 0;
6209	for (unsigned E = Slice.Length; NullIndex < E; ++NullIndex) {
6210	if (Slice.Array->getElementAsInteger(i: Slice.Offset + NullIndex) == 0)
6211	break;
6212	}
6213
6214	return NullIndex + 1;
6215	}
6216
6217	/// If we can compute the length of the string pointed to by
6218	/// the specified pointer, return 'len+1'. If we can't, return 0.
6219	uint64_t llvm::GetStringLength(const Value *V, unsigned CharSize) {
6220	if (!V->getType()->isPointerTy())
6221	return 0;
6222
6223	SmallPtrSet<const PHINode*, 32> PHIs;
6224	uint64_t Len = GetStringLengthH(V, PHIs, CharSize);
6225	// If Len is ~0ULL, we had an infinite phi cycle: this is dead code, so return
6226	// an empty string as a length.
6227	return Len == ~0ULL ? 1 : Len;
6228	}
6229
6230	const Value *
6231	llvm::getArgumentAliasingToReturnedPointer(const CallBase *Call,
6232	bool MustPreserveNullness) {
6233	assert(Call &&
6234	"getArgumentAliasingToReturnedPointer only works on nonnull calls");
6235	if (const Value *RV = Call->getReturnedArgOperand())
6236	return RV;
6237	// This can be used only as a aliasing property.
6238	if (isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
6239	Call, MustPreserveNullness))
6240	return Call->getArgOperand(i: 0);
6241	return nullptr;
6242	}
6243
6244	bool llvm::isIntrinsicReturningPointerAliasingArgumentWithoutCapturing(
6245	const CallBase *Call, bool MustPreserveNullness) {
6246	switch (Call->getIntrinsicID()) {
6247	case Intrinsic::launder_invariant_group:
6248	case Intrinsic::strip_invariant_group:
6249	case Intrinsic::aarch64_irg:
6250	case Intrinsic::aarch64_tagp:
6251	// The amdgcn_make_buffer_rsrc function does not alter the address of the
6252	// input pointer (and thus preserve null-ness for the purposes of escape
6253	// analysis, which is where the MustPreserveNullness flag comes in to play).
6254	// However, it will not necessarily map ptr addrspace(N) null to ptr
6255	// addrspace(8) null, aka the "null descriptor", which has "all loads return
6256	// 0, all stores are dropped" semantics. Given the context of this intrinsic
6257	// list, no one should be relying on such a strict interpretation of
6258	// MustPreserveNullness (and, at time of writing, they are not), but we
6259	// document this fact out of an abundance of caution.
6260	case Intrinsic::amdgcn_make_buffer_rsrc:
6261	return true;
6262	case Intrinsic::ptrmask:
6263	return !MustPreserveNullness;
6264	case Intrinsic::threadlocal_address:
6265	// The underlying variable changes with thread ID. The Thread ID may change
6266	// at coroutine suspend points.
6267	return !Call->getParent()->getParent()->isPresplitCoroutine();
6268	default:
6269	return false;
6270	}
6271	}
6272
6273	/// \p PN defines a loop-variant pointer to an object. Check if the
6274	/// previous iteration of the loop was referring to the same object as \p PN.
6275	static bool isSameUnderlyingObjectInLoop(const PHINode *PN,
6276	const LoopInfo *LI) {
6277	// Find the loop-defined value.
6278	Loop *L = LI->getLoopFor(BB: PN->getParent());
6279	if (PN->getNumIncomingValues() != 2)
6280	return true;
6281
6282	// Find the value from previous iteration.
6283	auto *PrevValue = dyn_cast<Instruction>(Val: PN->getIncomingValue(i: 0));
6284	if (!PrevValue || LI->getLoopFor(BB: PrevValue->getParent()) != L)
6285	PrevValue = dyn_cast<Instruction>(Val: PN->getIncomingValue(i: 1));
6286	if (!PrevValue || LI->getLoopFor(BB: PrevValue->getParent()) != L)
6287	return true;
6288
6289	// If a new pointer is loaded in the loop, the pointer references a different
6290	// object in every iteration. E.g.:
6291	// for (i)
6292	// int *p = a[i];
6293	// ...
6294	if (auto *Load = dyn_cast<LoadInst>(Val: PrevValue))
6295	if (!L->isLoopInvariant(V: Load->getPointerOperand()))
6296	return false;
6297	return true;
6298	}
6299
6300	const Value *llvm::getUnderlyingObject(const Value *V, unsigned MaxLookup) {
6301	if (!V->getType()->isPointerTy())
6302	return V;
6303	for (unsigned Count = 0; MaxLookup == 0 || Count < MaxLookup; ++Count) {
6304	if (auto *GEP = dyn_cast<GEPOperator>(Val: V)) {
6305	V = GEP->getPointerOperand();
6306	} else if (Operator::getOpcode(V) == Instruction::BitCast ||
6307	Operator::getOpcode(V) == Instruction::AddrSpaceCast) {
6308	V = cast<Operator>(Val: V)->getOperand(i: 0);
6309	if (!V->getType()->isPointerTy())
6310	return V;
6311	} else if (auto *GA = dyn_cast<GlobalAlias>(Val: V)) {
6312	if (GA->isInterposable())
6313	return V;
6314	V = GA->getAliasee();
6315	} else {
6316	if (auto *PHI = dyn_cast<PHINode>(Val: V)) {
6317	// Look through single-arg phi nodes created by LCSSA.
6318	if (PHI->getNumIncomingValues() == 1) {
6319	V = PHI->getIncomingValue(i: 0);
6320	continue;
6321	}
6322	} else if (auto *Call = dyn_cast<CallBase>(Val: V)) {
6323	// CaptureTracking can know about special capturing properties of some
6324	// intrinsics like launder.invariant.group, that can't be expressed with
6325	// the attributes, but have properties like returning aliasing pointer.
6326	// Because some analysis may assume that nocaptured pointer is not
6327	// returned from some special intrinsic (because function would have to
6328	// be marked with returns attribute), it is crucial to use this function
6329	// because it should be in sync with CaptureTracking. Not using it may
6330	// cause weird miscompilations where 2 aliasing pointers are assumed to
6331	// noalias.
6332	if (auto *RP = getArgumentAliasingToReturnedPointer(Call, MustPreserveNullness: false)) {
6333	V = RP;
6334	continue;
6335	}
6336	}
6337
6338	return V;
6339	}
6340	assert(V->getType()->isPointerTy() && "Unexpected operand type!");
6341	}
6342	return V;
6343	}
6344
6345	void llvm::getUnderlyingObjects(const Value *V,
6346	SmallVectorImpl<const Value *> &Objects,
6347	LoopInfo *LI, unsigned MaxLookup) {
6348	SmallPtrSet<const Value *, 4> Visited;
6349	SmallVector<const Value *, 4> Worklist;
6350	Worklist.push_back(Elt: V);
6351	do {
6352	const Value *P = Worklist.pop_back_val();
6353	P = getUnderlyingObject(V: P, MaxLookup);
6354
6355	if (!Visited.insert(Ptr: P).second)
6356	continue;
6357
6358	if (auto *SI = dyn_cast<SelectInst>(Val: P)) {
6359	Worklist.push_back(Elt: SI->getTrueValue());
6360	Worklist.push_back(Elt: SI->getFalseValue());
6361	continue;
6362	}
6363
6364	if (auto *PN = dyn_cast<PHINode>(Val: P)) {
6365	// If this PHI changes the underlying object in every iteration of the
6366	// loop, don't look through it. Consider:
6367	// int **A;
6368	// for (i) {
6369	// Prev = Curr; // Prev = PHI (Prev_0, Curr)
6370	// Curr = A[i];
6371	// *Prev, *Curr;
6372	//
6373	// Prev is tracking Curr one iteration behind so they refer to different
6374	// underlying objects.
6375	if (!LI || !LI->isLoopHeader(BB: PN->getParent()) ||
6376	isSameUnderlyingObjectInLoop(PN, LI))
6377	append_range(C&: Worklist, R: PN->incoming_values());
6378	else
6379	Objects.push_back(Elt: P);
6380	continue;
6381	}
6382
6383	Objects.push_back(Elt: P);
6384	} while (!Worklist.empty());
6385	}
6386
6387	/// This is the function that does the work of looking through basic
6388	/// ptrtoint+arithmetic+inttoptr sequences.
6389	static const Value *getUnderlyingObjectFromInt(const Value *V) {
6390	do {
6391	if (const Operator *U = dyn_cast<Operator>(Val: V)) {
6392	// If we find a ptrtoint, we can transfer control back to the
6393	// regular getUnderlyingObjectFromInt.
6394	if (U->getOpcode() == Instruction::PtrToInt)
6395	return U->getOperand(i: 0);
6396	// If we find an add of a constant, a multiplied value, or a phi, it's
6397	// likely that the other operand will lead us to the base
6398	// object. We don't have to worry about the case where the
6399	// object address is somehow being computed by the multiply,
6400	// because our callers only care when the result is an
6401	// identifiable object.
6402	if (U->getOpcode() != Instruction::Add ||
6403	(!isa<ConstantInt>(Val: U->getOperand(i: 1)) &&
6404	Operator::getOpcode(V: U->getOperand(i: 1)) != Instruction::Mul &&
6405	!isa<PHINode>(Val: U->getOperand(i: 1))))
6406	return V;
6407	V = U->getOperand(i: 0);
6408	} else {
6409	return V;
6410	}
6411	assert(V->getType()->isIntegerTy() && "Unexpected operand type!");
6412	} while (true);
6413	}
6414
6415	/// This is a wrapper around getUnderlyingObjects and adds support for basic
6416	/// ptrtoint+arithmetic+inttoptr sequences.
6417	/// It returns false if unidentified object is found in getUnderlyingObjects.
6418	bool llvm::getUnderlyingObjectsForCodeGen(const Value *V,
6419	SmallVectorImpl<Value *> &Objects) {
6420	SmallPtrSet<const Value *, 16> Visited;
6421	SmallVector<const Value *, 4> Working(1, V);
6422	do {
6423	V = Working.pop_back_val();
6424
6425	SmallVector<const Value *, 4> Objs;
6426	getUnderlyingObjects(V, Objects&: Objs);
6427
6428	for (const Value *V : Objs) {
6429	if (!Visited.insert(Ptr: V).second)
6430	continue;
6431	if (Operator::getOpcode(V) == Instruction::IntToPtr) {
6432	const Value *O =
6433	getUnderlyingObjectFromInt(V: cast<User>(Val: V)->getOperand(i: 0));
6434	if (O->getType()->isPointerTy()) {
6435	Working.push_back(Elt: O);
6436	continue;
6437	}
6438	}
6439	// If getUnderlyingObjects fails to find an identifiable object,
6440	// getUnderlyingObjectsForCodeGen also fails for safety.
6441	if (!isIdentifiedObject(V)) {
6442	Objects.clear();
6443	return false;
6444	}
6445	Objects.push_back(Elt: const_cast<Value *>(V));
6446	}
6447	} while (!Working.empty());
6448	return true;
6449	}
6450
6451	AllocaInst *llvm::findAllocaForValue(Value *V, bool OffsetZero) {
6452	AllocaInst *Result = nullptr;
6453	SmallPtrSet<Value *, 4> Visited;
6454	SmallVector<Value *, 4> Worklist;
6455
6456	auto AddWork = [&](Value *V) {
6457	if (Visited.insert(Ptr: V).second)
6458	Worklist.push_back(Elt: V);
6459	};
6460
6461	AddWork(V);
6462	do {
6463	V = Worklist.pop_back_val();
6464	assert(Visited.count(V));
6465
6466	if (AllocaInst *AI = dyn_cast<AllocaInst>(Val: V)) {
6467	if (Result && Result != AI)
6468	return nullptr;
6469	Result = AI;
6470	} else if (CastInst *CI = dyn_cast<CastInst>(Val: V)) {
6471	AddWork(CI->getOperand(i_nocapture: 0));
6472	} else if (PHINode *PN = dyn_cast<PHINode>(Val: V)) {
6473	for (Value *IncValue : PN->incoming_values())
6474	AddWork(IncValue);
6475	} else if (auto *SI = dyn_cast<SelectInst>(Val: V)) {
6476	AddWork(SI->getTrueValue());
6477	AddWork(SI->getFalseValue());
6478	} else if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(Val: V)) {
6479	if (OffsetZero && !GEP->hasAllZeroIndices())
6480	return nullptr;
6481	AddWork(GEP->getPointerOperand());
6482	} else if (CallBase *CB = dyn_cast<CallBase>(Val: V)) {
6483	Value *Returned = CB->getReturnedArgOperand();
6484	if (Returned)
6485	AddWork(Returned);
6486	else
6487	return nullptr;
6488	} else {
6489	return nullptr;
6490	}
6491	} while (!Worklist.empty());
6492
6493	return Result;
6494	}
6495
6496	static bool onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
6497	const Value *V, bool AllowLifetime, bool AllowDroppable) {
6498	for (const User *U : V->users()) {
6499	const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Val: U);
6500	if (!II)
6501	return false;
6502
6503	if (AllowLifetime && II->isLifetimeStartOrEnd())
6504	continue;
6505
6506	if (AllowDroppable && II->isDroppable())
6507	continue;
6508
6509	return false;
6510	}
6511	return true;
6512	}
6513
6514	bool llvm::onlyUsedByLifetimeMarkers(const Value *V) {
6515	return onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
6516	V, /* AllowLifetime */ true, /* AllowDroppable */ false);
6517	}
6518	bool llvm::onlyUsedByLifetimeMarkersOrDroppableInsts(const Value *V) {
6519	return onlyUsedByLifetimeMarkersOrDroppableInstsHelper(
6520	V, /* AllowLifetime */ true, /* AllowDroppable */ true);
6521	}
6522
6523	bool llvm::mustSuppressSpeculation(const LoadInst &LI) {
6524	if (!LI.isUnordered())
6525	return true;
6526	const Function &F = *LI.getFunction();
6527	// Speculative load may create a race that did not exist in the source.
6528	return F.hasFnAttribute(Attribute::SanitizeThread) ||
6529	// Speculative load may load data from dirty regions.
6530	F.hasFnAttribute(Attribute::SanitizeAddress) ||
6531	F.hasFnAttribute(Attribute::SanitizeHWAddress);
6532	}
6533
6534	bool llvm::isSafeToSpeculativelyExecute(const Instruction *Inst,
6535	const Instruction *CtxI,
6536	AssumptionCache *AC,
6537	const DominatorTree *DT,
6538	const TargetLibraryInfo *TLI) {
6539	return isSafeToSpeculativelyExecuteWithOpcode(Opcode: Inst->getOpcode(), Inst, CtxI,
6540	AC, DT, TLI);
6541	}
6542
6543	bool llvm::isSafeToSpeculativelyExecuteWithOpcode(
6544	unsigned Opcode, const Instruction *Inst, const Instruction *CtxI,
6545	AssumptionCache *AC, const DominatorTree *DT,
6546	const TargetLibraryInfo *TLI) {
6547	#ifndef NDEBUG
6548	if (Inst->getOpcode() != Opcode) {
6549	// Check that the operands are actually compatible with the Opcode override.
6550	auto hasEqualReturnAndLeadingOperandTypes =
6551	[](const Instruction *Inst, unsigned NumLeadingOperands) {
6552	if (Inst->getNumOperands() < NumLeadingOperands)
6553	return false;
6554	const Type *ExpectedType = Inst->getType();
6555	for (unsigned ItOp = 0; ItOp < NumLeadingOperands; ++ItOp)
6556	if (Inst->getOperand(i: ItOp)->getType() != ExpectedType)
6557	return false;
6558	return true;
6559	};
6560	assert(!Instruction::isBinaryOp(Opcode) ||
6561	hasEqualReturnAndLeadingOperandTypes(Inst, 2));
6562	assert(!Instruction::isUnaryOp(Opcode) ||
6563	hasEqualReturnAndLeadingOperandTypes(Inst, 1));
6564	}
6565	#endif
6566
6567	switch (Opcode) {
6568	default:
6569	return true;
6570	case Instruction::UDiv:
6571	case Instruction::URem: {
6572	// x / y is undefined if y == 0.
6573	const APInt *V;
6574	if (match(V: Inst->getOperand(i: 1), P: m_APInt(Res&: V)))
6575	return *V != 0;
6576	return false;
6577	}
6578	case Instruction::SDiv:
6579	case Instruction::SRem: {
6580	// x / y is undefined if y == 0 or x == INT_MIN and y == -1
6581	const APInt *Numerator, *Denominator;
6582	if (!match(V: Inst->getOperand(i: 1), P: m_APInt(Res&: Denominator)))
6583	return false;
6584	// We cannot hoist this division if the denominator is 0.
6585	if (*Denominator == 0)
6586	return false;
6587	// It's safe to hoist if the denominator is not 0 or -1.
6588	if (!Denominator->isAllOnes())
6589	return true;
6590	// At this point we know that the denominator is -1. It is safe to hoist as
6591	// long we know that the numerator is not INT_MIN.
6592	if (match(V: Inst->getOperand(i: 0), P: m_APInt(Res&: Numerator)))
6593	return !Numerator->isMinSignedValue();
6594	// The numerator *might* be MinSignedValue.
6595	return false;
6596	}
6597	case Instruction::Load: {
6598	const LoadInst *LI = dyn_cast<LoadInst>(Val: Inst);
6599	if (!LI)
6600	return false;
6601	if (mustSuppressSpeculation(LI: *LI))
6602	return false;
6603	const DataLayout &DL = LI->getModule()->getDataLayout();
6604	return isDereferenceableAndAlignedPointer(V: LI->getPointerOperand(),
6605	Ty: LI->getType(), Alignment: LI->getAlign(), DL,
6606	CtxI, AC, DT, TLI);
6607	}
6608	case Instruction::Call: {
6609	auto *CI = dyn_cast<const CallInst>(Val: Inst);
6610	if (!CI)
6611	return false;
6612	const Function *Callee = CI->getCalledFunction();
6613
6614	// The called function could have undefined behavior or side-effects, even
6615	// if marked readnone nounwind.
6616	return Callee && Callee->isSpeculatable();
6617	}
6618	case Instruction::VAArg:
6619	case Instruction::Alloca:
6620	case Instruction::Invoke:
6621	case Instruction::CallBr:
6622	case Instruction::PHI:
6623	case Instruction::Store:
6624	case Instruction::Ret:
6625	case Instruction::Br:
6626	case Instruction::IndirectBr:
6627	case Instruction::Switch:
6628	case Instruction::Unreachable:
6629	case Instruction::Fence:
6630	case Instruction::AtomicRMW:
6631	case Instruction::AtomicCmpXchg:
6632	case Instruction::LandingPad:
6633	case Instruction::Resume:
6634	case Instruction::CatchSwitch:
6635	case Instruction::CatchPad:
6636	case Instruction::CatchRet:
6637	case Instruction::CleanupPad:
6638	case Instruction::CleanupRet:
6639	return false; // Misc instructions which have effects
6640	}
6641	}
6642
6643	bool llvm::mayHaveNonDefUseDependency(const Instruction &I) {
6644	if (I.mayReadOrWriteMemory())
6645	// Memory dependency possible
6646	return true;
6647	if (!isSafeToSpeculativelyExecute(Inst: &I))
6648	// Can't move above a maythrow call or infinite loop. Or if an
6649	// inalloca alloca, above a stacksave call.
6650	return true;
6651	if (!isGuaranteedToTransferExecutionToSuccessor(I: &I))
6652	// 1) Can't reorder two inf-loop calls, even if readonly
6653	// 2) Also can't reorder an inf-loop call below a instruction which isn't
6654	// safe to speculative execute. (Inverse of above)
6655	return true;
6656	return false;
6657	}
6658
6659	/// Convert ConstantRange OverflowResult into ValueTracking OverflowResult.
6660	static OverflowResult mapOverflowResult(ConstantRange::OverflowResult OR) {
6661	switch (OR) {
6662	case ConstantRange::OverflowResult::MayOverflow:
6663	return OverflowResult::MayOverflow;
6664	case ConstantRange::OverflowResult::AlwaysOverflowsLow:
6665	return OverflowResult::AlwaysOverflowsLow;
6666	case ConstantRange::OverflowResult::AlwaysOverflowsHigh:
6667	return OverflowResult::AlwaysOverflowsHigh;
6668	case ConstantRange::OverflowResult::NeverOverflows:
6669	return OverflowResult::NeverOverflows;
6670	}
6671	llvm_unreachable("Unknown OverflowResult");
6672	}
6673
6674	/// Combine constant ranges from computeConstantRange() and computeKnownBits().
