1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
|
//===- Reassociate.h - Reassociate binary expressions -----------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This pass reassociates commutative expressions in an order that is designed
// to promote better constant propagation, GCSE, LICM, PRE, etc.
//
// For example: 4 + (x + 5) -> x + (4 + 5)
//
// In the implementation of this algorithm, constants are assigned rank = 0,
// function arguments are rank = 1, and other values are assigned ranks
// corresponding to the reverse post order traversal of current function
// (starting at 2), which effectively gives values in deep loops higher rank
// than values not in loops.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_TRANSFORMS_SCALAR_REASSOCIATE_H
#define LLVM_TRANSFORMS_SCALAR_REASSOCIATE_H
#include "llvm/ADT/PostOrderIterator.h"
#include "llvm/ADT/SetVector.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/Operator.h"
#include "llvm/IR/PassManager.h"
namespace llvm {
/// A private "module" namespace for types and utilities used by Reassociate.
/// These are implementation details and should not be used by clients.
namespace reassociate {
struct ValueEntry {
unsigned Rank;
Value *Op;
ValueEntry(unsigned R, Value *O) : Rank(R), Op(O) {}
};
inline bool operator<(const ValueEntry &LHS, const ValueEntry &RHS) {
return LHS.Rank > RHS.Rank; // Sort so that highest rank goes to start.
}
/// \brief Utility class representing a base and exponent pair which form one
/// factor of some product.
struct Factor {
Value *Base;
unsigned Power;
Factor(Value *Base, unsigned Power) : Base(Base), Power(Power) {}
};
class XorOpnd;
}
/// Reassociate commutative expressions.
class ReassociatePass : public PassInfoMixin<ReassociatePass> {
DenseMap<BasicBlock *, unsigned> RankMap;
DenseMap<AssertingVH<Value>, unsigned> ValueRankMap;
SetVector<AssertingVH<Instruction>> RedoInsts;
bool MadeChange;
public:
PreservedAnalyses run(Function &F, FunctionAnalysisManager &);
private:
void BuildRankMap(Function &F);
unsigned getRank(Value *V);
void canonicalizeOperands(Instruction *I);
void ReassociateExpression(BinaryOperator *I);
void RewriteExprTree(BinaryOperator *I,
SmallVectorImpl<reassociate::ValueEntry> &Ops);
Value *OptimizeExpression(BinaryOperator *I,
SmallVectorImpl<reassociate::ValueEntry> &Ops);
Value *OptimizeAdd(Instruction *I,
SmallVectorImpl<reassociate::ValueEntry> &Ops);
Value *OptimizeXor(Instruction *I,
SmallVectorImpl<reassociate::ValueEntry> &Ops);
bool CombineXorOpnd(Instruction *I, reassociate::XorOpnd *Opnd1,
APInt &ConstOpnd, Value *&Res);
bool CombineXorOpnd(Instruction *I, reassociate::XorOpnd *Opnd1,
reassociate::XorOpnd *Opnd2, APInt &ConstOpnd,
Value *&Res);
bool collectMultiplyFactors(SmallVectorImpl<reassociate::ValueEntry> &Ops,
SmallVectorImpl<reassociate::Factor> &Factors);
Value *buildMinimalMultiplyDAG(IRBuilder<> &Builder,
SmallVectorImpl<reassociate::Factor> &Factors);
Value *OptimizeMul(BinaryOperator *I,
SmallVectorImpl<reassociate::ValueEntry> &Ops);
Value *RemoveFactorFromExpression(Value *V, Value *Factor);
void EraseInst(Instruction *I);
void RecursivelyEraseDeadInsts(Instruction *I,
SetVector<AssertingVH<Instruction>> &Insts);
void OptimizeInst(Instruction *I);
Instruction *canonicalizeNegConstExpr(Instruction *I);
};
}
#endif // LLVM_TRANSFORMS_SCALAR_REASSOCIATE_H
|
