LLVM 19.0.0git
ConstantFolder.h
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1//===- ConstantFolder.h - Constant folding helper ---------------*- 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// This file defines the ConstantFolder class, a helper for IRBuilder.
10// It provides IRBuilder with a set of methods for creating constants
11// with minimal folding. For general constant creation and folding,
12// use ConstantExpr and the routines in llvm/Analysis/ConstantFolding.h.
13//
14//===----------------------------------------------------------------------===//
15
16#ifndef LLVM_IR_CONSTANTFOLDER_H
17#define LLVM_IR_CONSTANTFOLDER_H
18
19#include "llvm/ADT/ArrayRef.h"
20#include "llvm/ADT/STLExtras.h"
22#include "llvm/IR/Constants.h"
24#include "llvm/IR/Instruction.h"
25#include "llvm/IR/Operator.h"
26
27namespace llvm {
28
29/// ConstantFolder - Create constants with minimum, target independent, folding.
30class ConstantFolder final : public IRBuilderFolder {
31 virtual void anchor();
32
33public:
34 explicit ConstantFolder() = default;
35
36 //===--------------------------------------------------------------------===//
37 // Value-based folders.
38 //
39 // Return an existing value or a constant if the operation can be simplified.
40 // Otherwise return nullptr.
41 //===--------------------------------------------------------------------===//
42
44 Value *RHS) const override {
45 auto *LC = dyn_cast<Constant>(LHS);
46 auto *RC = dyn_cast<Constant>(RHS);
47 if (LC && RC) {
49 return ConstantExpr::get(Opc, LC, RC);
50 return ConstantFoldBinaryInstruction(Opc, LC, RC);
51 }
52 return nullptr;
53 }
54
56 bool IsExact) const override {
57 auto *LC = dyn_cast<Constant>(LHS);
58 auto *RC = dyn_cast<Constant>(RHS);
59 if (LC && RC) {
61 return ConstantExpr::get(Opc, LC, RC,
62 IsExact ? PossiblyExactOperator::IsExact : 0);
63 return ConstantFoldBinaryInstruction(Opc, LC, RC);
64 }
65 return nullptr;
66 }
67
69 bool HasNUW, bool HasNSW) const override {
70 auto *LC = dyn_cast<Constant>(LHS);
71 auto *RC = dyn_cast<Constant>(RHS);
72 if (LC && RC) {
74 unsigned Flags = 0;
75 if (HasNUW)
77 if (HasNSW)
79 return ConstantExpr::get(Opc, LC, RC, Flags);
80 }
81 return ConstantFoldBinaryInstruction(Opc, LC, RC);
82 }
83 return nullptr;
84 }
85
87 FastMathFlags FMF) const override {
88 return FoldBinOp(Opc, LHS, RHS);
89 }
90
92 FastMathFlags FMF) const override {
93 if (Constant *C = dyn_cast<Constant>(V))
95 return nullptr;
96 }
97
99 auto *LC = dyn_cast<Constant>(LHS);
100 auto *RC = dyn_cast<Constant>(RHS);
101 if (LC && RC)
102 return ConstantExpr::getCompare(P, LC, RC);
103 return nullptr;
104 }
105
107 bool IsInBounds = false) const override {
109 return nullptr;
110
111 if (auto *PC = dyn_cast<Constant>(Ptr)) {
112 // Every index must be constant.