6675	ConstantRange
6676	llvm::computeConstantRangeIncludingKnownBits(const WithCache<const Value *> &V,
6677	bool ForSigned,
6678	const SimplifyQuery &SQ) {
6679	ConstantRange CR1 =
6680	ConstantRange::fromKnownBits(Known: V.getKnownBits(Q: SQ), IsSigned: ForSigned);
6681	ConstantRange CR2 = computeConstantRange(V, ForSigned, UseInstrInfo: SQ.IIQ.UseInstrInfo);
6682	ConstantRange::PreferredRangeType RangeType =
6683	ForSigned ? ConstantRange::Signed : ConstantRange::Unsigned;
6684	return CR1.intersectWith(CR: CR2, Type: RangeType);
6685	}
6686
6687	OverflowResult llvm::computeOverflowForUnsignedMul(const Value *LHS,
6688	const Value *RHS,
6689	const SimplifyQuery &SQ) {
6690	KnownBits LHSKnown = computeKnownBits(V: LHS, /*Depth=*/0, Q: SQ);
6691	KnownBits RHSKnown = computeKnownBits(V: RHS, /*Depth=*/0, Q: SQ);
6692	ConstantRange LHSRange = ConstantRange::fromKnownBits(Known: LHSKnown, IsSigned: false);
6693	ConstantRange RHSRange = ConstantRange::fromKnownBits(Known: RHSKnown, IsSigned: false);
6694	return mapOverflowResult(OR: LHSRange.unsignedMulMayOverflow(Other: RHSRange));
6695	}
6696
6697	OverflowResult llvm::computeOverflowForSignedMul(const Value *LHS,
6698	const Value *RHS,
6699	const SimplifyQuery &SQ) {
6700	// Multiplying n * m significant bits yields a result of n + m significant
6701	// bits. If the total number of significant bits does not exceed the
6702	// result bit width (minus 1), there is no overflow.
6703	// This means if we have enough leading sign bits in the operands
6704	// we can guarantee that the result does not overflow.
6705	// Ref: "Hacker's Delight" by Henry Warren
6706	unsigned BitWidth = LHS->getType()->getScalarSizeInBits();
6707
6708	// Note that underestimating the number of sign bits gives a more
6709	// conservative answer.
6710	unsigned SignBits =
6711	::ComputeNumSignBits(V: LHS, Depth: 0, Q: SQ) + ::ComputeNumSignBits(V: RHS, Depth: 0, Q: SQ);
6712
6713	// First handle the easy case: if we have enough sign bits there's
6714	// definitely no overflow.
6715	if (SignBits > BitWidth + 1)
6716	return OverflowResult::NeverOverflows;
6717
6718	// There are two ambiguous cases where there can be no overflow:
6719	// SignBits == BitWidth + 1 and
6720	// SignBits == BitWidth
6721	// The second case is difficult to check, therefore we only handle the
6722	// first case.
6723	if (SignBits == BitWidth + 1) {
6724	// It overflows only when both arguments are negative and the true
6725	// product is exactly the minimum negative number.
6726	// E.g. mul i16 with 17 sign bits: 0xff00 * 0xff80 = 0x8000
6727	// For simplicity we just check if at least one side is not negative.
6728	KnownBits LHSKnown = computeKnownBits(V: LHS, /*Depth=*/0, Q: SQ);
6729	KnownBits RHSKnown = computeKnownBits(V: RHS, /*Depth=*/0, Q: SQ);
6730	if (LHSKnown.isNonNegative() || RHSKnown.isNonNegative())
6731	return OverflowResult::NeverOverflows;
6732	}
6733	return OverflowResult::MayOverflow;
6734	}
6735
6736	OverflowResult
6737	llvm::computeOverflowForUnsignedAdd(const WithCache<const Value *> &LHS,
6738	const WithCache<const Value *> &RHS,
6739	const SimplifyQuery &SQ) {
6740	ConstantRange LHSRange =
6741	computeConstantRangeIncludingKnownBits(V: LHS, /*ForSigned=*/false, SQ);
6742	ConstantRange RHSRange =
6743	computeConstantRangeIncludingKnownBits(V: RHS, /*ForSigned=*/false, SQ);
6744	return mapOverflowResult(OR: LHSRange.unsignedAddMayOverflow(Other: RHSRange));
6745	}
6746
6747	static OverflowResult
6748	computeOverflowForSignedAdd(const WithCache<const Value *> &LHS,
6749	const WithCache<const Value *> &RHS,
6750	const AddOperator *Add, const SimplifyQuery &SQ) {
6751	if (Add && Add->hasNoSignedWrap()) {
6752	return OverflowResult::NeverOverflows;
6753	}
6754
6755	// If LHS and RHS each have at least two sign bits, the addition will look
6756	// like
6757	//
6758	// XX..... +
6759	// YY.....
6760	//
6761	// If the carry into the most significant position is 0, X and Y can't both
6762	// be 1 and therefore the carry out of the addition is also 0.
6763	//
6764	// If the carry into the most significant position is 1, X and Y can't both
6765	// be 0 and therefore the carry out of the addition is also 1.
6766	//
6767	// Since the carry into the most significant position is always equal to
6768	// the carry out of the addition, there is no signed overflow.
6769	if (::ComputeNumSignBits(V: LHS, Depth: 0, Q: SQ) > 1 &&
6770	::ComputeNumSignBits(V: RHS, Depth: 0, Q: SQ) > 1)
6771	return OverflowResult::NeverOverflows;
6772
6773	ConstantRange LHSRange =
6774	computeConstantRangeIncludingKnownBits(V: LHS, /*ForSigned=*/true, SQ);
6775	ConstantRange RHSRange =
6776	computeConstantRangeIncludingKnownBits(V: RHS, /*ForSigned=*/true, SQ);
6777	OverflowResult OR =
6778	mapOverflowResult(OR: LHSRange.signedAddMayOverflow(Other: RHSRange));
6779	if (OR != OverflowResult::MayOverflow)
6780	return OR;
6781
6782	// The remaining code needs Add to be available. Early returns if not so.
6783	if (!Add)
6784	return OverflowResult::MayOverflow;
6785
6786	// If the sign of Add is the same as at least one of the operands, this add
6787	// CANNOT overflow. If this can be determined from the known bits of the
6788	// operands the above signedAddMayOverflow() check will have already done so.
6789	// The only other way to improve on the known bits is from an assumption, so
6790	// call computeKnownBitsFromContext() directly.
6791	bool LHSOrRHSKnownNonNegative =
6792	(LHSRange.isAllNonNegative() || RHSRange.isAllNonNegative());
6793	bool LHSOrRHSKnownNegative =
6794	(LHSRange.isAllNegative() || RHSRange.isAllNegative());
6795	if (LHSOrRHSKnownNonNegative || LHSOrRHSKnownNegative) {
6796	KnownBits AddKnown(LHSRange.getBitWidth());
6797	computeKnownBitsFromContext(V: Add, Known&: AddKnown, /*Depth=*/0, Q: SQ);
6798	if ((AddKnown.isNonNegative() && LHSOrRHSKnownNonNegative) ||
6799	(AddKnown.isNegative() && LHSOrRHSKnownNegative))
6800	return OverflowResult::NeverOverflows;
6801	}
6802
6803	return OverflowResult::MayOverflow;
6804	}
6805
6806	OverflowResult llvm::computeOverflowForUnsignedSub(const Value *LHS,
6807	const Value *RHS,
6808	const SimplifyQuery &SQ) {
6809	// X - (X % ?)
6810	// The remainder of a value can't have greater magnitude than itself,
6811	// so the subtraction can't overflow.
6812
6813	// X - (X -nuw ?)
6814	// In the minimal case, this would simplify to "?", so there's no subtract
6815	// at all. But if this analysis is used to peek through casts, for example,
6816	// then determining no-overflow may allow other transforms.
6817
6818	// TODO: There are other patterns like this.
6819	// See simplifyICmpWithBinOpOnLHS() for candidates.
6820	if (match(V: RHS, P: m_URem(L: m_Specific(V: LHS), R: m_Value())) ||
6821	match(V: RHS, P: m_NUWSub(L: m_Specific(V: LHS), R: m_Value())))
6822	if (isGuaranteedNotToBeUndef(V: LHS, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
6823	return OverflowResult::NeverOverflows;
6824
6825	// Checking for conditions implied by dominating conditions may be expensive.
6826	// Limit it to usub_with_overflow calls for now.
6827	if (match(SQ.CxtI,
6828	m_Intrinsic<Intrinsic::usub_with_overflow>(m_Value(), m_Value())))
6829	if (auto C = isImpliedByDomCondition(Pred: CmpInst::ICMP_UGE, LHS, RHS, ContextI: SQ.CxtI,
6830	DL: SQ.DL)) {
6831	if (*C)
6832	return OverflowResult::NeverOverflows;
6833	return OverflowResult::AlwaysOverflowsLow;
6834	}
6835	ConstantRange LHSRange =
6836	computeConstantRangeIncludingKnownBits(V: LHS, /*ForSigned=*/false, SQ);
6837	ConstantRange RHSRange =
6838	computeConstantRangeIncludingKnownBits(V: RHS, /*ForSigned=*/false, SQ);
6839	return mapOverflowResult(OR: LHSRange.unsignedSubMayOverflow(Other: RHSRange));
6840	}
6841
6842	OverflowResult llvm::computeOverflowForSignedSub(const Value *LHS,
6843	const Value *RHS,
6844	const SimplifyQuery &SQ) {
6845	// X - (X % ?)
6846	// The remainder of a value can't have greater magnitude than itself,
6847	// so the subtraction can't overflow.
6848
6849	// X - (X -nsw ?)
6850	// In the minimal case, this would simplify to "?", so there's no subtract
6851	// at all. But if this analysis is used to peek through casts, for example,
6852	// then determining no-overflow may allow other transforms.
6853	if (match(V: RHS, P: m_SRem(L: m_Specific(V: LHS), R: m_Value())) ||
6854	match(V: RHS, P: m_NSWSub(L: m_Specific(V: LHS), R: m_Value())))
6855	if (isGuaranteedNotToBeUndef(V: LHS, AC: SQ.AC, CtxI: SQ.CxtI, DT: SQ.DT))
6856	return OverflowResult::NeverOverflows;
6857
6858	// If LHS and RHS each have at least two sign bits, the subtraction
6859	// cannot overflow.
6860	if (::ComputeNumSignBits(V: LHS, Depth: 0, Q: SQ) > 1 &&
6861	::ComputeNumSignBits(V: RHS, Depth: 0, Q: SQ) > 1)
6862	return OverflowResult::NeverOverflows;
6863
6864	ConstantRange LHSRange =
6865	computeConstantRangeIncludingKnownBits(V: LHS, /*ForSigned=*/true, SQ);
6866	ConstantRange RHSRange =
6867	computeConstantRangeIncludingKnownBits(V: RHS, /*ForSigned=*/true, SQ);
6868	return mapOverflowResult(OR: LHSRange.signedSubMayOverflow(Other: RHSRange));
6869	}
6870
6871	bool llvm::isOverflowIntrinsicNoWrap(const WithOverflowInst *WO,
6872	const DominatorTree &DT) {
6873	SmallVector<const BranchInst *, 2> GuardingBranches;
6874	SmallVector<const ExtractValueInst *, 2> Results;
6875
6876	for (const User *U : WO->users()) {
6877	if (const auto *EVI = dyn_cast<ExtractValueInst>(Val: U)) {
6878	assert(EVI->getNumIndices() == 1 && "Obvious from CI's type");
6879
6880	if (EVI->getIndices()[0] == 0)
6881	Results.push_back(Elt: EVI);
6882	else {
6883	assert(EVI->getIndices()[0] == 1 && "Obvious from CI's type");
6884
6885	for (const auto *U : EVI->users())
6886	if (const auto *B = dyn_cast<BranchInst>(Val: U)) {
6887	assert(B->isConditional() && "How else is it using an i1?");
6888	GuardingBranches.push_back(Elt: B);
6889	}
6890	}
6891	} else {
6892	// We are using the aggregate directly in a way we don't want to analyze
6893	// here (storing it to a global, say).
6894	return false;
6895	}
6896	}
6897
6898	auto AllUsesGuardedByBranch = [&](const BranchInst *BI) {
6899	BasicBlockEdge NoWrapEdge(BI->getParent(), BI->getSuccessor(i: 1));
6900	if (!NoWrapEdge.isSingleEdge())
6901	return false;
6902
6903	// Check if all users of the add are provably no-wrap.
6904	for (const auto *Result : Results) {
6905	// If the extractvalue itself is not executed on overflow, the we don't
6906	// need to check each use separately, since domination is transitive.
6907	if (DT.dominates(BBE: NoWrapEdge, BB: Result->getParent()))
6908	continue;
6909
6910	for (const auto &RU : Result->uses())
6911	if (!DT.dominates(BBE: NoWrapEdge, U: RU))
6912	return false;
6913	}
6914
6915	return true;
6916	};
6917
6918	return llvm::any_of(Range&: GuardingBranches, P: AllUsesGuardedByBranch);
6919	}
6920
6921	/// Shifts return poison if shiftwidth is larger than the bitwidth.
6922	static bool shiftAmountKnownInRange(const Value *ShiftAmount) {
6923	auto *C = dyn_cast<Constant>(Val: ShiftAmount);
6924	if (!C)
6925	return false;
6926
6927	// Shifts return poison if shiftwidth is larger than the bitwidth.
6928	SmallVector<const Constant *, 4> ShiftAmounts;
6929	if (auto *FVTy = dyn_cast<FixedVectorType>(Val: C->getType())) {
6930	unsigned NumElts = FVTy->getNumElements();
6931	for (unsigned i = 0; i < NumElts; ++i)
6932	ShiftAmounts.push_back(Elt: C->getAggregateElement(Elt: i));
6933	} else if (isa<ScalableVectorType>(Val: C->getType()))
6934	return false; // Can't tell, just return false to be safe
6935	else
6936	ShiftAmounts.push_back(Elt: C);
6937
6938	bool Safe = llvm::all_of(Range&: ShiftAmounts, P: [](const Constant *C) {
6939	auto *CI = dyn_cast_or_null<ConstantInt>(Val: C);
6940	return CI && CI->getValue().ult(RHS: C->getType()->getIntegerBitWidth());
6941	});
6942
6943	return Safe;
6944	}
6945
6946	enum class UndefPoisonKind {
6947	PoisonOnly = (1 << 0),
6948	UndefOnly = (1 << 1),
6949	UndefOrPoison = PoisonOnly | UndefOnly,
6950	};
6951
6952	static bool includesPoison(UndefPoisonKind Kind) {
6953	return (unsigned(Kind) & unsigned(UndefPoisonKind::PoisonOnly)) != 0;
6954	}
6955
6956	static bool includesUndef(UndefPoisonKind Kind) {
6957	return (unsigned(Kind) & unsigned(UndefPoisonKind::UndefOnly)) != 0;
6958	}
6959
6960	static bool canCreateUndefOrPoison(const Operator *Op, UndefPoisonKind Kind,
6961	bool ConsiderFlagsAndMetadata) {
6962
6963	if (ConsiderFlagsAndMetadata && includesPoison(Kind) &&
6964	Op->hasPoisonGeneratingAnnotations())
6965	return true;
6966
6967	unsigned Opcode = Op->getOpcode();
6968
6969	// Check whether opcode is a poison/undef-generating operation
6970	switch (Opcode) {
6971	case Instruction::Shl:
6972	case Instruction::AShr:
6973	case Instruction::LShr:
6974	return includesPoison(Kind) && !shiftAmountKnownInRange(ShiftAmount: Op->getOperand(i: 1));
6975	case Instruction::FPToSI:
6976	case Instruction::FPToUI:
6977	// fptosi/ui yields poison if the resulting value does not fit in the
6978	// destination type.
6979	return true;
6980	case Instruction::Call:
6981	if (auto *II = dyn_cast<IntrinsicInst>(Val: Op)) {
6982	switch (II->getIntrinsicID()) {
6983	// TODO: Add more intrinsics.
6984	case Intrinsic::ctlz:
6985	case Intrinsic::cttz:
6986	case Intrinsic::abs:
6987	if (cast<ConstantInt>(Val: II->getArgOperand(i: 1))->isNullValue())
6988	return false;
6989	break;
6990	case Intrinsic::ctpop:
6991	case Intrinsic::bswap:
6992	case Intrinsic::bitreverse:
6993	case Intrinsic::fshl:
6994	case Intrinsic::fshr:
6995	case Intrinsic::smax:
6996	case Intrinsic::smin:
6997	case Intrinsic::umax:
6998	case Intrinsic::umin:
6999	case Intrinsic::ptrmask:
7000	case Intrinsic::fptoui_sat:
7001	case Intrinsic::fptosi_sat:
7002	case Intrinsic::sadd_with_overflow:
7003	case Intrinsic::ssub_with_overflow:
7004	case Intrinsic::smul_with_overflow:
7005	case Intrinsic::uadd_with_overflow:
7006	case Intrinsic::usub_with_overflow:
7007	case Intrinsic::umul_with_overflow:
7008	case Intrinsic::sadd_sat:
7009	case Intrinsic::uadd_sat:
7010	case Intrinsic::ssub_sat:
7011	case Intrinsic::usub_sat:
7012	return false;
7013	case Intrinsic::sshl_sat:
7014	case Intrinsic::ushl_sat:
7015	return includesPoison(Kind) &&
7016	!shiftAmountKnownInRange(ShiftAmount: II->getArgOperand(i: 1));
7017	case Intrinsic::fma:
7018	case Intrinsic::fmuladd:
7019	case Intrinsic::sqrt:
7020	case Intrinsic::powi:
7021	case Intrinsic::sin:
7022	case Intrinsic::cos:
7023	case Intrinsic::pow:
7024	case Intrinsic::log:
7025	case Intrinsic::log10:
7026	case Intrinsic::log2:
7027	case Intrinsic::exp:
7028	case Intrinsic::exp2:
7029	case Intrinsic::exp10:
7030	case Intrinsic::fabs:
7031	case Intrinsic::copysign:
7032	case Intrinsic::floor:
7033	case Intrinsic::ceil:
7034	case Intrinsic::trunc:
7035	case Intrinsic::rint:
7036	case Intrinsic::nearbyint:
7037	case Intrinsic::round:
7038	case Intrinsic::roundeven:
7039	case Intrinsic::fptrunc_round:
7040	case Intrinsic::canonicalize:
7041	case Intrinsic::arithmetic_fence:
7042	case Intrinsic::minnum:
7043	case Intrinsic::maxnum:
7044	case Intrinsic::minimum:
7045	case Intrinsic::maximum:
7046	case Intrinsic::is_fpclass:
7047	case Intrinsic::ldexp:
7048	case Intrinsic::frexp:
7049	return false;
7050	case Intrinsic::lround:
7051	case Intrinsic::llround:
7052	case Intrinsic::lrint:
7053	case Intrinsic::llrint:
7054	// If the value doesn't fit an unspecified value is returned (but this
7055	// is not poison).
7056	return false;
7057	}
7058	}
7059	[[fallthrough]];
7060	case Instruction::CallBr:
7061	case Instruction::Invoke: {
7062	const auto *CB = cast<CallBase>(Val: Op);
7063	return !CB->hasRetAttr(Attribute::NoUndef);
7064	}
7065	case Instruction::InsertElement:
7066	case Instruction::ExtractElement: {
7067	// If index exceeds the length of the vector, it returns poison
7068	auto *VTy = cast<VectorType>(Val: Op->getOperand(i: 0)->getType());
7069	unsigned IdxOp = Op->getOpcode() == Instruction::InsertElement ? 2 : 1;
7070	auto *Idx = dyn_cast<ConstantInt>(Val: Op->getOperand(i: IdxOp));
7071	if (includesPoison(Kind))
7072	return !Idx ||
7073	Idx->getValue().uge(RHS: VTy->getElementCount().getKnownMinValue());
7074	return false;
7075	}
7076	case Instruction::ShuffleVector: {
7077	ArrayRef<int> Mask = isa<ConstantExpr>(Val: Op)
7078	? cast<ConstantExpr>(Val: Op)->getShuffleMask()
7079	: cast<ShuffleVectorInst>(Val: Op)->getShuffleMask();
7080	return includesPoison(Kind) && is_contained(Range&: Mask, Element: PoisonMaskElem);
7081	}
7082	case Instruction::FNeg:
7083	case Instruction::PHI:
7084	case Instruction::Select:
7085	case Instruction::URem:
7086	case Instruction::SRem:
7087	case Instruction::ExtractValue:
7088	case Instruction::InsertValue:
7089	case Instruction::Freeze:
7090	case Instruction::ICmp:
7091	case Instruction::FCmp:
7092	case Instruction::FAdd:
7093	case Instruction::FSub:
7094	case Instruction::FMul:
7095	case Instruction::FDiv:
7096	case Instruction::FRem:
7097	return false;
7098	case Instruction::GetElementPtr:
7099	// inbounds is handled above
7100	// TODO: what about inrange on constexpr?
