1	//===- InstCombineAddSub.cpp ------------------------------------*- C++ -*-===//
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 implements the visit functions for add, fadd, sub, and fsub.
10	//
11	//===----------------------------------------------------------------------===//
12
13	#include "InstCombineInternal.h"
14	#include "llvm/ADT/APFloat.h"
15	#include "llvm/ADT/APInt.h"
16	#include "llvm/ADT/STLExtras.h"
17	#include "llvm/ADT/SmallVector.h"
18	#include "llvm/Analysis/InstructionSimplify.h"
19	#include "llvm/Analysis/ValueTracking.h"
20	#include "llvm/IR/Constant.h"
21	#include "llvm/IR/Constants.h"
22	#include "llvm/IR/InstrTypes.h"
23	#include "llvm/IR/Instruction.h"
24	#include "llvm/IR/Instructions.h"
25	#include "llvm/IR/Operator.h"
26	#include "llvm/IR/PatternMatch.h"
27	#include "llvm/IR/Type.h"
28	#include "llvm/IR/Value.h"
29	#include "llvm/Support/AlignOf.h"
30	#include "llvm/Support/Casting.h"
31	#include "llvm/Support/KnownBits.h"
32	#include "llvm/Transforms/InstCombine/InstCombiner.h"
33	#include <cassert>
34	#include <utility>
35
36	using namespace llvm;
37	using namespace PatternMatch;
38
39	#define DEBUG_TYPE "instcombine"
40
41	namespace {
42
43	/// Class representing coefficient of floating-point addend.
44	/// This class needs to be highly efficient, which is especially true for
45	/// the constructor. As of I write this comment, the cost of the default
46	/// constructor is merely 4-byte-store-zero (Assuming compiler is able to
47	/// perform write-merging).
48	///
49	class FAddendCoef {
50	public:
51	// The constructor has to initialize a APFloat, which is unnecessary for
52	// most addends which have coefficient either 1 or -1. So, the constructor
53	// is expensive. In order to avoid the cost of the constructor, we should
54	// reuse some instances whenever possible. The pre-created instances
55	// FAddCombine::Add[0-5] embodies this idea.
56	FAddendCoef() = default;
57	~FAddendCoef();
58
59	// If possible, don't define operator+/operator- etc because these
60	// operators inevitably call FAddendCoef's constructor which is not cheap.
61	void operator=(const FAddendCoef &A);
62	void operator+=(const FAddendCoef &A);
63	void operator*=(const FAddendCoef &S);
64
65	void set(short C) {
66	assert(!insaneIntVal(C) && "Insane coefficient");
67	IsFp = false; IntVal = C;
68	}
69
70	void set(const APFloat& C);
71
72	void negate();
73
74	bool isZero() const { return isInt() ? !IntVal : getFpVal().isZero(); }
75	Value *getValue(Type *) const;
76
77	bool isOne() const { return isInt() && IntVal == 1; }
78	bool isTwo() const { return isInt() && IntVal == 2; }
79	bool isMinusOne() const { return isInt() && IntVal == -1; }
80	bool isMinusTwo() const { return isInt() && IntVal == -2; }
81
82	private:
83	bool insaneIntVal(int V) { return V > 4 || V < -4; }
84
85	APFloat *getFpValPtr() { return reinterpret_cast<APFloat *>(&FpValBuf); }
86
87	const APFloat *getFpValPtr() const {
88	return reinterpret_cast<const APFloat *>(&FpValBuf);
89	}
90
91	const APFloat &getFpVal() const {
92	assert(IsFp && BufHasFpVal && "Incorret state");
93	return *getFpValPtr();
94	}
95
96	APFloat &getFpVal() {
97	assert(IsFp && BufHasFpVal && "Incorret state");
98	return *getFpValPtr();
99	}
100
101	bool isInt() const { return !IsFp; }
102
103	// If the coefficient is represented by an integer, promote it to a
104	// floating point.
105	void convertToFpType(const fltSemantics &Sem);
106
107	// Construct an APFloat from a signed integer.
108	// TODO: We should get rid of this function when APFloat can be constructed
109	// from an *SIGNED* integer.
110	APFloat createAPFloatFromInt(const fltSemantics &Sem, int Val);
111
112	bool IsFp = false;
113
114	// True iff FpValBuf contains an instance of APFloat.
115	bool BufHasFpVal = false;
116
117	// The integer coefficient of an individual addend is either 1 or -1,
118	// and we try to simplify at most 4 addends from neighboring at most
119	// two instructions. So the range of <IntVal> falls in [-4, 4]. APInt
120	// is overkill of this end.
121	short IntVal = 0;
122
123	AlignedCharArrayUnion<APFloat> FpValBuf;
124	};
125
126	/// FAddend is used to represent floating-point addend. An addend is
127	/// represented as <C, V>, where the V is a symbolic value, and C is a
128	/// constant coefficient. A constant addend is represented as <C, 0>.
129	class FAddend {
130	public:
131	FAddend() = default;
132
133	void operator+=(const FAddend &T) {
134	assert((Val == T.Val) && "Symbolic-values disagree");
135	Coeff += T.Coeff;
136	}
137
138	Value *getSymVal() const { return Val; }
139	const FAddendCoef &getCoef() const { return Coeff; }
140
141	bool isConstant() const { return Val == nullptr; }
142	bool isZero() const { return Coeff.isZero(); }
143
144	void set(short Coefficient, Value *V) {
145	Coeff.set(Coefficient);
146	Val = V;
147	}
148	void set(const APFloat &Coefficient, Value *V) {
149	Coeff.set(Coefficient);
150	Val = V;
151	}
152	void set(const ConstantFP *Coefficient, Value *V) {
153	Coeff.set(Coefficient->getValueAPF());
154	Val = V;
155	}
156
157	void negate() { Coeff.negate(); }
158
159	/// Drill down the U-D chain one step to find the definition of V, and
160	/// try to break the definition into one or two addends.
161	static unsigned drillValueDownOneStep(Value* V, FAddend &A0, FAddend &A1);
162
163	/// Similar to FAddend::drillDownOneStep() except that the value being
164	/// splitted is the addend itself.
165	unsigned drillAddendDownOneStep(FAddend &Addend0, FAddend &Addend1) const;
166
167	private:
168	void Scale(const FAddendCoef& ScaleAmt) { Coeff *= ScaleAmt; }
169
170	// This addend has the value of "Coeff * Val".
171	Value *Val = nullptr;
172	FAddendCoef Coeff;
173	};
174
175	/// FAddCombine is the class for optimizing an unsafe fadd/fsub along
176	/// with its neighboring at most two instructions.
177	///
178	class FAddCombine {
179	public:
180	FAddCombine(InstCombiner::BuilderTy &B) : Builder(B) {}
181
182	Value *simplify(Instruction *FAdd);
183
184	private:
185	using AddendVect = SmallVector<const FAddend *, 4>;
186
187	Value *simplifyFAdd(AddendVect& V, unsigned InstrQuota);
188
189	/// Convert given addend to a Value
190	Value *createAddendVal(const FAddend &A, bool& NeedNeg);
191
192	/// Return the number of instructions needed to emit the N-ary addition.
193	unsigned calcInstrNumber(const AddendVect& Vect);
194
195	Value *createFSub(Value *Opnd0, Value *Opnd1);
196	Value *createFAdd(Value *Opnd0, Value *Opnd1);
197	Value *createFMul(Value *Opnd0, Value *Opnd1);
198	Value *createFNeg(Value *V);
199	Value *createNaryFAdd(const AddendVect& Opnds, unsigned InstrQuota);
200	void createInstPostProc(Instruction *NewInst, bool NoNumber = false);
201
202	// Debugging stuff are clustered here.
203	#ifndef NDEBUG
204	unsigned CreateInstrNum;
205	void initCreateInstNum() { CreateInstrNum = 0; }
206	void incCreateInstNum() { CreateInstrNum++; }
207	#else
208	void initCreateInstNum() {}
209	void incCreateInstNum() {}
210	#endif
211
212	InstCombiner::BuilderTy &Builder;
213	Instruction *Instr = nullptr;
214	};
215
216	} // end anonymous namespace
217
218	//===----------------------------------------------------------------------===//
219	//
220	// Implementation of
221	// {FAddendCoef, FAddend, FAddition, FAddCombine}.
222	//
223	//===----------------------------------------------------------------------===//
224	FAddendCoef::~FAddendCoef() {
225	if (BufHasFpVal)
226	getFpValPtr()->~APFloat();
227	}
228
229	void FAddendCoef::set(const APFloat& C) {
230	APFloat *P = getFpValPtr();
231
232	if (isInt()) {
233	// As the buffer is meanless byte stream, we cannot call
234	// APFloat::operator=().
235	new(P) APFloat(C);
236	} else
237	*P = C;
238
239	IsFp = BufHasFpVal = true;
240	}
241
242	void FAddendCoef::convertToFpType(const fltSemantics &Sem) {
243	if (!isInt())
244	return;
245
246	APFloat *P = getFpValPtr();
247	if (IntVal > 0)
248	new(P) APFloat(Sem, IntVal);
249	else {
250	new(P) APFloat(Sem, 0 - IntVal);
251	P->changeSign();
252	}
253	IsFp = BufHasFpVal = true;
254	}
255
256	APFloat FAddendCoef::createAPFloatFromInt(const fltSemantics &Sem, int Val) {
257	if (Val >= 0)
258	return APFloat(Sem, Val);
259
260	APFloat T(Sem, 0 - Val);
261	T.changeSign();
262
263	return T;
264	}
265
266	void FAddendCoef::operator=(const FAddendCoef &That) {
267	if (That.isInt())
268	set(That.IntVal);
269	else
270	set(That.getFpVal());
271	}
272
273	void FAddendCoef::operator+=(const FAddendCoef &That) {
274	RoundingMode RndMode = RoundingMode::NearestTiesToEven;
275	if (isInt() == That.isInt()) {
276	if (isInt())
277	IntVal += That.IntVal;
278	else
279	getFpVal().add(RHS: That.getFpVal(), RM: RndMode);
280	return;
281	}
282
283	if (isInt()) {
284	const APFloat &T = That.getFpVal();
285	convertToFpType(Sem: T.getSemantics());
286	getFpVal().add(RHS: T, RM: RndMode);
287	return;
288	}
289
290	APFloat &T = getFpVal();
291	T.add(RHS: createAPFloatFromInt(Sem: T.getSemantics(), Val: That.IntVal), RM: RndMode);
292	}
293
294	void FAddendCoef::operator*=(const FAddendCoef &That) {
295	if (That.isOne())
296	return;
297
298	if (That.isMinusOne()) {
299	negate();
300	return;
301	}
302
303	if (isInt() && That.isInt()) {
304	int Res = IntVal * (int)That.IntVal;
305	assert(!insaneIntVal(Res) && "Insane int value");
306	IntVal = Res;
307	return;
308	}
309
310	const fltSemantics &Semantic =
311	isInt() ? That.getFpVal().getSemantics() : getFpVal().getSemantics();
312
313	if (isInt())
314	convertToFpType(Sem: Semantic);
315	APFloat &F0 = getFpVal();
316
317	if (That.isInt())
318	F0.multiply(RHS: createAPFloatFromInt(Sem: Semantic, Val: That.IntVal),
319	RM: APFloat::rmNearestTiesToEven);
320	else
321	F0.multiply(RHS: That.getFpVal(), RM: APFloat::rmNearestTiesToEven);
322	}
323
324	void FAddendCoef::negate() {
325	if (isInt())
326	IntVal = 0 - IntVal;
327	else
328	getFpVal().changeSign();
329	}
330
331	Value *FAddendCoef::getValue(Type *Ty) const {
332	return isInt() ?
333	ConstantFP::get(Ty, V: float(IntVal)) :
334	ConstantFP::get(Context&: Ty->getContext(), V: getFpVal());
335	}
336
337	// The definition of <Val> Addends
338	// =========================================
339	// A + B <1, A>, <1,B>
340	// A - B <1, A>, <1,B>
341	// 0 - B <-1, B>
342	// C * A, <C, A>
343	// A + C <1, A> <C, NULL>
344	// 0 +/- 0 <0, NULL> (corner case)
345	//
346	// Legend: A and B are not constant, C is constant
347	unsigned FAddend::drillValueDownOneStep
348	(Value *Val, FAddend &Addend0, FAddend &Addend1) {
349	Instruction *I = nullptr;
350	if (!Val || !(I = dyn_cast<Instruction>(Val)))
351	return 0;
352
353	unsigned Opcode = I->getOpcode();
354
355	if (Opcode == Instruction::FAdd || Opcode == Instruction::FSub) {
356	ConstantFP *C0, *C1;
357	Value *Opnd0 = I->getOperand(i: 0);
358	Value *Opnd1 = I->getOperand(i: 1);
359	if ((C0 = dyn_cast<ConstantFP>(Val: Opnd0)) && C0->isZero())
360	Opnd0 = nullptr;
361
362	if ((C1 = dyn_cast<ConstantFP>(Val: Opnd1)) && C1->isZero())
363	Opnd1 = nullptr;
364
365	if (Opnd0) {
366	if (!C0)
367	Addend0.set(Coefficient: 1, V: Opnd0);
368	else
369	Addend0.set(Coefficient: C0, V: nullptr);
370	}
371
372	if (Opnd1) {
373	FAddend &Addend = Opnd0 ? Addend1 : Addend0;
374	if (!C1)
375	Addend.set(Coefficient: 1, V: Opnd1);
376	else
377	Addend.set(Coefficient: C1, V: nullptr);
378	if (Opcode == Instruction::FSub)
379	Addend.negate();
380	}
381
382	if (Opnd0 || Opnd1)
383	return Opnd0 && Opnd1 ? 2 : 1;
384
385	// Both operands are zero. Weird!
386	Addend0.set(Coefficient: APFloat(C0->getValueAPF().getSemantics()), V: nullptr);
387	return 1;
388	}
389
390	if (I->getOpcode() == Instruction::FMul) {
391	Value *V0 = I->getOperand(i: 0);
392	Value *V1 = I->getOperand(i: 1);
393	if (ConstantFP *C = dyn_cast<ConstantFP>(Val: V0)) {
394	Addend0.set(Coefficient: C, V: V1);
395	return 1;
396	}
397
398	if (ConstantFP *C = dyn_cast<ConstantFP>(Val: V1)) {
399	Addend0.set(Coefficient: C, V: V0);
400	return 1;
401	}
402	}
403
404	return 0;
405	}
406
407	// Try to break *this* addend into two addends. e.g. Suppose this addend is
408	// <2.3, V>, and V = X + Y, by calling this function, we obtain two addends,
409	// i.e. <2.3, X> and <2.3, Y>.
410	unsigned FAddend::drillAddendDownOneStep
411	(FAddend &Addend0, FAddend &Addend1) const {
412	if (isConstant())
413	return 0;
414
415	unsigned BreakNum = FAddend::drillValueDownOneStep(Val, Addend0, Addend1);
416	if (!BreakNum || Coeff.isOne())
417	return BreakNum;
418
419	Addend0.Scale(ScaleAmt: Coeff);
420
421	if (BreakNum == 2)
422	Addend1.Scale(ScaleAmt: Coeff);
423
424	return BreakNum;
425	}
426
427	Value *FAddCombine::simplify(Instruction *I) {
428	assert(I->hasAllowReassoc() && I->hasNoSignedZeros() &&
429	"Expected 'reassoc'+'nsz' instruction");
430
431	// Currently we are not able to handle vector type.
432	if (I->getType()->isVectorTy())
433	return nullptr;
434
435	assert((I->getOpcode() == Instruction::FAdd ||
436	I->getOpcode() == Instruction::FSub) && "Expect add/sub");
437
438	// Save the instruction before calling other member-functions.
439	Instr = I;
440
441	FAddend Opnd0, Opnd1, Opnd0_0, Opnd0_1, Opnd1_0, Opnd1_1;
442
443	unsigned OpndNum = FAddend::drillValueDownOneStep(Val: I, Addend0&: Opnd0, Addend1&: Opnd1);
444
445	// Step 1: Expand the 1st addend into Opnd0_0 and Opnd0_1.
446	unsigned Opnd0_ExpNum = 0;
447	unsigned Opnd1_ExpNum = 0;
448
449	if (!Opnd0.isConstant())
450	Opnd0_ExpNum = Opnd0.drillAddendDownOneStep(Addend0&: Opnd0_0, Addend1&: Opnd0_1);
451
452	// Step 2: Expand the 2nd addend into Opnd1_0 and Opnd1_1.
453	if (OpndNum == 2 && !Opnd1.isConstant())
454	Opnd1_ExpNum = Opnd1.drillAddendDownOneStep(Addend0&: Opnd1_0, Addend1&: Opnd1_1);
455
456	// Step 3: Try to optimize Opnd0_0 + Opnd0_1 + Opnd1_0 + Opnd1_1
457	if (Opnd0_ExpNum && Opnd1_ExpNum) {
458	AddendVect AllOpnds;
459	AllOpnds.push_back(Elt: &Opnd0_0);
460	AllOpnds.push_back(Elt: &Opnd1_0);
461	if (Opnd0_ExpNum == 2)
462	AllOpnds.push_back(Elt: &Opnd0_1);
463	if (Opnd1_ExpNum == 2)
464	AllOpnds.push_back(Elt: &Opnd1_1);
465
466	// Compute instruction quota. We should save at least one instruction.
467	unsigned InstQuota = 0;
468
469	Value *V0 = I->getOperand(i: 0);
470	Value *V1 = I->getOperand(i: 1);
471	InstQuota = ((!isa<Constant>(Val: V0) && V0->hasOneUse()) &&
472	(!isa<Constant>(Val: V1) && V1->hasOneUse())) ? 2 : 1;
473
474	if (Value *R = simplifyFAdd(V&: AllOpnds, InstrQuota: InstQuota))
475	return R;
476	}
477
478	if (OpndNum != 2) {
479	// The input instruction is : "I=0.0 +/- V". If the "V" were able to be
480	// splitted into two addends, say "V = X - Y", the instruction would have
481	// been optimized into "I = Y - X" in the previous steps.
482	//
483	const FAddendCoef &CE = Opnd0.getCoef();
484	return CE.isOne() ? Opnd0.getSymVal() : nullptr;
485	}
486
487	// step 4: Try to optimize Opnd0 + Opnd1_0 [+ Opnd1_1]
488	if (Opnd1_ExpNum) {
489	AddendVect AllOpnds;
490	AllOpnds.push_back(Elt: &Opnd0);
491	AllOpnds.push_back(Elt: &Opnd1_0);
492	if (Opnd1_ExpNum == 2)
493	AllOpnds.push_back(Elt: &Opnd1_1);
494
495	if (Value *R = simplifyFAdd(V&: AllOpnds, InstrQuota: 1))
496	return R;
497	}
498
499	// step 5: Try to optimize Opnd1 + Opnd0_0 [+ Opnd0_1]
500	if (Opnd0_ExpNum) {
501	AddendVect AllOpnds;
502	AllOpnds.push_back(Elt: &Opnd1);
503	AllOpnds.push_back(Elt: &Opnd0_0);
504	if (Opnd0_ExpNum == 2)
505	AllOpnds.push_back(Elt: &Opnd0_1);
506
507	if (Value *R = simplifyFAdd(V&: AllOpnds, InstrQuota: 1))
508	return R;
509	}
510
511	return nullptr;
512	}
513
514	Value *FAddCombine::simplifyFAdd(AddendVect& Addends, unsigned InstrQuota) {
515	unsigned AddendNum = Addends.size();
516	assert(AddendNum <= 4 && "Too many addends");
517
518	// For saving intermediate results;
519	unsigned NextTmpIdx = 0;
520	FAddend TmpResult[3];
521
522	// Simplified addends are placed <SimpVect>.
523	AddendVect SimpVect;
524
525	// The outer loop works on one symbolic-value at a time. Suppose the input
526	// addends are : <a1, x>, <b1, y>, <a2, x>, <c1, z>, <b2, y>, ...
527	// The symbolic-values will be processed in this order: x, y, z.
528	for (unsigned SymIdx = 0; SymIdx < AddendNum; SymIdx++) {
529
530	const FAddend *ThisAddend = Addends[SymIdx];
531	if (!ThisAddend) {
532	// This addend was processed before.
