LLVM  6.0.0svn
SelectionDAGAddressAnalysis.h
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1 //===- SelectionDAGAddressAnalysis.h - DAG Address Analysis -----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #ifndef LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
11 #define LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
12 
14 #include <cstdint>
15 
16 namespace llvm {
17 
18 class 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)))))
34 private:
35  SDValue Base;
36  SDValue Index;
37  int64_t Offset = 0;
38  bool IsIndexSignExt = false;
39 
40 public:
41  BaseIndexOffset() = default;
42  BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset,
43  bool IsIndexSignExt)
44  : Base(Base), Index(Index), Offset(Offset),
45  IsIndexSignExt(IsIndexSignExt) {}
46 
47  SDValue getBase() { return Base; }
48  SDValue getIndex() { return Index; }
49 
50  bool equalBaseIndex(BaseIndexOffset &Other, const SelectionDAG &DAG) {
51  int64_t Off;
52  return equalBaseIndex(Other, DAG, Off);
53  }
54 
56  int64_t &Off);
57 
58  /// Parses tree in Ptr for base, index, offset addresses.
59  static BaseIndexOffset match(SDValue Ptr, const SelectionDAG &DAG);
60 };
61 
62 } // end namespace llvm
63 
64 #endif // LLVM_CODEGEN_SELECTIONDAGADDRESSANALYSIS_H
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
bool equalBaseIndex(BaseIndexOffset &Other, const SelectionDAG &DAG)
ELFYAML::ELF_STO Other
Definition: ELFYAML.cpp:736
BaseIndexOffset(SDValue Base, SDValue Index, int64_t Offset, bool IsIndexSignExt)
static BaseIndexOffset match(SDValue Ptr, const SelectionDAG &DAG)
Parses tree in Ptr for base, index, offset addresses.
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:209
Unlike LLVM values, Selection DAG nodes may return multiple values as the result of a computation...