7101	return false;
7102	default: {
7103	const auto *CE = dyn_cast<ConstantExpr>(Val: Op);
7104	if (isa<CastInst>(Val: Op) || (CE && CE->isCast()))
7105	return false;
7106	else if (Instruction::isBinaryOp(Opcode))
7107	return false;
7108	// Be conservative and return true.
7109	return true;
7110	}
7111	}
7112	}
7113
7114	bool llvm::canCreateUndefOrPoison(const Operator *Op,
7115	bool ConsiderFlagsAndMetadata) {
7116	return ::canCreateUndefOrPoison(Op, Kind: UndefPoisonKind::UndefOrPoison,
7117	ConsiderFlagsAndMetadata);
7118	}
7119
7120	bool llvm::canCreatePoison(const Operator *Op, bool ConsiderFlagsAndMetadata) {
7121	return ::canCreateUndefOrPoison(Op, Kind: UndefPoisonKind::PoisonOnly,
7122	ConsiderFlagsAndMetadata);
7123	}
7124
7125	static bool directlyImpliesPoison(const Value *ValAssumedPoison, const Value *V,
7126	unsigned Depth) {
7127	if (ValAssumedPoison == V)
7128	return true;
7129
7130	const unsigned MaxDepth = 2;
7131	if (Depth >= MaxDepth)
7132	return false;
7133
7134	if (const auto *I = dyn_cast<Instruction>(Val: V)) {
7135	if (any_of(Range: I->operands(), P: [=](const Use &Op) {
7136	return propagatesPoison(PoisonOp: Op) &&
7137	directlyImpliesPoison(ValAssumedPoison, V: Op, Depth: Depth + 1);
7138	}))
7139	return true;
7140
7141	// V = extractvalue V0, idx
7142	// V2 = extractvalue V0, idx2
7143	// V0's elements are all poison or not. (e.g., add_with_overflow)
7144	const WithOverflowInst *II;
7145	if (match(V: I, P: m_ExtractValue(V: m_WithOverflowInst(I&: II))) &&
7146	(match(V: ValAssumedPoison, P: m_ExtractValue(V: m_Specific(V: II))) ||
7147	llvm::is_contained(Range: II->args(), Element: ValAssumedPoison)))
7148	return true;
7149	}
7150	return false;
7151	}
7152
7153	static bool impliesPoison(const Value *ValAssumedPoison, const Value *V,
7154	unsigned Depth) {
7155	if (isGuaranteedNotToBePoison(V: ValAssumedPoison))
7156	return true;
7157
7158	if (directlyImpliesPoison(ValAssumedPoison, V, /* Depth */ 0))
7159	return true;
7160
7161	const unsigned MaxDepth = 2;
7162	if (Depth >= MaxDepth)
7163	return false;
7164
7165	const auto *I = dyn_cast<Instruction>(Val: ValAssumedPoison);
7166	if (I && !canCreatePoison(Op: cast<Operator>(Val: I))) {
7167	return all_of(Range: I->operands(), P: [=](const Value *Op) {
7168	return impliesPoison(ValAssumedPoison: Op, V, Depth: Depth + 1);
7169	});
7170	}
7171	return false;
7172	}
7173
7174	bool llvm::impliesPoison(const Value *ValAssumedPoison, const Value *V) {
7175	return ::impliesPoison(ValAssumedPoison, V, /* Depth */ 0);
7176	}
7177
7178	static bool programUndefinedIfUndefOrPoison(const Value *V, bool PoisonOnly);
7179
7180	static bool isGuaranteedNotToBeUndefOrPoison(
7181	const Value *V, AssumptionCache *AC, const Instruction *CtxI,
7182	const DominatorTree *DT, unsigned Depth, UndefPoisonKind Kind) {
7183	if (Depth >= MaxAnalysisRecursionDepth)
7184	return false;
7185
7186	if (isa<MetadataAsValue>(Val: V))
7187	return false;
7188
7189	if (const auto *A = dyn_cast<Argument>(Val: V)) {
7190	if (A->hasAttribute(Attribute::NoUndef) ||
7191	A->hasAttribute(Attribute::Dereferenceable) ||
7192	A->hasAttribute(Attribute::DereferenceableOrNull))
7193	return true;
7194	}
7195
7196	if (auto *C = dyn_cast<Constant>(Val: V)) {
7197	if (isa<PoisonValue>(Val: C))
7198	return !includesPoison(Kind);
7199
7200	if (isa<UndefValue>(Val: C))
7201	return !includesUndef(Kind);
7202
7203	if (isa<ConstantInt>(Val: C) || isa<GlobalVariable>(Val: C) || isa<ConstantFP>(Val: V) ||
7204	isa<ConstantPointerNull>(Val: C) || isa<Function>(Val: C))
7205	return true;
7206
7207	if (C->getType()->isVectorTy() && !isa<ConstantExpr>(Val: C))
7208	return (!includesUndef(Kind) ? !C->containsPoisonElement()
7209	: !C->containsUndefOrPoisonElement()) &&
7210	!C->containsConstantExpression();
7211	}
7212
7213	// Strip cast operations from a pointer value.
7214	// Note that stripPointerCastsSameRepresentation can strip off getelementptr
7215	// inbounds with zero offset. To guarantee that the result isn't poison, the
7216	// stripped pointer is checked as it has to be pointing into an allocated
7217	// object or be null `null` to ensure `inbounds` getelement pointers with a
7218	// zero offset could not produce poison.
7219	// It can strip off addrspacecast that do not change bit representation as
7220	// well. We believe that such addrspacecast is equivalent to no-op.
7221	auto *StrippedV = V->stripPointerCastsSameRepresentation();
7222	if (isa<AllocaInst>(Val: StrippedV) || isa<GlobalVariable>(Val: StrippedV) ||
7223	isa<Function>(Val: StrippedV) || isa<ConstantPointerNull>(Val: StrippedV))
7224	return true;
7225
7226	auto OpCheck = [&](const Value *V) {
7227	return isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth: Depth + 1, Kind);
7228	};
7229
7230	if (auto *Opr = dyn_cast<Operator>(Val: V)) {
7231	// If the value is a freeze instruction, then it can never
7232	// be undef or poison.
7233	if (isa<FreezeInst>(Val: V))
7234	return true;
7235
7236	if (const auto *CB = dyn_cast<CallBase>(Val: V)) {
7237	if (CB->hasRetAttr(Attribute::NoUndef) ||
7238	CB->hasRetAttr(Attribute::Dereferenceable) ||
7239	CB->hasRetAttr(Attribute::DereferenceableOrNull))
7240	return true;
7241	}
7242
7243	if (const auto *PN = dyn_cast<PHINode>(Val: V)) {
7244	unsigned Num = PN->getNumIncomingValues();
7245	bool IsWellDefined = true;
7246	for (unsigned i = 0; i < Num; ++i) {
7247	auto *TI = PN->getIncomingBlock(i)->getTerminator();
7248	if (!isGuaranteedNotToBeUndefOrPoison(V: PN->getIncomingValue(i), AC, CtxI: TI,
7249	DT, Depth: Depth + 1, Kind)) {
7250	IsWellDefined = false;
7251	break;
7252	}
7253	}
7254	if (IsWellDefined)
7255	return true;
7256	} else if (!::canCreateUndefOrPoison(Op: Opr, Kind,
7257	/*ConsiderFlagsAndMetadata*/ true) &&
7258	all_of(Range: Opr->operands(), P: OpCheck))
7259	return true;
7260	}
7261
7262	if (auto *I = dyn_cast<LoadInst>(Val: V))
7263	if (I->hasMetadata(KindID: LLVMContext::MD_noundef) ||
7264	I->hasMetadata(KindID: LLVMContext::MD_dereferenceable) ||
7265	I->hasMetadata(KindID: LLVMContext::MD_dereferenceable_or_null))
7266	return true;
7267
7268	if (programUndefinedIfUndefOrPoison(V, PoisonOnly: !includesUndef(Kind)))
7269	return true;
7270
7271	// CxtI may be null or a cloned instruction.
7272	if (!CtxI || !CtxI->getParent() || !DT)
7273	return false;
7274
7275	auto *DNode = DT->getNode(BB: CtxI->getParent());
7276	if (!DNode)
7277	// Unreachable block
7278	return false;
7279
7280	// If V is used as a branch condition before reaching CtxI, V cannot be
7281	// undef or poison.
7282	// br V, BB1, BB2
7283	// BB1:
7284	// CtxI ; V cannot be undef or poison here
7285	auto *Dominator = DNode->getIDom();
7286	while (Dominator) {
7287	auto *TI = Dominator->getBlock()->getTerminator();
7288
7289	Value *Cond = nullptr;
7290	if (auto BI = dyn_cast_or_null<BranchInst>(Val: TI)) {
7291	if (BI->isConditional())
7292	Cond = BI->getCondition();
7293	} else if (auto SI = dyn_cast_or_null<SwitchInst>(Val: TI)) {
7294	Cond = SI->getCondition();
7295	}
7296
7297	if (Cond) {
7298	if (Cond == V)
7299	return true;
7300	else if (!includesUndef(Kind) && isa<Operator>(Val: Cond)) {
7301	// For poison, we can analyze further
7302	auto *Opr = cast<Operator>(Val: Cond);
7303	if (any_of(Range: Opr->operands(),
7304	P: [V](const Use &U) { return V == U && propagatesPoison(PoisonOp: U); }))
7305	return true;
7306	}
7307	}
7308
7309	Dominator = Dominator->getIDom();
7310	}
7311
7312	if (getKnowledgeValidInContext(V, {Attribute::NoUndef}, CtxI, DT, AC))
7313	return true;
7314
7315	return false;
7316	}
7317
7318	bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V, AssumptionCache *AC,
7319	const Instruction *CtxI,
7320	const DominatorTree *DT,
7321	unsigned Depth) {
7322	return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth,
7323	Kind: UndefPoisonKind::UndefOrPoison);
7324	}
7325
7326	bool llvm::isGuaranteedNotToBePoison(const Value *V, AssumptionCache *AC,
7327	const Instruction *CtxI,
7328	const DominatorTree *DT, unsigned Depth) {
7329	return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth,
7330	Kind: UndefPoisonKind::PoisonOnly);
7331	}
7332
7333	bool llvm::isGuaranteedNotToBeUndef(const Value *V, AssumptionCache *AC,
7334	const Instruction *CtxI,
7335	const DominatorTree *DT, unsigned Depth) {
7336	return ::isGuaranteedNotToBeUndefOrPoison(V, AC, CtxI, DT, Depth,
7337	Kind: UndefPoisonKind::UndefOnly);
7338	}
7339
7340	/// Return true if undefined behavior would provably be executed on the path to
7341	/// OnPathTo if Root produced a posion result. Note that this doesn't say
7342	/// anything about whether OnPathTo is actually executed or whether Root is
7343	/// actually poison. This can be used to assess whether a new use of Root can
7344	/// be added at a location which is control equivalent with OnPathTo (such as
7345	/// immediately before it) without introducing UB which didn't previously
7346	/// exist. Note that a false result conveys no information.
7347	bool llvm::mustExecuteUBIfPoisonOnPathTo(Instruction *Root,
7348	Instruction *OnPathTo,
7349	DominatorTree *DT) {
7350	// Basic approach is to assume Root is poison, propagate poison forward
7351	// through all users we can easily track, and then check whether any of those
7352	// users are provable UB and must execute before out exiting block might
7353	// exit.
7354
7355	// The set of all recursive users we've visited (which are assumed to all be
7356	// poison because of said visit)
7357	SmallSet<const Value *, 16> KnownPoison;
7358	SmallVector<const Instruction*, 16> Worklist;
7359	Worklist.push_back(Elt: Root);
7360	while (!Worklist.empty()) {
7361	const Instruction *I = Worklist.pop_back_val();
7362
7363	// If we know this must trigger UB on a path leading our target.
7364	if (mustTriggerUB(I, KnownPoison) && DT->dominates(Def: I, User: OnPathTo))
7365	return true;
7366
7367	// If we can't analyze propagation through this instruction, just skip it
7368	// and transitive users. Safe as false is a conservative result.
7369	if (I != Root && !any_of(Range: I->operands(), P: [&KnownPoison](const Use &U) {
7370	return KnownPoison.contains(Ptr: U) && propagatesPoison(PoisonOp: U);
7371	}))
7372	continue;
7373
7374	if (KnownPoison.insert(Ptr: I).second)
7375	for (const User *User : I->users())
7376	Worklist.push_back(Elt: cast<Instruction>(Val: User));
7377	}
7378
7379	// Might be non-UB, or might have a path we couldn't prove must execute on
7380	// way to exiting bb.
7381	return false;
7382	}
7383
7384	OverflowResult llvm::computeOverflowForSignedAdd(const AddOperator *Add,
7385	const SimplifyQuery &SQ) {
7386	return ::computeOverflowForSignedAdd(LHS: Add->getOperand(i_nocapture: 0), RHS: Add->getOperand(i_nocapture: 1),
7387	Add, SQ);
7388	}
7389
7390	OverflowResult
7391	llvm::computeOverflowForSignedAdd(const WithCache<const Value *> &LHS,
7392	const WithCache<const Value *> &RHS,
7393	const SimplifyQuery &SQ) {
7394	return ::computeOverflowForSignedAdd(LHS, RHS, Add: nullptr, SQ);
7395	}
7396
7397	bool llvm::isGuaranteedToTransferExecutionToSuccessor(const Instruction *I) {
7398	// Note: An atomic operation isn't guaranteed to return in a reasonable amount
7399	// of time because it's possible for another thread to interfere with it for an
7400	// arbitrary length of time, but programs aren't allowed to rely on that.
7401
7402	// If there is no successor, then execution can't transfer to it.
7403	if (isa<ReturnInst>(Val: I))
7404	return false;
7405	if (isa<UnreachableInst>(Val: I))
7406	return false;
7407
7408	// Note: Do not add new checks here; instead, change Instruction::mayThrow or
7409	// Instruction::willReturn.
7410	//
7411	// FIXME: Move this check into Instruction::willReturn.
7412	if (isa<CatchPadInst>(Val: I)) {
7413	switch (classifyEHPersonality(Pers: I->getFunction()->getPersonalityFn())) {
7414	default:
7415	// A catchpad may invoke exception object constructors and such, which
7416	// in some languages can be arbitrary code, so be conservative by default.
7417	return false;
7418	case EHPersonality::CoreCLR:
7419	// For CoreCLR, it just involves a type test.
7420	return true;
7421	}
7422	}
7423
7424	// An instruction that returns without throwing must transfer control flow
7425	// to a successor.
7426	return !I->mayThrow() && I->willReturn();
7427	}
7428
7429	bool llvm::isGuaranteedToTransferExecutionToSuccessor(const BasicBlock *BB) {
7430	// TODO: This is slightly conservative for invoke instruction since exiting
7431	// via an exception *is* normal control for them.
7432	for (const Instruction &I : *BB)
7433	if (!isGuaranteedToTransferExecutionToSuccessor(I: &I))
7434	return false;
7435	return true;
7436	}
7437
7438	bool llvm::isGuaranteedToTransferExecutionToSuccessor(
7439	BasicBlock::const_iterator Begin, BasicBlock::const_iterator End,
7440	unsigned ScanLimit) {
7441	return isGuaranteedToTransferExecutionToSuccessor(Range: make_range(x: Begin, y: End),
7442	ScanLimit);
7443	}
7444
7445	bool llvm::isGuaranteedToTransferExecutionToSuccessor(
7446	iterator_range<BasicBlock::const_iterator> Range, unsigned ScanLimit) {
7447	assert(ScanLimit && "scan limit must be non-zero");
7448	for (const Instruction &I : Range) {
7449	if (isa<DbgInfoIntrinsic>(Val: I))
7450	continue;
7451	if (--ScanLimit == 0)
7452	return false;
7453	if (!isGuaranteedToTransferExecutionToSuccessor(I: &I))
7454	return false;
7455	}
7456	return true;
7457	}
7458
7459	bool llvm::isGuaranteedToExecuteForEveryIteration(const Instruction *I,
7460	const Loop *L) {
7461	// The loop header is guaranteed to be executed for every iteration.
7462	//
7463	// FIXME: Relax this constraint to cover all basic blocks that are
7464	// guaranteed to be executed at every iteration.
7465	if (I->getParent() != L->getHeader()) return false;
7466
7467	for (const Instruction &LI : *L->getHeader()) {
7468	if (&LI == I) return true;
7469	if (!isGuaranteedToTransferExecutionToSuccessor(I: &LI)) return false;
7470	}
7471	llvm_unreachable("Instruction not contained in its own parent basic block.");
7472	}
7473
7474	bool llvm::propagatesPoison(const Use &PoisonOp) {
7475	const Operator *I = cast<Operator>(Val: PoisonOp.getUser());
7476	switch (I->getOpcode()) {
7477	case Instruction::Freeze:
7478	case Instruction::PHI:
7479	case Instruction::Invoke:
7480	return false;
7481	case Instruction::Select:
7482	return PoisonOp.getOperandNo() == 0;
7483	case Instruction::Call:
7484	if (auto *II = dyn_cast<IntrinsicInst>(Val: I)) {
7485	switch (II->getIntrinsicID()) {
7486	// TODO: Add more intrinsics.
7487	case Intrinsic::sadd_with_overflow:
7488	case Intrinsic::ssub_with_overflow:
7489	case Intrinsic::smul_with_overflow:
7490	case Intrinsic::uadd_with_overflow:
7491	case Intrinsic::usub_with_overflow:
7492	case Intrinsic::umul_with_overflow:
7493	// If an input is a vector containing a poison element, the
7494	// two output vectors (calculated results, overflow bits)'
7495	// corresponding lanes are poison.
7496	return true;
7497	case Intrinsic::ctpop:
7498	case Intrinsic::ctlz:
7499	case Intrinsic::cttz:
7500	case Intrinsic::abs:
7501	case Intrinsic::smax:
7502	case Intrinsic::smin:
7503	case Intrinsic::umax:
7504	case Intrinsic::umin:
7505	case Intrinsic::bitreverse:
7506	case Intrinsic::bswap:
7507	case Intrinsic::sadd_sat:
7508	case Intrinsic::ssub_sat:
7509	case Intrinsic::sshl_sat:
7510	case Intrinsic::uadd_sat:
7511	case Intrinsic::usub_sat:
7512	case Intrinsic::ushl_sat:
7513	return true;
7514	}
7515	}
7516	return false;
7517	case Instruction::ICmp:
7518	case Instruction::FCmp:
7519	case Instruction::GetElementPtr:
7520	return true;
7521	default:
7522	if (isa<BinaryOperator>(Val: I) || isa<UnaryOperator>(Val: I) || isa<CastInst>(Val: I))
7523	return true;
7524
7525	// Be conservative and return false.
7526	return false;
7527	}
7528	}
7529
7530	/// Enumerates all operands of \p I that are guaranteed to not be undef or
7531	/// poison. If the callback \p Handle returns true, stop processing and return
7532	/// true. Otherwise, return false.