533	continue;
534	}
535
536	Value *Val = ThisAddend->getSymVal();
537
538	// If the resulting expr has constant-addend, this constant-addend is
539	// desirable to reside at the top of the resulting expression tree. Placing
540	// constant close to super-expr(s) will potentially reveal some
541	// optimization opportunities in super-expr(s). Here we do not implement
542	// this logic intentionally and rely on SimplifyAssociativeOrCommutative
543	// call later.
544
545	unsigned StartIdx = SimpVect.size();
546	SimpVect.push_back(Elt: ThisAddend);
547
548	// The inner loop collects addends sharing same symbolic-value, and these
549	// addends will be later on folded into a single addend. Following above
550	// example, if the symbolic value "y" is being processed, the inner loop
551	// will collect two addends "<b1,y>" and "<b2,Y>". These two addends will
552	// be later on folded into "<b1+b2, y>".
553	for (unsigned SameSymIdx = SymIdx + 1;
554	SameSymIdx < AddendNum; SameSymIdx++) {
555	const FAddend *T = Addends[SameSymIdx];
556	if (T && T->getSymVal() == Val) {
557	// Set null such that next iteration of the outer loop will not process
558	// this addend again.
559	Addends[SameSymIdx] = nullptr;
560	SimpVect.push_back(Elt: T);
561	}
562	}
563
564	// If multiple addends share same symbolic value, fold them together.
565	if (StartIdx + 1 != SimpVect.size()) {
566	FAddend &R = TmpResult[NextTmpIdx ++];
567	R = *SimpVect[StartIdx];
568	for (unsigned Idx = StartIdx + 1; Idx < SimpVect.size(); Idx++)
569	R += *SimpVect[Idx];
570
571	// Pop all addends being folded and push the resulting folded addend.
572	SimpVect.resize(N: StartIdx);
573	if (!R.isZero()) {
574	SimpVect.push_back(Elt: &R);
575	}
576	}
577	}
578
579	assert((NextTmpIdx <= std::size(TmpResult) + 1) && "out-of-bound access");
580
581	Value *Result;
582	if (!SimpVect.empty())
583	Result = createNaryFAdd(Opnds: SimpVect, InstrQuota);
584	else {
585	// The addition is folded to 0.0.
586	Result = ConstantFP::get(Ty: Instr->getType(), V: 0.0);
587	}
588
589	return Result;
590	}
591
592	Value *FAddCombine::createNaryFAdd
593	(const AddendVect &Opnds, unsigned InstrQuota) {
594	assert(!Opnds.empty() && "Expect at least one addend");
595
596	// Step 1: Check if the # of instructions needed exceeds the quota.
597
598	unsigned InstrNeeded = calcInstrNumber(Vect: Opnds);
599	if (InstrNeeded > InstrQuota)
600	return nullptr;
601
602	initCreateInstNum();
603
604	// step 2: Emit the N-ary addition.
605	// Note that at most three instructions are involved in Fadd-InstCombine: the
606	// addition in question, and at most two neighboring instructions.
607	// The resulting optimized addition should have at least one less instruction
608	// than the original addition expression tree. This implies that the resulting
609	// N-ary addition has at most two instructions, and we don't need to worry
610	// about tree-height when constructing the N-ary addition.
611
612	Value *LastVal = nullptr;
613	bool LastValNeedNeg = false;
614
615	// Iterate the addends, creating fadd/fsub using adjacent two addends.
616	for (const FAddend *Opnd : Opnds) {
617	bool NeedNeg;
618	Value *V = createAddendVal(A: *Opnd, NeedNeg);
619	if (!LastVal) {
620	LastVal = V;
621	LastValNeedNeg = NeedNeg;
622	continue;
623	}
624
625	if (LastValNeedNeg == NeedNeg) {
626	LastVal = createFAdd(Opnd0: LastVal, Opnd1: V);
627	continue;
628	}
629
630	if (LastValNeedNeg)
631	LastVal = createFSub(Opnd0: V, Opnd1: LastVal);
632	else
633	LastVal = createFSub(Opnd0: LastVal, Opnd1: V);
634
635	LastValNeedNeg = false;
636	}
637
638	if (LastValNeedNeg) {
639	LastVal = createFNeg(V: LastVal);
640	}
641
642	#ifndef NDEBUG
643	assert(CreateInstrNum == InstrNeeded &&
644	"Inconsistent in instruction numbers");
645	#endif
646
647	return LastVal;
648	}
649
650	Value *FAddCombine::createFSub(Value *Opnd0, Value *Opnd1) {
651	Value *V = Builder.CreateFSub(L: Opnd0, R: Opnd1);
652	if (Instruction *I = dyn_cast<Instruction>(Val: V))
653	createInstPostProc(NewInst: I);
654	return V;
655	}
656
657	Value *FAddCombine::createFNeg(Value *V) {
658	Value *NewV = Builder.CreateFNeg(V);
659	if (Instruction *I = dyn_cast<Instruction>(Val: NewV))
660	createInstPostProc(NewInst: I, NoNumber: true); // fneg's don't receive instruction numbers.
661	return NewV;
662	}
663
664	Value *FAddCombine::createFAdd(Value *Opnd0, Value *Opnd1) {
665	Value *V = Builder.CreateFAdd(L: Opnd0, R: Opnd1);
666	if (Instruction *I = dyn_cast<Instruction>(Val: V))
667	createInstPostProc(NewInst: I);
668	return V;
669	}
670
671	Value *FAddCombine::createFMul(Value *Opnd0, Value *Opnd1) {
672	Value *V = Builder.CreateFMul(L: Opnd0, R: Opnd1);
673	if (Instruction *I = dyn_cast<Instruction>(Val: V))
674	createInstPostProc(NewInst: I);
675	return V;
676	}
677
678	void FAddCombine::createInstPostProc(Instruction *NewInstr, bool NoNumber) {
679	NewInstr->setDebugLoc(Instr->getDebugLoc());
680
681	// Keep track of the number of instruction created.
682	if (!NoNumber)
683	incCreateInstNum();
684
685	// Propagate fast-math flags
686	NewInstr->setFastMathFlags(Instr->getFastMathFlags());
687	}
688
689	// Return the number of instruction needed to emit the N-ary addition.
690	// NOTE: Keep this function in sync with createAddendVal().
691	unsigned FAddCombine::calcInstrNumber(const AddendVect &Opnds) {
692	unsigned OpndNum = Opnds.size();
693	unsigned InstrNeeded = OpndNum - 1;
694
695	// Adjust the number of instructions needed to emit the N-ary add.
696	for (const FAddend *Opnd : Opnds) {
697	if (Opnd->isConstant())
698	continue;
699
700	// The constant check above is really for a few special constant
701	// coefficients.
702	if (isa<UndefValue>(Val: Opnd->getSymVal()))
703	continue;
704
705	const FAddendCoef &CE = Opnd->getCoef();
706	// Let the addend be "c * x". If "c == +/-1", the value of the addend
707	// is immediately available; otherwise, it needs exactly one instruction
708	// to evaluate the value.
709	if (!CE.isMinusOne() && !CE.isOne())
710	InstrNeeded++;
711	}
712	return InstrNeeded;
713	}
714
715	// Input Addend Value NeedNeg(output)
716	// ================================================================
717	// Constant C C false
718	// <+/-1, V> V coefficient is -1
719	// <2/-2, V> "fadd V, V" coefficient is -2
720	// <C, V> "fmul V, C" false
721	//
722	// NOTE: Keep this function in sync with FAddCombine::calcInstrNumber.
723	Value *FAddCombine::createAddendVal(const FAddend &Opnd, bool &NeedNeg) {
724	const FAddendCoef &Coeff = Opnd.getCoef();
725
726	if (Opnd.isConstant()) {
727	NeedNeg = false;
728	return Coeff.getValue(Ty: Instr->getType());
729	}
730
731	Value *OpndVal = Opnd.getSymVal();
732
733	if (Coeff.isMinusOne() || Coeff.isOne()) {
734	NeedNeg = Coeff.isMinusOne();
735	return OpndVal;
736	}
737
738	if (Coeff.isTwo() || Coeff.isMinusTwo()) {
739	NeedNeg = Coeff.isMinusTwo();
740	return createFAdd(Opnd0: OpndVal, Opnd1: OpndVal);
741	}
742
743	NeedNeg = false;
744	return createFMul(Opnd0: OpndVal, Opnd1: Coeff.getValue(Ty: Instr->getType()));
745	}
746
747	// Checks if any operand is negative and we can convert add to sub.
748	// This function checks for following negative patterns
749	// ADD(XOR(OR(Z, NOT(C)), C)), 1) == NEG(AND(Z, C))
750	// ADD(XOR(AND(Z, C), C), 1) == NEG(OR(Z, ~C))
751	// XOR(AND(Z, C), (C + 1)) == NEG(OR(Z, ~C)) if C is even
752	static Value *checkForNegativeOperand(BinaryOperator &I,
753	InstCombiner::BuilderTy &Builder) {
754	Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
755
756	// This function creates 2 instructions to replace ADD, we need at least one
757	// of LHS or RHS to have one use to ensure benefit in transform.
758	if (!LHS->hasOneUse() && !RHS->hasOneUse())
759	return nullptr;
760
761	Value *X = nullptr, *Y = nullptr, *Z = nullptr;
762	const APInt *C1 = nullptr, *C2 = nullptr;
763
764	// if ONE is on other side, swap
765	if (match(V: RHS, P: m_Add(L: m_Value(V&: X), R: m_One())))
766	std::swap(a&: LHS, b&: RHS);
767
768	if (match(V: LHS, P: m_Add(L: m_Value(V&: X), R: m_One()))) {
769	// if XOR on other side, swap
770	if (match(V: RHS, P: m_Xor(L: m_Value(V&: Y), R: m_APInt(Res&: C1))))
771	std::swap(a&: X, b&: RHS);
772
773	if (match(V: X, P: m_Xor(L: m_Value(V&: Y), R: m_APInt(Res&: C1)))) {
774	// X = XOR(Y, C1), Y = OR(Z, C2), C2 = NOT(C1) ==> X == NOT(AND(Z, C1))
775	// ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, AND(Z, C1))
776	if (match(V: Y, P: m_Or(L: m_Value(V&: Z), R: m_APInt(Res&: C2))) && (*C2 == ~(*C1))) {
777	Value *NewAnd = Builder.CreateAnd(LHS: Z, RHS: *C1);
778	return Builder.CreateSub(LHS: RHS, RHS: NewAnd, Name: "sub");
779	} else if (match(V: Y, P: m_And(L: m_Value(V&: Z), R: m_APInt(Res&: C2))) && (*C1 == *C2)) {
780	// X = XOR(Y, C1), Y = AND(Z, C2), C2 == C1 ==> X == NOT(OR(Z, ~C1))
781	// ADD(ADD(X, 1), RHS) == ADD(X, ADD(RHS, 1)) == SUB(RHS, OR(Z, ~C1))
782	Value *NewOr = Builder.CreateOr(LHS: Z, RHS: ~(*C1));
783	return Builder.CreateSub(LHS: RHS, RHS: NewOr, Name: "sub");
784	}
785	}
786	}
787
788	// Restore LHS and RHS
789	LHS = I.getOperand(i_nocapture: 0);
790	RHS = I.getOperand(i_nocapture: 1);
791
792	// if XOR is on other side, swap
793	if (match(V: RHS, P: m_Xor(L: m_Value(V&: Y), R: m_APInt(Res&: C1))))
794	std::swap(a&: LHS, b&: RHS);
795
796	// C2 is ODD
797	// LHS = XOR(Y, C1), Y = AND(Z, C2), C1 == (C2 + 1) => LHS == NEG(OR(Z, ~C2))
798	// ADD(LHS, RHS) == SUB(RHS, OR(Z, ~C2))
799	if (match(V: LHS, P: m_Xor(L: m_Value(V&: Y), R: m_APInt(Res&: C1))))
800	if (C1->countr_zero() == 0)
801	if (match(V: Y, P: m_And(L: m_Value(V&: Z), R: m_APInt(Res&: C2))) && *C1 == (*C2 + 1)) {
802	Value *NewOr = Builder.CreateOr(LHS: Z, RHS: ~(*C2));
803	return Builder.CreateSub(LHS: RHS, RHS: NewOr, Name: "sub");
804	}
805	return nullptr;
806	}
807
808	/// Wrapping flags may allow combining constants separated by an extend.
809	static Instruction *foldNoWrapAdd(BinaryOperator &Add,
810	InstCombiner::BuilderTy &Builder) {
811	Value *Op0 = Add.getOperand(i_nocapture: 0), *Op1 = Add.getOperand(i_nocapture: 1);
812	Type *Ty = Add.getType();
813	Constant *Op1C;
814	if (!match(V: Op1, P: m_Constant(C&: Op1C)))
815	return nullptr;
816
817	// Try this match first because it results in an add in the narrow type.
818	// (zext (X +nuw C2)) + C1 --> zext (X + (C2 + trunc(C1)))
819	Value *X;
820	const APInt *C1, *C2;
821	if (match(V: Op1, P: m_APInt(Res&: C1)) &&
822	match(V: Op0, P: m_OneUse(SubPattern: m_ZExt(Op: m_NUWAddLike(L: m_Value(V&: X), R: m_APInt(Res&: C2))))) &&
823	C1->isNegative() && C1->sge(RHS: -C2->sext(width: C1->getBitWidth()))) {
824	Constant *NewC =
825	ConstantInt::get(Ty: X->getType(), V: *C2 + C1->trunc(width: C2->getBitWidth()));
826	return new ZExtInst(Builder.CreateNUWAdd(LHS: X, RHS: NewC), Ty);
827	}
828
829	// More general combining of constants in the wide type.
830	// (sext (X +nsw NarrowC)) + C --> (sext X) + (sext(NarrowC) + C)
831	// or (zext nneg (X +nsw NarrowC)) + C --> (sext X) + (sext(NarrowC) + C)
832	Constant *NarrowC;
833	if (match(V: Op0, P: m_OneUse(SubPattern: m_SExtLike(
834	Op: m_NSWAddLike(L: m_Value(V&: X), R: m_Constant(C&: NarrowC)))))) {
835	Value *WideC = Builder.CreateSExt(V: NarrowC, DestTy: Ty);
836	Value *NewC = Builder.CreateAdd(LHS: WideC, RHS: Op1C);
837	Value *WideX = Builder.CreateSExt(V: X, DestTy: Ty);
838	return BinaryOperator::CreateAdd(V1: WideX, V2: NewC);
839	}
840	// (zext (X +nuw NarrowC)) + C --> (zext X) + (zext(NarrowC) + C)
841	if (match(V: Op0,
842	P: m_OneUse(SubPattern: m_ZExt(Op: m_NUWAddLike(L: m_Value(V&: X), R: m_Constant(C&: NarrowC)))))) {
843	Value *WideC = Builder.CreateZExt(V: NarrowC, DestTy: Ty);
844	Value *NewC = Builder.CreateAdd(LHS: WideC, RHS: Op1C);
845	Value *WideX = Builder.CreateZExt(V: X, DestTy: Ty);
846	return BinaryOperator::CreateAdd(V1: WideX, V2: NewC);
847	}
848	return nullptr;
849	}
850
851	Instruction *InstCombinerImpl::foldAddWithConstant(BinaryOperator &Add) {
852	Value *Op0 = Add.getOperand(i_nocapture: 0), *Op1 = Add.getOperand(i_nocapture: 1);
853	Type *Ty = Add.getType();
854	Constant *Op1C;
855	if (!match(V: Op1, P: m_ImmConstant(C&: Op1C)))
856	return nullptr;
857
858	if (Instruction *NV = foldBinOpIntoSelectOrPhi(I&: Add))
859	return NV;
860
861	Value *X;
862	Constant *Op00C;
863
864	// add (sub C1, X), C2 --> sub (add C1, C2), X
865	if (match(V: Op0, P: m_Sub(L: m_Constant(C&: Op00C), R: m_Value(V&: X))))
866	return BinaryOperator::CreateSub(V1: ConstantExpr::getAdd(C1: Op00C, C2: Op1C), V2: X);
867
868	Value *Y;
869
870	// add (sub X, Y), -1 --> add (not Y), X
871	if (match(V: Op0, P: m_OneUse(SubPattern: m_Sub(L: m_Value(V&: X), R: m_Value(V&: Y)))) &&
872	match(V: Op1, P: m_AllOnes()))
873	return BinaryOperator::CreateAdd(V1: Builder.CreateNot(V: Y), V2: X);
874
875	// zext(bool) + C -> bool ? C + 1 : C
876	if (match(V: Op0, P: m_ZExt(Op: m_Value(V&: X))) &&
877	X->getType()->getScalarSizeInBits() == 1)
878	return SelectInst::Create(C: X, S1: InstCombiner::AddOne(C: Op1C), S2: Op1);
879	// sext(bool) + C -> bool ? C - 1 : C
880	if (match(V: Op0, P: m_SExt(Op: m_Value(V&: X))) &&
881	X->getType()->getScalarSizeInBits() == 1)
882	return SelectInst::Create(C: X, S1: InstCombiner::SubOne(C: Op1C), S2: Op1);
883
884	// ~X + C --> (C-1) - X
885	if (match(V: Op0, P: m_Not(V: m_Value(V&: X)))) {
886	// ~X + C has NSW and (C-1) won't oveflow => (C-1)-X can have NSW
887	auto *COne = ConstantInt::get(Ty: Op1C->getType(), V: 1);
888	bool WillNotSOV = willNotOverflowSignedSub(LHS: Op1C, RHS: COne, CxtI: Add);
889	BinaryOperator *Res =
890	BinaryOperator::CreateSub(V1: ConstantExpr::getSub(C1: Op1C, C2: COne), V2: X);
891	Res->setHasNoSignedWrap(Add.hasNoSignedWrap() && WillNotSOV);
892	return Res;
893	}
894
895	// (iN X s>> (N - 1)) + 1 --> zext (X > -1)
896	const APInt *C;
897	unsigned BitWidth = Ty->getScalarSizeInBits();
898	if (match(V: Op0, P: m_OneUse(SubPattern: m_AShr(L: m_Value(V&: X),
899	R: m_SpecificIntAllowPoison(V: BitWidth - 1)))) &&
900	match(V: Op1, P: m_One()))
901	return new ZExtInst(Builder.CreateIsNotNeg(Arg: X, Name: "isnotneg"), Ty);
902
903	if (!match(V: Op1, P: m_APInt(Res&: C)))
904	return nullptr;
905
906	// (X | Op01C) + Op1C --> X + (Op01C + Op1C) iff the `or` is actually an `add`
907	Constant *Op01C;
908	if (match(V: Op0, P: m_DisjointOr(L: m_Value(V&: X), R: m_ImmConstant(C&: Op01C))))
909	return BinaryOperator::CreateAdd(V1: X, V2: ConstantExpr::getAdd(C1: Op01C, C2: Op1C));
910
911	// (X | C2) + C --> (X | C2) ^ C2 iff (C2 == -C)
912	const APInt *C2;
913	if (match(V: Op0, P: m_Or(L: m_Value(), R: m_APInt(Res&: C2))) && *C2 == -*C)
914	return BinaryOperator::CreateXor(V1: Op0, V2: ConstantInt::get(Ty: Add.getType(), V: *C2));
915
916	if (C->isSignMask()) {
917	// If wrapping is not allowed, then the addition must set the sign bit:
918	// X + (signmask) --> X | signmask
919	if (Add.hasNoSignedWrap() || Add.hasNoUnsignedWrap())
920	return BinaryOperator::CreateOr(V1: Op0, V2: Op1);
921
922	// If wrapping is allowed, then the addition flips the sign bit of LHS:
923	// X + (signmask) --> X ^ signmask
924	return BinaryOperator::CreateXor(V1: Op0, V2: Op1);
925	}
926
927	// Is this add the last step in a convoluted sext?
