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SelectionDAGAddressAnalysis.h
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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 
13 #include <cstdint>
14 
15 namespace llvm {
16 
17 class SelectionDAG;
18 
19 /// Helper struct to parse and store a memory address as base + index + offset.
20 /// We ignore sign extensions when it is safe to do so.
21 /// The following two expressions are not equivalent. To differentiate we need
22 /// to store whether there was a sign extension involved in the index
23 /// computation.
24 /// (load (i64 add (i64 copyfromreg %c)
25 /// (i64 signextend (add (i8 load %index)
26 /// (i8 1))))
27 /// vs
28 ///
29 /// (load (i64 add (i64 copyfromreg %c)
30 /// (i64 signextend (i32 add (i32 signextend (i8 load %index))
31 /// (i32 1)))))
33 private:
34  SDValue Base;
35  SDValue Index;
37  bool IsIndexSignExt = false;
38 
39 public:
40  BaseIndexOffset() = default;
44  bool IsIndexSignExt)
47 
48  SDValue getBase() { return Base; }
49  SDValue getBase() const { return Base; }
50  SDValue getIndex() { return Index; }
51  SDValue getIndex() const { return Index; }
52  void addToOffset(int64_t VectorOff) {
53  Offset = Offset.value_or(0) + VectorOff;
54  }
55  bool hasValidOffset() const { return Offset.has_value(); }
56  int64_t getOffset() const { return *Offset; }
57 
58  // Returns true if `Other` and `*this` are both some offset from the same base
59  // pointer. In that case, `Off` is set to the offset between `*this` and
60  // `Other` (negative if `Other` is before `*this`).
61  bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG,
62  int64_t &Off) const;
63 
64  bool equalBaseIndex(const BaseIndexOffset &Other,
65  const SelectionDAG &DAG) const {
66  int64_t Off;
67  return equalBaseIndex(Other, DAG, Off);
68  }
69 
70  // Returns true if `Other` (with size `OtherSize`) can be proven to be fully
71  // contained in `*this` (with size `Size`).
72  bool contains(const SelectionDAG &DAG, int64_t BitSize,
73  const BaseIndexOffset &Other, int64_t OtherBitSize,
74  int64_t &BitOffset) const;
75 
76  bool contains(const SelectionDAG &DAG, int64_t BitSize,
77  const BaseIndexOffset &Other, int64_t OtherBitSize) const {
78  int64_t BitOffset;
79  return contains(DAG, BitSize, Other, OtherBitSize, BitOffset);
80  }
81 
82  // Returns true `Op0` and `Op1` can be proven to alias/not alias, in
83  // which case `IsAlias` is set to true/false.
84  static bool computeAliasing(const SDNode *Op0,
85  const Optional<int64_t> NumBytes0,
86  const SDNode *Op1,
87  const Optional<int64_t> NumBytes1,
88  const SelectionDAG &DAG, bool &IsAlias);
89 
90  /// Parses tree in N for base, index, offset addresses.
91  static BaseIndexOffset match(const SDNode *N, const SelectionDAG &DAG);
92 
93  void print(raw_ostream& OS) const;
94  void dump() const;
95 };
96 
97 } // end namespace llvm
98 
99 #endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
llvm::GISelAddressing::BaseIndexOffset
Helper struct to store a base, index and offset that forms an address.
Definition: LoadStoreOpt.h:36
llvm
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
contains
return AArch64::GPR64RegClass contains(Reg)
llvm::BaseIndexOffset::BaseIndexOffset
BaseIndexOffset(SDValue Base, SDValue Index, bool IsIndexSignExt)
Definition: SelectionDAGAddressAnalysis.h:41
llvm::BaseIndexOffset::equalBaseIndex
bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG) const
Definition: SelectionDAGAddressAnalysis.h:64
llvm::SDNode
Represents one node in the SelectionDAG.
Definition: SelectionDAGNodes.h:463
llvm::BaseIndexOffset::getBase
SDValue getBase()
Definition: SelectionDAGAddressAnalysis.h:48
llvm::Optional< int64_t >
llvm::dump
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
Definition: SparseBitVector.h:877
llvm::SelectionDAG
This is used to represent a portion of an LLVM function in a low-level Data Dependence DAG representa...
Definition: SelectionDAG.h:220
SelectionDAGNodes.h
llvm::PatternMatch::match
bool match(Val *V, const Pattern &P)
Definition: PatternMatch.h:49
llvm::dwarf::Index
Index
Definition: Dwarf.h:472
llvm::raw_ostream
This class implements an extremely fast bulk output stream that can only output to a stream.
Definition: raw_ostream.h:52
llvm::GISelAddressing::BaseIndexOffset::IsIndexSignExt
bool IsIndexSignExt
Definition: LoadStoreOpt.h:40
Index
uint32_t Index
Definition: ELFObjHandler.cpp:83
llvm::BaseIndexOffset::addToOffset
void addToOffset(int64_t VectorOff)
Definition: SelectionDAGAddressAnalysis.h:52
llvm::print
Printable print(const GCNRegPressure &RP, const GCNSubtarget *ST=nullptr)
Definition: GCNRegPressure.cpp:138
llvm::BaseIndexOffset::getBase
SDValue getBase() const
Definition: SelectionDAGAddressAnalysis.h:49
llvm::BaseIndexOffset::getOffset
int64_t getOffset() const
Definition: SelectionDAGAddressAnalysis.h:56
llvm::BaseIndexOffset::equalBaseIndex
bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG, int64_t &Off) const
Definition: SelectionDAGAddressAnalysis.cpp:24
llvm::BaseIndexOffset::contains
bool contains(const SelectionDAG &DAG, int64_t BitSize, const BaseIndexOffset &Other, int64_t OtherBitSize) const
Definition: SelectionDAGAddressAnalysis.h:76
llvm::BaseIndexOffset::getIndex
SDValue getIndex()
Definition: SelectionDAGAddressAnalysis.h:50
llvm::GISelAddressing::BaseIndexOffset::Offset
int64_t Offset
Definition: LoadStoreOpt.h:39
llvm::SDValue
Unlike LLVM values, Selection DAG nodes may return multiple values as the result of a computation.
Definition: SelectionDAGNodes.h:145
llvm::BaseIndexOffset::hasValidOffset
bool hasValidOffset() const
Definition: SelectionDAGAddressAnalysis.h:55
N
#define N
llvm::BaseIndexOffset::BaseIndexOffset
BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset, bool IsIndexSignExt)
Definition: SelectionDAGAddressAnalysis.h:43
llvm::BaseIndexOffset::getIndex
SDValue getIndex() const
Definition: SelectionDAGAddressAnalysis.h:51
llvm::sampleprof::Base
@ Base
Definition: Discriminator.h:58
Other
Optional< std::vector< StOtherPiece > > Other
Definition: ELFYAML.cpp:1251