7533	template <typename CallableT>
7534	static bool handleGuaranteedWellDefinedOps(const Instruction *I,
7535	const CallableT &Handle) {
7536	switch (I->getOpcode()) {
7537	case Instruction::Store:
7538	if (Handle(cast<StoreInst>(Val: I)->getPointerOperand()))
7539	return true;
7540	break;
7541
7542	case Instruction::Load:
7543	if (Handle(cast<LoadInst>(Val: I)->getPointerOperand()))
7544	return true;
7545	break;
7546
7547	// Since dereferenceable attribute imply noundef, atomic operations
7548	// also implicitly have noundef pointers too
7549	case Instruction::AtomicCmpXchg:
7550	if (Handle(cast<AtomicCmpXchgInst>(Val: I)->getPointerOperand()))
7551	return true;
7552	break;
7553
7554	case Instruction::AtomicRMW:
7555	if (Handle(cast<AtomicRMWInst>(Val: I)->getPointerOperand()))
7556	return true;
7557	break;
7558
7559	case Instruction::Call:
7560	case Instruction::Invoke: {
7561	const CallBase *CB = cast<CallBase>(Val: I);
7562	if (CB->isIndirectCall() && Handle(CB->getCalledOperand()))
7563	return true;
7564	for (unsigned i = 0; i < CB->arg_size(); ++i)
7565	if ((CB->paramHasAttr(i, Attribute::NoUndef) ||
7566	CB->paramHasAttr(i, Attribute::Dereferenceable) ||
7567	CB->paramHasAttr(i, Attribute::DereferenceableOrNull)) &&
7568	Handle(CB->getArgOperand(i)))
7569	return true;
7570	break;
7571	}
7572	case Instruction::Ret:
7573	if (I->getFunction()->hasRetAttribute(Attribute::NoUndef) &&
7574	Handle(I->getOperand(0)))
7575	return true;
7576	break;
7577	case Instruction::Switch:
7578	if (Handle(cast<SwitchInst>(Val: I)->getCondition()))
7579	return true;
7580	break;
7581	case Instruction::Br: {
7582	auto *BR = cast<BranchInst>(Val: I);
7583	if (BR->isConditional() && Handle(BR->getCondition()))
7584	return true;
7585	break;
7586	}
7587	default:
7588	break;
7589	}
7590
7591	return false;
7592	}
7593
7594	void llvm::getGuaranteedWellDefinedOps(
7595	const Instruction *I, SmallVectorImpl<const Value *> &Operands) {
7596	handleGuaranteedWellDefinedOps(I, Handle: [&](const Value *V) {
7597	Operands.push_back(Elt: V);
7598	return false;
7599	});
7600	}
7601
7602	/// Enumerates all operands of \p I that are guaranteed to not be poison.
7603	template <typename CallableT>
7604	static bool handleGuaranteedNonPoisonOps(const Instruction *I,
7605	const CallableT &Handle) {
7606	if (handleGuaranteedWellDefinedOps(I, Handle))
7607	return true;
7608	switch (I->getOpcode()) {
7609	// Divisors of these operations are allowed to be partially undef.
7610	case Instruction::UDiv:
7611	case Instruction::SDiv:
7612	case Instruction::URem:
7613	case Instruction::SRem:
7614	return Handle(I->getOperand(i: 1));
7615	default:
7616	return false;
7617	}
7618	}
7619
7620	void llvm::getGuaranteedNonPoisonOps(const Instruction *I,
7621	SmallVectorImpl<const Value *> &Operands) {
7622	handleGuaranteedNonPoisonOps(I, Handle: [&](const Value *V) {
7623	Operands.push_back(Elt: V);
7624	return false;
7625	});
7626	}
7627
7628	bool llvm::mustTriggerUB(const Instruction *I,
7629	const SmallPtrSetImpl<const Value *> &KnownPoison) {
7630	return handleGuaranteedNonPoisonOps(
7631	I, Handle: [&](const Value *V) { return KnownPoison.count(Ptr: V); });
7632	}
7633
7634	static bool programUndefinedIfUndefOrPoison(const Value *V,
7635	bool PoisonOnly) {
7636	// We currently only look for uses of values within the same basic
7637	// block, as that makes it easier to guarantee that the uses will be
7638	// executed given that Inst is executed.
7639	//
7640	// FIXME: Expand this to consider uses beyond the same basic block. To do
7641	// this, look out for the distinction between post-dominance and strong
7642	// post-dominance.
7643	const BasicBlock *BB = nullptr;
7644	BasicBlock::const_iterator Begin;
7645	if (const auto *Inst = dyn_cast<Instruction>(Val: V)) {
7646	BB = Inst->getParent();
7647	Begin = Inst->getIterator();
7648	Begin++;
7649	} else if (const auto *Arg = dyn_cast<Argument>(Val: V)) {
7650	if (Arg->getParent()->isDeclaration())
7651	return false;
7652	BB = &Arg->getParent()->getEntryBlock();
7653	Begin = BB->begin();
7654	} else {
7655	return false;
7656	}
7657
7658	// Limit number of instructions we look at, to avoid scanning through large
7659	// blocks. The current limit is chosen arbitrarily.
7660	unsigned ScanLimit = 32;
7661	BasicBlock::const_iterator End = BB->end();
7662
7663	if (!PoisonOnly) {
7664	// Since undef does not propagate eagerly, be conservative & just check
7665	// whether a value is directly passed to an instruction that must take
7666	// well-defined operands.
7667
7668	for (const auto &I : make_range(x: Begin, y: End)) {
7669	if (isa<DbgInfoIntrinsic>(Val: I))
7670	continue;
7671	if (--ScanLimit == 0)
7672	break;
7673
7674	if (handleGuaranteedWellDefinedOps(I: &I, Handle: [V](const Value *WellDefinedOp) {
7675	return WellDefinedOp == V;
7676	}))
7677	return true;
7678
7679	if (!isGuaranteedToTransferExecutionToSuccessor(I: &I))
7680	break;
7681	}
7682	return false;
7683	}
7684
7685	// Set of instructions that we have proved will yield poison if Inst
7686	// does.
7687	SmallSet<const Value *, 16> YieldsPoison;
7688	SmallSet<const BasicBlock *, 4> Visited;
7689
7690	YieldsPoison.insert(Ptr: V);
7691	Visited.insert(Ptr: BB);
7692
7693	while (true) {
7694	for (const auto &I : make_range(x: Begin, y: End)) {
7695	if (isa<DbgInfoIntrinsic>(Val: I))
7696	continue;
7697	if (--ScanLimit == 0)
7698	return false;
7699	if (mustTriggerUB(I: &I, KnownPoison: YieldsPoison))
7700	return true;
7701	if (!isGuaranteedToTransferExecutionToSuccessor(I: &I))
7702	return false;
7703
7704	// If an operand is poison and propagates it, mark I as yielding poison.
7705	for (const Use &Op : I.operands()) {
7706	if (YieldsPoison.count(Ptr: Op) && propagatesPoison(PoisonOp: Op)) {
7707	YieldsPoison.insert(Ptr: &I);
7708	break;
7709	}
7710	}
7711
7712	// Special handling for select, which returns poison if its operand 0 is
7713	// poison (handled in the loop above) *or* if both its true/false operands
7714	// are poison (handled here).
7715	if (I.getOpcode() == Instruction::Select &&
7716	YieldsPoison.count(Ptr: I.getOperand(i: 1)) &&
7717	YieldsPoison.count(Ptr: I.getOperand(i: 2))) {
7718	YieldsPoison.insert(Ptr: &I);
7719	}
7720	}
7721
7722	BB = BB->getSingleSuccessor();
7723	if (!BB || !Visited.insert(Ptr: BB).second)
7724	break;
7725
7726	Begin = BB->getFirstNonPHI()->getIterator();
7727	End = BB->end();
7728	}
7729	return false;
7730	}
7731
7732	bool llvm::programUndefinedIfUndefOrPoison(const Instruction *Inst) {
7733	return ::programUndefinedIfUndefOrPoison(V: Inst, PoisonOnly: false);
7734	}
7735
7736	bool llvm::programUndefinedIfPoison(const Instruction *Inst) {
7737	return ::programUndefinedIfUndefOrPoison(V: Inst, PoisonOnly: true);
7738	}
7739
7740	static bool isKnownNonNaN(const Value *V, FastMathFlags FMF) {
7741	if (FMF.noNaNs())
7742	return true;
7743
7744	if (auto *C = dyn_cast<ConstantFP>(Val: V))
7745	return !C->isNaN();
7746
7747	if (auto *C = dyn_cast<ConstantDataVector>(Val: V)) {
7748	if (!C->getElementType()->isFloatingPointTy())
7749	return false;
7750	for (unsigned I = 0, E = C->getNumElements(); I < E; ++I) {
7751	if (C->getElementAsAPFloat(i: I).isNaN())
7752	return false;
7753	}
7754	return true;
7755	}
7756
7757	if (isa<ConstantAggregateZero>(Val: V))
7758	return true;
7759
7760	return false;
7761	}
7762
7763	static bool isKnownNonZero(const Value *V) {
7764	if (auto *C = dyn_cast<ConstantFP>(Val: V))
7765	return !C->isZero();
7766
7767	if (auto *C = dyn_cast<ConstantDataVector>(Val: V)) {
7768	if (!C->getElementType()->isFloatingPointTy())
7769	return false;
7770	for (unsigned I = 0, E = C->getNumElements(); I < E; ++I) {
7771	if (C->getElementAsAPFloat(i: I).isZero())
7772	return false;
7773	}
7774	return true;
7775	}
7776
7777	return false;
7778	}
7779
7780	/// Match clamp pattern for float types without care about NaNs or signed zeros.
7781	/// Given non-min/max outer cmp/select from the clamp pattern this
7782	/// function recognizes if it can be substitued by a "canonical" min/max
7783	/// pattern.
7784	static SelectPatternResult matchFastFloatClamp(CmpInst::Predicate Pred,
7785	Value *CmpLHS, Value *CmpRHS,
7786	Value *TrueVal, Value *FalseVal,
7787	Value *&LHS, Value *&RHS) {
7788	// Try to match
7789	// X < C1 ? C1 : Min(X, C2) --> Max(C1, Min(X, C2))
7790	// X > C1 ? C1 : Max(X, C2) --> Min(C1, Max(X, C2))
7791	// and return description of the outer Max/Min.
7792
7793	// First, check if select has inverse order:
7794	if (CmpRHS == FalseVal) {
7795	std::swap(a&: TrueVal, b&: FalseVal);
7796	Pred = CmpInst::getInversePredicate(pred: Pred);
7797	}
7798
7799	// Assume success now. If there's no match, callers should not use these anyway.
7800	LHS = TrueVal;
7801	RHS = FalseVal;
7802
7803	const APFloat *FC1;
7804	if (CmpRHS != TrueVal || !match(V: CmpRHS, P: m_APFloat(Res&: FC1)) || !FC1->isFinite())
7805	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7806
7807	const APFloat *FC2;
7808	switch (Pred) {
7809	case CmpInst::FCMP_OLT:
7810	case CmpInst::FCMP_OLE:
7811	case CmpInst::FCMP_ULT:
7812	case CmpInst::FCMP_ULE:
7813	if (match(V: FalseVal,
7814	P: m_CombineOr(L: m_OrdFMin(L: m_Specific(V: CmpLHS), R: m_APFloat(Res&: FC2)),
7815	R: m_UnordFMin(L: m_Specific(V: CmpLHS), R: m_APFloat(Res&: FC2)))) &&
7816	*FC1 < *FC2)
7817	return {.Flavor: SPF_FMAXNUM, .NaNBehavior: SPNB_RETURNS_ANY, .Ordered: false};
7818	break;
7819	case CmpInst::FCMP_OGT:
7820	case CmpInst::FCMP_OGE:
7821	case CmpInst::FCMP_UGT:
7822	case CmpInst::FCMP_UGE:
7823	if (match(V: FalseVal,
7824	P: m_CombineOr(L: m_OrdFMax(L: m_Specific(V: CmpLHS), R: m_APFloat(Res&: FC2)),
7825	R: m_UnordFMax(L: m_Specific(V: CmpLHS), R: m_APFloat(Res&: FC2)))) &&
7826	*FC1 > *FC2)
7827	return {.Flavor: SPF_FMINNUM, .NaNBehavior: SPNB_RETURNS_ANY, .Ordered: false};
7828	break;
7829	default:
7830	break;
7831	}
7832
7833	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7834	}
7835
7836	/// Recognize variations of:
7837	/// CLAMP(v,l,h) ==> ((v) < (l) ? (l) : ((v) > (h) ? (h) : (v)))
7838	static SelectPatternResult matchClamp(CmpInst::Predicate Pred,
7839	Value *CmpLHS, Value *CmpRHS,
7840	Value *TrueVal, Value *FalseVal) {
7841	// Swap the select operands and predicate to match the patterns below.
7842	if (CmpRHS != TrueVal) {
7843	Pred = ICmpInst::getSwappedPredicate(pred: Pred);
7844	std::swap(a&: TrueVal, b&: FalseVal);
7845	}
7846	const APInt *C1;
7847	if (CmpRHS == TrueVal && match(V: CmpRHS, P: m_APInt(Res&: C1))) {
7848	const APInt *C2;
7849	// (X <s C1) ? C1 : SMIN(X, C2) ==> SMAX(SMIN(X, C2), C1)
7850	if (match(V: FalseVal, P: m_SMin(L: m_Specific(V: CmpLHS), R: m_APInt(Res&: C2))) &&
7851	C1->slt(RHS: *C2) && Pred == CmpInst::ICMP_SLT)
7852	return {.Flavor: SPF_SMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
7853
7854	// (X >s C1) ? C1 : SMAX(X, C2) ==> SMIN(SMAX(X, C2), C1)
7855	if (match(V: FalseVal, P: m_SMax(L: m_Specific(V: CmpLHS), R: m_APInt(Res&: C2))) &&
7856	C1->sgt(RHS: *C2) && Pred == CmpInst::ICMP_SGT)
7857	return {.Flavor: SPF_SMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
7858
7859	// (X <u C1) ? C1 : UMIN(X, C2) ==> UMAX(UMIN(X, C2), C1)
7860	if (match(V: FalseVal, P: m_UMin(L: m_Specific(V: CmpLHS), R: m_APInt(Res&: C2))) &&
7861	C1->ult(RHS: *C2) && Pred == CmpInst::ICMP_ULT)
7862	return {.Flavor: SPF_UMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
7863
7864	// (X >u C1) ? C1 : UMAX(X, C2) ==> UMIN(UMAX(X, C2), C1)
7865	if (match(V: FalseVal, P: m_UMax(L: m_Specific(V: CmpLHS), R: m_APInt(Res&: C2))) &&
7866	C1->ugt(RHS: *C2) && Pred == CmpInst::ICMP_UGT)
7867	return {.Flavor: SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
7868	}
7869	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7870	}
7871
7872	/// Recognize variations of:
7873	/// a < c ? min(a,b) : min(b,c) ==> min(min(a,b),min(b,c))
7874	static SelectPatternResult matchMinMaxOfMinMax(CmpInst::Predicate Pred,
7875	Value *CmpLHS, Value *CmpRHS,
7876	Value *TVal, Value *FVal,
7877	unsigned Depth) {
7878	// TODO: Allow FP min/max with nnan/nsz.
7879	assert(CmpInst::isIntPredicate(Pred) && "Expected integer comparison");
7880
7881	Value *A = nullptr, *B = nullptr;
7882	SelectPatternResult L = matchSelectPattern(V: TVal, LHS&: A, RHS&: B, CastOp: nullptr, Depth: Depth + 1);
7883	if (!SelectPatternResult::isMinOrMax(SPF: L.Flavor))
7884	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7885
7886	Value *C = nullptr, *D = nullptr;
7887	SelectPatternResult R = matchSelectPattern(V: FVal, LHS&: C, RHS&: D, CastOp: nullptr, Depth: Depth + 1);
7888	if (L.Flavor != R.Flavor)
7889	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7890
7891	// We have something like: x Pred y ? min(a, b) : min(c, d).
7892	// Try to match the compare to the min/max operations of the select operands.
7893	// First, make sure we have the right compare predicate.
7894	switch (L.Flavor) {
7895	case SPF_SMIN:
7896	if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE) {
7897	Pred = ICmpInst::getSwappedPredicate(pred: Pred);
7898	std::swap(a&: CmpLHS, b&: CmpRHS);
7899	}
7900	if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE)
7901	break;
7902	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7903	case SPF_SMAX:
7904	if (Pred == ICmpInst::ICMP_SLT || Pred == ICmpInst::ICMP_SLE) {
7905	Pred = ICmpInst::getSwappedPredicate(pred: Pred);
7906	std::swap(a&: CmpLHS, b&: CmpRHS);
7907	}
7908	if (Pred == ICmpInst::ICMP_SGT || Pred == ICmpInst::ICMP_SGE)
7909	break;
7910	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7911	case SPF_UMIN:
7912	if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE) {
7913	Pred = ICmpInst::getSwappedPredicate(pred: Pred);
7914	std::swap(a&: CmpLHS, b&: CmpRHS);
7915	}
7916	if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE)
7917	break;
7918	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7919	case SPF_UMAX:
7920	if (Pred == ICmpInst::ICMP_ULT || Pred == ICmpInst::ICMP_ULE) {
7921	Pred = ICmpInst::getSwappedPredicate(pred: Pred);
7922	std::swap(a&: CmpLHS, b&: CmpRHS);
7923	}
7924	if (Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_UGE)
7925	break;
7926	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7927	default:
7928	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7929	}
7930
7931	// If there is a common operand in the already matched min/max and the other
7932	// min/max operands match the compare operands (either directly or inverted),
7933	// then this is min/max of the same flavor.
7934
7935	// a pred c ? m(a, b) : m(c, b) --> m(m(a, b), m(c, b))
7936	// ~c pred ~a ? m(a, b) : m(c, b) --> m(m(a, b), m(c, b))
7937	if (D == B) {
7938	if ((CmpLHS == A && CmpRHS == C) || (match(V: C, P: m_Not(V: m_Specific(V: CmpLHS))) &&
7939	match(V: A, P: m_Not(V: m_Specific(V: CmpRHS)))))
7940	return {.Flavor: L.Flavor, .NaNBehavior: SPNB_NA, .Ordered: false};
7941	}
7942	// a pred d ? m(a, b) : m(b, d) --> m(m(a, b), m(b, d))
7943	// ~d pred ~a ? m(a, b) : m(b, d) --> m(m(a, b), m(b, d))
7944	if (C == B) {
7945	if ((CmpLHS == A && CmpRHS == D) || (match(V: D, P: m_Not(V: m_Specific(V: CmpLHS))) &&
7946	match(V: A, P: m_Not(V: m_Specific(V: CmpRHS)))))
7947	return {.Flavor: L.Flavor, .NaNBehavior: SPNB_NA, .Ordered: false};
7948	}
7949	// b pred c ? m(a, b) : m(c, a) --> m(m(a, b), m(c, a))
7950	// ~c pred ~b ? m(a, b) : m(c, a) --> m(m(a, b), m(c, a))
7951	if (D == A) {
7952	if ((CmpLHS == B && CmpRHS == C) || (match(V: C, P: m_Not(V: m_Specific(V: CmpLHS))) &&
7953	match(V: B, P: m_Not(V: m_Specific(V: CmpRHS)))))
7954	return {.Flavor: L.Flavor, .NaNBehavior: SPNB_NA, .Ordered: false};
7955	}
7956	// b pred d ? m(a, b) : m(a, d) --> m(m(a, b), m(a, d))
7957	// ~d pred ~b ? m(a, b) : m(a, d) --> m(m(a, b), m(a, d))
7958	if (C == A) {
7959	if ((CmpLHS == B && CmpRHS == D) || (match(V: D, P: m_Not(V: m_Specific(V: CmpLHS))) &&
7960	match(V: B, P: m_Not(V: m_Specific(V: CmpRHS)))))
7961	return {.Flavor: L.Flavor, .NaNBehavior: SPNB_NA, .Ordered: false};
7962	}
7963
7964	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
7965	}
7966
7967	/// If the input value is the result of a 'not' op, constant integer, or vector
7968	/// splat of a constant integer, return the bitwise-not source value.
7969	/// TODO: This could be extended to handle non-splat vector integer constants.
7970	static Value *getNotValue(Value *V) {
7971	Value *NotV;
7972	if (match(V, P: m_Not(V: m_Value(V&: NotV))))
7973	return NotV;
7974
7975	const APInt *C;
7976	if (match(V, P: m_APInt(Res&: C)))
7977	return ConstantInt::get(Ty: V->getType(), V: ~(*C));
7978
7979	return nullptr;
7980	}
7981
7982	/// Match non-obvious integer minimum and maximum sequences.