928	// add(zext(xor i16 X, -32768), -32768) --> sext X
929	if (match(V: Op0, P: m_ZExt(Op: m_Xor(L: m_Value(V&: X), R: m_APInt(Res&: C2)))) &&
930	C2->isMinSignedValue() && C2->sext(width: Ty->getScalarSizeInBits()) == *C)
931	return CastInst::Create(Instruction::SExt, S: X, Ty);
932
933	if (match(V: Op0, P: m_Xor(L: m_Value(V&: X), R: m_APInt(Res&: C2)))) {
934	// (X ^ signmask) + C --> (X + (signmask ^ C))
935	if (C2->isSignMask())
936	return BinaryOperator::CreateAdd(V1: X, V2: ConstantInt::get(Ty, V: *C2 ^ *C));
937
938	// If X has no high-bits set above an xor mask:
939	// add (xor X, LowMaskC), C --> sub (LowMaskC + C), X
940	if (C2->isMask()) {
941	KnownBits LHSKnown = computeKnownBits(V: X, Depth: 0, CxtI: &Add);
942	if ((*C2 | LHSKnown.Zero).isAllOnes())
943	return BinaryOperator::CreateSub(V1: ConstantInt::get(Ty, V: *C2 + *C), V2: X);
944	}
945
946	// Look for a math+logic pattern that corresponds to sext-in-register of a
947	// value with cleared high bits. Convert that into a pair of shifts:
948	// add (xor X, 0x80), 0xF..F80 --> (X << ShAmtC) >>s ShAmtC
949	// add (xor X, 0xF..F80), 0x80 --> (X << ShAmtC) >>s ShAmtC
950	if (Op0->hasOneUse() && *C2 == -(*C)) {
951	unsigned BitWidth = Ty->getScalarSizeInBits();
952	unsigned ShAmt = 0;
953	if (C->isPowerOf2())
954	ShAmt = BitWidth - C->logBase2() - 1;
955	else if (C2->isPowerOf2())
956	ShAmt = BitWidth - C2->logBase2() - 1;
957	if (ShAmt && MaskedValueIsZero(V: X, Mask: APInt::getHighBitsSet(numBits: BitWidth, hiBitsSet: ShAmt),
958	Depth: 0, CxtI: &Add)) {
959	Constant *ShAmtC = ConstantInt::get(Ty, V: ShAmt);
960	Value *NewShl = Builder.CreateShl(LHS: X, RHS: ShAmtC, Name: "sext");
961	return BinaryOperator::CreateAShr(V1: NewShl, V2: ShAmtC);
962	}
963	}
964	}
965
966	if (C->isOne() && Op0->hasOneUse()) {
967	// add (sext i1 X), 1 --> zext (not X)
968	// TODO: The smallest IR representation is (select X, 0, 1), and that would
969	// not require the one-use check. But we need to remove a transform in
970	// visitSelect and make sure that IR value tracking for select is equal or
971	// better than for these ops.
972	if (match(V: Op0, P: m_SExt(Op: m_Value(V&: X))) &&
973	X->getType()->getScalarSizeInBits() == 1)
974	return new ZExtInst(Builder.CreateNot(V: X), Ty);
975
976	// Shifts and add used to flip and mask off the low bit:
977	// add (ashr (shl i32 X, 31), 31), 1 --> and (not X), 1
978	const APInt *C3;
979	if (match(V: Op0, P: m_AShr(L: m_Shl(L: m_Value(V&: X), R: m_APInt(Res&: C2)), R: m_APInt(Res&: C3))) &&
980	C2 == C3 && *C2 == Ty->getScalarSizeInBits() - 1) {
981	Value *NotX = Builder.CreateNot(V: X);
982	return BinaryOperator::CreateAnd(V1: NotX, V2: ConstantInt::get(Ty, V: 1));
983	}
984	}
985
986	// Fold (add (zext (add X, -1)), 1) -> (zext X) if X is non-zero.
987	// TODO: There's a general form for any constant on the outer add.
988	if (C->isOne()) {
989	if (match(V: Op0, P: m_ZExt(Op: m_Add(L: m_Value(V&: X), R: m_AllOnes())))) {
990	const SimplifyQuery Q = SQ.getWithInstruction(I: &Add);
991	if (llvm::isKnownNonZero(V: X, Q))
992	return new ZExtInst(X, Ty);
993	}
994	}
995
996	return nullptr;
997	}
998
999	// match variations of a^2 + 2*a*b + b^2
1000	//
1001	// to reuse the code between the FP and Int versions, the instruction OpCodes
1002	// and constant types have been turned into template parameters.
1003	//
1004	// Mul2Rhs: The constant to perform the multiplicative equivalent of X*2 with;
1005	// should be `m_SpecificFP(2.0)` for FP and `m_SpecificInt(1)` for Int
1006	// (we're matching `X<<1` instead of `X*2` for Int)
1007	template <bool FP, typename Mul2Rhs>
1008	static bool matchesSquareSum(BinaryOperator &I, Mul2Rhs M2Rhs, Value *&A,
1009	Value *&B) {
1010	constexpr unsigned MulOp = FP ? Instruction::FMul : Instruction::Mul;
1011	constexpr unsigned AddOp = FP ? Instruction::FAdd : Instruction::Add;
1012	constexpr unsigned Mul2Op = FP ? Instruction::FMul : Instruction::Shl;
1013
1014	// (a * a) + (((a * 2) + b) * b)
1015	if (match(&I, m_c_BinOp(
1016	AddOp, m_OneUse(SubPattern: m_BinOp(Opcode: MulOp, L: m_Value(V&: A), R: m_Deferred(V: A))),
1017	m_OneUse(m_BinOp(
1018	MulOp,
1019	m_c_BinOp(AddOp, m_BinOp(Mul2Op, m_Deferred(V: A), M2Rhs),
1020	m_Value(V&: B)),
1021	m_Deferred(V: B))))))
1022	return true;
1023
1024	// ((a * b) * 2) or ((a * 2) * b)
1025	// +
1026	// (a * a + b * b) or (b * b + a * a)
1027	return match(
1028	&I,
1029	m_c_BinOp(AddOp,
1030	m_CombineOr(
1031	m_OneUse(m_BinOp(
1032	Mul2Op, m_BinOp(Opcode: MulOp, L: m_Value(V&: A), R: m_Value(V&: B)), M2Rhs)),
1033	m_OneUse(m_BinOp(MulOp, m_BinOp(Mul2Op, m_Value(V&: A), M2Rhs),
1034	m_Value(V&: B)))),
1035	m_OneUse(SubPattern: m_c_BinOp(
1036	Opcode: AddOp, L: m_BinOp(Opcode: MulOp, L: m_Deferred(V: A), R: m_Deferred(V: A)),
1037	R: m_BinOp(Opcode: MulOp, L: m_Deferred(V: B), R: m_Deferred(V: B))))));
1038	}
1039
1040	// Fold integer variations of a^2 + 2*a*b + b^2 -> (a + b)^2
1041	Instruction *InstCombinerImpl::foldSquareSumInt(BinaryOperator &I) {
1042	Value *A, *B;
1043	if (matchesSquareSum</*FP*/ false>(I, M2Rhs: m_SpecificInt(V: 1), A, B)) {
1044	Value *AB = Builder.CreateAdd(LHS: A, RHS: B);
1045	return BinaryOperator::CreateMul(V1: AB, V2: AB);
1046	}
1047	return nullptr;
1048	}
1049
1050	// Fold floating point variations of a^2 + 2*a*b + b^2 -> (a + b)^2
1051	// Requires `nsz` and `reassoc`.
1052	Instruction *InstCombinerImpl::foldSquareSumFP(BinaryOperator &I) {
1053	assert(I.hasAllowReassoc() && I.hasNoSignedZeros() && "Assumption mismatch");
1054	Value *A, *B;
1055	if (matchesSquareSum</*FP*/ true>(I, M2Rhs: m_SpecificFP(V: 2.0), A, B)) {
1056	Value *AB = Builder.CreateFAddFMF(L: A, R: B, FMFSource: &I);
1057	return BinaryOperator::CreateFMulFMF(V1: AB, V2: AB, FMFSource: &I);
1058	}
1059	return nullptr;
1060	}
1061
1062	// Matches multiplication expression Op * C where C is a constant. Returns the
1063	// constant value in C and the other operand in Op. Returns true if such a
1064	// match is found.
1065	static bool MatchMul(Value *E, Value *&Op, APInt &C) {
1066	const APInt *AI;
1067	if (match(V: E, P: m_Mul(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1068	C = *AI;
1069	return true;
1070	}
1071	if (match(V: E, P: m_Shl(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1072	C = APInt(AI->getBitWidth(), 1);
1073	C <<= *AI;
1074	return true;
1075	}
1076	return false;
1077	}
1078
1079	// Matches remainder expression Op % C where C is a constant. Returns the
1080	// constant value in C and the other operand in Op. Returns the signedness of
1081	// the remainder operation in IsSigned. Returns true if such a match is
1082	// found.
1083	static bool MatchRem(Value *E, Value *&Op, APInt &C, bool &IsSigned) {
1084	const APInt *AI;
1085	IsSigned = false;
1086	if (match(V: E, P: m_SRem(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1087	IsSigned = true;
1088	C = *AI;
1089	return true;
1090	}
1091	if (match(V: E, P: m_URem(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1092	C = *AI;
1093	return true;
1094	}
1095	if (match(V: E, P: m_And(L: m_Value(V&: Op), R: m_APInt(Res&: AI))) && (*AI + 1).isPowerOf2()) {
1096	C = *AI + 1;
1097	return true;
1098	}
1099	return false;
1100	}
1101
1102	// Matches division expression Op / C with the given signedness as indicated
1103	// by IsSigned, where C is a constant. Returns the constant value in C and the
1104	// other operand in Op. Returns true if such a match is found.
1105	static bool MatchDiv(Value *E, Value *&Op, APInt &C, bool IsSigned) {
1106	const APInt *AI;
1107	if (IsSigned && match(V: E, P: m_SDiv(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1108	C = *AI;
1109	return true;
1110	}
1111	if (!IsSigned) {
1112	if (match(V: E, P: m_UDiv(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1113	C = *AI;
1114	return true;
1115	}
1116	if (match(V: E, P: m_LShr(L: m_Value(V&: Op), R: m_APInt(Res&: AI)))) {
1117	C = APInt(AI->getBitWidth(), 1);
1118	C <<= *AI;
1119	return true;
1120	}
1121	}
1122	return false;
1123	}
1124
1125	// Returns whether C0 * C1 with the given signedness overflows.
1126	static bool MulWillOverflow(APInt &C0, APInt &C1, bool IsSigned) {
1127	bool overflow;
1128	if (IsSigned)
1129	(void)C0.smul_ov(RHS: C1, Overflow&: overflow);
1130	else
1131	(void)C0.umul_ov(RHS: C1, Overflow&: overflow);
1132	return overflow;
1133	}
1134
1135	// Simplifies X % C0 + (( X / C0 ) % C1) * C0 to X % (C0 * C1), where (C0 * C1)
1136	// does not overflow.
1137	// Simplifies (X / C0) * C1 + (X % C0) * C2 to
1138	// (X / C0) * (C1 - C2 * C0) + X * C2
1139	Value *InstCombinerImpl::SimplifyAddWithRemainder(BinaryOperator &I) {
1140	Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
1141	Value *X, *MulOpV;
1142	APInt C0, MulOpC;
1143	bool IsSigned;
1144	// Match I = X % C0 + MulOpV * C0
1145	if (((MatchRem(E: LHS, Op&: X, C&: C0, IsSigned) && MatchMul(E: RHS, Op&: MulOpV, C&: MulOpC)) ||
1146	(MatchRem(E: RHS, Op&: X, C&: C0, IsSigned) && MatchMul(E: LHS, Op&: MulOpV, C&: MulOpC))) &&
1147	C0 == MulOpC) {
1148	Value *RemOpV;
1149	APInt C1;
1150	bool Rem2IsSigned;
1151	// Match MulOpC = RemOpV % C1
1152	if (MatchRem(E: MulOpV, Op&: RemOpV, C&: C1, IsSigned&: Rem2IsSigned) &&
1153	IsSigned == Rem2IsSigned) {
1154	Value *DivOpV;
1155	APInt DivOpC;
1156	// Match RemOpV = X / C0
1157	if (MatchDiv(E: RemOpV, Op&: DivOpV, C&: DivOpC, IsSigned) && X == DivOpV &&
1158	C0 == DivOpC && !MulWillOverflow(C0, C1, IsSigned)) {
1159	Value *NewDivisor = ConstantInt::get(Ty: X->getType(), V: C0 * C1);
1160	return IsSigned ? Builder.CreateSRem(LHS: X, RHS: NewDivisor, Name: "srem")
1161	: Builder.CreateURem(LHS: X, RHS: NewDivisor, Name: "urem");
1162	}
1163	}
1164	}
1165
1166	// Match I = (X / C0) * C1 + (X % C0) * C2
1167	Value *Div, *Rem;
1168	APInt C1, C2;
1169	if (!LHS->hasOneUse() || !MatchMul(E: LHS, Op&: Div, C&: C1))
1170	Div = LHS, C1 = APInt(I.getType()->getScalarSizeInBits(), 1);
1171	if (!RHS->hasOneUse() || !MatchMul(E: RHS, Op&: Rem, C&: C2))
1172	Rem = RHS, C2 = APInt(I.getType()->getScalarSizeInBits(), 1);
1173	if (match(V: Div, P: m_IRem(L: m_Value(), R: m_Value()))) {
1174	std::swap(a&: Div, b&: Rem);
1175	std::swap(a&: C1, b&: C2);
1176	}
1177	Value *DivOpV;
1178	APInt DivOpC;
1179	if (MatchRem(E: Rem, Op&: X, C&: C0, IsSigned) &&
1180	MatchDiv(E: Div, Op&: DivOpV, C&: DivOpC, IsSigned) && X == DivOpV && C0 == DivOpC) {
1181	APInt NewC = C1 - C2 * C0;
1182	if (!NewC.isZero() && !Rem->hasOneUse())
1183	return nullptr;
1184	if (!isGuaranteedNotToBeUndef(V: X, AC: &AC, CtxI: &I, DT: &DT))
1185	return nullptr;
1186	Value *MulXC2 = Builder.CreateMul(LHS: X, RHS: ConstantInt::get(Ty: X->getType(), V: C2));
1187	if (NewC.isZero())
1188	return MulXC2;
1189	return Builder.CreateAdd(
1190	LHS: Builder.CreateMul(LHS: Div, RHS: ConstantInt::get(Ty: X->getType(), V: NewC)), RHS: MulXC2);
1191	}
1192
1193	return nullptr;
1194	}
1195
1196	/// Fold
1197	/// (1 << NBits) - 1
1198	/// Into:
1199	/// ~(-(1 << NBits))
1200	/// Because a 'not' is better for bit-tracking analysis and other transforms
1201	/// than an 'add'. The new shl is always nsw, and is nuw if old `and` was.
1202	static Instruction *canonicalizeLowbitMask(BinaryOperator &I,
1203	InstCombiner::BuilderTy &Builder) {
1204	Value *NBits;
1205	if (!match(V: &I, P: m_Add(L: m_OneUse(SubPattern: m_Shl(L: m_One(), R: m_Value(V&: NBits))), R: m_AllOnes())))
1206	return nullptr;
1207
1208	Constant *MinusOne = Constant::getAllOnesValue(Ty: NBits->getType());
1209	Value *NotMask = Builder.CreateShl(LHS: MinusOne, RHS: NBits, Name: "notmask");
1210	// Be wary of constant folding.
1211	if (auto *BOp = dyn_cast<BinaryOperator>(Val: NotMask)) {
1212	// Always NSW. But NUW propagates from `add`.
1213	BOp->setHasNoSignedWrap();
1214	BOp->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
1215	}
1216
1217	return BinaryOperator::CreateNot(Op: NotMask, Name: I.getName());
1218	}
1219
1220	static Instruction *foldToUnsignedSaturatedAdd(BinaryOperator &I) {
1221	assert(I.getOpcode() == Instruction::Add && "Expecting add instruction");
1222	Type *Ty = I.getType();
1223	auto getUAddSat = [&]() {
1224	return Intrinsic::getDeclaration(I.getModule(), Intrinsic::uadd_sat, Ty);
1225	};
1226
1227	// add (umin X, ~Y), Y --> uaddsat X, Y
1228	Value *X, *Y;
1229	if (match(V: &I, P: m_c_Add(L: m_c_UMin(L: m_Value(V&: X), R: m_Not(V: m_Value(V&: Y))),
1230	R: m_Deferred(V: Y))))
1231	return CallInst::Create(getUAddSat(), { X, Y });
1232
1233	// add (umin X, ~C), C --> uaddsat X, C
1234	const APInt *C, *NotC;
1235	if (match(V: &I, P: m_Add(L: m_UMin(L: m_Value(V&: X), R: m_APInt(Res&: NotC)), R: m_APInt(Res&: C))) &&
1236	*C == ~*NotC)
1237	return CallInst::Create(getUAddSat(), { X, ConstantInt::get(Ty, V: *C) });
1238
1239	return nullptr;
1240	}
1241
1242	// Transform:
1243	// (add A, (shl (neg B), Y))
1244	// -> (sub A, (shl B, Y))
1245	static Instruction *combineAddSubWithShlAddSub(InstCombiner::BuilderTy &Builder,
1246	const BinaryOperator &I) {
1247	Value *A, *B, *Cnt;
1248	if (match(V: &I,
1249	P: m_c_Add(L: m_OneUse(SubPattern: m_Shl(L: m_OneUse(SubPattern: m_Neg(V: m_Value(V&: B))), R: m_Value(V&: Cnt))),
1250	R: m_Value(V&: A)))) {
1251	Value *NewShl = Builder.CreateShl(LHS: B, RHS: Cnt);
1252	return BinaryOperator::CreateSub(V1: A, V2: NewShl);
1253	}
1254	return nullptr;
1255	}
1256
1257	/// Try to reduce signed division by power-of-2 to an arithmetic shift right.
1258	static Instruction *foldAddToAshr(BinaryOperator &Add) {
1259	// Division must be by power-of-2, but not the minimum signed value.
1260	Value *X;
1261	const APInt *DivC;
1262	if (!match(V: Add.getOperand(i_nocapture: 0), P: m_SDiv(L: m_Value(V&: X), R: m_Power2(V&: DivC))) ||
1263	DivC->isNegative())
1264	return nullptr;
1265
1266	// Rounding is done by adding -1 if the dividend (X) is negative and has any
1267	// low bits set. It recognizes two canonical patterns:
1268	// 1. For an 'ugt' cmp with the signed minimum value (SMIN), the
1269	// pattern is: sext (icmp ugt (X & (DivC - 1)), SMIN).
1270	// 2. For an 'eq' cmp, the pattern's: sext (icmp eq X & (SMIN + 1), SMIN + 1).
1271	// Note that, by the time we end up here, if possible, ugt has been
1272	// canonicalized into eq.
1273	const APInt *MaskC, *MaskCCmp;
1274	ICmpInst::Predicate Pred;
1275	if (!match(V: Add.getOperand(i_nocapture: 1),
1276	P: m_SExt(Op: m_ICmp(Pred, L: m_And(L: m_Specific(V: X), R: m_APInt(Res&: MaskC)),
1277	R: m_APInt(Res&: MaskCCmp)))))
1278	return nullptr;
1279
1280	if ((Pred != ICmpInst::ICMP_UGT || !MaskCCmp->isSignMask()) &&
1281	(Pred != ICmpInst::ICMP_EQ || *MaskCCmp != *MaskC))
1282	return nullptr;
1283
1284	APInt SMin = APInt::getSignedMinValue(numBits: Add.getType()->getScalarSizeInBits());
1285	bool IsMaskValid = Pred == ICmpInst::ICMP_UGT
1286	? (*MaskC == (SMin | (*DivC - 1)))
1287	: (*DivC == 2 && *MaskC == SMin + 1);
1288	if (!IsMaskValid)
1289	return nullptr;
1290
1291	// (X / DivC) + sext ((X & (SMin | (DivC - 1)) >u SMin) --> X >>s log2(DivC)
1292	return BinaryOperator::CreateAShr(
1293	V1: X, V2: ConstantInt::get(Ty: Add.getType(), V: DivC->exactLogBase2()));
1294	}
1295
1296	Instruction *InstCombinerImpl::
1297	canonicalizeCondSignextOfHighBitExtractToSignextHighBitExtract(
1298	BinaryOperator &I) {
1299	assert((I.getOpcode() == Instruction::Add ||
1300	I.getOpcode() == Instruction::Or ||
1301	I.getOpcode() == Instruction::Sub) &&
1302	"Expecting add/or/sub instruction");
1303
1304	// We have a subtraction/addition between a (potentially truncated) *logical*
1305	// right-shift of X and a "select".