113 if (any_of(IdxList, [](Value *V) { return !isa<Constant>(V); }))
114 return nullptr;
115
116 if (IsInBounds)
117 return ConstantExpr::getInBoundsGetElementPtr(Ty, PC, IdxList);
118 else
119 return ConstantExpr::getGetElementPtr(Ty, PC, IdxList);
120 }
121 return nullptr;
122 }
123
124 Value *FoldSelect(Value *C, Value *True, Value *False) const override {
125 auto *CC = dyn_cast<Constant>(C);
126 auto *TC = dyn_cast<Constant>(True);
127 auto *FC = dyn_cast<Constant>(False);
128 if (CC && TC && FC)
129 return ConstantFoldSelectInstruction(CC, TC, FC);
130 return nullptr;
131 }
132
134 ArrayRef<unsigned> IdxList) const override {
135 if (auto *CAgg = dyn_cast<Constant>(Agg))
136 return ConstantFoldExtractValueInstruction(CAgg, IdxList);
137 return nullptr;
138 };
139
141 ArrayRef<unsigned> IdxList) const override {
142 auto *CAgg = dyn_cast<Constant>(Agg);
143 auto *CVal = dyn_cast<Constant>(Val);
144 if (CAgg && CVal)
145 return ConstantFoldInsertValueInstruction(CAgg, CVal, IdxList);
146 return nullptr;
147 }
148
149 Value *FoldExtractElement(Value *Vec, Value *Idx) const override {
150 auto *CVec = dyn_cast<Constant>(Vec);
151 auto *CIdx = dyn_cast<Constant>(Idx);
152 if (CVec && CIdx)
153 return ConstantExpr::getExtractElement(CVec, CIdx);
154 return nullptr;
155 }
156
158 Value *Idx) const override {
159 auto *CVec = dyn_cast<Constant>(Vec);
160 auto *CNewElt = dyn_cast<Constant>(NewElt);
161 auto *CIdx = dyn_cast<Constant>(Idx);
162 if (CVec && CNewElt && CIdx)
163 return ConstantExpr::getInsertElement(CVec, CNewElt, CIdx);
164 return nullptr;
165 }
166
168 ArrayRef<int> Mask) const override {
169 auto *C1 = dyn_cast<Constant>(V1);
170 auto *C2 = dyn_cast<Constant>(V2);
171 if (C1 && C2)
172 return ConstantExpr::getShuffleVector(C1, C2, Mask);
173 return nullptr;
174 }
175
177 Type *DestTy) const override {
178 if (auto *C = dyn_cast<Constant>(V)) {
180 return ConstantExpr::getCast(Op, C, DestTy);
181 return ConstantFoldCastInstruction(Op, C, DestTy);
182 }
183 return nullptr;
184 }
185
187 Instruction *FMFSource) const override {
188 // Use TargetFolder or InstSimplifyFolder instead.
189 return nullptr;
190 }
191
192 //===--------------------------------------------------------------------===//
193 // Cast/Conversion Operators
194 //===--------------------------------------------------------------------===//
195
196 Constant *CreatePointerCast(Constant *C, Type *DestTy) const override {
197 return ConstantExpr::getPointerCast(C, DestTy);
198 }
199
201 Type *DestTy) const override {
203 }
204
205 //===--------------------------------------------------------------------===//
206 // Compare Instructions
207 //===--------------------------------------------------------------------===//
208
210 Constant *RHS) const override {
212 }
213};
214
215} // end namespace llvm
216
217#endif // LLVM_IR_CONSTANTFOLDER_H
This file contains the declarations for the subclasses of Constant, which represent the different fla...
Returns the sub type a function will return at a given Idx Should correspond to the result type of an ExtractValue instruction executed with just that one unsigned Idx
#define P(N)
This file contains some templates that are useful if you are working with the STL at all.
Value * RHS
Value * LHS
ArrayRef - Represent a constant reference to an array (0 or more elements consecutively in memory),...
Definition: ArrayRef.h:41
Predicate
This enumeration lists the possible predicates for CmpInst subclasses.
Definition: InstrTypes.h:960
static Constant * getExtractElement(Constant *Vec, Constant *Idx, Type *OnlyIfReducedTy=nullptr)
Definition: Constants.cpp:2452
static Constant * getInBoundsGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant * > IdxList)
Create an "inbounds" getelementptr.
Definition: Constants.h:1226
static Constant * getPointerCast(Constant *C, Type *Ty)
Create a BitCast, AddrSpaceCast, or a PtrToInt cast constant expression.
Definition: Constants.cpp:2072
static Constant * getPointerBitCastOrAddrSpaceCast(Constant *C, Type *Ty)
Create a BitCast or AddrSpaceCast for a pointer type depending on the address space.
Definition: Constants.cpp:2087
static bool isDesirableCastOp(unsigned Opcode)
Whether creating a constant expression for this cast is desirable.
Definition: Constants.cpp:2261
static Constant * getCast(unsigned ops, Constant *C, Type *Ty, bool OnlyIfReduced=false)
Convenience function for getting a Cast operation.
Definition: Constants.cpp:2041
static Constant * getInsertElement(Constant *Vec, Constant *Elt, Constant *Idx, Type *OnlyIfReducedTy=nullptr)
Definition: Constants.cpp:2474
static Constant * getGetElementPtr(Type *Ty, Constant *C, ArrayRef< Constant * > IdxList, bool InBounds=false, std::optional< ConstantRange > InRange=std::nullopt, Type *OnlyIfReducedTy=nullptr)
Getelementptr form.