7983	static SelectPatternResult matchMinMax(CmpInst::Predicate Pred,
7984	Value *CmpLHS, Value *CmpRHS,
7985	Value *TrueVal, Value *FalseVal,
7986	Value *&LHS, Value *&RHS,
7987	unsigned Depth) {
7988	// Assume success. If there's no match, callers should not use these anyway.
7989	LHS = TrueVal;
7990	RHS = FalseVal;
7991
7992	SelectPatternResult SPR = matchClamp(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal);
7993	if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
7994	return SPR;
7995
7996	SPR = matchMinMaxOfMinMax(Pred, CmpLHS, CmpRHS, TVal: TrueVal, FVal: FalseVal, Depth);
7997	if (SPR.Flavor != SelectPatternFlavor::SPF_UNKNOWN)
7998	return SPR;
7999
8000	// Look through 'not' ops to find disguised min/max.
8001	// (X > Y) ? ~X : ~Y ==> (~X < ~Y) ? ~X : ~Y ==> MIN(~X, ~Y)
8002	// (X < Y) ? ~X : ~Y ==> (~X > ~Y) ? ~X : ~Y ==> MAX(~X, ~Y)
8003	if (CmpLHS == getNotValue(V: TrueVal) && CmpRHS == getNotValue(V: FalseVal)) {
8004	switch (Pred) {
8005	case CmpInst::ICMP_SGT: return {.Flavor: SPF_SMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8006	case CmpInst::ICMP_SLT: return {.Flavor: SPF_SMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8007	case CmpInst::ICMP_UGT: return {.Flavor: SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8008	case CmpInst::ICMP_ULT: return {.Flavor: SPF_UMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8009	default: break;
8010	}
8011	}
8012
8013	// (X > Y) ? ~Y : ~X ==> (~X < ~Y) ? ~Y : ~X ==> MAX(~Y, ~X)
8014	// (X < Y) ? ~Y : ~X ==> (~X > ~Y) ? ~Y : ~X ==> MIN(~Y, ~X)
8015	if (CmpLHS == getNotValue(V: FalseVal) && CmpRHS == getNotValue(V: TrueVal)) {
8016	switch (Pred) {
8017	case CmpInst::ICMP_SGT: return {.Flavor: SPF_SMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8018	case CmpInst::ICMP_SLT: return {.Flavor: SPF_SMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8019	case CmpInst::ICMP_UGT: return {.Flavor: SPF_UMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8020	case CmpInst::ICMP_ULT: return {.Flavor: SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8021	default: break;
8022	}
8023	}
8024
8025	if (Pred != CmpInst::ICMP_SGT && Pred != CmpInst::ICMP_SLT)
8026	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8027
8028	const APInt *C1;
8029	if (!match(V: CmpRHS, P: m_APInt(Res&: C1)))
8030	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8031
8032	// An unsigned min/max can be written with a signed compare.
8033	const APInt *C2;
8034	if ((CmpLHS == TrueVal && match(V: FalseVal, P: m_APInt(Res&: C2))) ||
8035	(CmpLHS == FalseVal && match(V: TrueVal, P: m_APInt(Res&: C2)))) {
8036	// Is the sign bit set?
8037	// (X <s 0) ? X : MAXVAL ==> (X >u MAXVAL) ? X : MAXVAL ==> UMAX
8038	// (X <s 0) ? MAXVAL : X ==> (X >u MAXVAL) ? MAXVAL : X ==> UMIN
8039	if (Pred == CmpInst::ICMP_SLT && C1->isZero() && C2->isMaxSignedValue())
8040	return {.Flavor: CmpLHS == TrueVal ? SPF_UMAX : SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8041
8042	// Is the sign bit clear?
8043	// (X >s -1) ? MINVAL : X ==> (X <u MINVAL) ? MINVAL : X ==> UMAX
8044	// (X >s -1) ? X : MINVAL ==> (X <u MINVAL) ? X : MINVAL ==> UMIN
8045	if (Pred == CmpInst::ICMP_SGT && C1->isAllOnes() && C2->isMinSignedValue())
8046	return {.Flavor: CmpLHS == FalseVal ? SPF_UMAX : SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8047	}
8048
8049	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8050	}
8051
8052	bool llvm::isKnownNegation(const Value *X, const Value *Y, bool NeedNSW,
8053	bool AllowPoison) {
8054	assert(X && Y && "Invalid operand");
8055
8056	auto IsNegationOf = [&](const Value *X, const Value *Y) {
8057	if (!match(V: X, P: m_Neg(V: m_Specific(V: Y))))
8058	return false;
8059
8060	auto *BO = cast<BinaryOperator>(Val: X);
8061	if (NeedNSW && !BO->hasNoSignedWrap())
8062	return false;
8063
8064	auto *Zero = cast<Constant>(Val: BO->getOperand(i_nocapture: 0));
8065	if (!AllowPoison && !Zero->isNullValue())
8066	return false;
8067
8068	return true;
8069	};
8070
8071	// X = -Y or Y = -X
8072	if (IsNegationOf(X, Y) || IsNegationOf(Y, X))
8073	return true;
8074
8075	// X = sub (A, B), Y = sub (B, A) || X = sub nsw (A, B), Y = sub nsw (B, A)
8076	Value *A, *B;
8077	return (!NeedNSW && (match(V: X, P: m_Sub(L: m_Value(V&: A), R: m_Value(V&: B))) &&
8078	match(V: Y, P: m_Sub(L: m_Specific(V: B), R: m_Specific(V: A))))) ||
8079	(NeedNSW && (match(V: X, P: m_NSWSub(L: m_Value(V&: A), R: m_Value(V&: B))) &&
8080	match(V: Y, P: m_NSWSub(L: m_Specific(V: B), R: m_Specific(V: A)))));
8081	}
8082
8083	static SelectPatternResult matchSelectPattern(CmpInst::Predicate Pred,
8084	FastMathFlags FMF,
8085	Value *CmpLHS, Value *CmpRHS,
8086	Value *TrueVal, Value *FalseVal,
8087	Value *&LHS, Value *&RHS,
8088	unsigned Depth) {
8089	bool HasMismatchedZeros = false;
8090	if (CmpInst::isFPPredicate(P: Pred)) {
8091	// IEEE-754 ignores the sign of 0.0 in comparisons. So if the select has one
8092	// 0.0 operand, set the compare's 0.0 operands to that same value for the
8093	// purpose of identifying min/max. Disregard vector constants with undefined
8094	// elements because those can not be back-propagated for analysis.
8095	Value *OutputZeroVal = nullptr;
8096	if (match(V: TrueVal, P: m_AnyZeroFP()) && !match(V: FalseVal, P: m_AnyZeroFP()) &&
8097	!cast<Constant>(Val: TrueVal)->containsUndefOrPoisonElement())
8098	OutputZeroVal = TrueVal;
8099	else if (match(V: FalseVal, P: m_AnyZeroFP()) && !match(V: TrueVal, P: m_AnyZeroFP()) &&
8100	!cast<Constant>(Val: FalseVal)->containsUndefOrPoisonElement())
8101	OutputZeroVal = FalseVal;
8102
8103	if (OutputZeroVal) {
8104	if (match(V: CmpLHS, P: m_AnyZeroFP()) && CmpLHS != OutputZeroVal) {
8105	HasMismatchedZeros = true;
8106	CmpLHS = OutputZeroVal;
8107	}
8108	if (match(V: CmpRHS, P: m_AnyZeroFP()) && CmpRHS != OutputZeroVal) {
8109	HasMismatchedZeros = true;
8110	CmpRHS = OutputZeroVal;
8111	}
8112	}
8113	}
8114
8115	LHS = CmpLHS;
8116	RHS = CmpRHS;
8117
8118	// Signed zero may return inconsistent results between implementations.
8119	// (0.0 <= -0.0) ? 0.0 : -0.0 // Returns 0.0
8120	// minNum(0.0, -0.0) // May return -0.0 or 0.0 (IEEE 754-2008 5.3.1)
8121	// Therefore, we behave conservatively and only proceed if at least one of the
8122	// operands is known to not be zero or if we don't care about signed zero.
8123	switch (Pred) {
8124	default: break;
8125	case CmpInst::FCMP_OGT: case CmpInst::FCMP_OLT:
8126	case CmpInst::FCMP_UGT: case CmpInst::FCMP_ULT:
8127	if (!HasMismatchedZeros)
8128	break;
8129	[[fallthrough]];
8130	case CmpInst::FCMP_OGE: case CmpInst::FCMP_OLE:
8131	case CmpInst::FCMP_UGE: case CmpInst::FCMP_ULE:
8132	if (!FMF.noSignedZeros() && !isKnownNonZero(V: CmpLHS) &&
8133	!isKnownNonZero(V: CmpRHS))
8134	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8135	}
8136
8137	SelectPatternNaNBehavior NaNBehavior = SPNB_NA;
8138	bool Ordered = false;
8139
8140	// When given one NaN and one non-NaN input:
8141	// - maxnum/minnum (C99 fmaxf()/fminf()) return the non-NaN input.
8142	// - A simple C99 (a < b ? a : b) construction will return 'b' (as the
8143	// ordered comparison fails), which could be NaN or non-NaN.
8144	// so here we discover exactly what NaN behavior is required/accepted.
8145	if (CmpInst::isFPPredicate(P: Pred)) {
8146	bool LHSSafe = isKnownNonNaN(V: CmpLHS, FMF);
8147	bool RHSSafe = isKnownNonNaN(V: CmpRHS, FMF);
8148
8149	if (LHSSafe && RHSSafe) {
8150	// Both operands are known non-NaN.
8151	NaNBehavior = SPNB_RETURNS_ANY;
8152	} else if (CmpInst::isOrdered(predicate: Pred)) {
8153	// An ordered comparison will return false when given a NaN, so it
8154	// returns the RHS.
8155	Ordered = true;
8156	if (LHSSafe)
8157	// LHS is non-NaN, so if RHS is NaN then NaN will be returned.
8158	NaNBehavior = SPNB_RETURNS_NAN;
8159	else if (RHSSafe)
8160	NaNBehavior = SPNB_RETURNS_OTHER;
8161	else
8162	// Completely unsafe.
8163	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8164	} else {
8165	Ordered = false;
8166	// An unordered comparison will return true when given a NaN, so it
8167	// returns the LHS.
8168	if (LHSSafe)
8169	// LHS is non-NaN, so if RHS is NaN then non-NaN will be returned.
8170	NaNBehavior = SPNB_RETURNS_OTHER;
8171	else if (RHSSafe)
8172	NaNBehavior = SPNB_RETURNS_NAN;
8173	else
8174	// Completely unsafe.
8175	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8176	}
8177	}
8178
8179	if (TrueVal == CmpRHS && FalseVal == CmpLHS) {
8180	std::swap(a&: CmpLHS, b&: CmpRHS);
8181	Pred = CmpInst::getSwappedPredicate(pred: Pred);
8182	if (NaNBehavior == SPNB_RETURNS_NAN)
8183	NaNBehavior = SPNB_RETURNS_OTHER;
8184	else if (NaNBehavior == SPNB_RETURNS_OTHER)
8185	NaNBehavior = SPNB_RETURNS_NAN;
8186	Ordered = !Ordered;
8187	}
8188
8189	// ([if]cmp X, Y) ? X : Y
8190	if (TrueVal == CmpLHS && FalseVal == CmpRHS) {
8191	switch (Pred) {
8192	default: return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false}; // Equality.
8193	case ICmpInst::ICMP_UGT:
8194	case ICmpInst::ICMP_UGE: return {.Flavor: SPF_UMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8195	case ICmpInst::ICMP_SGT:
8196	case ICmpInst::ICMP_SGE: return {.Flavor: SPF_SMAX, .NaNBehavior: SPNB_NA, .Ordered: false};
8197	case ICmpInst::ICMP_ULT:
8198	case ICmpInst::ICMP_ULE: return {.Flavor: SPF_UMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8199	case ICmpInst::ICMP_SLT:
8200	case ICmpInst::ICMP_SLE: return {.Flavor: SPF_SMIN, .NaNBehavior: SPNB_NA, .Ordered: false};
8201	case FCmpInst::FCMP_UGT:
8202	case FCmpInst::FCMP_UGE:
8203	case FCmpInst::FCMP_OGT:
8204	case FCmpInst::FCMP_OGE: return {.Flavor: SPF_FMAXNUM, .NaNBehavior: NaNBehavior, .Ordered: Ordered};
8205	case FCmpInst::FCMP_ULT:
8206	case FCmpInst::FCMP_ULE:
8207	case FCmpInst::FCMP_OLT:
8208	case FCmpInst::FCMP_OLE: return {.Flavor: SPF_FMINNUM, .NaNBehavior: NaNBehavior, .Ordered: Ordered};
8209	}
8210	}
8211
8212	if (isKnownNegation(X: TrueVal, Y: FalseVal)) {
8213	// Sign-extending LHS does not change its sign, so TrueVal/FalseVal can
8214	// match against either LHS or sext(LHS).
8215	auto MaybeSExtCmpLHS =
8216	m_CombineOr(L: m_Specific(V: CmpLHS), R: m_SExt(Op: m_Specific(V: CmpLHS)));
8217	auto ZeroOrAllOnes = m_CombineOr(L: m_ZeroInt(), R: m_AllOnes());
8218	auto ZeroOrOne = m_CombineOr(L: m_ZeroInt(), R: m_One());
8219	if (match(V: TrueVal, P: MaybeSExtCmpLHS)) {
8220	// Set the return values. If the compare uses the negated value (-X >s 0),
8221	// swap the return values because the negated value is always 'RHS'.
8222	LHS = TrueVal;
8223	RHS = FalseVal;
8224	if (match(V: CmpLHS, P: m_Neg(V: m_Specific(V: FalseVal))))
8225	std::swap(a&: LHS, b&: RHS);
8226
8227	// (X >s 0) ? X : -X or (X >s -1) ? X : -X --> ABS(X)
8228	// (-X >s 0) ? -X : X or (-X >s -1) ? -X : X --> ABS(X)
8229	if (Pred == ICmpInst::ICMP_SGT && match(V: CmpRHS, P: ZeroOrAllOnes))
8230	return {.Flavor: SPF_ABS, .NaNBehavior: SPNB_NA, .Ordered: false};
8231
8232	// (X >=s 0) ? X : -X or (X >=s 1) ? X : -X --> ABS(X)
8233	if (Pred == ICmpInst::ICMP_SGE && match(V: CmpRHS, P: ZeroOrOne))
8234	return {.Flavor: SPF_ABS, .NaNBehavior: SPNB_NA, .Ordered: false};
8235
8236	// (X <s 0) ? X : -X or (X <s 1) ? X : -X --> NABS(X)
8237	// (-X <s 0) ? -X : X or (-X <s 1) ? -X : X --> NABS(X)
8238	if (Pred == ICmpInst::ICMP_SLT && match(V: CmpRHS, P: ZeroOrOne))
8239	return {.Flavor: SPF_NABS, .NaNBehavior: SPNB_NA, .Ordered: false};
8240	}
8241	else if (match(V: FalseVal, P: MaybeSExtCmpLHS)) {
8242	// Set the return values. If the compare uses the negated value (-X >s 0),
8243	// swap the return values because the negated value is always 'RHS'.
8244	LHS = FalseVal;
8245	RHS = TrueVal;
8246	if (match(V: CmpLHS, P: m_Neg(V: m_Specific(V: TrueVal))))
8247	std::swap(a&: LHS, b&: RHS);
8248
8249	// (X >s 0) ? -X : X or (X >s -1) ? -X : X --> NABS(X)
8250	// (-X >s 0) ? X : -X or (-X >s -1) ? X : -X --> NABS(X)
8251	if (Pred == ICmpInst::ICMP_SGT && match(V: CmpRHS, P: ZeroOrAllOnes))
8252	return {.Flavor: SPF_NABS, .NaNBehavior: SPNB_NA, .Ordered: false};
8253
8254	// (X <s 0) ? -X : X or (X <s 1) ? -X : X --> ABS(X)
8255	// (-X <s 0) ? X : -X or (-X <s 1) ? X : -X --> ABS(X)
8256	if (Pred == ICmpInst::ICMP_SLT && match(V: CmpRHS, P: ZeroOrOne))
8257	return {.Flavor: SPF_ABS, .NaNBehavior: SPNB_NA, .Ordered: false};
8258	}
8259	}
8260
8261	if (CmpInst::isIntPredicate(P: Pred))
8262	return matchMinMax(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal, LHS, RHS, Depth);
8263
8264	// According to (IEEE 754-2008 5.3.1), minNum(0.0, -0.0) and similar
8265	// may return either -0.0 or 0.0, so fcmp/select pair has stricter
8266	// semantics than minNum. Be conservative in such case.
8267	if (NaNBehavior != SPNB_RETURNS_ANY ||
8268	(!FMF.noSignedZeros() && !isKnownNonZero(V: CmpLHS) &&
8269	!isKnownNonZero(V: CmpRHS)))
8270	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8271
8272	return matchFastFloatClamp(Pred, CmpLHS, CmpRHS, TrueVal, FalseVal, LHS, RHS);
8273	}
8274
8275	/// Helps to match a select pattern in case of a type mismatch.
8276	///
8277	/// The function processes the case when type of true and false values of a
8278	/// select instruction differs from type of the cmp instruction operands because
8279	/// of a cast instruction. The function checks if it is legal to move the cast
8280	/// operation after "select". If yes, it returns the new second value of
8281	/// "select" (with the assumption that cast is moved):
8282	/// 1. As operand of cast instruction when both values of "select" are same cast
8283	/// instructions.
8284	/// 2. As restored constant (by applying reverse cast operation) when the first
8285	/// value of the "select" is a cast operation and the second value is a
8286	/// constant.
8287	/// NOTE: We return only the new second value because the first value could be
8288	/// accessed as operand of cast instruction.
8289	static Value *lookThroughCast(CmpInst *CmpI, Value *V1, Value *V2,
8290	Instruction::CastOps *CastOp) {
8291	auto *Cast1 = dyn_cast<CastInst>(Val: V1);
8292	if (!Cast1)
8293	return nullptr;
8294
8295	*CastOp = Cast1->getOpcode();
8296	Type *SrcTy = Cast1->getSrcTy();
8297	if (auto *Cast2 = dyn_cast<CastInst>(Val: V2)) {
8298	// If V1 and V2 are both the same cast from the same type, look through V1.
8299	if (*CastOp == Cast2->getOpcode() && SrcTy == Cast2->getSrcTy())
8300	return Cast2->getOperand(i_nocapture: 0);
8301	return nullptr;
8302	}
8303
8304	auto *C = dyn_cast<Constant>(Val: V2);
8305	if (!C)
8306	return nullptr;
8307
8308	const DataLayout &DL = CmpI->getModule()->getDataLayout();
8309	Constant *CastedTo = nullptr;
8310	switch (*CastOp) {
8311	case Instruction::ZExt:
8312	if (CmpI->isUnsigned())
8313	CastedTo = ConstantExpr::getTrunc(C, Ty: SrcTy);
8314	break;
8315	case Instruction::SExt:
8316	if (CmpI->isSigned())
8317	CastedTo = ConstantExpr::getTrunc(C, Ty: SrcTy, OnlyIfReduced: true);
8318	break;
8319	case Instruction::Trunc:
8320	Constant *CmpConst;
8321	if (match(V: CmpI->getOperand(i_nocapture: 1), P: m_Constant(C&: CmpConst)) &&
8322	CmpConst->getType() == SrcTy) {
8323	// Here we have the following case:
8324	//
8325	// %cond = cmp iN %x, CmpConst
8326	// %tr = trunc iN %x to iK
8327	// %narrowsel = select i1 %cond, iK %t, iK C
8328	//
8329	// We can always move trunc after select operation:
8330	//
8331	// %cond = cmp iN %x, CmpConst
8332	// %widesel = select i1 %cond, iN %x, iN CmpConst
8333	// %tr = trunc iN %widesel to iK
8334	//
8335	// Note that C could be extended in any way because we don't care about
8336	// upper bits after truncation. It can't be abs pattern, because it would
8337	// look like:
8338	//
8339	// select i1 %cond, x, -x.
8340	//
8341	// So only min/max pattern could be matched. Such match requires widened C
8342	// == CmpConst. That is why set widened C = CmpConst, condition trunc
8343	// CmpConst == C is checked below.