1306	Value *X, *Select;
1307	Instruction *LowBitsToSkip, *Extract;
1308	if (!match(V: &I, P: m_c_BinOp(L: m_TruncOrSelf(Op: m_CombineAnd(
1309	L: m_LShr(L: m_Value(V&: X), R: m_Instruction(I&: LowBitsToSkip)),
1310	R: m_Instruction(I&: Extract))),
1311	R: m_Value(V&: Select))))
1312	return nullptr;
1313
1314	// `add`/`or` is commutative; but for `sub`, "select" *must* be on RHS.
1315	if (I.getOpcode() == Instruction::Sub && I.getOperand(i_nocapture: 1) != Select)
1316	return nullptr;
1317
1318	Type *XTy = X->getType();
1319	bool HadTrunc = I.getType() != XTy;
1320
1321	// If there was a truncation of extracted value, then we'll need to produce
1322	// one extra instruction, so we need to ensure one instruction will go away.
1323	if (HadTrunc && !match(V: &I, P: m_c_BinOp(L: m_OneUse(SubPattern: m_Value()), R: m_Value())))
1324	return nullptr;
1325
1326	// Extraction should extract high NBits bits, with shift amount calculated as:
1327	// low bits to skip = shift bitwidth - high bits to extract
1328	// The shift amount itself may be extended, and we need to look past zero-ext
1329	// when matching NBits, that will matter for matching later.
1330	Constant *C;
1331	Value *NBits;
1332	if (!match(
1333	V: LowBitsToSkip,
1334	P: m_ZExtOrSelf(Op: m_Sub(L: m_Constant(C), R: m_ZExtOrSelf(Op: m_Value(V&: NBits))))) ||
1335	!match(V: C, P: m_SpecificInt_ICMP(Predicate: ICmpInst::Predicate::ICMP_EQ,
1336	Threshold: APInt(C->getType()->getScalarSizeInBits(),
1337	X->getType()->getScalarSizeInBits()))))
1338	return nullptr;
1339
1340	// Sign-extending value can be zero-extended if we `sub`tract it,
1341	// or sign-extended otherwise.
1342	auto SkipExtInMagic = [&I](Value *&V) {
1343	if (I.getOpcode() == Instruction::Sub)
1344	match(V, P: m_ZExtOrSelf(Op: m_Value(V)));
1345	else
1346	match(V, P: m_SExtOrSelf(Op: m_Value(V)));
1347	};
1348
1349	// Now, finally validate the sign-extending magic.
1350	// `select` itself may be appropriately extended, look past that.
1351	SkipExtInMagic(Select);
1352
1353	ICmpInst::Predicate Pred;
1354	const APInt *Thr;
1355	Value *SignExtendingValue, *Zero;
1356	bool ShouldSignext;
1357	// It must be a select between two values we will later establish to be a
1358	// sign-extending value and a zero constant. The condition guarding the
1359	// sign-extension must be based on a sign bit of the same X we had in `lshr`.
1360	if (!match(V: Select, P: m_Select(C: m_ICmp(Pred, L: m_Specific(V: X), R: m_APInt(Res&: Thr)),
1361	L: m_Value(V&: SignExtendingValue), R: m_Value(V&: Zero))) ||
1362	!isSignBitCheck(Pred, RHS: *Thr, TrueIfSigned&: ShouldSignext))
1363	return nullptr;
1364
1365	// icmp-select pair is commutative.
1366	if (!ShouldSignext)
1367	std::swap(a&: SignExtendingValue, b&: Zero);
1368
1369	// If we should not perform sign-extension then we must add/or/subtract zero.
1370	if (!match(V: Zero, P: m_Zero()))
1371	return nullptr;
1372	// Otherwise, it should be some constant, left-shifted by the same NBits we
1373	// had in `lshr`. Said left-shift can also be appropriately extended.
1374	// Again, we must look past zero-ext when looking for NBits.
1375	SkipExtInMagic(SignExtendingValue);
1376	Constant *SignExtendingValueBaseConstant;
1377	if (!match(V: SignExtendingValue,
1378	P: m_Shl(L: m_Constant(C&: SignExtendingValueBaseConstant),
1379	R: m_ZExtOrSelf(Op: m_Specific(V: NBits)))))
1380	return nullptr;
1381	// If we `sub`, then the constant should be one, else it should be all-ones.
1382	if (I.getOpcode() == Instruction::Sub
1383	? !match(V: SignExtendingValueBaseConstant, P: m_One())
1384	: !match(V: SignExtendingValueBaseConstant, P: m_AllOnes()))
1385	return nullptr;
1386
1387	auto *NewAShr = BinaryOperator::CreateAShr(V1: X, V2: LowBitsToSkip,
1388	Name: Extract->getName() + ".sext");
1389	NewAShr->copyIRFlags(V: Extract); // Preserve `exact`-ness.
1390	if (!HadTrunc)
1391	return NewAShr;
1392
1393	Builder.Insert(I: NewAShr);
1394	return TruncInst::CreateTruncOrBitCast(S: NewAShr, Ty: I.getType());
1395	}
1396
1397	/// This is a specialization of a more general transform from
1398	/// foldUsingDistributiveLaws. If that code can be made to work optimally
1399	/// for multi-use cases or propagating nsw/nuw, then we would not need this.
1400	static Instruction *factorizeMathWithShlOps(BinaryOperator &I,
1401	InstCombiner::BuilderTy &Builder) {
1402	// TODO: Also handle mul by doubling the shift amount?
1403	assert((I.getOpcode() == Instruction::Add ||
1404	I.getOpcode() == Instruction::Sub) &&
1405	"Expected add/sub");
1406	auto *Op0 = dyn_cast<BinaryOperator>(Val: I.getOperand(i_nocapture: 0));
1407	auto *Op1 = dyn_cast<BinaryOperator>(Val: I.getOperand(i_nocapture: 1));
1408	if (!Op0 || !Op1 || !(Op0->hasOneUse() || Op1->hasOneUse()))
1409	return nullptr;
1410
1411	Value *X, *Y, *ShAmt;
1412	if (!match(V: Op0, P: m_Shl(L: m_Value(V&: X), R: m_Value(V&: ShAmt))) ||
1413	!match(V: Op1, P: m_Shl(L: m_Value(V&: Y), R: m_Specific(V: ShAmt))))
1414	return nullptr;
1415
1416	// No-wrap propagates only when all ops have no-wrap.
1417	bool HasNSW = I.hasNoSignedWrap() && Op0->hasNoSignedWrap() &&
1418	Op1->hasNoSignedWrap();
1419	bool HasNUW = I.hasNoUnsignedWrap() && Op0->hasNoUnsignedWrap() &&
1420	Op1->hasNoUnsignedWrap();
1421
1422	// add/sub (X << ShAmt), (Y << ShAmt) --> (add/sub X, Y) << ShAmt
1423	Value *NewMath = Builder.CreateBinOp(Opc: I.getOpcode(), LHS: X, RHS: Y);
1424	if (auto *NewI = dyn_cast<BinaryOperator>(Val: NewMath)) {
1425	NewI->setHasNoSignedWrap(HasNSW);
1426	NewI->setHasNoUnsignedWrap(HasNUW);
1427	}
1428	auto *NewShl = BinaryOperator::CreateShl(V1: NewMath, V2: ShAmt);
1429	NewShl->setHasNoSignedWrap(HasNSW);
1430	NewShl->setHasNoUnsignedWrap(HasNUW);
1431	return NewShl;
1432	}
1433
1434	/// Reduce a sequence of masked half-width multiplies to a single multiply.
1435	/// ((XLow * YHigh) + (YLow * XHigh)) << HalfBits) + (XLow * YLow) --> X * Y
1436	static Instruction *foldBoxMultiply(BinaryOperator &I) {
1437	unsigned BitWidth = I.getType()->getScalarSizeInBits();
1438	// Skip the odd bitwidth types.
1439	if ((BitWidth & 0x1))
1440	return nullptr;
1441
1442	unsigned HalfBits = BitWidth >> 1;
1443	APInt HalfMask = APInt::getMaxValue(numBits: HalfBits);
1444
1445	// ResLo = (CrossSum << HalfBits) + (YLo * XLo)
1446	Value *XLo, *YLo;
1447	Value *CrossSum;
1448	// Require one-use on the multiply to avoid increasing the number of
1449	// multiplications.
1450	if (!match(V: &I, P: m_c_Add(L: m_Shl(L: m_Value(V&: CrossSum), R: m_SpecificInt(V: HalfBits)),
1451	R: m_OneUse(SubPattern: m_Mul(L: m_Value(V&: YLo), R: m_Value(V&: XLo))))))
1452	return nullptr;
1453
1454	// XLo = X & HalfMask
1455	// YLo = Y & HalfMask
1456	// TODO: Refactor with SimplifyDemandedBits or KnownBits known leading zeros
1457	// to enhance robustness
1458	Value *X, *Y;
1459	if (!match(V: XLo, P: m_And(L: m_Value(V&: X), R: m_SpecificInt(V: HalfMask))) ||
1460	!match(V: YLo, P: m_And(L: m_Value(V&: Y), R: m_SpecificInt(V: HalfMask))))
1461	return nullptr;
1462
1463	// CrossSum = (X' * (Y >> Halfbits)) + (Y' * (X >> HalfBits))
1464	// X' can be either X or XLo in the pattern (and the same for Y')
1465	if (match(V: CrossSum,
1466	P: m_c_Add(L: m_c_Mul(L: m_LShr(L: m_Specific(V: Y), R: m_SpecificInt(V: HalfBits)),
1467	R: m_CombineOr(L: m_Specific(V: X), R: m_Specific(V: XLo))),
1468	R: m_c_Mul(L: m_LShr(L: m_Specific(V: X), R: m_SpecificInt(V: HalfBits)),
1469	R: m_CombineOr(L: m_Specific(V: Y), R: m_Specific(V: YLo))))))
1470	return BinaryOperator::CreateMul(V1: X, V2: Y);
1471
1472	return nullptr;
1473	}
1474
1475	Instruction *InstCombinerImpl::visitAdd(BinaryOperator &I) {
1476	if (Value *V = simplifyAddInst(LHS: I.getOperand(i_nocapture: 0), RHS: I.getOperand(i_nocapture: 1),
1477	IsNSW: I.hasNoSignedWrap(), IsNUW: I.hasNoUnsignedWrap(),
1478	Q: SQ.getWithInstruction(I: &I)))
1479	return replaceInstUsesWith(I, V);
1480
1481	if (SimplifyAssociativeOrCommutative(I))
1482	return &I;
1483
1484	if (Instruction *X = foldVectorBinop(Inst&: I))
1485	return X;
1486
1487	if (Instruction *Phi = foldBinopWithPhiOperands(BO&: I))
1488	return Phi;
1489
1490	// (A*B)+(A*C) -> A*(B+C) etc
1491	if (Value *V = foldUsingDistributiveLaws(I))
1492	return replaceInstUsesWith(I, V);
1493
1494	if (Instruction *R = foldBoxMultiply(I))
1495	return R;
1496
1497	if (Instruction *R = factorizeMathWithShlOps(I, Builder))
1498	return R;
1499
1500	if (Instruction *X = foldAddWithConstant(Add&: I))
1501	return X;
1502
1503	if (Instruction *X = foldNoWrapAdd(Add&: I, Builder))
1504	return X;
1505
1506	if (Instruction *R = foldBinOpShiftWithShift(I))
1507	return R;
1508
1509	if (Instruction *R = combineAddSubWithShlAddSub(Builder, I))
1510	return R;
1511
1512	Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
1513	Type *Ty = I.getType();
1514	if (Ty->isIntOrIntVectorTy(BitWidth: 1))
1515	return BinaryOperator::CreateXor(V1: LHS, V2: RHS);
1516
1517	// X + X --> X << 1
1518	if (LHS == RHS) {
1519	auto *Shl = BinaryOperator::CreateShl(V1: LHS, V2: ConstantInt::get(Ty, V: 1));
1520	Shl->setHasNoSignedWrap(I.hasNoSignedWrap());
1521	Shl->setHasNoUnsignedWrap(I.hasNoUnsignedWrap());
1522	return Shl;
1523	}
1524
1525	Value *A, *B;
1526	if (match(V: LHS, P: m_Neg(V: m_Value(V&: A)))) {
1527	// -A + -B --> -(A + B)
1528	if (match(V: RHS, P: m_Neg(V: m_Value(V&: B))))
1529	return BinaryOperator::CreateNeg(Op: Builder.CreateAdd(LHS: A, RHS: B));
1530
1531	// -A + B --> B - A
1532	auto *Sub = BinaryOperator::CreateSub(V1: RHS, V2: A);
1533	auto *OB0 = cast<OverflowingBinaryOperator>(Val: LHS);
1534	Sub->setHasNoSignedWrap(I.hasNoSignedWrap() && OB0->hasNoSignedWrap());
1535
1536	return Sub;
1537	}
1538
1539	// A + -B --> A - B
1540	if (match(V: RHS, P: m_Neg(V: m_Value(V&: B))))
1541	return BinaryOperator::CreateSub(V1: LHS, V2: B);
1542
1543	if (Value *V = checkForNegativeOperand(I, Builder))
1544	return replaceInstUsesWith(I, V);
1545
1546	// (A + 1) + ~B --> A - B
1547	// ~B + (A + 1) --> A - B
1548	// (~B + A) + 1 --> A - B
1549	// (A + ~B) + 1 --> A - B
1550	if (match(V: &I, P: m_c_BinOp(L: m_Add(L: m_Value(V&: A), R: m_One()), R: m_Not(V: m_Value(V&: B)))) ||
1551	match(V: &I, P: m_BinOp(L: m_c_Add(L: m_Not(V: m_Value(V&: B)), R: m_Value(V&: A)), R: m_One())))
1552	return BinaryOperator::CreateSub(V1: A, V2: B);
1553
1554	// (A + RHS) + RHS --> A + (RHS << 1)
1555	if (match(V: LHS, P: m_OneUse(SubPattern: m_c_Add(L: m_Value(V&: A), R: m_Specific(V: RHS)))))
1556	return BinaryOperator::CreateAdd(V1: A, V2: Builder.CreateShl(LHS: RHS, RHS: 1, Name: "reass.add"));
1557
1558	// LHS + (A + LHS) --> A + (LHS << 1)
1559	if (match(V: RHS, P: m_OneUse(SubPattern: m_c_Add(L: m_Value(V&: A), R: m_Specific(V: LHS)))))
1560	return BinaryOperator::CreateAdd(V1: A, V2: Builder.CreateShl(LHS, RHS: 1, Name: "reass.add"));
1561
1562	{
1563	// (A + C1) + (C2 - B) --> (A - B) + (C1 + C2)
1564	Constant *C1, *C2;
1565	if (match(V: &I, P: m_c_Add(L: m_Add(L: m_Value(V&: A), R: m_ImmConstant(C&: C1)),
1566	R: m_Sub(L: m_ImmConstant(C&: C2), R: m_Value(V&: B)))) &&
1567	(LHS->hasOneUse() || RHS->hasOneUse())) {
1568	Value *Sub = Builder.CreateSub(LHS: A, RHS: B);
1569	return BinaryOperator::CreateAdd(V1: Sub, V2: ConstantExpr::getAdd(C1, C2));
1570	}
1571
1572	// Canonicalize a constant sub operand as an add operand for better folding:
1573	// (C1 - A) + B --> (B - A) + C1
1574	if (match(V: &I, P: m_c_Add(L: m_OneUse(SubPattern: m_Sub(L: m_ImmConstant(C&: C1), R: m_Value(V&: A))),
1575	R: m_Value(V&: B)))) {
1576	Value *Sub = Builder.CreateSub(LHS: B, RHS: A, Name: "reass.sub");
1577	return BinaryOperator::CreateAdd(V1: Sub, V2: C1);
1578	}
1579	}
1580
1581	// X % C0 + (( X / C0 ) % C1) * C0 => X % (C0 * C1)
1582	if (Value *V = SimplifyAddWithRemainder(I)) return replaceInstUsesWith(I, V);
1583
1584	// ((X s/ C1) << C2) + X => X s% -C1 where -C1 is 1 << C2
1585	const APInt *C1, *C2;
1586	if (match(V: LHS, P: m_Shl(L: m_SDiv(L: m_Specific(V: RHS), R: m_APInt(Res&: C1)), R: m_APInt(Res&: C2)))) {
1587	APInt one(C2->getBitWidth(), 1);
1588	APInt minusC1 = -(*C1);
1589	if (minusC1 == (one << *C2)) {
1590	Constant *NewRHS = ConstantInt::get(Ty: RHS->getType(), V: minusC1);
1591	return BinaryOperator::CreateSRem(V1: RHS, V2: NewRHS);
1592	}
1593	}
1594
1595	// (A & 2^C1) + A => A & (2^C1 - 1) iff bit C1 in A is a sign bit
1596	if (match(V: &I, P: m_c_Add(L: m_And(L: m_Value(V&: A), R: m_APInt(Res&: C1)), R: m_Deferred(V: A))) &&
1597	C1->isPowerOf2() && (ComputeNumSignBits(Op: A) > C1->countl_zero())) {
1598	Constant *NewMask = ConstantInt::get(Ty: RHS->getType(), V: *C1 - 1);
1599	return BinaryOperator::CreateAnd(V1: A, V2: NewMask);
1600	}
1601
1602	// ZExt (B - A) + ZExt(A) --> ZExt(B)
1603	if ((match(V: RHS, P: m_ZExt(Op: m_Value(V&: A))) &&
1604	match(V: LHS, P: m_ZExt(Op: m_NUWSub(L: m_Value(V&: B), R: m_Specific(V: A))))) ||
1605	(match(V: LHS, P: m_ZExt(Op: m_Value(V&: A))) &&
1606	match(V: RHS, P: m_ZExt(Op: m_NUWSub(L: m_Value(V&: B), R: m_Specific(V: A))))))
1607	return new ZExtInst(B, LHS->getType());
1608
1609	// zext(A) + sext(A) --> 0 if A is i1
1610	if (match(V: &I, P: m_c_BinOp(L: m_ZExt(Op: m_Value(V&: A)), R: m_SExt(Op: m_Deferred(V: A)))) &&
1611	A->getType()->isIntOrIntVectorTy(BitWidth: 1))
1612	return replaceInstUsesWith(I, V: Constant::getNullValue(Ty: I.getType()));
1613
1614	// A+B --> A|B iff A and B have no bits set in common.
1615	WithCache<const Value *> LHSCache(LHS), RHSCache(RHS);
1616	if (haveNoCommonBitsSet(LHSCache, RHSCache, SQ: SQ.getWithInstruction(I: &I)))
1617	return BinaryOperator::CreateDisjointOr(V1: LHS, V2: RHS);
1618
1619	if (Instruction *Ext = narrowMathIfNoOverflow(I))
1620	return Ext;
1621
1622	// (add (xor A, B) (and A, B)) --> (or A, B)
1623	// (add (and A, B) (xor A, B)) --> (or A, B)
1624	if (match(V: &I, P: m_c_BinOp(L: m_Xor(L: m_Value(V&: A), R: m_Value(V&: B)),
1625	R: m_c_And(L: m_Deferred(V: A), R: m_Deferred(V: B)))))
1626	return BinaryOperator::CreateOr(V1: A, V2: B);
1627
1628	// (add (or A, B) (and A, B)) --> (add A, B)
1629	// (add (and A, B) (or A, B)) --> (add A, B)
1630	if (match(V: &I, P: m_c_BinOp(L: m_Or(L: m_Value(V&: A), R: m_Value(V&: B)),
1631	R: m_c_And(L: m_Deferred(V: A), R: m_Deferred(V: B))))) {
1632	// Replacing operands in-place to preserve nuw/nsw flags.
1633	replaceOperand(I, OpNum: 0, V: A);
1634	replaceOperand(I, OpNum: 1, V: B);
1635	return &I;
1636	}
1637
1638	// (add A (or A, -A)) --> (and (add A, -1) A)
1639	// (add A (or -A, A)) --> (and (add A, -1) A)
1640	// (add (or A, -A) A) --> (and (add A, -1) A)
1641	// (add (or -A, A) A) --> (and (add A, -1) A)
1642	if (match(V: &I, P: m_c_BinOp(L: m_Value(V&: A), R: m_OneUse(SubPattern: m_c_Or(L: m_Neg(V: m_Deferred(V: A)),
1643	R: m_Deferred(V: A)))))) {
1644	Value *Add =
1645	Builder.CreateAdd(LHS: A, RHS: Constant::getAllOnesValue(Ty: A->getType()), Name: "",
1646	HasNUW: I.hasNoUnsignedWrap(), HasNSW: I.hasNoSignedWrap());
1647	return BinaryOperator::CreateAnd(V1: Add, V2: A);
1648	}
1649
1650	// Canonicalize ((A & -A) - 1) --> ((A - 1) & ~A)
1651	// Forms all commutable operations, and simplifies ctpop -> cttz folds.
