LLVM  9.0.0svn
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;
36  int64_t Offset = 0;
37  bool IsIndexSignExt = false;
38 
39 public:
40  BaseIndexOffset() = default;
41  BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
42  bool IsIndexSignExt)
43  : Base(Base), Index(Index), Offset(Offset),
44  IsIndexSignExt(IsIndexSignExt) {}
45 
46  SDValue getBase() { return Base; }
47  SDValue getBase() const { return Base; }
48  SDValue getIndex() { return Index; }
49  SDValue getIndex() const { return Index; }
50 
51  bool equalBaseIndex(const BaseIndexOffset &Other,
52  const SelectionDAG &DAG) const {
53  int64_t Off;
54  return equalBaseIndex(Other, DAG, Off);
55  }
56 
57  bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG,
58  int64_t &Off) const;
59 
60  /// Parses tree in Ptr for base, index, offset addresses.
61  static BaseIndexOffset match(const LSBaseSDNode *N, const SelectionDAG &DAG);
62 
63  void print(raw_ostream& OS) const;
64  void dump() const;
65 };
66 
67 } // end namespace llvm
68 
69 #endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
This class represents lattice values for constants.
Definition: AllocatorList.h:23
Base class for LoadSDNode and StoreSDNode.
ELFYAML::ELF_STO Other
Definition: ELFYAML.cpp:810
BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset, bool IsIndexSignExt)
Helper struct to parse and store a memory address as base + index + offset.
This is used to represent a portion of an LLVM function in a low-level Data Dependence DAG representa...
Definition: SelectionDAG.h:221
void print(raw_ostream &OS) const
static BaseIndexOffset match(const LSBaseSDNode *N, const SelectionDAG &DAG)
Parses tree in Ptr for base, index, offset addresses.
#define N
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
bool equalBaseIndex(const BaseIndexOffset &Other, const SelectionDAG &DAG) const
Unlike LLVM values, Selection DAG nodes may return multiple values as the result of a computation...