8344	CastedTo = CmpConst;
8345	} else {
8346	unsigned ExtOp = CmpI->isSigned() ? Instruction::SExt : Instruction::ZExt;
8347	CastedTo = ConstantFoldCastOperand(Opcode: ExtOp, C, DestTy: SrcTy, DL);
8348	}
8349	break;
8350	case Instruction::FPTrunc:
8351	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::FPExt, C, DestTy: SrcTy, DL);
8352	break;
8353	case Instruction::FPExt:
8354	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::FPTrunc, C, DestTy: SrcTy, DL);
8355	break;
8356	case Instruction::FPToUI:
8357	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::UIToFP, C, DestTy: SrcTy, DL);
8358	break;
8359	case Instruction::FPToSI:
8360	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::SIToFP, C, DestTy: SrcTy, DL);
8361	break;
8362	case Instruction::UIToFP:
8363	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::FPToUI, C, DestTy: SrcTy, DL);
8364	break;
8365	case Instruction::SIToFP:
8366	CastedTo = ConstantFoldCastOperand(Opcode: Instruction::FPToSI, C, DestTy: SrcTy, DL);
8367	break;
8368	default:
8369	break;
8370	}
8371
8372	if (!CastedTo)
8373	return nullptr;
8374
8375	// Make sure the cast doesn't lose any information.
8376	Constant *CastedBack =
8377	ConstantFoldCastOperand(Opcode: *CastOp, C: CastedTo, DestTy: C->getType(), DL);
8378	if (CastedBack && CastedBack != C)
8379	return nullptr;
8380
8381	return CastedTo;
8382	}
8383
8384	SelectPatternResult llvm::matchSelectPattern(Value *V, Value *&LHS, Value *&RHS,
8385	Instruction::CastOps *CastOp,
8386	unsigned Depth) {
8387	if (Depth >= MaxAnalysisRecursionDepth)
8388	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8389
8390	SelectInst *SI = dyn_cast<SelectInst>(Val: V);
8391	if (!SI) return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8392
8393	CmpInst *CmpI = dyn_cast<CmpInst>(Val: SI->getCondition());
8394	if (!CmpI) return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8395
8396	Value *TrueVal = SI->getTrueValue();
8397	Value *FalseVal = SI->getFalseValue();
8398
8399	return llvm::matchDecomposedSelectPattern(CmpI, TrueVal, FalseVal, LHS, RHS,
8400	CastOp, Depth);
8401	}
8402
8403	SelectPatternResult llvm::matchDecomposedSelectPattern(
8404	CmpInst *CmpI, Value *TrueVal, Value *FalseVal, Value *&LHS, Value *&RHS,
8405	Instruction::CastOps *CastOp, unsigned Depth) {
8406	CmpInst::Predicate Pred = CmpI->getPredicate();
8407	Value *CmpLHS = CmpI->getOperand(i_nocapture: 0);
8408	Value *CmpRHS = CmpI->getOperand(i_nocapture: 1);
8409	FastMathFlags FMF;
8410	if (isa<FPMathOperator>(Val: CmpI))
8411	FMF = CmpI->getFastMathFlags();
8412
8413	// Bail out early.
8414	if (CmpI->isEquality())
8415	return {.Flavor: SPF_UNKNOWN, .NaNBehavior: SPNB_NA, .Ordered: false};
8416
8417	// Deal with type mismatches.
8418	if (CastOp && CmpLHS->getType() != TrueVal->getType()) {
8419	if (Value *C = lookThroughCast(CmpI, V1: TrueVal, V2: FalseVal, CastOp)) {
8420	// If this is a potential fmin/fmax with a cast to integer, then ignore
8421	// -0.0 because there is no corresponding integer value.
8422	if (*CastOp == Instruction::FPToSI || *CastOp == Instruction::FPToUI)
8423	FMF.setNoSignedZeros();
8424	return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS,
8425	TrueVal: cast<CastInst>(Val: TrueVal)->getOperand(i_nocapture: 0), FalseVal: C,
8426	LHS, RHS, Depth);
8427	}
8428	if (Value *C = lookThroughCast(CmpI, V1: FalseVal, V2: TrueVal, CastOp)) {
8429	// If this is a potential fmin/fmax with a cast to integer, then ignore
8430	// -0.0 because there is no corresponding integer value.
8431	if (*CastOp == Instruction::FPToSI || *CastOp == Instruction::FPToUI)
8432	FMF.setNoSignedZeros();
8433	return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS,
8434	TrueVal: C, FalseVal: cast<CastInst>(Val: FalseVal)->getOperand(i_nocapture: 0),
8435	LHS, RHS, Depth);
8436	}
8437	}
8438	return ::matchSelectPattern(Pred, FMF, CmpLHS, CmpRHS, TrueVal, FalseVal,
8439	LHS, RHS, Depth);
8440	}
8441
8442	CmpInst::Predicate llvm::getMinMaxPred(SelectPatternFlavor SPF, bool Ordered) {
8443	if (SPF == SPF_SMIN) return ICmpInst::ICMP_SLT;
8444	if (SPF == SPF_UMIN) return ICmpInst::ICMP_ULT;
8445	if (SPF == SPF_SMAX) return ICmpInst::ICMP_SGT;
8446	if (SPF == SPF_UMAX) return ICmpInst::ICMP_UGT;
8447	if (SPF == SPF_FMINNUM)
8448	return Ordered ? FCmpInst::FCMP_OLT : FCmpInst::FCMP_ULT;
8449	if (SPF == SPF_FMAXNUM)
8450	return Ordered ? FCmpInst::FCMP_OGT : FCmpInst::FCMP_UGT;
8451	llvm_unreachable("unhandled!");
8452	}
8453
8454	SelectPatternFlavor llvm::getInverseMinMaxFlavor(SelectPatternFlavor SPF) {
8455	if (SPF == SPF_SMIN) return SPF_SMAX;
8456	if (SPF == SPF_UMIN) return SPF_UMAX;
8457	if (SPF == SPF_SMAX) return SPF_SMIN;
8458	if (SPF == SPF_UMAX) return SPF_UMIN;
8459	llvm_unreachable("unhandled!");
8460	}
8461
8462	Intrinsic::ID llvm::getInverseMinMaxIntrinsic(Intrinsic::ID MinMaxID) {
8463	switch (MinMaxID) {
8464	case Intrinsic::smax: return Intrinsic::smin;
8465	case Intrinsic::smin: return Intrinsic::smax;
8466	case Intrinsic::umax: return Intrinsic::umin;
8467	case Intrinsic::umin: return Intrinsic::umax;
8468	// Please note that next four intrinsics may produce the same result for
8469	// original and inverted case even if X != Y due to NaN is handled specially.
8470	case Intrinsic::maximum: return Intrinsic::minimum;
8471	case Intrinsic::minimum: return Intrinsic::maximum;
8472	case Intrinsic::maxnum: return Intrinsic::minnum;
8473	case Intrinsic::minnum: return Intrinsic::maxnum;
8474	default: llvm_unreachable("Unexpected intrinsic");
8475	}
8476	}
8477
8478	APInt llvm::getMinMaxLimit(SelectPatternFlavor SPF, unsigned BitWidth) {
8479	switch (SPF) {
8480	case SPF_SMAX: return APInt::getSignedMaxValue(numBits: BitWidth);
8481	case SPF_SMIN: return APInt::getSignedMinValue(numBits: BitWidth);
8482	case SPF_UMAX: return APInt::getMaxValue(numBits: BitWidth);
8483	case SPF_UMIN: return APInt::getMinValue(numBits: BitWidth);
8484	default: llvm_unreachable("Unexpected flavor");
8485	}
8486	}
8487
8488	std::pair<Intrinsic::ID, bool>
8489	llvm::canConvertToMinOrMaxIntrinsic(ArrayRef<Value *> VL) {
8490	// Check if VL contains select instructions that can be folded into a min/max
8491	// vector intrinsic and return the intrinsic if it is possible.
8492	// TODO: Support floating point min/max.
8493	bool AllCmpSingleUse = true;
8494	SelectPatternResult SelectPattern;
8495	SelectPattern.Flavor = SPF_UNKNOWN;
8496	if (all_of(Range&: VL, P: [&SelectPattern, &AllCmpSingleUse](Value *I) {
8497	Value *LHS, *RHS;
8498	auto CurrentPattern = matchSelectPattern(V: I, LHS, RHS);
8499	if (!SelectPatternResult::isMinOrMax(SPF: CurrentPattern.Flavor) ||
8500	CurrentPattern.Flavor == SPF_FMINNUM ||
8501	CurrentPattern.Flavor == SPF_FMAXNUM ||
8502	!I->getType()->isIntOrIntVectorTy())
8503	return false;
8504	if (SelectPattern.Flavor != SPF_UNKNOWN &&
8505	SelectPattern.Flavor != CurrentPattern.Flavor)
8506	return false;
8507	SelectPattern = CurrentPattern;
8508	AllCmpSingleUse &=
8509	match(V: I, P: m_Select(C: m_OneUse(SubPattern: m_Value()), L: m_Value(), R: m_Value()));
8510	return true;
8511	})) {
8512	switch (SelectPattern.Flavor) {
8513	case SPF_SMIN:
8514	return {Intrinsic::smin, AllCmpSingleUse};
8515	case SPF_UMIN:
8516	return {Intrinsic::umin, AllCmpSingleUse};
8517	case SPF_SMAX:
8518	return {Intrinsic::smax, AllCmpSingleUse};
8519	case SPF_UMAX:
8520	return {Intrinsic::umax, AllCmpSingleUse};
8521	default:
8522	llvm_unreachable("unexpected select pattern flavor");
8523	}
8524	}
8525	return {Intrinsic::not_intrinsic, false};
8526	}
8527
8528	bool llvm::matchSimpleRecurrence(const PHINode *P, BinaryOperator *&BO,
8529	Value *&Start, Value *&Step) {
8530	// Handle the case of a simple two-predecessor recurrence PHI.
8531	// There's a lot more that could theoretically be done here, but
8532	// this is sufficient to catch some interesting cases.
8533	if (P->getNumIncomingValues() != 2)
8534	return false;
8535
8536	for (unsigned i = 0; i != 2; ++i) {
8537	Value *L = P->getIncomingValue(i);
8538	Value *R = P->getIncomingValue(i: !i);
8539	auto *LU = dyn_cast<BinaryOperator>(Val: L);
8540	if (!LU)
8541	continue;
8542	unsigned Opcode = LU->getOpcode();
8543
8544	switch (Opcode) {
8545	default:
8546	continue;
8547	// TODO: Expand list -- xor, div, gep, uaddo, etc..
8548	case Instruction::LShr:
8549	case Instruction::AShr:
8550	case Instruction::Shl:
8551	case Instruction::Add:
8552	case Instruction::Sub:
8553	case Instruction::And:
8554	case Instruction::Or:
8555	case Instruction::Mul:
8556	case Instruction::FMul: {
8557	Value *LL = LU->getOperand(i_nocapture: 0);
8558	Value *LR = LU->getOperand(i_nocapture: 1);
8559	// Find a recurrence.
8560	if (LL == P)
8561	L = LR;
8562	else if (LR == P)
8563	L = LL;
8564	else
8565	continue; // Check for recurrence with L and R flipped.
8566
8567	break; // Match!
8568	}
8569	};
8570
8571	// We have matched a recurrence of the form:
8572	// %iv = [R, %entry], [%iv.next, %backedge]
8573	// %iv.next = binop %iv, L
8574	// OR
8575	// %iv = [R, %entry], [%iv.next, %backedge]
8576	// %iv.next = binop L, %iv
8577	BO = LU;
8578	Start = R;
8579	Step = L;
8580	return true;
8581	}
8582	return false;
8583	}
8584
8585	bool llvm::matchSimpleRecurrence(const BinaryOperator *I, PHINode *&P,
8586	Value *&Start, Value *&Step) {
8587	BinaryOperator *BO = nullptr;
8588	P = dyn_cast<PHINode>(Val: I->getOperand(i_nocapture: 0));
8589	if (!P)
8590	P = dyn_cast<PHINode>(Val: I->getOperand(i_nocapture: 1));
8591	return P && matchSimpleRecurrence(P, BO, Start, Step) && BO == I;
8592	}
8593
8594	/// Return true if "icmp Pred LHS RHS" is always true.
8595	static bool isTruePredicate(CmpInst::Predicate Pred, const Value *LHS,
8596	const Value *RHS) {
8597	if (ICmpInst::isTrueWhenEqual(predicate: Pred) && LHS == RHS)
8598	return true;
8599
8600	switch (Pred) {
8601	default:
8602	return false;
8603
8604	case CmpInst::ICMP_SLE: {
8605	const APInt *C;
8606
8607	// LHS s<= LHS +_{nsw} C if C >= 0
8608	// LHS s<= LHS | C if C >= 0
8609	if (match(V: RHS, P: m_NSWAdd(L: m_Specific(V: LHS), R: m_APInt(Res&: C))) ||
8610	match(V: RHS, P: m_Or(L: m_Specific(V: LHS), R: m_APInt(Res&: C))))
8611	return !C->isNegative();
8612
8613	// LHS s<= smax(LHS, V) for any V
8614	if (match(V: RHS, P: m_c_SMax(L: m_Specific(V: LHS), R: m_Value())))
8615	return true;
8616
8617	// smin(RHS, V) s<= RHS for any V
8618	if (match(V: LHS, P: m_c_SMin(L: m_Specific(V: RHS), R: m_Value())))
8619	return true;
8620
8621	// Match A to (X +_{nsw} CA) and B to (X +_{nsw} CB)
8622	const Value *X;
8623	const APInt *CLHS, *CRHS;
8624	if (match(V: LHS, P: m_NSWAddLike(L: m_Value(V&: X), R: m_APInt(Res&: CLHS))) &&
8625	match(V: RHS, P: m_NSWAddLike(L: m_Specific(V: X), R: m_APInt(Res&: CRHS))))
8626	return CLHS->sle(RHS: *CRHS);
8627
8628	return false;
8629	}
8630
8631	case CmpInst::ICMP_ULE: {
8632	// LHS u<= LHS +_{nuw} V for any V
8633	if (match(V: RHS, P: m_c_Add(L: m_Specific(V: LHS), R: m_Value())) &&
8634	cast<OverflowingBinaryOperator>(Val: RHS)->hasNoUnsignedWrap())
8635	return true;
8636
8637	// LHS u<= LHS | V for any V
8638	if (match(V: RHS, P: m_c_Or(L: m_Specific(V: LHS), R: m_Value())))
8639	return true;
8640
8641	// LHS u<= umax(LHS, V) for any V
8642	if (match(V: RHS, P: m_c_UMax(L: m_Specific(V: LHS), R: m_Value())))
8643	return true;
8644
8645	// RHS >> V u<= RHS for any V
8646	if (match(V: LHS, P: m_LShr(L: m_Specific(V: RHS), R: m_Value())))
8647	return true;
8648
8649	// RHS u/ C_ugt_1 u<= RHS
8650	const APInt *C;
8651	if (match(V: LHS, P: m_UDiv(L: m_Specific(V: RHS), R: m_APInt(Res&: C))) && C->ugt(RHS: 1))
8652	return true;
8653
8654	// RHS & V u<= RHS for any V
8655	if (match(V: LHS, P: m_c_And(L: m_Specific(V: RHS), R: m_Value())))
8656	return true;
8657
8658	// umin(RHS, V) u<= RHS for any V
8659	if (match(V: LHS, P: m_c_UMin(L: m_Specific(V: RHS), R: m_Value())))
8660	return true;
8661
8662	// Match A to (X +_{nuw} CA) and B to (X +_{nuw} CB)
8663	const Value *X;
8664	const APInt *CLHS, *CRHS;
8665	if (match(V: LHS, P: m_NUWAddLike(L: m_Value(V&: X), R: m_APInt(Res&: CLHS))) &&
8666	match(V: RHS, P: m_NUWAddLike(L: m_Specific(V: X), R: m_APInt(Res&: CRHS))))
8667	return CLHS->ule(RHS: *CRHS);
8668
8669	return false;
8670	}
8671	}
8672	}
8673
8674	/// Return true if "icmp Pred BLHS BRHS" is true whenever "icmp Pred
8675	/// ALHS ARHS" is true. Otherwise, return std::nullopt.
8676	static std::optional<bool>
8677	isImpliedCondOperands(CmpInst::Predicate Pred, const Value *ALHS,
8678	const Value *ARHS, const Value *BLHS, const Value *BRHS) {
8679	switch (Pred) {
8680	default:
8681	return std::nullopt;
8682
8683	case CmpInst::ICMP_SLT:
8684	case CmpInst::ICMP_SLE:
8685	if (isTruePredicate(Pred: CmpInst::ICMP_SLE, LHS: BLHS, RHS: ALHS) &&
8686	isTruePredicate(Pred: CmpInst::ICMP_SLE, LHS: ARHS, RHS: BRHS))
8687	return true;
8688	return std::nullopt;
8689
8690	case CmpInst::ICMP_SGT:
8691	case CmpInst::ICMP_SGE:
8692	if (isTruePredicate(Pred: CmpInst::ICMP_SLE, LHS: ALHS, RHS: BLHS) &&
8693	isTruePredicate(Pred: CmpInst::ICMP_SLE, LHS: BRHS, RHS: ARHS))
8694	return true;
8695	return std::nullopt;
8696
8697	case CmpInst::ICMP_ULT:
8698	case CmpInst::ICMP_ULE:
8699	if (isTruePredicate(Pred: CmpInst::ICMP_ULE, LHS: BLHS, RHS: ALHS) &&
8700	isTruePredicate(Pred: CmpInst::ICMP_ULE, LHS: ARHS, RHS: BRHS))
8701	return true;
8702	return std::nullopt;
8703
8704	case CmpInst::ICMP_UGT:
8705	case CmpInst::ICMP_UGE:
8706	if (isTruePredicate(Pred: CmpInst::ICMP_ULE, LHS: ALHS, RHS: BLHS) &&
8707	isTruePredicate(Pred: CmpInst::ICMP_ULE, LHS: BRHS, RHS: ARHS))
8708	return true;
8709	return std::nullopt;
8710	}
8711	}
8712
8713	/// Return true if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is true.
8714	/// Return false if "icmp1 LPred X, Y" implies "icmp2 RPred X, Y" is false.
8715	/// Otherwise, return std::nullopt if we can't infer anything.
8716	static std::optional<bool>
8717	isImpliedCondMatchingOperands(CmpInst::Predicate LPred,
8718	CmpInst::Predicate RPred) {
8719	if (CmpInst::isImpliedTrueByMatchingCmp(Pred1: LPred, Pred2: RPred))
8720	return true;
8721	if (CmpInst::isImpliedFalseByMatchingCmp(Pred1: LPred, Pred2: RPred))
8722	return false;
8723
8724	return std::nullopt;
8725	}
8726
8727	/// Return true if "icmp LPred X, LC" implies "icmp RPred X, RC" is true.
8728	/// Return false if "icmp LPred X, LC" implies "icmp RPred X, RC" is false.
8729	/// Otherwise, return std::nullopt if we can't infer anything.
8730	static std::optional<bool> isImpliedCondCommonOperandWithConstants(
8731	CmpInst::Predicate LPred, const APInt &LC, CmpInst::Predicate RPred,
8732	const APInt &RC) {
8733	ConstantRange DomCR = ConstantRange::makeExactICmpRegion(Pred: LPred, Other: LC);
8734	ConstantRange CR = ConstantRange::makeExactICmpRegion(Pred: RPred, Other: RC);
8735	ConstantRange Intersection = DomCR.intersectWith(CR);
8736	ConstantRange Difference = DomCR.difference(CR);
8737	if (Intersection.isEmptySet())
8738	return false;
8739	if (Difference.isEmptySet())
8740	return true;
8741	return std::nullopt;
8742	}
8743
8744	/// Return true if LHS implies RHS (expanded to its components as "R0 RPred R1")
8745	/// is true. Return false if LHS implies RHS is false. Otherwise, return
8746	/// std::nullopt if we can't infer anything.