1652	if (match(V: &I,
1653	P: m_Add(L: m_OneUse(SubPattern: m_c_And(L: m_Value(V&: A), R: m_OneUse(SubPattern: m_Neg(V: m_Deferred(V: A))))),
1654	R: m_AllOnes()))) {
1655	Constant *AllOnes = ConstantInt::getAllOnesValue(Ty: RHS->getType());
1656	Value *Dec = Builder.CreateAdd(LHS: A, RHS: AllOnes);
1657	Value *Not = Builder.CreateXor(LHS: A, RHS: AllOnes);
1658	return BinaryOperator::CreateAnd(V1: Dec, V2: Not);
1659	}
1660
1661	// Disguised reassociation/factorization:
1662	// ~(A * C1) + A
1663	// ((A * -C1) - 1) + A
1664	// ((A * -C1) + A) - 1
1665	// (A * (1 - C1)) - 1
1666	if (match(V: &I,
1667	P: m_c_Add(L: m_OneUse(SubPattern: m_Not(V: m_OneUse(SubPattern: m_Mul(L: m_Value(V&: A), R: m_APInt(Res&: C1))))),
1668	R: m_Deferred(V: A)))) {
1669	Type *Ty = I.getType();
1670	Constant *NewMulC = ConstantInt::get(Ty, V: 1 - *C1);
1671	Value *NewMul = Builder.CreateMul(LHS: A, RHS: NewMulC);
1672	return BinaryOperator::CreateAdd(V1: NewMul, V2: ConstantInt::getAllOnesValue(Ty));
1673	}
1674
1675	// (A * -2**C) + B --> B - (A << C)
1676	const APInt *NegPow2C;
1677	if (match(V: &I, P: m_c_Add(L: m_OneUse(SubPattern: m_Mul(L: m_Value(V&: A), R: m_NegatedPower2(V&: NegPow2C))),
1678	R: m_Value(V&: B)))) {
1679	Constant *ShiftAmtC = ConstantInt::get(Ty, V: NegPow2C->countr_zero());
1680	Value *Shl = Builder.CreateShl(LHS: A, RHS: ShiftAmtC);
1681	return BinaryOperator::CreateSub(V1: B, V2: Shl);
1682	}
1683
1684	// Canonicalize signum variant that ends in add:
1685	// (A s>> (BW - 1)) + (zext (A s> 0)) --> (A s>> (BW - 1)) | (zext (A != 0))
1686	ICmpInst::Predicate Pred;
1687	uint64_t BitWidth = Ty->getScalarSizeInBits();
1688	if (match(V: LHS, P: m_AShr(L: m_Value(V&: A), R: m_SpecificIntAllowPoison(V: BitWidth - 1))) &&
1689	match(V: RHS, P: m_OneUse(SubPattern: m_ZExt(
1690	Op: m_OneUse(SubPattern: m_ICmp(Pred, L: m_Specific(V: A), R: m_ZeroInt()))))) &&
1691	Pred == CmpInst::ICMP_SGT) {
1692	Value *NotZero = Builder.CreateIsNotNull(Arg: A, Name: "isnotnull");
1693	Value *Zext = Builder.CreateZExt(V: NotZero, DestTy: Ty, Name: "isnotnull.zext");
1694	return BinaryOperator::CreateOr(V1: LHS, V2: Zext);
1695	}
1696
1697	if (Instruction *Ashr = foldAddToAshr(Add&: I))
1698	return Ashr;
1699
1700	// (~X) + (~Y) --> -2 - (X + Y)
1701	{
1702	// To ensure we can save instructions we need to ensure that we consume both
1703	// LHS/RHS (i.e they have a `not`).
1704	bool ConsumesLHS, ConsumesRHS;
1705	if (isFreeToInvert(V: LHS, WillInvertAllUses: LHS->hasOneUse(), DoesConsume&: ConsumesLHS) && ConsumesLHS &&
1706	isFreeToInvert(V: RHS, WillInvertAllUses: RHS->hasOneUse(), DoesConsume&: ConsumesRHS) && ConsumesRHS) {
1707	Value *NotLHS = getFreelyInverted(V: LHS, WillInvertAllUses: LHS->hasOneUse(), Builder: &Builder);
1708	Value *NotRHS = getFreelyInverted(V: RHS, WillInvertAllUses: RHS->hasOneUse(), Builder: &Builder);
1709	assert(NotLHS != nullptr && NotRHS != nullptr &&
1710	"isFreeToInvert desynced with getFreelyInverted");
1711	Value *LHSPlusRHS = Builder.CreateAdd(LHS: NotLHS, RHS: NotRHS);
1712	return BinaryOperator::CreateSub(
1713	V1: ConstantInt::getSigned(Ty: RHS->getType(), V: -2), V2: LHSPlusRHS);
1714	}
1715	}
1716
1717	if (Instruction *R = tryFoldInstWithCtpopWithNot(I: &I))
1718	return R;
1719
1720	// TODO(jingyue): Consider willNotOverflowSignedAdd and
1721	// willNotOverflowUnsignedAdd to reduce the number of invocations of
1722	// computeKnownBits.
1723	bool Changed = false;
1724	if (!I.hasNoSignedWrap() && willNotOverflowSignedAdd(LHS: LHSCache, RHS: RHSCache, CxtI: I)) {
1725	Changed = true;
1726	I.setHasNoSignedWrap(true);
1727	}
1728	if (!I.hasNoUnsignedWrap() &&
1729	willNotOverflowUnsignedAdd(LHS: LHSCache, RHS: RHSCache, CxtI: I)) {
1730	Changed = true;
1731	I.setHasNoUnsignedWrap(true);
1732	}
1733
1734	if (Instruction *V = canonicalizeLowbitMask(I, Builder))
1735	return V;
1736
1737	if (Instruction *V =
1738	canonicalizeCondSignextOfHighBitExtractToSignextHighBitExtract(I))
1739	return V;
1740
1741	if (Instruction *SatAdd = foldToUnsignedSaturatedAdd(I))
1742	return SatAdd;
1743
1744	// usub.sat(A, B) + B => umax(A, B)
1745	if (match(&I, m_c_BinOp(
1746	m_OneUse(m_Intrinsic<Intrinsic::usub_sat>(m_Value(A), m_Value(B))),
1747	m_Deferred(B)))) {
1748	return replaceInstUsesWith(I,
1749	V: Builder.CreateIntrinsic(Intrinsic::umax, {I.getType()}, {A, B}));
1750	}
1751
1752	// ctpop(A) + ctpop(B) => ctpop(A | B) if A and B have no bits set in common.
1753	if (match(LHS, m_OneUse(m_Intrinsic<Intrinsic::ctpop>(m_Value(A)))) &&
1754	match(RHS, m_OneUse(m_Intrinsic<Intrinsic::ctpop>(m_Value(B)))) &&
1755	haveNoCommonBitsSet(A, B, SQ.getWithInstruction(&I)))
1756	return replaceInstUsesWith(
1757	I, V: Builder.CreateIntrinsic(Intrinsic::ctpop, {I.getType()},
1758	{Builder.CreateOr(LHS: A, RHS: B)}));
1759
1760	// Fold the log2_ceil idiom:
1761	// zext(ctpop(A) >u/!= 1) + (ctlz(A, true) ^ (BW - 1))
1762	// -->
1763	// BW - ctlz(A - 1, false)
1764	const APInt *XorC;
1765	if (match(&I,
1766	m_c_Add(
1767	m_ZExt(m_ICmp(Pred, m_Intrinsic<Intrinsic::ctpop>(m_Value(A)),
1768	m_One())),
1769	m_OneUse(m_ZExtOrSelf(m_OneUse(m_Xor(
1770	m_OneUse(m_TruncOrSelf(m_OneUse(
1771	m_Intrinsic<Intrinsic::ctlz>(m_Deferred(A), m_One())))),
1772	m_APInt(XorC))))))) &&
1773	(Pred == ICmpInst::ICMP_UGT || Pred == ICmpInst::ICMP_NE) &&
1774	*XorC == A->getType()->getScalarSizeInBits() - 1) {
1775	Value *Sub = Builder.CreateAdd(LHS: A, RHS: Constant::getAllOnesValue(Ty: A->getType()));
1776	Value *Ctlz = Builder.CreateIntrinsic(Intrinsic::ctlz, {A->getType()},
1777	{Sub, Builder.getFalse()});
1778	Value *Ret = Builder.CreateSub(
1779	LHS: ConstantInt::get(Ty: A->getType(), V: A->getType()->getScalarSizeInBits()),
1780	RHS: Ctlz, Name: "", /*HasNUW*/ true, /*HasNSW*/ true);
1781	return replaceInstUsesWith(I, V: Builder.CreateZExtOrTrunc(V: Ret, DestTy: I.getType()));
1782	}
1783
1784	if (Instruction *Res = foldSquareSumInt(I))
1785	return Res;
1786
1787	if (Instruction *Res = foldBinOpOfDisplacedShifts(I))
1788	return Res;
1789
1790	if (Instruction *Res = foldBinOpOfSelectAndCastOfSelectCondition(I))
1791	return Res;
1792
1793	return Changed ? &I : nullptr;
1794	}
1795
1796	/// Eliminate an op from a linear interpolation (lerp) pattern.
1797	static Instruction *factorizeLerp(BinaryOperator &I,
1798	InstCombiner::BuilderTy &Builder) {
1799	Value *X, *Y, *Z;
1800	if (!match(V: &I, P: m_c_FAdd(L: m_OneUse(SubPattern: m_c_FMul(L: m_Value(V&: Y),
1801	R: m_OneUse(SubPattern: m_FSub(L: m_FPOne(),
1802	R: m_Value(V&: Z))))),
1803	R: m_OneUse(SubPattern: m_c_FMul(L: m_Value(V&: X), R: m_Deferred(V: Z))))))
1804	return nullptr;
1805
1806	// (Y * (1.0 - Z)) + (X * Z) --> Y + Z * (X - Y) [8 commuted variants]
1807	Value *XY = Builder.CreateFSubFMF(L: X, R: Y, FMFSource: &I);
1808	Value *MulZ = Builder.CreateFMulFMF(L: Z, R: XY, FMFSource: &I);
1809	return BinaryOperator::CreateFAddFMF(V1: Y, V2: MulZ, FMFSource: &I);
1810	}
1811
1812	/// Factor a common operand out of fadd/fsub of fmul/fdiv.
1813	static Instruction *factorizeFAddFSub(BinaryOperator &I,
1814	InstCombiner::BuilderTy &Builder) {
1815	assert((I.getOpcode() == Instruction::FAdd ||
1816	I.getOpcode() == Instruction::FSub) && "Expecting fadd/fsub");
1817	assert(I.hasAllowReassoc() && I.hasNoSignedZeros() &&
1818	"FP factorization requires FMF");
1819
1820	if (Instruction *Lerp = factorizeLerp(I, Builder))
1821	return Lerp;
1822
1823	Value *Op0 = I.getOperand(i_nocapture: 0), *Op1 = I.getOperand(i_nocapture: 1);
1824	if (!Op0->hasOneUse() || !Op1->hasOneUse())
1825	return nullptr;
1826
1827	Value *X, *Y, *Z;
1828	bool IsFMul;
1829	if ((match(V: Op0, P: m_FMul(L: m_Value(V&: X), R: m_Value(V&: Z))) &&
1830	match(V: Op1, P: m_c_FMul(L: m_Value(V&: Y), R: m_Specific(V: Z)))) ||
1831	(match(V: Op0, P: m_FMul(L: m_Value(V&: Z), R: m_Value(V&: X))) &&
1832	match(V: Op1, P: m_c_FMul(L: m_Value(V&: Y), R: m_Specific(V: Z)))))
1833	IsFMul = true;
1834	else if (match(V: Op0, P: m_FDiv(L: m_Value(V&: X), R: m_Value(V&: Z))) &&
1835	match(V: Op1, P: m_FDiv(L: m_Value(V&: Y), R: m_Specific(V: Z))))
1836	IsFMul = false;
1837	else
1838	return nullptr;
1839
1840	// (X * Z) + (Y * Z) --> (X + Y) * Z
1841	// (X * Z) - (Y * Z) --> (X - Y) * Z
1842	// (X / Z) + (Y / Z) --> (X + Y) / Z
1843	// (X / Z) - (Y / Z) --> (X - Y) / Z
1844	bool IsFAdd = I.getOpcode() == Instruction::FAdd;
1845	Value *XY = IsFAdd ? Builder.CreateFAddFMF(L: X, R: Y, FMFSource: &I)
1846	: Builder.CreateFSubFMF(L: X, R: Y, FMFSource: &I);
1847
1848	// Bail out if we just created a denormal constant.
1849	// TODO: This is copied from a previous implementation. Is it necessary?
1850	const APFloat *C;
1851	if (match(V: XY, P: m_APFloat(Res&: C)) && !C->isNormal())
1852	return nullptr;
1853
1854	return IsFMul ? BinaryOperator::CreateFMulFMF(V1: XY, V2: Z, FMFSource: &I)
1855	: BinaryOperator::CreateFDivFMF(V1: XY, V2: Z, FMFSource: &I);
1856	}
1857
1858	Instruction *InstCombinerImpl::visitFAdd(BinaryOperator &I) {
1859	if (Value *V = simplifyFAddInst(LHS: I.getOperand(i_nocapture: 0), RHS: I.getOperand(i_nocapture: 1),
1860	FMF: I.getFastMathFlags(),
1861	Q: SQ.getWithInstruction(I: &I)))
1862	return replaceInstUsesWith(I, V);
1863
1864	if (SimplifyAssociativeOrCommutative(I))
1865	return &I;
1866
1867	if (Instruction *X = foldVectorBinop(Inst&: I))
1868	return X;
1869
1870	if (Instruction *Phi = foldBinopWithPhiOperands(BO&: I))
1871	return Phi;
1872
1873	if (Instruction *FoldedFAdd = foldBinOpIntoSelectOrPhi(I))
1874	return FoldedFAdd;
1875
1876	// (-X) + Y --> Y - X
1877	Value *X, *Y;
1878	if (match(V: &I, P: m_c_FAdd(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y))))
1879	return BinaryOperator::CreateFSubFMF(V1: Y, V2: X, FMFSource: &I);
1880
1881	// Similar to above, but look through fmul/fdiv for the negated term.
1882	// (-X * Y) + Z --> Z - (X * Y) [4 commuted variants]
1883	Value *Z;
1884	if (match(V: &I, P: m_c_FAdd(L: m_OneUse(SubPattern: m_c_FMul(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y))),
1885	R: m_Value(V&: Z)))) {
1886	Value *XY = Builder.CreateFMulFMF(L: X, R: Y, FMFSource: &I);
1887	return BinaryOperator::CreateFSubFMF(V1: Z, V2: XY, FMFSource: &I);
1888	}
1889	// (-X / Y) + Z --> Z - (X / Y) [2 commuted variants]
1890	// (X / -Y) + Z --> Z - (X / Y) [2 commuted variants]
1891	if (match(V: &I, P: m_c_FAdd(L: m_OneUse(SubPattern: m_FDiv(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y))),
1892	R: m_Value(V&: Z))) ||
1893	match(V: &I, P: m_c_FAdd(L: m_OneUse(SubPattern: m_FDiv(L: m_Value(V&: X), R: m_FNeg(X: m_Value(V&: Y)))),
1894	R: m_Value(V&: Z)))) {
1895	Value *XY = Builder.CreateFDivFMF(L: X, R: Y, FMFSource: &I);
1896	return BinaryOperator::CreateFSubFMF(V1: Z, V2: XY, FMFSource: &I);
1897	}
1898
1899	// Check for (fadd double (sitofp x), y), see if we can merge this into an
1900	// integer add followed by a promotion.
1901	if (Instruction *R = foldFBinOpOfIntCasts(I))
1902	return R;
1903
1904	Value *LHS = I.getOperand(i_nocapture: 0), *RHS = I.getOperand(i_nocapture: 1);
1905	// Handle specials cases for FAdd with selects feeding the operation
1906	if (Value *V = SimplifySelectsFeedingBinaryOp(I, LHS, RHS))
1907	return replaceInstUsesWith(I, V);
1908
1909	if (I.hasAllowReassoc() && I.hasNoSignedZeros()) {
1910	if (Instruction *F = factorizeFAddFSub(I, Builder))
1911	return F;
1912
1913	if (Instruction *F = foldSquareSumFP(I))
1914	return F;
1915
1916	// Try to fold fadd into start value of reduction intrinsic.
1917	if (match(&I, m_c_FAdd(m_OneUse(m_Intrinsic<Intrinsic::vector_reduce_fadd>(
1918	m_AnyZeroFP(), m_Value(X))),
1919	m_Value(Y)))) {
1920	// fadd (rdx 0.0, X), Y --> rdx Y, X
1921	return replaceInstUsesWith(
1922	I, V: Builder.CreateIntrinsic(Intrinsic::vector_reduce_fadd,
1923	{X->getType()}, {Y, X}, &I));
1924	}
1925	const APFloat *StartC, *C;
1926	if (match(LHS, m_OneUse(m_Intrinsic<Intrinsic::vector_reduce_fadd>(
1927	m_APFloat(StartC), m_Value(X)))) &&
1928	match(RHS, m_APFloat(C))) {
1929	// fadd (rdx StartC, X), C --> rdx (C + StartC), X
1930	Constant *NewStartC = ConstantFP::get(Ty: I.getType(), V: *C + *StartC);
1931	return replaceInstUsesWith(
1932	I, V: Builder.CreateIntrinsic(Intrinsic::vector_reduce_fadd,
1933	{X->getType()}, {NewStartC, X}, &I));
1934	}
1935
1936	// (X * MulC) + X --> X * (MulC + 1.0)
1937	Constant *MulC;
1938	if (match(V: &I, P: m_c_FAdd(L: m_FMul(L: m_Value(V&: X), R: m_ImmConstant(C&: MulC)),
1939	R: m_Deferred(V: X)))) {
1940	if (Constant *NewMulC = ConstantFoldBinaryOpOperands(
1941	Opcode: Instruction::FAdd, LHS: MulC, RHS: ConstantFP::get(Ty: I.getType(), V: 1.0), DL))
1942	return BinaryOperator::CreateFMulFMF(V1: X, V2: NewMulC, FMFSource: &I);
1943	}
1944
1945	// (-X - Y) + (X + Z) --> Z - Y
1946	if (match(V: &I, P: m_c_FAdd(L: m_FSub(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y)),
1947	R: m_c_FAdd(L: m_Deferred(V: X), R: m_Value(V&: Z)))))
1948	return BinaryOperator::CreateFSubFMF(V1: Z, V2: Y, FMFSource: &I);
1949
1950	if (Value *V = FAddCombine(Builder).simplify(I: &I))
1951	return replaceInstUsesWith(I, V);
1952	}
1953
1954	// minumum(X, Y) + maximum(X, Y) => X + Y.
1955	if (match(&I,
1956	m_c_FAdd(m_Intrinsic<Intrinsic::maximum>(m_Value(V&: X), m_Value(V&: Y)),
1957	m_c_Intrinsic<Intrinsic::minimum>(m_Deferred(V: X),
1958	m_Deferred(V: Y))))) {
1959	BinaryOperator *Result = BinaryOperator::CreateFAddFMF(V1: X, V2: Y, FMFSource: &I);
1960	// We cannot preserve ninf if nnan flag is not set.
1961	// If X is NaN and Y is Inf then in original program we had NaN + NaN,
1962	// while in optimized version NaN + Inf and this is a poison with ninf flag.
1963	if (!Result->hasNoNaNs())
1964	Result->setHasNoInfs(false);
1965	return Result;
1966	}
1967
1968	return nullptr;
1969	}
1970
1971	/// Optimize pointer differences into the same array into a size. Consider:
1972	/// &A[10] - &A[0]: we should compile this to "10". LHS/RHS are the pointer
1973	/// operands to the ptrtoint instructions for the LHS/RHS of the subtract.