Definition: Constants.h:1200
static Constant * getShuffleVector(Constant *V1, Constant *V2, ArrayRef< int > Mask, Type *OnlyIfReducedTy=nullptr)
Definition: Constants.cpp:2497
static bool isSupportedGetElementPtr(const Type *SrcElemTy)
Whether creating a constant expression for this getelementptr type is supported.
Definition: Constants.h:1315
static Constant * get(unsigned Opcode, Constant *C1, Constant *C2, unsigned Flags=0, Type *OnlyIfReducedTy=nullptr)
get - Return a binary or shift operator constant expression, folding if possible.
Definition: Constants.cpp:2159
static bool isDesirableBinOp(unsigned Opcode)
Whether creating a constant expression for this binary operator is desirable.
Definition: Constants.cpp:2207
static Constant * getCompare(unsigned short pred, Constant *C1, Constant *C2, bool OnlyIfReduced=false)
Return an ICmp or FCmp comparison operator constant expression.
Definition: Constants.cpp:2328
ConstantFolder - Create constants with minimum, target independent, folding.
Value * FoldBinOpFMF(Instruction::BinaryOps Opc, Value *LHS, Value *RHS, FastMathFlags FMF) const override
Value * FoldGEP(Type *Ty, Value *Ptr, ArrayRef< Value * > IdxList, bool IsInBounds=false) const override
Value * FoldCast(Instruction::CastOps Op, Value *V, Type *DestTy) const override
Constant * CreateFCmp(CmpInst::Predicate P, Constant *LHS, Constant *RHS) const override
Value * FoldExtractElement(Value *Vec, Value *Idx) const override
Value * FoldShuffleVector(Value *V1, Value *V2, ArrayRef< int > Mask) const override
Constant * CreatePointerBitCastOrAddrSpaceCast(Constant *C, Type *DestTy) const override
Value * FoldInsertValue(Value *Agg, Value *Val, ArrayRef< unsigned > IdxList) const override
Value * FoldICmp(CmpInst::Predicate P, Value *LHS, Value *RHS) const override
Value * FoldExactBinOp(Instruction::BinaryOps Opc, Value *LHS, Value *RHS, bool IsExact) const override
Value * FoldNoWrapBinOp(Instruction::BinaryOps Opc, Value *LHS, Value *RHS, bool HasNUW, bool HasNSW) const override
Constant * CreatePointerCast(Constant *C, Type *DestTy) const override
Value * FoldUnOpFMF(Instruction::UnaryOps Opc, Value *V, FastMathFlags FMF) const override
Value * FoldBinOp(Instruction::BinaryOps Opc, Value *LHS, Value *RHS) const override
Value * FoldInsertElement(Value *Vec, Value *NewElt, Value *Idx) const override
Value * FoldExtractValue(Value *Agg, ArrayRef< unsigned > IdxList) const override
Value * FoldBinaryIntrinsic(Intrinsic::ID ID, Value *LHS, Value *RHS, Type *Ty, Instruction *FMFSource) const override
ConstantFolder()=default
Value * FoldSelect(Value *C, Value *True, Value *False) const override
This is an important base class in LLVM.
Definition: Constant.h:41
This class represents an Operation in the Expression.
Convenience struct for specifying and reasoning about fast-math flags.
Definition: FMF.h:20
IRBuilderFolder - Interface for constant folding in IRBuilder.
The instances of the Type class are immutable: once they are created, they are never changed.
Definition: Type.h:45
LLVM Value Representation.
Definition: Value.h:74
@ C
The default llvm calling convention, compatible with C.
Definition: CallingConv.h:34
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
Constant * ConstantFoldSelectInstruction(Constant *Cond, Constant *V1, Constant *V2)
Attempt to constant fold a select instruction with the specified operands.
Constant * ConstantFoldUnaryInstruction(unsigned Opcode, Constant *V)
Constant * ConstantFoldExtractValueInstruction(Constant *Agg, ArrayRef< unsigned > Idxs)
Attempt to constant fold an extractvalue instruction with the specified operands and indices.
bool any_of(R &&range, UnaryPredicate P)
Provide wrappers to std::any_of which take ranges instead of having to pass begin/end explicitly.
Definition: STLExtras.h:1738
Constant * ConstantFoldCastInstruction(unsigned opcode, Constant *V, Type *DestTy)
Constant * ConstantFoldInsertValueInstruction(Constant *Agg, Constant *Val, ArrayRef< unsigned > Idxs)
ConstantFoldInsertValueInstruction - Attempt to constant fold an insertvalue instruction with the spe...
Constant * ConstantFoldBinaryInstruction(unsigned Opcode, Constant *V1, Constant *V2)