8747	static std::optional<bool> isImpliedCondICmps(const ICmpInst *LHS,
8748	CmpInst::Predicate RPred,
8749	const Value *R0, const Value *R1,
8750	const DataLayout &DL,
8751	bool LHSIsTrue) {
8752	Value *L0 = LHS->getOperand(i_nocapture: 0);
8753	Value *L1 = LHS->getOperand(i_nocapture: 1);
8754
8755	// The rest of the logic assumes the LHS condition is true. If that's not the
8756	// case, invert the predicate to make it so.
8757	CmpInst::Predicate LPred =
8758	LHSIsTrue ? LHS->getPredicate() : LHS->getInversePredicate();
8759
8760	// We can have non-canonical operands, so try to normalize any common operand
8761	// to L0/R0.
8762	if (L0 == R1) {
8763	std::swap(a&: R0, b&: R1);
8764	RPred = ICmpInst::getSwappedPredicate(pred: RPred);
8765	}
8766	if (R0 == L1) {
8767	std::swap(a&: L0, b&: L1);
8768	LPred = ICmpInst::getSwappedPredicate(pred: LPred);
8769	}
8770	if (L1 == R1) {
8771	// If we have L0 == R0 and L1 == R1, then make L1/R1 the constants.
8772	if (L0 != R0 || match(V: L0, P: m_ImmConstant())) {
8773	std::swap(a&: L0, b&: L1);
8774	LPred = ICmpInst::getSwappedPredicate(pred: LPred);
8775	std::swap(a&: R0, b&: R1);
8776	RPred = ICmpInst::getSwappedPredicate(pred: RPred);
8777	}
8778	}
8779
8780	// Can we infer anything when the 0-operands match and the 1-operands are
8781	// constants (not necessarily matching)?
8782	const APInt *LC, *RC;
8783	if (L0 == R0 && match(V: L1, P: m_APInt(Res&: LC)) && match(V: R1, P: m_APInt(Res&: RC)))
8784	return isImpliedCondCommonOperandWithConstants(LPred, LC: *LC, RPred, RC: *RC);
8785
8786	// Can we infer anything when the two compares have matching operands?
8787	if (L0 == R0 && L1 == R1)
8788	return isImpliedCondMatchingOperands(LPred, RPred);
8789
8790	// L0 = R0 = L1 + R1, L0 >=u L1 implies R0 >=u R1, L0 <u L1 implies R0 <u R1
8791	if (L0 == R0 &&
8792	(LPred == ICmpInst::ICMP_ULT || LPred == ICmpInst::ICMP_UGE) &&
8793	(RPred == ICmpInst::ICMP_ULT || RPred == ICmpInst::ICMP_UGE) &&
8794	match(V: L0, P: m_c_Add(L: m_Specific(V: L1), R: m_Specific(V: R1))))
8795	return LPred == RPred;
8796
8797	if (LPred == RPred)
8798	return isImpliedCondOperands(Pred: LPred, ALHS: L0, ARHS: L1, BLHS: R0, BRHS: R1);
8799
8800	return std::nullopt;
8801	}
8802
8803	/// Return true if LHS implies RHS is true. Return false if LHS implies RHS is
8804	/// false. Otherwise, return std::nullopt if we can't infer anything. We
8805	/// expect the RHS to be an icmp and the LHS to be an 'and', 'or', or a 'select'
8806	/// instruction.
8807	static std::optional<bool>
8808	isImpliedCondAndOr(const Instruction *LHS, CmpInst::Predicate RHSPred,
8809	const Value *RHSOp0, const Value *RHSOp1,
8810	const DataLayout &DL, bool LHSIsTrue, unsigned Depth) {
8811	// The LHS must be an 'or', 'and', or a 'select' instruction.
8812	assert((LHS->getOpcode() == Instruction::And ||
8813	LHS->getOpcode() == Instruction::Or ||
8814	LHS->getOpcode() == Instruction::Select) &&
8815	"Expected LHS to be 'and', 'or', or 'select'.");
8816
8817	assert(Depth <= MaxAnalysisRecursionDepth && "Hit recursion limit");
8818
8819	// If the result of an 'or' is false, then we know both legs of the 'or' are
8820	// false. Similarly, if the result of an 'and' is true, then we know both
8821	// legs of the 'and' are true.
8822	const Value *ALHS, *ARHS;
8823	if ((!LHSIsTrue && match(V: LHS, P: m_LogicalOr(L: m_Value(V&: ALHS), R: m_Value(V&: ARHS)))) ||
8824	(LHSIsTrue && match(V: LHS, P: m_LogicalAnd(L: m_Value(V&: ALHS), R: m_Value(V&: ARHS))))) {
8825	// FIXME: Make this non-recursion.
8826	if (std::optional<bool> Implication = isImpliedCondition(
8827	LHS: ALHS, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue, Depth: Depth + 1))
8828	return Implication;
8829	if (std::optional<bool> Implication = isImpliedCondition(
8830	LHS: ARHS, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue, Depth: Depth + 1))
8831	return Implication;
8832	return std::nullopt;
8833	}
8834	return std::nullopt;
8835	}
8836
8837	std::optional<bool>
8838	llvm::isImpliedCondition(const Value *LHS, CmpInst::Predicate RHSPred,
8839	const Value *RHSOp0, const Value *RHSOp1,
8840	const DataLayout &DL, bool LHSIsTrue, unsigned Depth) {
8841	// Bail out when we hit the limit.
8842	if (Depth == MaxAnalysisRecursionDepth)
8843	return std::nullopt;
8844
8845	// A mismatch occurs when we compare a scalar cmp to a vector cmp, for
8846	// example.
8847	if (RHSOp0->getType()->isVectorTy() != LHS->getType()->isVectorTy())
8848	return std::nullopt;
8849
8850	assert(LHS->getType()->isIntOrIntVectorTy(1) &&
8851	"Expected integer type only!");
8852
8853	// Match not
8854	if (match(V: LHS, P: m_Not(V: m_Value(V&: LHS))))
8855	LHSIsTrue = !LHSIsTrue;
8856
8857	// Both LHS and RHS are icmps.
8858	const ICmpInst *LHSCmp = dyn_cast<ICmpInst>(Val: LHS);
8859	if (LHSCmp)
8860	return isImpliedCondICmps(LHS: LHSCmp, RPred: RHSPred, R0: RHSOp0, R1: RHSOp1, DL, LHSIsTrue);
8861
8862	/// The LHS should be an 'or', 'and', or a 'select' instruction. We expect
8863	/// the RHS to be an icmp.
8864	/// FIXME: Add support for and/or/select on the RHS.
8865	if (const Instruction *LHSI = dyn_cast<Instruction>(Val: LHS)) {
8866	if ((LHSI->getOpcode() == Instruction::And ||
8867	LHSI->getOpcode() == Instruction::Or ||
8868	LHSI->getOpcode() == Instruction::Select))
8869	return isImpliedCondAndOr(LHS: LHSI, RHSPred, RHSOp0, RHSOp1, DL, LHSIsTrue,
8870	Depth);
8871	}
8872	return std::nullopt;
8873	}
8874
8875	std::optional<bool> llvm::isImpliedCondition(const Value *LHS, const Value *RHS,
8876	const DataLayout &DL,
8877	bool LHSIsTrue, unsigned Depth) {
8878	// LHS ==> RHS by definition
8879	if (LHS == RHS)
8880	return LHSIsTrue;
8881
8882	// Match not
8883	bool InvertRHS = false;
8884	if (match(V: RHS, P: m_Not(V: m_Value(V&: RHS)))) {
8885	if (LHS == RHS)
8886	return !LHSIsTrue;
8887	InvertRHS = true;
8888	}
8889
8890	if (const ICmpInst *RHSCmp = dyn_cast<ICmpInst>(Val: RHS)) {
8891	if (auto Implied = isImpliedCondition(
8892	LHS, RHSPred: RHSCmp->getPredicate(), RHSOp0: RHSCmp->getOperand(i_nocapture: 0),
8893	RHSOp1: RHSCmp->getOperand(i_nocapture: 1), DL, LHSIsTrue, Depth))
8894	return InvertRHS ? !*Implied : *Implied;
8895	return std::nullopt;
8896	}
8897
8898	if (Depth == MaxAnalysisRecursionDepth)
8899	return std::nullopt;
8900
8901	// LHS ==> (RHS1 || RHS2) if LHS ==> RHS1 or LHS ==> RHS2
8902	// LHS ==> !(RHS1 && RHS2) if LHS ==> !RHS1 or LHS ==> !RHS2
8903	const Value *RHS1, *RHS2;
8904	if (match(V: RHS, P: m_LogicalOr(L: m_Value(V&: RHS1), R: m_Value(V&: RHS2)))) {
8905	if (std::optional<bool> Imp =
8906	isImpliedCondition(LHS, RHS: RHS1, DL, LHSIsTrue, Depth: Depth + 1))
8907	if (*Imp == true)
8908	return !InvertRHS;
8909	if (std::optional<bool> Imp =
8910	isImpliedCondition(LHS, RHS: RHS2, DL, LHSIsTrue, Depth: Depth + 1))
8911	if (*Imp == true)
8912	return !InvertRHS;
8913	}
8914	if (match(V: RHS, P: m_LogicalAnd(L: m_Value(V&: RHS1), R: m_Value(V&: RHS2)))) {
8915	if (std::optional<bool> Imp =
8916	isImpliedCondition(LHS, RHS: RHS1, DL, LHSIsTrue, Depth: Depth + 1))
8917	if (*Imp == false)
8918	return InvertRHS;
8919	if (std::optional<bool> Imp =
8920	isImpliedCondition(LHS, RHS: RHS2, DL, LHSIsTrue, Depth: Depth + 1))
8921	if (*Imp == false)
8922	return InvertRHS;
8923	}
8924
8925	return std::nullopt;
8926	}
8927
8928	// Returns a pair (Condition, ConditionIsTrue), where Condition is a branch
8929	// condition dominating ContextI or nullptr, if no condition is found.
8930	static std::pair<Value *, bool>
8931	getDomPredecessorCondition(const Instruction *ContextI) {
8932	if (!ContextI || !ContextI->getParent())
8933	return {nullptr, false};
8934
8935	// TODO: This is a poor/cheap way to determine dominance. Should we use a
8936	// dominator tree (eg, from a SimplifyQuery) instead?
8937	const BasicBlock *ContextBB = ContextI->getParent();
8938	const BasicBlock *PredBB = ContextBB->getSinglePredecessor();
8939	if (!PredBB)
8940	return {nullptr, false};
8941
8942	// We need a conditional branch in the predecessor.
8943	Value *PredCond;
8944	BasicBlock *TrueBB, *FalseBB;
8945	if (!match(V: PredBB->getTerminator(), P: m_Br(C: m_Value(V&: PredCond), T&: TrueBB, F&: FalseBB)))
8946	return {nullptr, false};
8947
8948	// The branch should get simplified. Don't bother simplifying this condition.
8949	if (TrueBB == FalseBB)
8950	return {nullptr, false};
8951
8952	assert((TrueBB == ContextBB || FalseBB == ContextBB) &&
8953	"Predecessor block does not point to successor?");
8954
8955	// Is this condition implied by the predecessor condition?
8956	return {PredCond, TrueBB == ContextBB};
8957	}
8958
8959	std::optional<bool> llvm::isImpliedByDomCondition(const Value *Cond,
8960	const Instruction *ContextI,
8961	const DataLayout &DL) {
8962	assert(Cond->getType()->isIntOrIntVectorTy(1) && "Condition must be bool");
8963	auto PredCond = getDomPredecessorCondition(ContextI);
8964	if (PredCond.first)
8965	return isImpliedCondition(LHS: PredCond.first, RHS: Cond, DL, LHSIsTrue: PredCond.second);
8966	return std::nullopt;
8967	}
8968
8969	std::optional<bool> llvm::isImpliedByDomCondition(CmpInst::Predicate Pred,
8970	const Value *LHS,
8971	const Value *RHS,
8972	const Instruction *ContextI,
8973	const DataLayout &DL) {
8974	auto PredCond = getDomPredecessorCondition(ContextI);
8975	if (PredCond.first)
8976	return isImpliedCondition(LHS: PredCond.first, RHSPred: Pred, RHSOp0: LHS, RHSOp1: RHS, DL,
8977	LHSIsTrue: PredCond.second);
8978	return std::nullopt;
8979	}
8980
8981	static void setLimitsForBinOp(const BinaryOperator &BO, APInt &Lower,
8982	APInt &Upper, const InstrInfoQuery &IIQ,
8983	bool PreferSignedRange) {
8984	unsigned Width = Lower.getBitWidth();
8985	const APInt *C;
8986	switch (BO.getOpcode()) {
8987	case Instruction::Add:
8988	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)) && !C->isZero()) {
8989	bool HasNSW = IIQ.hasNoSignedWrap(Op: &BO);
8990	bool HasNUW = IIQ.hasNoUnsignedWrap(Op: &BO);
8991
8992	// If the caller expects a signed compare, then try to use a signed range.
8993	// Otherwise if both no-wraps are set, use the unsigned range because it
8994	// is never larger than the signed range. Example:
8995	// "add nuw nsw i8 X, -2" is unsigned [254,255] vs. signed [-128, 125].
8996	if (PreferSignedRange && HasNSW && HasNUW)
8997	HasNUW = false;
8998
8999	if (HasNUW) {
9000	// 'add nuw x, C' produces [C, UINT_MAX].
9001	Lower = *C;
9002	} else if (HasNSW) {
9003	if (C->isNegative()) {
9004	// 'add nsw x, -C' produces [SINT_MIN, SINT_MAX - C].
9005	Lower = APInt::getSignedMinValue(numBits: Width);
9006	Upper = APInt::getSignedMaxValue(numBits: Width) + *C + 1;
9007	} else {
9008	// 'add nsw x, +C' produces [SINT_MIN + C, SINT_MAX].
9009	Lower = APInt::getSignedMinValue(numBits: Width) + *C;
9010	Upper = APInt::getSignedMaxValue(numBits: Width) + 1;
9011	}
9012	}
9013	}
9014	break;
9015
9016	case Instruction::And:
9017	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9018	// 'and x, C' produces [0, C].
9019	Upper = *C + 1;
9020	// X & -X is a power of two or zero. So we can cap the value at max power of
9021	// two.
9022	if (match(V: BO.getOperand(i_nocapture: 0), P: m_Neg(V: m_Specific(V: BO.getOperand(i_nocapture: 1)))) ||
9023	match(V: BO.getOperand(i_nocapture: 1), P: m_Neg(V: m_Specific(V: BO.getOperand(i_nocapture: 0)))))
9024	Upper = APInt::getSignedMinValue(numBits: Width) + 1;
9025	break;
9026
9027	case Instruction::Or:
9028	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9029	// 'or x, C' produces [C, UINT_MAX].
9030	Lower = *C;
9031	break;
9032
9033	case Instruction::AShr:
9034	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)) && C->ult(RHS: Width)) {
9035	// 'ashr x, C' produces [INT_MIN >> C, INT_MAX >> C].
9036	Lower = APInt::getSignedMinValue(numBits: Width).ashr(ShiftAmt: *C);
9037	Upper = APInt::getSignedMaxValue(numBits: Width).ashr(ShiftAmt: *C) + 1;
9038	} else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9039	unsigned ShiftAmount = Width - 1;
9040	if (!C->isZero() && IIQ.isExact(Op: &BO))
9041	ShiftAmount = C->countr_zero();
9042	if (C->isNegative()) {
9043	// 'ashr C, x' produces [C, C >> (Width-1)]
9044	Lower = *C;
9045	Upper = C->ashr(ShiftAmt: ShiftAmount) + 1;
9046	} else {
9047	// 'ashr C, x' produces [C >> (Width-1), C]
9048	Lower = C->ashr(ShiftAmt: ShiftAmount);
9049	Upper = *C + 1;
9050	}
9051	}
9052	break;
9053
9054	case Instruction::LShr:
9055	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)) && C->ult(RHS: Width)) {
9056	// 'lshr x, C' produces [0, UINT_MAX >> C].
9057	Upper = APInt::getAllOnes(numBits: Width).lshr(ShiftAmt: *C) + 1;
9058	} else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9059	// 'lshr C, x' produces [C >> (Width-1), C].
9060	unsigned ShiftAmount = Width - 1;
9061	if (!C->isZero() && IIQ.isExact(Op: &BO))
9062	ShiftAmount = C->countr_zero();
9063	Lower = C->lshr(shiftAmt: ShiftAmount);
9064	Upper = *C + 1;
9065	}
9066	break;
9067
9068	case Instruction::Shl:
9069	if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9070	if (IIQ.hasNoUnsignedWrap(Op: &BO)) {
9071	// 'shl nuw C, x' produces [C, C << CLZ(C)]
9072	Lower = *C;
9073	Upper = Lower.shl(shiftAmt: Lower.countl_zero()) + 1;
9074	} else if (BO.hasNoSignedWrap()) { // TODO: What if both nuw+nsw?
9075	if (C->isNegative()) {
9076	// 'shl nsw C, x' produces [C << CLO(C)-1, C]
9077	unsigned ShiftAmount = C->countl_one() - 1;
9078	Lower = C->shl(shiftAmt: ShiftAmount);
9079	Upper = *C + 1;
9080	} else {
9081	// 'shl nsw C, x' produces [C, C << CLZ(C)-1]
9082	unsigned ShiftAmount = C->countl_zero() - 1;
9083	Lower = *C;
9084	Upper = C->shl(shiftAmt: ShiftAmount) + 1;
9085	}
9086	} else {
9087	// If lowbit is set, value can never be zero.
9088	if ((*C)[0])
9089	Lower = APInt::getOneBitSet(numBits: Width, BitNo: 0);
9090	// If we are shifting a constant the largest it can be is if the longest
9091	// sequence of consecutive ones is shifted to the highbits (breaking
9092	// ties for which sequence is higher). At the moment we take a liberal
9093	// upper bound on this by just popcounting the constant.
9094	// TODO: There may be a bitwise trick for it longest/highest
9095	// consecutative sequence of ones (naive method is O(Width) loop).
9096	Upper = APInt::getHighBitsSet(numBits: Width, hiBitsSet: C->popcount()) + 1;
9097	}
9098	} else if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)) && C->ult(RHS: Width)) {
9099	Upper = APInt::getBitsSetFrom(numBits: Width, loBit: C->getZExtValue()) + 1;
9100	}
9101	break;
9102
9103	case Instruction::SDiv:
9104	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C))) {
9105	APInt IntMin = APInt::getSignedMinValue(numBits: Width);
9106	APInt IntMax = APInt::getSignedMaxValue(numBits: Width);
9107	if (C->isAllOnes()) {
9108	// 'sdiv x, -1' produces [INT_MIN + 1, INT_MAX]
9109	// where C != -1 and C != 0 and C != 1
9110	Lower = IntMin + 1;
9111	Upper = IntMax + 1;
9112	} else if (C->countl_zero() < Width - 1) {
9113	// 'sdiv x, C' produces [INT_MIN / C, INT_MAX / C]
9114	// where C != -1 and C != 0 and C != 1
9115	Lower = IntMin.sdiv(RHS: *C);
9116	Upper = IntMax.sdiv(RHS: *C);
9117	if (Lower.sgt(RHS: Upper))
9118	std::swap(a&: Lower, b&: Upper);
9119	Upper = Upper + 1;
9120	assert(Upper != Lower && "Upper part of range has wrapped!");
9121	}
9122	} else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9123	if (C->isMinSignedValue()) {
9124	// 'sdiv INT_MIN, x' produces [INT_MIN, INT_MIN / -2].
9125	Lower = *C;
9126	Upper = Lower.lshr(shiftAmt: 1) + 1;
9127	} else {
9128	// 'sdiv C, x' produces [-|C|, |C|].
9129	Upper = C->abs() + 1;
9130	Lower = (-Upper) + 1;
9131	}
9132	}
9133	break;
9134
9135	case Instruction::UDiv:
9136	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)) && !C->isZero()) {
9137	// 'udiv x, C' produces [0, UINT_MAX / C].
9138	Upper = APInt::getMaxValue(numBits: Width).udiv(RHS: *C) + 1;
9139	} else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9140	// 'udiv C, x' produces [0, C].
9141	Upper = *C + 1;
9142	}
9143	break;
9144
9145	case Instruction::SRem:
9146	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C))) {
9147	// 'srem x, C' produces (-|C|, |C|).
9148	Upper = C->abs();
9149	Lower = (-Upper) + 1;
9150	} else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9151	if (C->isNegative()) {
9152	// 'srem -|C|, x' produces [-|C|, 0].