1974	Value *InstCombinerImpl::OptimizePointerDifference(Value *LHS, Value *RHS,
1975	Type *Ty, bool IsNUW) {
1976	// If LHS is a gep based on RHS or RHS is a gep based on LHS, we can optimize
1977	// this.
1978	bool Swapped = false;
1979	GEPOperator *GEP1 = nullptr, *GEP2 = nullptr;
1980	if (!isa<GEPOperator>(Val: LHS) && isa<GEPOperator>(Val: RHS)) {
1981	std::swap(a&: LHS, b&: RHS);
1982	Swapped = true;
1983	}
1984
1985	// Require at least one GEP with a common base pointer on both sides.
1986	if (auto *LHSGEP = dyn_cast<GEPOperator>(Val: LHS)) {
1987	// (gep X, ...) - X
1988	if (LHSGEP->getOperand(i_nocapture: 0)->stripPointerCasts() ==
1989	RHS->stripPointerCasts()) {
1990	GEP1 = LHSGEP;
1991	} else if (auto *RHSGEP = dyn_cast<GEPOperator>(Val: RHS)) {
1992	// (gep X, ...) - (gep X, ...)
1993	if (LHSGEP->getOperand(i_nocapture: 0)->stripPointerCasts() ==
1994	RHSGEP->getOperand(i_nocapture: 0)->stripPointerCasts()) {
1995	GEP1 = LHSGEP;
1996	GEP2 = RHSGEP;
1997	}
1998	}
1999	}
2000
2001	if (!GEP1)
2002	return nullptr;
2003
2004	if (GEP2) {
2005	// (gep X, ...) - (gep X, ...)
2006	//
2007	// Avoid duplicating the arithmetic if there are more than one non-constant
2008	// indices between the two GEPs and either GEP has a non-constant index and
2009	// multiple users. If zero non-constant index, the result is a constant and
2010	// there is no duplication. If one non-constant index, the result is an add
2011	// or sub with a constant, which is no larger than the original code, and
2012	// there's no duplicated arithmetic, even if either GEP has multiple
2013	// users. If more than one non-constant indices combined, as long as the GEP
2014	// with at least one non-constant index doesn't have multiple users, there
2015	// is no duplication.
2016	unsigned NumNonConstantIndices1 = GEP1->countNonConstantIndices();
2017	unsigned NumNonConstantIndices2 = GEP2->countNonConstantIndices();
2018	if (NumNonConstantIndices1 + NumNonConstantIndices2 > 1 &&
2019	((NumNonConstantIndices1 > 0 && !GEP1->hasOneUse()) ||
2020	(NumNonConstantIndices2 > 0 && !GEP2->hasOneUse()))) {
2021	return nullptr;
2022	}
2023	}
2024
2025	// Emit the offset of the GEP and an intptr_t.
2026	Value *Result = EmitGEPOffset(GEP: GEP1);
2027
2028	// If this is a single inbounds GEP and the original sub was nuw,
2029	// then the final multiplication is also nuw.
2030	if (auto *I = dyn_cast<Instruction>(Val: Result))
2031	if (IsNUW && !GEP2 && !Swapped && GEP1->isInBounds() &&
2032	I->getOpcode() == Instruction::Mul)
2033	I->setHasNoUnsignedWrap();
2034
2035	// If we have a 2nd GEP of the same base pointer, subtract the offsets.
2036	// If both GEPs are inbounds, then the subtract does not have signed overflow.
2037	if (GEP2) {
2038	Value *Offset = EmitGEPOffset(GEP: GEP2);
2039	Result = Builder.CreateSub(LHS: Result, RHS: Offset, Name: "gepdiff", /* NUW */ HasNUW: false,
2040	HasNSW: GEP1->isInBounds() && GEP2->isInBounds());
2041	}
2042
2043	// If we have p - gep(p, ...) then we have to negate the result.
2044	if (Swapped)
2045	Result = Builder.CreateNeg(V: Result, Name: "diff.neg");
2046
2047	return Builder.CreateIntCast(V: Result, DestTy: Ty, isSigned: true);
2048	}
2049
2050	static Instruction *foldSubOfMinMax(BinaryOperator &I,
2051	InstCombiner::BuilderTy &Builder) {
2052	Value *Op0 = I.getOperand(i_nocapture: 0);
2053	Value *Op1 = I.getOperand(i_nocapture: 1);
2054	Type *Ty = I.getType();
2055	auto *MinMax = dyn_cast<MinMaxIntrinsic>(Val: Op1);
2056	if (!MinMax)
2057	return nullptr;
2058
2059	// sub(add(X,Y), s/umin(X,Y)) --> s/umax(X,Y)
2060	// sub(add(X,Y), s/umax(X,Y)) --> s/umin(X,Y)
2061	Value *X = MinMax->getLHS();
2062	Value *Y = MinMax->getRHS();
2063	if (match(V: Op0, P: m_c_Add(L: m_Specific(V: X), R: m_Specific(V: Y))) &&
2064	(Op0->hasOneUse() || Op1->hasOneUse())) {
2065	Intrinsic::ID InvID = getInverseMinMaxIntrinsic(MinMaxID: MinMax->getIntrinsicID());
2066	Function *F = Intrinsic::getDeclaration(M: I.getModule(), id: InvID, Tys: Ty);
2067	return CallInst::Create(Func: F, Args: {X, Y});
2068	}
2069
2070	// sub(add(X,Y),umin(Y,Z)) --> add(X,usub.sat(Y,Z))
2071	// sub(add(X,Z),umin(Y,Z)) --> add(X,usub.sat(Z,Y))
2072	Value *Z;
2073	if (match(V: Op1, P: m_OneUse(SubPattern: m_UMin(L: m_Value(V&: Y), R: m_Value(V&: Z))))) {
2074	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_Add(L: m_Specific(V: Y), R: m_Value(V&: X))))) {
2075	Value *USub = Builder.CreateIntrinsic(Intrinsic::usub_sat, Ty, {Y, Z});
2076	return BinaryOperator::CreateAdd(V1: X, V2: USub);
2077	}
2078	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_Add(L: m_Specific(V: Z), R: m_Value(V&: X))))) {
2079	Value *USub = Builder.CreateIntrinsic(Intrinsic::usub_sat, Ty, {Z, Y});
2080	return BinaryOperator::CreateAdd(V1: X, V2: USub);
2081	}
2082	}
2083
2084	// sub Op0, smin((sub nsw Op0, Z), 0) --> smax Op0, Z
2085	// sub Op0, smax((sub nsw Op0, Z), 0) --> smin Op0, Z
2086	if (MinMax->isSigned() && match(V: Y, P: m_ZeroInt()) &&
2087	match(V: X, P: m_NSWSub(L: m_Specific(V: Op0), R: m_Value(V&: Z)))) {
2088	Intrinsic::ID InvID = getInverseMinMaxIntrinsic(MinMaxID: MinMax->getIntrinsicID());
2089	Function *F = Intrinsic::getDeclaration(M: I.getModule(), id: InvID, Tys: Ty);
2090	return CallInst::Create(Func: F, Args: {Op0, Z});
2091	}
2092
2093	return nullptr;
2094	}
2095
2096	Instruction *InstCombinerImpl::visitSub(BinaryOperator &I) {
2097	if (Value *V = simplifySubInst(LHS: I.getOperand(i_nocapture: 0), RHS: I.getOperand(i_nocapture: 1),
2098	IsNSW: I.hasNoSignedWrap(), IsNUW: I.hasNoUnsignedWrap(),
2099	Q: SQ.getWithInstruction(I: &I)))
2100	return replaceInstUsesWith(I, V);
2101
2102	if (Instruction *X = foldVectorBinop(Inst&: I))
2103	return X;
2104
2105	if (Instruction *Phi = foldBinopWithPhiOperands(BO&: I))
2106	return Phi;
2107
2108	Value *Op0 = I.getOperand(i_nocapture: 0), *Op1 = I.getOperand(i_nocapture: 1);
2109
2110	// If this is a 'B = x-(-A)', change to B = x+A.
2111	// We deal with this without involving Negator to preserve NSW flag.
2112	if (Value *V = dyn_castNegVal(V: Op1)) {
2113	BinaryOperator *Res = BinaryOperator::CreateAdd(V1: Op0, V2: V);
2114
2115	if (const auto *BO = dyn_cast<BinaryOperator>(Val: Op1)) {
2116	assert(BO->getOpcode() == Instruction::Sub &&
2117	"Expected a subtraction operator!");
2118	if (BO->hasNoSignedWrap() && I.hasNoSignedWrap())
2119	Res->setHasNoSignedWrap(true);
2120	} else {
2121	if (cast<Constant>(Val: Op1)->isNotMinSignedValue() && I.hasNoSignedWrap())
2122	Res->setHasNoSignedWrap(true);
2123	}
2124
2125	return Res;
2126	}
2127
2128	// Try this before Negator to preserve NSW flag.
2129	if (Instruction *R = factorizeMathWithShlOps(I, Builder))
2130	return R;
2131
2132	Constant *C;
2133	if (match(V: Op0, P: m_ImmConstant(C))) {
2134	Value *X;
2135	Constant *C2;
2136
2137	// C-(X+C2) --> (C-C2)-X
2138	if (match(V: Op1, P: m_Add(L: m_Value(V&: X), R: m_ImmConstant(C&: C2)))) {
2139	// C-C2 never overflow, and C-(X+C2), (X+C2) has NSW/NUW
2140	// => (C-C2)-X can have NSW/NUW
2141	bool WillNotSOV = willNotOverflowSignedSub(LHS: C, RHS: C2, CxtI: I);
2142	BinaryOperator *Res =
2143	BinaryOperator::CreateSub(V1: ConstantExpr::getSub(C1: C, C2), V2: X);
2144	auto *OBO1 = cast<OverflowingBinaryOperator>(Val: Op1);
2145	Res->setHasNoSignedWrap(I.hasNoSignedWrap() && OBO1->hasNoSignedWrap() &&
2146	WillNotSOV);
2147	Res->setHasNoUnsignedWrap(I.hasNoUnsignedWrap() &&
2148	OBO1->hasNoUnsignedWrap());
2149	return Res;
2150	}
2151	}
2152
2153	auto TryToNarrowDeduceFlags = [this, &I, &Op0, &Op1]() -> Instruction * {
2154	if (Instruction *Ext = narrowMathIfNoOverflow(I))
2155	return Ext;
2156
2157	bool Changed = false;
2158	if (!I.hasNoSignedWrap() && willNotOverflowSignedSub(LHS: Op0, RHS: Op1, CxtI: I)) {
2159	Changed = true;
2160	I.setHasNoSignedWrap(true);
2161	}
2162	if (!I.hasNoUnsignedWrap() && willNotOverflowUnsignedSub(LHS: Op0, RHS: Op1, CxtI: I)) {
2163	Changed = true;
2164	I.setHasNoUnsignedWrap(true);
2165	}
2166
2167	return Changed ? &I : nullptr;
2168	};
2169
2170	// First, let's try to interpret `sub a, b` as `add a, (sub 0, b)`,
2171	// and let's try to sink `(sub 0, b)` into `b` itself. But only if this isn't
2172	// a pure negation used by a select that looks like abs/nabs.
2173	bool IsNegation = match(V: Op0, P: m_ZeroInt());
2174	if (!IsNegation || none_of(Range: I.users(), P: [&I, Op1](const User *U) {
2175	const Instruction *UI = dyn_cast<Instruction>(Val: U);
2176	if (!UI)
2177	return false;
2178	return match(V: UI,
2179	P: m_Select(C: m_Value(), L: m_Specific(V: Op1), R: m_Specific(V: &I))) ||
2180	match(V: UI, P: m_Select(C: m_Value(), L: m_Specific(V: &I), R: m_Specific(V: Op1)));
2181	})) {
2182	if (Value *NegOp1 = Negator::Negate(LHSIsZero: IsNegation, /* IsNSW */ IsNegation &&
2183	I.hasNoSignedWrap(),
2184	Root: Op1, IC&: *this))
2185	return BinaryOperator::CreateAdd(V1: NegOp1, V2: Op0);
2186	}
2187	if (IsNegation)
2188	return TryToNarrowDeduceFlags(); // Should have been handled in Negator!
2189
2190	// (A*B)-(A*C) -> A*(B-C) etc
2191	if (Value *V = foldUsingDistributiveLaws(I))
2192	return replaceInstUsesWith(I, V);
2193
2194	if (I.getType()->isIntOrIntVectorTy(BitWidth: 1))
2195	return BinaryOperator::CreateXor(V1: Op0, V2: Op1);
2196
2197	// Replace (-1 - A) with (~A).
2198	if (match(V: Op0, P: m_AllOnes()))
2199	return BinaryOperator::CreateNot(Op: Op1);
2200
2201	// (X + -1) - Y --> ~Y + X
2202	Value *X, *Y;
2203	if (match(V: Op0, P: m_OneUse(SubPattern: m_Add(L: m_Value(V&: X), R: m_AllOnes()))))
2204	return BinaryOperator::CreateAdd(V1: Builder.CreateNot(V: Op1), V2: X);
2205
2206	// Reassociate sub/add sequences to create more add instructions and
2207	// reduce dependency chains:
2208	// ((X - Y) + Z) - Op1 --> (X + Z) - (Y + Op1)
2209	Value *Z;
2210	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_Add(L: m_OneUse(SubPattern: m_Sub(L: m_Value(V&: X), R: m_Value(V&: Y))),
2211	R: m_Value(V&: Z))))) {
2212	Value *XZ = Builder.CreateAdd(LHS: X, RHS: Z);
2213	Value *YW = Builder.CreateAdd(LHS: Y, RHS: Op1);
2214	return BinaryOperator::CreateSub(V1: XZ, V2: YW);
2215	}
2216
2217	// ((X - Y) - Op1) --> X - (Y + Op1)
2218	if (match(V: Op0, P: m_OneUse(SubPattern: m_Sub(L: m_Value(V&: X), R: m_Value(V&: Y))))) {
2219	OverflowingBinaryOperator *LHSSub = cast<OverflowingBinaryOperator>(Val: Op0);
2220	bool HasNUW = I.hasNoUnsignedWrap() && LHSSub->hasNoUnsignedWrap();
2221	bool HasNSW = HasNUW && I.hasNoSignedWrap() && LHSSub->hasNoSignedWrap();
2222	Value *Add = Builder.CreateAdd(LHS: Y, RHS: Op1, Name: "", /* HasNUW */ HasNUW,
2223	/* HasNSW */ HasNSW);
2224	BinaryOperator *Sub = BinaryOperator::CreateSub(V1: X, V2: Add);
2225	Sub->setHasNoUnsignedWrap(HasNUW);
2226	Sub->setHasNoSignedWrap(HasNSW);
2227	return Sub;
2228	}
2229
2230	{
2231	// (X + Z) - (Y + Z) --> (X - Y)
2232	// This is done in other passes, but we want to be able to consume this
2233	// pattern in InstCombine so we can generate it without creating infinite
2234	// loops.
2235	if (match(V: Op0, P: m_Add(L: m_Value(V&: X), R: m_Value(V&: Z))) &&
2236	match(V: Op1, P: m_c_Add(L: m_Value(V&: Y), R: m_Specific(V: Z))))
2237	return BinaryOperator::CreateSub(V1: X, V2: Y);
2238
2239	// (X + C0) - (Y + C1) --> (X - Y) + (C0 - C1)
2240	Constant *CX, *CY;
2241	if (match(V: Op0, P: m_OneUse(SubPattern: m_Add(L: m_Value(V&: X), R: m_ImmConstant(C&: CX)))) &&
2242	match(V: Op1, P: m_OneUse(SubPattern: m_Add(L: m_Value(V&: Y), R: m_ImmConstant(C&: CY))))) {
2243	Value *OpsSub = Builder.CreateSub(LHS: X, RHS: Y);
2244	Constant *ConstsSub = ConstantExpr::getSub(C1: CX, C2: CY);
2245	return BinaryOperator::CreateAdd(V1: OpsSub, V2: ConstsSub);
2246	}
2247	}
2248
2249	// (~X) - (~Y) --> Y - X
2250	{
2251	// Need to ensure we can consume at least one of the `not` instructions,
2252	// otherwise this can inf loop.
2253	bool ConsumesOp0, ConsumesOp1;
2254	if (isFreeToInvert(V: Op0, WillInvertAllUses: Op0->hasOneUse(), DoesConsume&: ConsumesOp0) &&
2255	isFreeToInvert(V: Op1, WillInvertAllUses: Op1->hasOneUse(), DoesConsume&: ConsumesOp1) &&
2256	(ConsumesOp0 || ConsumesOp1)) {
2257	Value *NotOp0 = getFreelyInverted(V: Op0, WillInvertAllUses: Op0->hasOneUse(), Builder: &Builder);
2258	Value *NotOp1 = getFreelyInverted(V: Op1, WillInvertAllUses: Op1->hasOneUse(), Builder: &Builder);
2259	assert(NotOp0 != nullptr && NotOp1 != nullptr &&
2260	"isFreeToInvert desynced with getFreelyInverted");
2261	return BinaryOperator::CreateSub(V1: NotOp1, V2: NotOp0);
2262	}
2263	}
2264
2265	auto m_AddRdx = [](Value *&Vec) {
2266	return m_OneUse(m_Intrinsic<Intrinsic::vector_reduce_add>(m_Value(Vec)));
2267	};
2268	Value *V0, *V1;
2269	if (match(Op0, m_AddRdx(V0)) && match(Op1, m_AddRdx(V1)) &&
2270	V0->getType() == V1->getType()) {
2271	// Difference of sums is sum of differences:
2272	// add_rdx(V0) - add_rdx(V1) --> add_rdx(V0 - V1)
2273	Value *Sub = Builder.CreateSub(LHS: V0, RHS: V1);
2274	Value *Rdx = Builder.CreateIntrinsic(Intrinsic::vector_reduce_add,
2275	{Sub->getType()}, {Sub});
2276	return replaceInstUsesWith(I, V: Rdx);
2277	}
2278
2279	if (Constant *C = dyn_cast<Constant>(Val: Op0)) {
2280	Value *X;
2281	if (match(V: Op1, P: m_ZExt(Op: m_Value(V&: X))) && X->getType()->isIntOrIntVectorTy(BitWidth: 1))
2282	// C - (zext bool) --> bool ? C - 1 : C
2283	return SelectInst::Create(C: X, S1: InstCombiner::SubOne(C), S2: C);
2284	if (match(V: Op1, P: m_SExt(Op: m_Value(V&: X))) && X->getType()->isIntOrIntVectorTy(BitWidth: 1))
2285	// C - (sext bool) --> bool ? C + 1 : C
2286	return SelectInst::Create(C: X, S1: InstCombiner::AddOne(C), S2: C);
2287
2288	// C - ~X == X + (1+C)
2289	if (match(V: Op1, P: m_Not(V: m_Value(V&: X))))
2290	return BinaryOperator::CreateAdd(V1: X, V2: InstCombiner::AddOne(C));
2291
2292	// Try to fold constant sub into select arguments.
2293	if (SelectInst *SI = dyn_cast<SelectInst>(Val: Op1))
2294	if (Instruction *R = FoldOpIntoSelect(Op&: I, SI))
2295	return R;
2296
2297	// Try to fold constant sub into PHI values.
2298	if (PHINode *PN = dyn_cast<PHINode>(Val: Op1))
2299	if (Instruction *R = foldOpIntoPhi(I, PN))
2300	return R;
2301
2302	Constant *C2;
2303
2304	// C-(C2-X) --> X+(C-C2)
2305	if (match(V: Op1, P: m_Sub(L: m_ImmConstant(C&: C2), R: m_Value(V&: X))))
2306	return BinaryOperator::CreateAdd(V1: X, V2: ConstantExpr::getSub(C1: C, C2));
2307	}
2308
2309	const APInt *Op0C;
2310	if (match(V: Op0, P: m_APInt(Res&: Op0C))) {
2311	if (Op0C->isMask()) {
2312	// Turn this into a xor if LHS is 2^n-1 and the remaining bits are known
2313	// zero. We don't use information from dominating conditions so this
2314	// transform is easier to reverse if necessary.
