1//===- SelectionDAGAddressAnalysis.h - DAG Address Analysis -----*- 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#ifndef LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
10#define LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
11
12#include "llvm/Analysis/MemoryLocation.h"
13#include "llvm/CodeGen/SelectionDAGNodes.h"
14#include <cstdint>
15
16namespace llvm {
17
18class SelectionDAG;
19
20/// Helper struct to parse and store a memory address as base + index + offset.
21/// We ignore sign extensions when it is safe to do so.
22/// The following two expressions are not equivalent. To differentiate we need
23/// to store whether there was a sign extension involved in the index
24/// computation.
25/// (load (i64 add (i64 copyfromreg %c)
26/// (i64 signextend (add (i8 load %index)
27/// (i8 1))))
28/// vs
29///
30/// (load (i64 add (i64 copyfromreg %c)
31/// (i64 signextend (i32 add (i32 signextend (i8 load %index))
32/// (i32 1)))))
33class BaseIndexOffset {
34private:
35 SDValue Base;
36 SDValue Index;
37 std::optional<int64_t> Offset;
38 bool IsIndexSignExt = false;
39
40public:
41 BaseIndexOffset() = default;
42 BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)
43 : Base(Base), Index(Index), IsIndexSignExt(IsIndexSignExt) {}
44 BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
45 bool IsIndexSignExt)
46 : Base(Base), Index(Index), Offset(Offset),
47 IsIndexSignExt(IsIndexSignExt) {}
48
49 SDValue getBase() { return Base; }
50 SDValue getBase() const { return Base; }
51 SDValue getIndex() { return Index; }
52 SDValue getIndex() const { return Index; }
53 void addToOffset(int64_t VectorOff) {
54 Offset = Offset.value_or(u: 0) + VectorOff;
55 }
56 bool hasValidOffset() const { return Offset.has_value(); }
57 int64_t getOffset() const { return *Offset; }
58
59 // Returns true if `Other` and `*this` are both some offset from the same base
60 // pointer. In that case, `Off` is set to the offset between `*this` and
61 // `Other` (negative if `Other` is before `*this`).
62 bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG,
63 int64_t &Off) const;
64
65 bool equalBaseIndex(const BaseIndexOffset &Other,
66 const SelectionDAG &DAG) const {
67 int64_t Off;
68 return equalBaseIndex(Other, DAG, Off);
69 }
70
71 // Returns true if `Other` (with size `OtherSize`) can be proven to be fully
72 // contained in `*this` (with size `Size`).
73 bool contains(const SelectionDAG &DAG, int64_t BitSize,
74 const BaseIndexOffset &Other, int64_t OtherBitSize,
75 int64_t &BitOffset) const;
76
77 bool contains(const SelectionDAG &DAG, int64_t BitSize,
78 const BaseIndexOffset &Other, int64_t OtherBitSize) const {
79 int64_t BitOffset;
80 return contains(DAG, BitSize, Other, OtherBitSize, BitOffset);
81 }
82
83 // Returns true `Op0` and `Op1` can be proven to alias/not alias, in
84 // which case `IsAlias` is set to true/false.
85 static bool computeAliasing(const SDNode *Op0, const LocationSize NumBytes0,
86 const SDNode *Op1, const LocationSize NumBytes1,
87 const SelectionDAG &DAG, bool &IsAlias);
88
89 /// Parses tree in N for base, index, offset addresses.
90 static BaseIndexOffset match(const SDNode *N, const SelectionDAG &DAG);
91
92 void print(raw_ostream& OS) const;
93 void dump() const;
94};
95
96} // end namespace llvm
97
98#endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
99

source code of llvm/include/llvm/CodeGen/SelectionDAGAddressAnalysis.h