9153	Upper = 1;
9154	Lower = *C;
9155	} else {
9156	// 'srem |C|, x' produces [0, |C|].
9157	Upper = *C + 1;
9158	}
9159	}
9160	break;
9161
9162	case Instruction::URem:
9163	if (match(V: BO.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9164	// 'urem x, C' produces [0, C).
9165	Upper = *C;
9166	else if (match(V: BO.getOperand(i_nocapture: 0), P: m_APInt(Res&: C)))
9167	// 'urem C, x' produces [0, C].
9168	Upper = *C + 1;
9169	break;
9170
9171	default:
9172	break;
9173	}
9174	}
9175
9176	static ConstantRange getRangeForIntrinsic(const IntrinsicInst &II) {
9177	unsigned Width = II.getType()->getScalarSizeInBits();
9178	const APInt *C;
9179	switch (II.getIntrinsicID()) {
9180	case Intrinsic::ctpop:
9181	case Intrinsic::ctlz:
9182	case Intrinsic::cttz:
9183	// Maximum of set/clear bits is the bit width.
9184	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width),
9185	Upper: APInt(Width, Width + 1));
9186	case Intrinsic::uadd_sat:
9187	// uadd.sat(x, C) produces [C, UINT_MAX].
9188	if (match(V: II.getOperand(i_nocapture: 0), P: m_APInt(Res&: C)) ||
9189	match(V: II.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9190	return ConstantRange::getNonEmpty(Lower: *C, Upper: APInt::getZero(numBits: Width));
9191	break;
9192	case Intrinsic::sadd_sat:
9193	if (match(V: II.getOperand(i_nocapture: 0), P: m_APInt(Res&: C)) ||
9194	match(V: II.getOperand(i_nocapture: 1), P: m_APInt(Res&: C))) {
9195	if (C->isNegative())
9196	// sadd.sat(x, -C) produces [SINT_MIN, SINT_MAX + (-C)].
9197	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width),
9198	Upper: APInt::getSignedMaxValue(numBits: Width) + *C +
9199	1);
9200
9201	// sadd.sat(x, +C) produces [SINT_MIN + C, SINT_MAX].
9202	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width) + *C,
9203	Upper: APInt::getSignedMaxValue(numBits: Width) + 1);
9204	}
9205	break;
9206	case Intrinsic::usub_sat:
9207	// usub.sat(C, x) produces [0, C].
9208	if (match(V: II.getOperand(i_nocapture: 0), P: m_APInt(Res&: C)))
9209	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width), Upper: *C + 1);
9210
9211	// usub.sat(x, C) produces [0, UINT_MAX - C].
9212	if (match(V: II.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9213	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width),
9214	Upper: APInt::getMaxValue(numBits: Width) - *C + 1);
9215	break;
9216	case Intrinsic::ssub_sat:
9217	if (match(V: II.getOperand(i_nocapture: 0), P: m_APInt(Res&: C))) {
9218	if (C->isNegative())
9219	// ssub.sat(-C, x) produces [SINT_MIN, -SINT_MIN + (-C)].
9220	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width),
9221	Upper: *C - APInt::getSignedMinValue(numBits: Width) +
9222	1);
9223
9224	// ssub.sat(+C, x) produces [-SINT_MAX + C, SINT_MAX].
9225	return ConstantRange::getNonEmpty(Lower: *C - APInt::getSignedMaxValue(numBits: Width),
9226	Upper: APInt::getSignedMaxValue(numBits: Width) + 1);
9227	} else if (match(V: II.getOperand(i_nocapture: 1), P: m_APInt(Res&: C))) {
9228	if (C->isNegative())
9229	// ssub.sat(x, -C) produces [SINT_MIN - (-C), SINT_MAX]:
9230	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width) - *C,
9231	Upper: APInt::getSignedMaxValue(numBits: Width) + 1);
9232
9233	// ssub.sat(x, +C) produces [SINT_MIN, SINT_MAX - C].
9234	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width),
9235	Upper: APInt::getSignedMaxValue(numBits: Width) - *C +
9236	1);
9237	}
9238	break;
9239	case Intrinsic::umin:
9240	case Intrinsic::umax:
9241	case Intrinsic::smin:
9242	case Intrinsic::smax:
9243	if (!match(V: II.getOperand(i_nocapture: 0), P: m_APInt(Res&: C)) &&
9244	!match(V: II.getOperand(i_nocapture: 1), P: m_APInt(Res&: C)))
9245	break;
9246
9247	switch (II.getIntrinsicID()) {
9248	case Intrinsic::umin:
9249	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width), Upper: *C + 1);
9250	case Intrinsic::umax:
9251	return ConstantRange::getNonEmpty(Lower: *C, Upper: APInt::getZero(numBits: Width));
9252	case Intrinsic::smin:
9253	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: Width),
9254	Upper: *C + 1);
9255	case Intrinsic::smax:
9256	return ConstantRange::getNonEmpty(Lower: *C,
9257	Upper: APInt::getSignedMaxValue(numBits: Width) + 1);
9258	default:
9259	llvm_unreachable("Must be min/max intrinsic");
9260	}
9261	break;
9262	case Intrinsic::abs:
9263	// If abs of SIGNED_MIN is poison, then the result is [0..SIGNED_MAX],
9264	// otherwise it is [0..SIGNED_MIN], as -SIGNED_MIN == SIGNED_MIN.
9265	if (match(V: II.getOperand(i_nocapture: 1), P: m_One()))
9266	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width),
9267	Upper: APInt::getSignedMaxValue(numBits: Width) + 1);
9268
9269	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: Width),
9270	Upper: APInt::getSignedMinValue(numBits: Width) + 1);
9271	case Intrinsic::vscale:
9272	if (!II.getParent() || !II.getFunction())
9273	break;
9274	return getVScaleRange(F: II.getFunction(), BitWidth: Width);
9275	default:
9276	break;
9277	}
9278
9279	return ConstantRange::getFull(BitWidth: Width);
9280	}
9281
9282	static ConstantRange getRangeForSelectPattern(const SelectInst &SI,
9283	const InstrInfoQuery &IIQ) {
9284	unsigned BitWidth = SI.getType()->getScalarSizeInBits();
9285	const Value *LHS = nullptr, *RHS = nullptr;
9286	SelectPatternResult R = matchSelectPattern(V: &SI, LHS, RHS);
9287	if (R.Flavor == SPF_UNKNOWN)
9288	return ConstantRange::getFull(BitWidth);
9289
9290	if (R.Flavor == SelectPatternFlavor::SPF_ABS) {
9291	// If the negation part of the abs (in RHS) has the NSW flag,
9292	// then the result of abs(X) is [0..SIGNED_MAX],
9293	// otherwise it is [0..SIGNED_MIN], as -SIGNED_MIN == SIGNED_MIN.
9294	if (match(V: RHS, P: m_Neg(V: m_Specific(V: LHS))) &&
9295	IIQ.hasNoSignedWrap(Op: cast<Instruction>(Val: RHS)))
9296	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: BitWidth),
9297	Upper: APInt::getSignedMaxValue(numBits: BitWidth) + 1);
9298
9299	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: BitWidth),
9300	Upper: APInt::getSignedMinValue(numBits: BitWidth) + 1);
9301	}
9302
9303	if (R.Flavor == SelectPatternFlavor::SPF_NABS) {
9304	// The result of -abs(X) is <= 0.
9305	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: BitWidth),
9306	Upper: APInt(BitWidth, 1));
9307	}
9308
9309	const APInt *C;
9310	if (!match(V: LHS, P: m_APInt(Res&: C)) && !match(V: RHS, P: m_APInt(Res&: C)))
9311	return ConstantRange::getFull(BitWidth);
9312
9313	switch (R.Flavor) {
9314	case SPF_UMIN:
9315	return ConstantRange::getNonEmpty(Lower: APInt::getZero(numBits: BitWidth), Upper: *C + 1);
9316	case SPF_UMAX:
9317	return ConstantRange::getNonEmpty(Lower: *C, Upper: APInt::getZero(numBits: BitWidth));
9318	case SPF_SMIN:
9319	return ConstantRange::getNonEmpty(Lower: APInt::getSignedMinValue(numBits: BitWidth),
9320	Upper: *C + 1);
9321	case SPF_SMAX:
9322	return ConstantRange::getNonEmpty(Lower: *C,
9323	Upper: APInt::getSignedMaxValue(numBits: BitWidth) + 1);
9324	default:
9325	return ConstantRange::getFull(BitWidth);
9326	}
9327	}
9328
9329	static void setLimitForFPToI(const Instruction *I, APInt &Lower, APInt &Upper) {
9330	// The maximum representable value of a half is 65504. For floats the maximum
9331	// value is 3.4e38 which requires roughly 129 bits.
9332	unsigned BitWidth = I->getType()->getScalarSizeInBits();
9333	if (!I->getOperand(i: 0)->getType()->getScalarType()->isHalfTy())
9334	return;
9335	if (isa<FPToSIInst>(Val: I) && BitWidth >= 17) {
9336	Lower = APInt(BitWidth, -65504);
9337	Upper = APInt(BitWidth, 65505);
9338	}
9339
9340	if (isa<FPToUIInst>(Val: I) && BitWidth >= 16) {
9341	// For a fptoui the lower limit is left as 0.
9342	Upper = APInt(BitWidth, 65505);
9343	}
9344	}
9345
9346	ConstantRange llvm::computeConstantRange(const Value *V, bool ForSigned,
9347	bool UseInstrInfo, AssumptionCache *AC,
9348	const Instruction *CtxI,
9349	const DominatorTree *DT,
9350	unsigned Depth) {
9351	assert(V->getType()->isIntOrIntVectorTy() && "Expected integer instruction");
9352
9353	if (Depth == MaxAnalysisRecursionDepth)
9354	return ConstantRange::getFull(BitWidth: V->getType()->getScalarSizeInBits());
9355
9356	const APInt *C;
9357	if (match(V, P: m_APInt(Res&: C)))
9358	return ConstantRange(*C);
9359	unsigned BitWidth = V->getType()->getScalarSizeInBits();
9360
9361	if (auto *VC = dyn_cast<ConstantDataVector>(Val: V)) {
9362	ConstantRange CR = ConstantRange::getEmpty(BitWidth);
9363	for (unsigned ElemIdx = 0, NElem = VC->getNumElements(); ElemIdx < NElem;
9364	++ElemIdx)
9365	CR = CR.unionWith(CR: VC->getElementAsAPInt(i: ElemIdx));
9366	return CR;
9367	}
9368
9369	InstrInfoQuery IIQ(UseInstrInfo);
9370	ConstantRange CR = ConstantRange::getFull(BitWidth);
9371	if (auto *BO = dyn_cast<BinaryOperator>(Val: V)) {
9372	APInt Lower = APInt(BitWidth, 0);
9373	APInt Upper = APInt(BitWidth, 0);
9374	// TODO: Return ConstantRange.
9375	setLimitsForBinOp(BO: *BO, Lower, Upper, IIQ, PreferSignedRange: ForSigned);
9376	CR = ConstantRange::getNonEmpty(Lower, Upper);
9377	} else if (auto *II = dyn_cast<IntrinsicInst>(Val: V))
9378	CR = getRangeForIntrinsic(II: *II);
9379	else if (auto *SI = dyn_cast<SelectInst>(Val: V)) {
9380	ConstantRange CRTrue = computeConstantRange(
9381	V: SI->getTrueValue(), ForSigned, UseInstrInfo, AC, CtxI, DT, Depth: Depth + 1);
9382	ConstantRange CRFalse = computeConstantRange(
9383	V: SI->getFalseValue(), ForSigned, UseInstrInfo, AC, CtxI, DT, Depth: Depth + 1);
9384	CR = CRTrue.unionWith(CR: CRFalse);
9385	CR = CR.intersectWith(CR: getRangeForSelectPattern(SI: *SI, IIQ));
9386	} else if (isa<FPToUIInst>(Val: V) || isa<FPToSIInst>(Val: V)) {
9387	APInt Lower = APInt(BitWidth, 0);
9388	APInt Upper = APInt(BitWidth, 0);
9389	// TODO: Return ConstantRange.
9390	setLimitForFPToI(I: cast<Instruction>(Val: V), Lower, Upper);
9391	CR = ConstantRange::getNonEmpty(Lower, Upper);
9392	} else if (const auto *A = dyn_cast<Argument>(Val: V))
9393	if (std::optional<ConstantRange> Range = A->getRange())
9394	CR = *Range;
9395
9396	if (auto *I = dyn_cast<Instruction>(Val: V)) {
9397	if (auto *Range = IIQ.getMetadata(I, KindID: LLVMContext::MD_range))
9398	CR = CR.intersectWith(CR: getConstantRangeFromMetadata(RangeMD: *Range));
9399
9400	if (const auto *CB = dyn_cast<CallBase>(Val: V))
9401	if (std::optional<ConstantRange> Range = CB->getRange())
9402	CR = CR.intersectWith(CR: *Range);
9403	}
9404
9405	if (CtxI && AC) {
9406	// Try to restrict the range based on information from assumptions.
9407	for (auto &AssumeVH : AC->assumptionsFor(V)) {
9408	if (!AssumeVH)
9409	continue;
9410	CallInst *I = cast<CallInst>(Val&: AssumeVH);
9411	assert(I->getParent()->getParent() == CtxI->getParent()->getParent() &&
9412	"Got assumption for the wrong function!");
9413	assert(I->getCalledFunction()->getIntrinsicID() == Intrinsic::assume &&
9414	"must be an assume intrinsic");
9415
9416	if (!isValidAssumeForContext(Inv: I, CxtI: CtxI, DT))
9417	continue;
9418	Value *Arg = I->getArgOperand(i: 0);
9419	ICmpInst *Cmp = dyn_cast<ICmpInst>(Val: Arg);
9420	// Currently we just use information from comparisons.
9421	if (!Cmp || Cmp->getOperand(i_nocapture: 0) != V)
9422	continue;
9423	// TODO: Set "ForSigned" parameter via Cmp->isSigned()?
9424	ConstantRange RHS =
9425	computeConstantRange(V: Cmp->getOperand(i_nocapture: 1), /* ForSigned */ false,
9426	UseInstrInfo, AC, CtxI: I, DT, Depth: Depth + 1);
9427	CR = CR.intersectWith(
9428	CR: ConstantRange::makeAllowedICmpRegion(Pred: Cmp->getPredicate(), Other: RHS));
9429	}
9430	}
9431
9432	return CR;
9433	}
9434
9435	static void
9436	addValueAffectedByCondition(Value *V,
9437	function_ref<void(Value *)> InsertAffected) {
9438	assert(V != nullptr);
9439	if (isa<Argument>(Val: V) || isa<GlobalValue>(Val: V)) {
9440	InsertAffected(V);
9441	} else if (auto *I = dyn_cast<Instruction>(Val: V)) {
9442	InsertAffected(V);
9443
9444	// Peek through unary operators to find the source of the condition.
9445	Value *Op;
9446	if (match(V: I, P: m_CombineOr(L: m_PtrToInt(Op: m_Value(V&: Op)), R: m_Trunc(Op: m_Value(V&: Op))))) {
9447	if (isa<Instruction>(Val: Op) || isa<Argument>(Val: Op))
9448	InsertAffected(Op);
9449	}
9450	}
9451	}
9452
9453	void llvm::findValuesAffectedByCondition(
9454	Value *Cond, bool IsAssume, function_ref<void(Value *)> InsertAffected) {
9455	auto AddAffected = [&InsertAffected](Value *V) {
9456	addValueAffectedByCondition(V, InsertAffected);
9457	};
9458
9459	auto AddCmpOperands = [&AddAffected, IsAssume](Value *LHS, Value *RHS) {
9460	if (IsAssume) {
9461	AddAffected(LHS);
9462	AddAffected(RHS);
9463	} else if (match(V: RHS, P: m_Constant()))
9464	AddAffected(LHS);
9465	};
9466
9467	SmallVector<Value *, 8> Worklist;
9468	SmallPtrSet<Value *, 8> Visited;
9469	Worklist.push_back(Elt: Cond);
9470	while (!Worklist.empty()) {
9471	Value *V = Worklist.pop_back_val();
9472	if (!Visited.insert(Ptr: V).second)
9473	continue;
9474
9475	CmpInst::Predicate Pred;
9476	Value *A, *B, *X;
9477
9478	if (IsAssume) {
9479	AddAffected(V);
9480	if (match(V, P: m_Not(V: m_Value(V&: X))))
9481	AddAffected(X);
9482	}
9483
9484	if (match(V, P: m_LogicalOp(L: m_Value(V&: A), R: m_Value(V&: B)))) {
9485	// assume(A && B) is split to -> assume(A); assume(B);
9486	// assume(!(A || B)) is split to -> assume(!A); assume(!B);
9487	// Finally, assume(A || B) / assume(!(A && B)) generally don't provide
9488	// enough information to be worth handling (intersection of information as
9489	// opposed to union).
9490	if (!IsAssume) {
9491	Worklist.push_back(Elt: A);
9492	Worklist.push_back(Elt: B);
9493	}
9494	} else if (match(V, P: m_ICmp(Pred, L: m_Value(V&: A), R: m_Value(V&: B)))) {
9495	AddCmpOperands(A, B);
9496
9497	if (ICmpInst::isEquality(P: Pred)) {
9498	if (match(V: B, P: m_ConstantInt())) {
9499	Value *Y;
9500	// (X & C) or (X | C) or (X ^ C).
9501	// (X << C) or (X >>_s C) or (X >>_u C).
9502	if (match(V: A, P: m_BitwiseLogic(L: m_Value(V&: X), R: m_ConstantInt())) ||
9503	match(V: A, P: m_Shift(L: m_Value(V&: X), R: m_ConstantInt())))
9504	AddAffected(X);
9505	else if (match(V: A, P: m_And(L: m_Value(V&: X), R: m_Value(V&: Y))) ||
9506	match(V: A, P: m_Or(L: m_Value(V&: X), R: m_Value(V&: Y)))) {
9507	AddAffected(X);
9508	AddAffected(Y);
9509	}
9510	}
9511	} else {
9512	if (match(V: B, P: m_ConstantInt())) {
9513	// Handle (A + C1) u< C2, which is the canonical form of
9514	// A > C3 && A < C4.
9515	if (match(V: A, P: m_AddLike(L: m_Value(V&: X), R: m_ConstantInt())))
9516	AddAffected(X);
9517
9518	Value *Y;
9519	// X & Y u> C -> X >u C && Y >u C
9520	// X | Y u< C -> X u< C && Y u< C
9521	if (ICmpInst::isUnsigned(predicate: Pred) &&
9522	(match(V: A, P: m_And(L: m_Value(V&: X), R: m_Value(V&: Y))) ||
9523	match(V: A, P: m_Or(L: m_Value(V&: X), R: m_Value(V&: Y))))) {
9524	AddAffected(X);
9525	AddAffected(Y);
9526	}
9527	}
9528
9529	// Handle icmp slt/sgt (bitcast X to int), 0/-1, which is supported
9530	// by computeKnownFPClass().
9531	if (match(V: A, P: m_ElementWiseBitCast(Op: m_Value(V&: X)))) {
9532	if (Pred == ICmpInst::ICMP_SLT && match(V: B, P: m_Zero()))
9533	InsertAffected(X);
9534	else if (Pred == ICmpInst::ICMP_SGT && match(V: B, P: m_AllOnes()))
9535	InsertAffected(X);
9536	}
9537	}
9538	} else if (match(V: Cond, P: m_FCmp(Pred, L: m_Value(V&: A), R: m_Value(V&: B)))) {
9539	AddCmpOperands(A, B);
9540
9541	// fcmp fneg(x), y
9542	// fcmp fabs(x), y
9543	// fcmp fneg(fabs(x)), y
9544	if (match(V: A, P: m_FNeg(X: m_Value(V&: A))))
9545	AddAffected(A);
9546	if (match(V: A, P: m_FAbs(Op0: m_Value(V&: A))))
9547	AddAffected(A);
9548
9549	} else if (match(V, m_Intrinsic<Intrinsic::is_fpclass>(m_Value(A),
9550	m_Value()))) {
9551	// Handle patterns that computeKnownFPClass() support.
9552	AddAffected(A);
9553	}
9554	}
9555	}
9556