2315	KnownBits RHSKnown = llvm::computeKnownBits(
2316	V: Op1, Depth: 0, Q: SQ.getWithInstruction(I: &I).getWithoutDomCondCache());
2317	if ((*Op0C | RHSKnown.Zero).isAllOnes())
2318	return BinaryOperator::CreateXor(V1: Op1, V2: Op0);
2319	}
2320
2321	// C - ((C3 -nuw X) & C2) --> (C - (C2 & C3)) + (X & C2) when:
2322	// (C3 - ((C2 & C3) - 1)) is pow2
2323	// ((C2 + C3) & ((C2 & C3) - 1)) == ((C2 & C3) - 1)
2324	// C2 is negative pow2 || sub nuw
2325	const APInt *C2, *C3;
2326	BinaryOperator *InnerSub;
2327	if (match(V: Op1, P: m_OneUse(SubPattern: m_And(L: m_BinOp(I&: InnerSub), R: m_APInt(Res&: C2)))) &&
2328	match(V: InnerSub, P: m_Sub(L: m_APInt(Res&: C3), R: m_Value(V&: X))) &&
2329	(InnerSub->hasNoUnsignedWrap() || C2->isNegatedPowerOf2())) {
2330	APInt C2AndC3 = *C2 & *C3;
2331	APInt C2AndC3Minus1 = C2AndC3 - 1;
2332	APInt C2AddC3 = *C2 + *C3;
2333	if ((*C3 - C2AndC3Minus1).isPowerOf2() &&
2334	C2AndC3Minus1.isSubsetOf(RHS: C2AddC3)) {
2335	Value *And = Builder.CreateAnd(LHS: X, RHS: ConstantInt::get(Ty: I.getType(), V: *C2));
2336	return BinaryOperator::CreateAdd(
2337	V1: And, V2: ConstantInt::get(Ty: I.getType(), V: *Op0C - C2AndC3));
2338	}
2339	}
2340	}
2341
2342	{
2343	Value *Y;
2344	// X-(X+Y) == -Y X-(Y+X) == -Y
2345	if (match(V: Op1, P: m_c_Add(L: m_Specific(V: Op0), R: m_Value(V&: Y))))
2346	return BinaryOperator::CreateNeg(Op: Y);
2347
2348	// (X-Y)-X == -Y
2349	if (match(V: Op0, P: m_Sub(L: m_Specific(V: Op1), R: m_Value(V&: Y))))
2350	return BinaryOperator::CreateNeg(Op: Y);
2351	}
2352
2353	// (sub (or A, B) (and A, B)) --> (xor A, B)
2354	{
2355	Value *A, *B;
2356	if (match(V: Op1, P: m_And(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2357	match(V: Op0, P: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B))))
2358	return BinaryOperator::CreateXor(V1: A, V2: B);
2359	}
2360
2361	// (sub (add A, B) (or A, B)) --> (and A, B)
2362	{
2363	Value *A, *B;
2364	if (match(V: Op0, P: m_Add(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2365	match(V: Op1, P: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B))))
2366	return BinaryOperator::CreateAnd(V1: A, V2: B);
2367	}
2368
2369	// (sub (add A, B) (and A, B)) --> (or A, B)
2370	{
2371	Value *A, *B;
2372	if (match(V: Op0, P: m_Add(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2373	match(V: Op1, P: m_c_And(L: m_Specific(V: A), R: m_Specific(V: B))))
2374	return BinaryOperator::CreateOr(V1: A, V2: B);
2375	}
2376
2377	// (sub (and A, B) (or A, B)) --> neg (xor A, B)
2378	{
2379	Value *A, *B;
2380	if (match(V: Op0, P: m_And(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2381	match(V: Op1, P: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B))) &&
2382	(Op0->hasOneUse() || Op1->hasOneUse()))
2383	return BinaryOperator::CreateNeg(Op: Builder.CreateXor(LHS: A, RHS: B));
2384	}
2385
2386	// (sub (or A, B), (xor A, B)) --> (and A, B)
2387	{
2388	Value *A, *B;
2389	if (match(V: Op1, P: m_Xor(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2390	match(V: Op0, P: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B))))
2391	return BinaryOperator::CreateAnd(V1: A, V2: B);
2392	}
2393
2394	// (sub (xor A, B) (or A, B)) --> neg (and A, B)
2395	{
2396	Value *A, *B;
2397	if (match(V: Op0, P: m_Xor(L: m_Value(V&: A), R: m_Value(V&: B))) &&
2398	match(V: Op1, P: m_c_Or(L: m_Specific(V: A), R: m_Specific(V: B))) &&
2399	(Op0->hasOneUse() || Op1->hasOneUse()))
2400	return BinaryOperator::CreateNeg(Op: Builder.CreateAnd(LHS: A, RHS: B));
2401	}
2402
2403	{
2404	Value *Y;
2405	// ((X | Y) - X) --> (~X & Y)
2406	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_Or(L: m_Value(V&: Y), R: m_Specific(V: Op1)))))
2407	return BinaryOperator::CreateAnd(
2408	V1: Y, V2: Builder.CreateNot(V: Op1, Name: Op1->getName() + ".not"));
2409	}
2410
2411	{
2412	// (sub (and Op1, (neg X)), Op1) --> neg (and Op1, (add X, -1))
2413	Value *X;
2414	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_And(L: m_Specific(V: Op1),
2415	R: m_OneUse(SubPattern: m_Neg(V: m_Value(V&: X))))))) {
2416	return BinaryOperator::CreateNeg(Op: Builder.CreateAnd(
2417	LHS: Op1, RHS: Builder.CreateAdd(LHS: X, RHS: Constant::getAllOnesValue(Ty: I.getType()))));
2418	}
2419	}
2420
2421	{
2422	// (sub (and Op1, C), Op1) --> neg (and Op1, ~C)
2423	Constant *C;
2424	if (match(V: Op0, P: m_OneUse(SubPattern: m_And(L: m_Specific(V: Op1), R: m_Constant(C))))) {
2425	return BinaryOperator::CreateNeg(
2426	Op: Builder.CreateAnd(LHS: Op1, RHS: Builder.CreateNot(V: C)));
2427	}
2428	}
2429
2430	{
2431	// (sub (xor X, (sext C)), (sext C)) => (select C, (neg X), X)
2432	// (sub (sext C), (xor X, (sext C))) => (select C, X, (neg X))
2433	Value *C, *X;
2434	auto m_SubXorCmp = [&C, &X](Value *LHS, Value *RHS) {
2435	return match(V: LHS, P: m_OneUse(SubPattern: m_c_Xor(L: m_Value(V&: X), R: m_Specific(V: RHS)))) &&
2436	match(V: RHS, P: m_SExt(Op: m_Value(V&: C))) &&
2437	(C->getType()->getScalarSizeInBits() == 1);
2438	};
2439	if (m_SubXorCmp(Op0, Op1))
2440	return SelectInst::Create(C, S1: Builder.CreateNeg(V: X), S2: X);
2441	if (m_SubXorCmp(Op1, Op0))
2442	return SelectInst::Create(C, S1: X, S2: Builder.CreateNeg(V: X));
2443	}
2444
2445	if (Instruction *R = tryFoldInstWithCtpopWithNot(I: &I))
2446	return R;
2447
2448	if (Instruction *R = foldSubOfMinMax(I, Builder))
2449	return R;
2450
2451	{
2452	// If we have a subtraction between some value and a select between
2453	// said value and something else, sink subtraction into select hands, i.e.:
2454	// sub (select %Cond, %TrueVal, %FalseVal), %Op1
2455	// ->
2456	// select %Cond, (sub %TrueVal, %Op1), (sub %FalseVal, %Op1)
2457	// or
2458	// sub %Op0, (select %Cond, %TrueVal, %FalseVal)
2459	// ->
2460	// select %Cond, (sub %Op0, %TrueVal), (sub %Op0, %FalseVal)
2461	// This will result in select between new subtraction and 0.
2462	auto SinkSubIntoSelect =
2463	[Ty = I.getType()](Value *Select, Value *OtherHandOfSub,
2464	auto SubBuilder) -> Instruction * {
2465	Value *Cond, *TrueVal, *FalseVal;
2466	if (!match(V: Select, P: m_OneUse(SubPattern: m_Select(C: m_Value(V&: Cond), L: m_Value(V&: TrueVal),
2467	R: m_Value(V&: FalseVal)))))
2468	return nullptr;
2469	if (OtherHandOfSub != TrueVal && OtherHandOfSub != FalseVal)
2470	return nullptr;
2471	// While it is really tempting to just create two subtractions and let
2472	// InstCombine fold one of those to 0, it isn't possible to do so
2473	// because of worklist visitation order. So ugly it is.
2474	bool OtherHandOfSubIsTrueVal = OtherHandOfSub == TrueVal;
2475	Value *NewSub = SubBuilder(OtherHandOfSubIsTrueVal ? FalseVal : TrueVal);
2476	Constant *Zero = Constant::getNullValue(Ty);
2477	SelectInst *NewSel =
2478	SelectInst::Create(C: Cond, S1: OtherHandOfSubIsTrueVal ? Zero : NewSub,
2479	S2: OtherHandOfSubIsTrueVal ? NewSub : Zero);
2480	// Preserve prof metadata if any.
2481	NewSel->copyMetadata(SrcInst: cast<Instruction>(Val&: *Select));
2482	return NewSel;
2483	};
2484	if (Instruction *NewSel = SinkSubIntoSelect(
2485	/*Select=*/Op0, /*OtherHandOfSub=*/Op1,
2486	[Builder = &Builder, Op1](Value *OtherHandOfSelect) {
2487	return Builder->CreateSub(LHS: OtherHandOfSelect,
2488	/*OtherHandOfSub=*/RHS: Op1);
2489	}))
2490	return NewSel;
2491	if (Instruction *NewSel = SinkSubIntoSelect(
2492	/*Select=*/Op1, /*OtherHandOfSub=*/Op0,
2493	[Builder = &Builder, Op0](Value *OtherHandOfSelect) {
2494	return Builder->CreateSub(/*OtherHandOfSub=*/LHS: Op0,
2495	RHS: OtherHandOfSelect);
2496	}))
2497	return NewSel;
2498	}
2499
2500	// (X - (X & Y)) --> (X & ~Y)
2501	if (match(V: Op1, P: m_c_And(L: m_Specific(V: Op0), R: m_Value(V&: Y))) &&
2502	(Op1->hasOneUse() || isa<Constant>(Val: Y)))
2503	return BinaryOperator::CreateAnd(
2504	V1: Op0, V2: Builder.CreateNot(V: Y, Name: Y->getName() + ".not"));
2505
2506	// ~X - Min/Max(~X, Y) -> ~Min/Max(X, ~Y) - X
2507	// ~X - Min/Max(Y, ~X) -> ~Min/Max(X, ~Y) - X
2508	// Min/Max(~X, Y) - ~X -> X - ~Min/Max(X, ~Y)
2509	// Min/Max(Y, ~X) - ~X -> X - ~Min/Max(X, ~Y)
2510	// As long as Y is freely invertible, this will be neutral or a win.
2511	// Note: We don't generate the inverse max/min, just create the 'not' of
2512	// it and let other folds do the rest.
2513	if (match(V: Op0, P: m_Not(V: m_Value(V&: X))) &&
2514	match(V: Op1, P: m_c_MaxOrMin(L: m_Specific(V: Op0), R: m_Value(V&: Y))) &&
2515	!Op0->hasNUsesOrMore(N: 3) && isFreeToInvert(V: Y, WillInvertAllUses: Y->hasOneUse())) {
2516	Value *Not = Builder.CreateNot(V: Op1);
2517	return BinaryOperator::CreateSub(V1: Not, V2: X);
2518	}
2519	if (match(V: Op1, P: m_Not(V: m_Value(V&: X))) &&
2520	match(V: Op0, P: m_c_MaxOrMin(L: m_Specific(V: Op1), R: m_Value(V&: Y))) &&
2521	!Op1->hasNUsesOrMore(N: 3) && isFreeToInvert(V: Y, WillInvertAllUses: Y->hasOneUse())) {
2522	Value *Not = Builder.CreateNot(V: Op0);
2523	return BinaryOperator::CreateSub(V1: X, V2: Not);
2524	}
2525
2526	// Optimize pointer differences into the same array into a size. Consider:
2527	// &A[10] - &A[0]: we should compile this to "10".
2528	Value *LHSOp, *RHSOp;
2529	if (match(V: Op0, P: m_PtrToInt(Op: m_Value(V&: LHSOp))) &&
2530	match(V: Op1, P: m_PtrToInt(Op: m_Value(V&: RHSOp))))
2531	if (Value *Res = OptimizePointerDifference(LHS: LHSOp, RHS: RHSOp, Ty: I.getType(),
2532	IsNUW: I.hasNoUnsignedWrap()))
2533	return replaceInstUsesWith(I, V: Res);
2534
2535	// trunc(p)-trunc(q) -> trunc(p-q)
2536	if (match(V: Op0, P: m_Trunc(Op: m_PtrToInt(Op: m_Value(V&: LHSOp)))) &&
2537	match(V: Op1, P: m_Trunc(Op: m_PtrToInt(Op: m_Value(V&: RHSOp)))))
2538	if (Value *Res = OptimizePointerDifference(LHS: LHSOp, RHS: RHSOp, Ty: I.getType(),
2539	/* IsNUW */ false))
2540	return replaceInstUsesWith(I, V: Res);
2541
2542	// Canonicalize a shifty way to code absolute value to the common pattern.
2543	// There are 2 potential commuted variants.
2544	// We're relying on the fact that we only do this transform when the shift has
2545	// exactly 2 uses and the xor has exactly 1 use (otherwise, we might increase
2546	// instructions).
2547	Value *A;
2548	const APInt *ShAmt;
2549	Type *Ty = I.getType();
2550	unsigned BitWidth = Ty->getScalarSizeInBits();
2551	if (match(V: Op1, P: m_AShr(L: m_Value(V&: A), R: m_APInt(Res&: ShAmt))) &&
2552	Op1->hasNUses(N: 2) && *ShAmt == BitWidth - 1 &&
2553	match(V: Op0, P: m_OneUse(SubPattern: m_c_Xor(L: m_Specific(V: A), R: m_Specific(V: Op1))))) {
2554	// B = ashr i32 A, 31 ; smear the sign bit
2555	// sub (xor A, B), B ; flip bits if negative and subtract -1 (add 1)
2556	// --> (A < 0) ? -A : A
2557	Value *IsNeg = Builder.CreateIsNeg(Arg: A);
2558	// Copy the nsw flags from the sub to the negate.
2559	Value *NegA = I.hasNoUnsignedWrap()
2560	? Constant::getNullValue(Ty: A->getType())
2561	: Builder.CreateNeg(V: A, Name: "", HasNSW: I.hasNoSignedWrap());
2562	return SelectInst::Create(C: IsNeg, S1: NegA, S2: A);
2563	}
2564
2565	// If we are subtracting a low-bit masked subset of some value from an add
2566	// of that same value with no low bits changed, that is clearing some low bits
2567	// of the sum:
2568	// sub (X + AddC), (X & AndC) --> and (X + AddC), ~AndC
2569	const APInt *AddC, *AndC;
2570	if (match(V: Op0, P: m_Add(L: m_Value(V&: X), R: m_APInt(Res&: AddC))) &&
2571	match(V: Op1, P: m_And(L: m_Specific(V: X), R: m_APInt(Res&: AndC)))) {
2572	unsigned Cttz = AddC->countr_zero();
2573	APInt HighMask(APInt::getHighBitsSet(numBits: BitWidth, hiBitsSet: BitWidth - Cttz));
2574	if ((HighMask & *AndC).isZero())
2575	return BinaryOperator::CreateAnd(V1: Op0, V2: ConstantInt::get(Ty, V: ~(*AndC)));
2576	}
2577
2578	if (Instruction *V =
2579	canonicalizeCondSignextOfHighBitExtractToSignextHighBitExtract(I))
2580	return V;
2581
2582	// X - usub.sat(X, Y) => umin(X, Y)
2583	if (match(Op1, m_OneUse(m_Intrinsic<Intrinsic::usub_sat>(m_Specific(Op0),
2584	m_Value(Y)))))
2585	return replaceInstUsesWith(
2586	I, V: Builder.CreateIntrinsic(Intrinsic::umin, {I.getType()}, {Op0, Y}));
2587
2588	// umax(X, Op1) - Op1 --> usub.sat(X, Op1)
2589	// TODO: The one-use restriction is not strictly necessary, but it may
2590	// require improving other pattern matching and/or codegen.
2591	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_UMax(L: m_Value(V&: X), R: m_Specific(V: Op1)))))
2592	return replaceInstUsesWith(
2593	I, V: Builder.CreateIntrinsic(Intrinsic::usub_sat, {Ty}, {X, Op1}));
2594
2595	// Op0 - umin(X, Op0) --> usub.sat(Op0, X)
2596	if (match(V: Op1, P: m_OneUse(SubPattern: m_c_UMin(L: m_Value(V&: X), R: m_Specific(V: Op0)))))
2597	return replaceInstUsesWith(
2598	I, V: Builder.CreateIntrinsic(Intrinsic::usub_sat, {Ty}, {Op0, X}));
2599
2600	// Op0 - umax(X, Op0) --> 0 - usub.sat(X, Op0)
2601	if (match(V: Op1, P: m_OneUse(SubPattern: m_c_UMax(L: m_Value(V&: X), R: m_Specific(V: Op0))))) {
2602	Value *USub = Builder.CreateIntrinsic(Intrinsic::usub_sat, {Ty}, {X, Op0});
2603	return BinaryOperator::CreateNeg(Op: USub);
2604	}
2605
2606	// umin(X, Op1) - Op1 --> 0 - usub.sat(Op1, X)
2607	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_UMin(L: m_Value(V&: X), R: m_Specific(V: Op1))))) {
2608	Value *USub = Builder.CreateIntrinsic(Intrinsic::usub_sat, {Ty}, {Op1, X});
2609	return BinaryOperator::CreateNeg(Op: USub);
2610	}
2611
2612	// C - ctpop(X) => ctpop(~X) if C is bitwidth
2613	if (match(Op0, m_SpecificInt(BitWidth)) &&
2614	match(Op1, m_OneUse(m_Intrinsic<Intrinsic::ctpop>(m_Value(X)))))
2615	return replaceInstUsesWith(
2616	I, V: Builder.CreateIntrinsic(Intrinsic::ctpop, {I.getType()},
2617	{Builder.CreateNot(V: X)}));
2618
2619	// Reduce multiplies for difference-of-squares by factoring:
2620	// (X * X) - (Y * Y) --> (X + Y) * (X - Y)
2621	if (match(V: Op0, P: m_OneUse(SubPattern: m_Mul(L: m_Value(V&: X), R: m_Deferred(V: X)))) &&
2622	match(V: Op1, P: m_OneUse(SubPattern: m_Mul(L: m_Value(V&: Y), R: m_Deferred(V: Y))))) {
2623	auto *OBO0 = cast<OverflowingBinaryOperator>(Val: Op0);
2624	auto *OBO1 = cast<OverflowingBinaryOperator>(Val: Op1);
2625	bool PropagateNSW = I.hasNoSignedWrap() && OBO0->hasNoSignedWrap() &&
2626	OBO1->hasNoSignedWrap() && BitWidth > 2;
2627	bool PropagateNUW = I.hasNoUnsignedWrap() && OBO0->hasNoUnsignedWrap() &&
2628	OBO1->hasNoUnsignedWrap() && BitWidth > 1;
2629	Value *Add = Builder.CreateAdd(LHS: X, RHS: Y, Name: "add", HasNUW: PropagateNUW, HasNSW: PropagateNSW);
2630	Value *Sub = Builder.CreateSub(LHS: X, RHS: Y, Name: "sub", HasNUW: PropagateNUW, HasNSW: PropagateNSW);
2631	Value *Mul = Builder.CreateMul(LHS: Add, RHS: Sub, Name: "", HasNUW: PropagateNUW, HasNSW: PropagateNSW);
2632	return replaceInstUsesWith(I, V: Mul);
2633	}
2634
2635	// max(X,Y) nsw/nuw - min(X,Y) --> abs(X nsw - Y)
2636	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_SMax(L: m_Value(V&: X), R: m_Value(V&: Y)))) &&
2637	match(V: Op1, P: m_OneUse(SubPattern: m_c_SMin(L: m_Specific(V: X), R: m_Specific(V: Y))))) {
2638	if (I.hasNoUnsignedWrap() || I.hasNoSignedWrap()) {
2639	Value *Sub =
2640	Builder.CreateSub(LHS: X, RHS: Y, Name: "sub", /*HasNUW=*/false, /*HasNSW=*/true);
2641	Value *Call =
2642	Builder.CreateBinaryIntrinsic(Intrinsic::ID: abs, LHS: Sub, RHS: Builder.getTrue());
2643	return replaceInstUsesWith(I, V: Call);
2644	}
2645	}
2646
2647	if (Instruction *Res = foldBinOpOfSelectAndCastOfSelectCondition(I))
2648	return Res;
2649
2650	return TryToNarrowDeduceFlags();
2651	}
2652
2653	/// This eliminates floating-point negation in either 'fneg(X)' or
2654	/// 'fsub(-0.0, X)' form by combining into a constant operand.
