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 "llvm/Support/Compiler.h"
15#include <cstdint>
16
17namespace llvm {
18
19class SelectionDAG;
20
21/// Helper struct to parse and store a memory address as base + index + offset.
22/// We ignore sign extensions when it is safe to do so.
23/// The following two expressions are not equivalent. To differentiate we need
24/// to store whether there was a sign extension involved in the index
25/// computation.
26/// (load (i64 add (i64 copyfromreg %c)
27/// (i64 signextend (add (i8 load %index)
28/// (i8 1))))
29/// vs
30///
31/// (load (i64 add (i64 copyfromreg %c)
32/// (i64 signextend (i32 add (i32 signextend (i8 load %index))
33/// (i32 1)))))
34class BaseIndexOffset {
35private:
36 SDValue Base;
37 SDValue Index;
38 std::optional<int64_t> Offset;
39 bool IsIndexSignExt = false;
40
41public:
42 BaseIndexOffset() = default;
43 BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)
44 : Base(Base), Index(Index), IsIndexSignExt(IsIndexSignExt) {}
45 BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
46 bool IsIndexSignExt)
47 : Base(Base), Index(Index), Offset(Offset),
48 IsIndexSignExt(IsIndexSignExt) {}
49
50 SDValue getBase() { return Base; }
51 SDValue getBase() const { return Base; }
52 SDValue getIndex() { return Index; }
53 SDValue getIndex() const { return Index; }
54 void addToOffset(int64_t VectorOff) {
55 Offset = Offset.value_or(u: 0) + VectorOff;
56 }
57 bool hasValidOffset() const { return Offset.has_value(); }
58 int64_t getOffset() const { return *Offset; }
59
60 // Returns true if `Other` and `*this` are both some offset from the same base
61 // pointer. In that case, `Off` is set to the offset between `*this` and
62 // `Other` (negative if `Other` is before `*this`).
63 LLVM_ABI bool equalBaseIndex(const BaseIndexOffset &Other,
64 const SelectionDAG &DAG, int64_t &Off) const;
65
66 bool equalBaseIndex(const BaseIndexOffset &Other,
67 const SelectionDAG &DAG) const {
68 int64_t Off;
69 return equalBaseIndex(Other, DAG, Off);
70 }
71
72 // Returns true if `Other` (with size `OtherSize`) can be proven to be fully
73 // contained in `*this` (with size `Size`).
74 LLVM_ABI bool contains(const SelectionDAG &DAG, int64_t BitSize,
75 const BaseIndexOffset &Other, int64_t OtherBitSize,
76 int64_t &BitOffset) const;
77
78 bool contains(const SelectionDAG &DAG, int64_t BitSize,
79 const BaseIndexOffset &Other, int64_t OtherBitSize) const {
80 int64_t BitOffset;
81 return contains(DAG, BitSize, Other, OtherBitSize, BitOffset);
82 }
83
84 // Returns true `Op0` and `Op1` can be proven to alias/not alias, in
85 // which case `IsAlias` is set to true/false.
86 LLVM_ABI static bool computeAliasing(const SDNode *Op0,
87 const LocationSize NumBytes0,
88 const SDNode *Op1,
89 const LocationSize NumBytes1,
90 const SelectionDAG &DAG, bool &IsAlias);
91
92 /// Parses tree in N for base, index, offset addresses.
93 LLVM_ABI static BaseIndexOffset match(const SDNode *N,
94 const SelectionDAG &DAG);
95
96 LLVM_ABI void print(raw_ostream &OS) const;
97 LLVM_ABI void dump() const;
98};
99
100} // end namespace llvm
101
102#endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
103

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