2655	static Instruction *foldFNegIntoConstant(Instruction &I, const DataLayout &DL) {
2656	// This is limited with one-use because fneg is assumed better for
2657	// reassociation and cheaper in codegen than fmul/fdiv.
2658	// TODO: Should the m_OneUse restriction be removed?
2659	Instruction *FNegOp;
2660	if (!match(V: &I, P: m_FNeg(X: m_OneUse(SubPattern: m_Instruction(I&: FNegOp)))))
2661	return nullptr;
2662
2663	Value *X;
2664	Constant *C;
2665
2666	// Fold negation into constant operand.
2667	// -(X * C) --> X * (-C)
2668	if (match(V: FNegOp, P: m_FMul(L: m_Value(V&: X), R: m_Constant(C))))
2669	if (Constant *NegC = ConstantFoldUnaryOpOperand(Opcode: Instruction::FNeg, Op: C, DL))
2670	return BinaryOperator::CreateFMulFMF(V1: X, V2: NegC, FMFSource: &I);
2671	// -(X / C) --> X / (-C)
2672	if (match(V: FNegOp, P: m_FDiv(L: m_Value(V&: X), R: m_Constant(C))))
2673	if (Constant *NegC = ConstantFoldUnaryOpOperand(Opcode: Instruction::FNeg, Op: C, DL))
2674	return BinaryOperator::CreateFDivFMF(V1: X, V2: NegC, FMFSource: &I);
2675	// -(C / X) --> (-C) / X
2676	if (match(V: FNegOp, P: m_FDiv(L: m_Constant(C), R: m_Value(V&: X))))
2677	if (Constant *NegC = ConstantFoldUnaryOpOperand(Opcode: Instruction::FNeg, Op: C, DL)) {
2678	Instruction *FDiv = BinaryOperator::CreateFDivFMF(V1: NegC, V2: X, FMFSource: &I);
2679
2680	// Intersect 'nsz' and 'ninf' because those special value exceptions may
2681	// not apply to the fdiv. Everything else propagates from the fneg.
2682	// TODO: We could propagate nsz/ninf from fdiv alone?
2683	FastMathFlags FMF = I.getFastMathFlags();
2684	FastMathFlags OpFMF = FNegOp->getFastMathFlags();
2685	FDiv->setHasNoSignedZeros(FMF.noSignedZeros() && OpFMF.noSignedZeros());
2686	FDiv->setHasNoInfs(FMF.noInfs() && OpFMF.noInfs());
2687	return FDiv;
2688	}
2689	// With NSZ [ counter-example with -0.0: -(-0.0 + 0.0) != 0.0 + -0.0 ]:
2690	// -(X + C) --> -X + -C --> -C - X
2691	if (I.hasNoSignedZeros() && match(V: FNegOp, P: m_FAdd(L: m_Value(V&: X), R: m_Constant(C))))
2692	if (Constant *NegC = ConstantFoldUnaryOpOperand(Opcode: Instruction::FNeg, Op: C, DL))
2693	return BinaryOperator::CreateFSubFMF(V1: NegC, V2: X, FMFSource: &I);
2694
2695	return nullptr;
2696	}
2697
2698	Instruction *InstCombinerImpl::hoistFNegAboveFMulFDiv(Value *FNegOp,
2699	Instruction &FMFSource) {
2700	Value *X, *Y;
2701	if (match(V: FNegOp, P: m_FMul(L: m_Value(V&: X), R: m_Value(V&: Y)))) {
2702	return cast<Instruction>(Val: Builder.CreateFMulFMF(
2703	L: Builder.CreateFNegFMF(V: X, FMFSource: &FMFSource), R: Y, FMFSource: &FMFSource));
2704	}
2705
2706	if (match(V: FNegOp, P: m_FDiv(L: m_Value(V&: X), R: m_Value(V&: Y)))) {
2707	return cast<Instruction>(Val: Builder.CreateFDivFMF(
2708	L: Builder.CreateFNegFMF(V: X, FMFSource: &FMFSource), R: Y, FMFSource: &FMFSource));
2709	}
2710
2711	if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Val: FNegOp)) {
2712	// Make sure to preserve flags and metadata on the call.
2713	if (II->getIntrinsicID() == Intrinsic::ldexp) {
2714	FastMathFlags FMF = FMFSource.getFastMathFlags() | II->getFastMathFlags();
2715	IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
2716	Builder.setFastMathFlags(FMF);
2717
2718	CallInst *New = Builder.CreateCall(
2719	Callee: II->getCalledFunction(),
2720	Args: {Builder.CreateFNeg(V: II->getArgOperand(i: 0)), II->getArgOperand(i: 1)});
2721	New->copyMetadata(SrcInst: *II);
2722	return New;
2723	}
2724	}
2725
2726	return nullptr;
2727	}
2728
2729	Instruction *InstCombinerImpl::visitFNeg(UnaryOperator &I) {
2730	Value *Op = I.getOperand(i_nocapture: 0);
2731
2732	if (Value *V = simplifyFNegInst(Op, FMF: I.getFastMathFlags(),
2733	Q: getSimplifyQuery().getWithInstruction(I: &I)))
2734	return replaceInstUsesWith(I, V);
2735
2736	if (Instruction *X = foldFNegIntoConstant(I, DL))
2737	return X;
2738
2739	Value *X, *Y;
2740
2741	// If we can ignore the sign of zeros: -(X - Y) --> (Y - X)
2742	if (I.hasNoSignedZeros() &&
2743	match(V: Op, P: m_OneUse(SubPattern: m_FSub(L: m_Value(V&: X), R: m_Value(V&: Y)))))
2744	return BinaryOperator::CreateFSubFMF(V1: Y, V2: X, FMFSource: &I);
2745
2746	Value *OneUse;
2747	if (!match(V: Op, P: m_OneUse(SubPattern: m_Value(V&: OneUse))))
2748	return nullptr;
2749
2750	if (Instruction *R = hoistFNegAboveFMulFDiv(FNegOp: OneUse, FMFSource&: I))
2751	return replaceInstUsesWith(I, V: R);
2752
2753	// Try to eliminate fneg if at least 1 arm of the select is negated.
2754	Value *Cond;
2755	if (match(V: OneUse, P: m_Select(C: m_Value(V&: Cond), L: m_Value(V&: X), R: m_Value(V&: Y)))) {
2756	// Unlike most transforms, this one is not safe to propagate nsz unless
2757	// it is present on the original select. We union the flags from the select
2758	// and fneg and then remove nsz if needed.
2759	auto propagateSelectFMF = [&](SelectInst *S, bool CommonOperand) {
2760	S->copyFastMathFlags(I: &I);
2761	if (auto *OldSel = dyn_cast<SelectInst>(Val: Op)) {
2762	FastMathFlags FMF = I.getFastMathFlags() | OldSel->getFastMathFlags();
2763	S->setFastMathFlags(FMF);
2764	if (!OldSel->hasNoSignedZeros() && !CommonOperand &&
2765	!isGuaranteedNotToBeUndefOrPoison(V: OldSel->getCondition()))
2766	S->setHasNoSignedZeros(false);
2767	}
2768	};
2769	// -(Cond ? -P : Y) --> Cond ? P : -Y
2770	Value *P;
2771	if (match(V: X, P: m_FNeg(X: m_Value(V&: P)))) {
2772	Value *NegY = Builder.CreateFNegFMF(V: Y, FMFSource: &I, Name: Y->getName() + ".neg");
2773	SelectInst *NewSel = SelectInst::Create(C: Cond, S1: P, S2: NegY);
2774	propagateSelectFMF(NewSel, P == Y);
2775	return NewSel;
2776	}
2777	// -(Cond ? X : -P) --> Cond ? -X : P
2778	if (match(V: Y, P: m_FNeg(X: m_Value(V&: P)))) {
2779	Value *NegX = Builder.CreateFNegFMF(V: X, FMFSource: &I, Name: X->getName() + ".neg");
2780	SelectInst *NewSel = SelectInst::Create(C: Cond, S1: NegX, S2: P);
2781	propagateSelectFMF(NewSel, P == X);
2782	return NewSel;
2783	}
2784	}
2785
2786	// fneg (copysign x, y) -> copysign x, (fneg y)
2787	if (match(V: OneUse, P: m_CopySign(Op0: m_Value(V&: X), Op1: m_Value(V&: Y)))) {
2788	// The source copysign has an additional value input, so we can't propagate
2789	// flags the copysign doesn't also have.
2790	FastMathFlags FMF = I.getFastMathFlags();
2791	FMF &= cast<FPMathOperator>(Val: OneUse)->getFastMathFlags();
2792
2793	IRBuilder<>::FastMathFlagGuard FMFGuard(Builder);
2794	Builder.setFastMathFlags(FMF);
2795
2796	Value *NegY = Builder.CreateFNeg(V: Y);
2797	Value *NewCopySign = Builder.CreateCopySign(LHS: X, RHS: NegY);
2798	return replaceInstUsesWith(I, V: NewCopySign);
2799	}
2800
2801	return nullptr;
2802	}
2803
2804	Instruction *InstCombinerImpl::visitFSub(BinaryOperator &I) {
2805	if (Value *V = simplifyFSubInst(LHS: I.getOperand(i_nocapture: 0), RHS: I.getOperand(i_nocapture: 1),
2806	FMF: I.getFastMathFlags(),
2807	Q: getSimplifyQuery().getWithInstruction(I: &I)))
2808	return replaceInstUsesWith(I, V);
2809
2810	if (Instruction *X = foldVectorBinop(Inst&: I))
2811	return X;
2812
2813	if (Instruction *Phi = foldBinopWithPhiOperands(BO&: I))
2814	return Phi;
2815
2816	// Subtraction from -0.0 is the canonical form of fneg.
2817	// fsub -0.0, X ==> fneg X
2818	// fsub nsz 0.0, X ==> fneg nsz X
2819	//
2820	// FIXME This matcher does not respect FTZ or DAZ yet:
2821	// fsub -0.0, Denorm ==> +-0
2822	// fneg Denorm ==> -Denorm
2823	Value *Op;
2824	if (match(V: &I, P: m_FNeg(X: m_Value(V&: Op))))
2825	return UnaryOperator::CreateFNegFMF(Op, FMFSource: &I);
2826
2827	if (Instruction *X = foldFNegIntoConstant(I, DL))
2828	return X;
2829
2830	if (Instruction *R = foldFBinOpOfIntCasts(I))
2831	return R;
2832
2833	Value *X, *Y;
2834	Constant *C;
2835
2836	Value *Op0 = I.getOperand(i_nocapture: 0), *Op1 = I.getOperand(i_nocapture: 1);
2837	// If Op0 is not -0.0 or we can ignore -0.0: Z - (X - Y) --> Z + (Y - X)
2838	// Canonicalize to fadd to make analysis easier.
2839	// This can also help codegen because fadd is commutative.
2840	// Note that if this fsub was really an fneg, the fadd with -0.0 will get
2841	// killed later. We still limit that particular transform with 'hasOneUse'
2842	// because an fneg is assumed better/cheaper than a generic fsub.
2843	if (I.hasNoSignedZeros() ||
2844	cannotBeNegativeZero(V: Op0, Depth: 0, SQ: getSimplifyQuery().getWithInstruction(I: &I))) {
2845	if (match(V: Op1, P: m_OneUse(SubPattern: m_FSub(L: m_Value(V&: X), R: m_Value(V&: Y))))) {
2846	Value *NewSub = Builder.CreateFSubFMF(L: Y, R: X, FMFSource: &I);
2847	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: NewSub, FMFSource: &I);
2848	}
2849	}
2850
2851	// (-X) - Op1 --> -(X + Op1)
2852	if (I.hasNoSignedZeros() && !isa<ConstantExpr>(Val: Op0) &&
2853	match(V: Op0, P: m_OneUse(SubPattern: m_FNeg(X: m_Value(V&: X))))) {
2854	Value *FAdd = Builder.CreateFAddFMF(L: X, R: Op1, FMFSource: &I);
2855	return UnaryOperator::CreateFNegFMF(Op: FAdd, FMFSource: &I);
2856	}
2857
2858	if (isa<Constant>(Val: Op0))
2859	if (SelectInst *SI = dyn_cast<SelectInst>(Val: Op1))
2860	if (Instruction *NV = FoldOpIntoSelect(Op&: I, SI))
2861	return NV;
2862
2863	// X - C --> X + (-C)
2864	// But don't transform constant expressions because there's an inverse fold
2865	// for X + (-Y) --> X - Y.
2866	if (match(V: Op1, P: m_ImmConstant(C)))
2867	if (Constant *NegC = ConstantFoldUnaryOpOperand(Opcode: Instruction::FNeg, Op: C, DL))
2868	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: NegC, FMFSource: &I);
2869
2870	// X - (-Y) --> X + Y
2871	if (match(V: Op1, P: m_FNeg(X: m_Value(V&: Y))))
2872	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: Y, FMFSource: &I);
2873
2874	// Similar to above, but look through a cast of the negated value:
2875	// X - (fptrunc(-Y)) --> X + fptrunc(Y)
2876	Type *Ty = I.getType();
2877	if (match(V: Op1, P: m_OneUse(SubPattern: m_FPTrunc(Op: m_FNeg(X: m_Value(V&: Y))))))
2878	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: Builder.CreateFPTrunc(V: Y, DestTy: Ty), FMFSource: &I);
2879
2880	// X - (fpext(-Y)) --> X + fpext(Y)
2881	if (match(V: Op1, P: m_OneUse(SubPattern: m_FPExt(Op: m_FNeg(X: m_Value(V&: Y))))))
2882	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: Builder.CreateFPExt(V: Y, DestTy: Ty), FMFSource: &I);
2883
2884	// Similar to above, but look through fmul/fdiv of the negated value:
2885	// Op0 - (-X * Y) --> Op0 + (X * Y)
2886	// Op0 - (Y * -X) --> Op0 + (X * Y)
2887	if (match(V: Op1, P: m_OneUse(SubPattern: m_c_FMul(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y))))) {
2888	Value *FMul = Builder.CreateFMulFMF(L: X, R: Y, FMFSource: &I);
2889	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: FMul, FMFSource: &I);
2890	}
2891	// Op0 - (-X / Y) --> Op0 + (X / Y)
2892	// Op0 - (X / -Y) --> Op0 + (X / Y)
2893	if (match(V: Op1, P: m_OneUse(SubPattern: m_FDiv(L: m_FNeg(X: m_Value(V&: X)), R: m_Value(V&: Y)))) ||
2894	match(V: Op1, P: m_OneUse(SubPattern: m_FDiv(L: m_Value(V&: X), R: m_FNeg(X: m_Value(V&: Y)))))) {
2895	Value *FDiv = Builder.CreateFDivFMF(L: X, R: Y, FMFSource: &I);
2896	return BinaryOperator::CreateFAddFMF(V1: Op0, V2: FDiv, FMFSource: &I);
2897	}
2898
2899	// Handle special cases for FSub with selects feeding the operation
2900	if (Value *V = SimplifySelectsFeedingBinaryOp(I, LHS: Op0, RHS: Op1))
2901	return replaceInstUsesWith(I, V);
2902
2903	if (I.hasAllowReassoc() && I.hasNoSignedZeros()) {
2904	// (Y - X) - Y --> -X
2905	if (match(V: Op0, P: m_FSub(L: m_Specific(V: Op1), R: m_Value(V&: X))))
2906	return UnaryOperator::CreateFNegFMF(Op: X, FMFSource: &I);
2907
2908	// Y - (X + Y) --> -X
2909	// Y - (Y + X) --> -X
2910	if (match(V: Op1, P: m_c_FAdd(L: m_Specific(V: Op0), R: m_Value(V&: X))))
2911	return UnaryOperator::CreateFNegFMF(Op: X, FMFSource: &I);
2912
2913	// (X * C) - X --> X * (C - 1.0)
2914	if (match(V: Op0, P: m_FMul(L: m_Specific(V: Op1), R: m_Constant(C)))) {
2915	if (Constant *CSubOne = ConstantFoldBinaryOpOperands(
2916	Opcode: Instruction::FSub, LHS: C, RHS: ConstantFP::get(Ty, V: 1.0), DL))
2917	return BinaryOperator::CreateFMulFMF(V1: Op1, V2: CSubOne, FMFSource: &I);
2918	}
2919	// X - (X * C) --> X * (1.0 - C)
2920	if (match(V: Op1, P: m_FMul(L: m_Specific(V: Op0), R: m_Constant(C)))) {
2921	if (Constant *OneSubC = ConstantFoldBinaryOpOperands(
2922	Opcode: Instruction::FSub, LHS: ConstantFP::get(Ty, V: 1.0), RHS: C, DL))
2923	return BinaryOperator::CreateFMulFMF(V1: Op0, V2: OneSubC, FMFSource: &I);
2924	}
2925
2926	// Reassociate fsub/fadd sequences to create more fadd instructions and
2927	// reduce dependency chains:
2928	// ((X - Y) + Z) - Op1 --> (X + Z) - (Y + Op1)
2929	Value *Z;
2930	if (match(V: Op0, P: m_OneUse(SubPattern: m_c_FAdd(L: m_OneUse(SubPattern: m_FSub(L: m_Value(V&: X), R: m_Value(V&: Y))),
2931	R: m_Value(V&: Z))))) {
2932	Value *XZ = Builder.CreateFAddFMF(L: X, R: Z, FMFSource: &I);
2933	Value *YW = Builder.CreateFAddFMF(L: Y, R: Op1, FMFSource: &I);
2934	return BinaryOperator::CreateFSubFMF(V1: XZ, V2: YW, FMFSource: &I);
2935	}
2936
2937	auto m_FaddRdx = [](Value *&Sum, Value *&Vec) {
2938	return m_OneUse(m_Intrinsic<Intrinsic::vector_reduce_fadd>(m_Value(Sum),
2939	m_Value(Vec)));
2940	};
2941	Value *A0, *A1, *V0, *V1;
2942	if (match(Op0, m_FaddRdx(A0, V0)) && match(Op1, m_FaddRdx(A1, V1)) &&
2943	V0->getType() == V1->getType()) {
2944	// Difference of sums is sum of differences:
2945	// add_rdx(A0, V0) - add_rdx(A1, V1) --> add_rdx(A0, V0 - V1) - A1
2946	Value *Sub = Builder.CreateFSubFMF(L: V0, R: V1, FMFSource: &I);
2947	Value *Rdx = Builder.CreateIntrinsic(Intrinsic::vector_reduce_fadd,
2948	{Sub->getType()}, {A0, Sub}, &I);
2949	return BinaryOperator::CreateFSubFMF(V1: Rdx, V2: A1, FMFSource: &I);
2950	}
2951
2952	if (Instruction *F = factorizeFAddFSub(I, Builder))
2953	return F;
2954
2955	// TODO: This performs reassociative folds for FP ops. Some fraction of the
2956	// functionality has been subsumed by simple pattern matching here and in
2957	// InstSimplify. We should let a dedicated reassociation pass handle more
2958	// complex pattern matching and remove this from InstCombine.
2959	if (Value *V = FAddCombine(Builder).simplify(I: &I))
2960	return replaceInstUsesWith(I, V);
2961
2962	// (X - Y) - Op1 --> X - (Y + Op1)
2963	if (match(V: Op0, P: m_OneUse(SubPattern: m_FSub(L: m_Value(V&: X), R: m_Value(V&: Y))))) {
2964	Value *FAdd = Builder.CreateFAddFMF(L: Y, R: Op1, FMFSource: &I);
2965	return BinaryOperator::CreateFSubFMF(V1: X, V2: FAdd, FMFSource: &I);
2966	}
2967	}
2968
2969	return nullptr;
2970	}
2971