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//===- ConstantFolder.h - Constant folding helper ---------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file defines the ConstantFolder class, a helper for IRBuilder.
// It provides IRBuilder with a set of methods for creating constants
// with minimal folding. For general constant creation and folding,
// use ConstantExpr and the routines in llvm/Analysis/ConstantFolding.h.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_IR_CONSTANTFOLDER_H
#define LLVM_IR_CONSTANTFOLDER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/IR/ConstantFold.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/IRBuilderFolder.h"
#include "llvm/IR/Instruction.h"
#include "llvm/IR/Operator.h"
namespace llvm {
/// ConstantFolder - Create constants with minimum, target independent, folding.
class ConstantFolder final : public IRBuilderFolder {
virtual void anchor();
public:
explicit ConstantFolder() = default;
//===--------------------------------------------------------------------===//
// Value-based folders.
//
// Return an existing value or a constant if the operation can be simplified.
// Otherwise return nullptr.
//===--------------------------------------------------------------------===//
Value *FoldBinOp(Instruction::BinaryOps Opc, Value *LHS,
Value *RHS) const override {
auto *LC = dyn_cast<Constant>(LHS);
auto *RC = dyn_cast<Constant>(RHS);
if (LC && RC) {
if (ConstantExpr::isDesirableBinOp(Opc))
return ConstantExpr::get(Opc, LC, RC);
return ConstantFoldBinaryInstruction(Opc, LC, RC);
}
return nullptr;
}
Value *FoldExactBinOp(Instruction::BinaryOps Opc, Value *LHS, Value *RHS,
bool IsExact) const override {
auto *LC = dyn_cast<Constant>(LHS);
auto *RC = dyn_cast<Constant>(RHS);
if (LC && RC) {
if (ConstantExpr::isDesirableBinOp(Opc))
return ConstantExpr::get(Opc, LC, RC,
IsExact ? PossiblyExactOperator::IsExact : 0);
return ConstantFoldBinaryInstruction(Opc, LC, RC);
}
return nullptr;
}
Value *FoldNoWrapBinOp(Instruction::BinaryOps Opc, Value *LHS, Value *RHS,
bool HasNUW, bool HasNSW) const override {
auto *LC = dyn_cast<Constant>(LHS);
auto *RC = dyn_cast<Constant>(RHS);
if (LC && RC) {
if (ConstantExpr::isDesirableBinOp(Opc)) {
unsigned Flags = 0;
if (HasNUW)
Flags |= OverflowingBinaryOperator::NoUnsignedWrap;
if (HasNSW)
Flags |= OverflowingBinaryOperator::NoSignedWrap;
return ConstantExpr::get(Opc, LC, RC, Flags);
}
return ConstantFoldBinaryInstruction(Opc, LC, RC);
}
return nullptr;
}
Value *FoldBinOpFMF(Instruction::BinaryOps Opc, Value *LHS, Value *RHS,
FastMathFlags FMF) const override {
return FoldBinOp(Opc, LHS, RHS);
}
Value *FoldUnOpFMF(Instruction::UnaryOps Opc, Value *V,
FastMathFlags FMF) const override {
if (Constant *C = dyn_cast<Constant>(V))
return ConstantFoldUnaryInstruction(Opc, C);
return nullptr;
}
Value *FoldCmp(CmpInst::Predicate P, Value *LHS, Value *RHS) const override {
auto *LC = dyn_cast<Constant>(LHS);
auto *RC = dyn_cast<Constant>(RHS);
if (LC && RC)
return ConstantFoldCompareInstruction(P, LC, RC);
return nullptr;
}
Value *FoldGEP(Type *Ty, Value *Ptr, ArrayRef<Value *> IdxList,
GEPNoWrapFlags NW) const override {
if (!ConstantExpr::isSupportedGetElementPtr(Ty))
return nullptr;
if (auto *PC = dyn_cast<Constant>(Ptr)) {
// Every index must be constant.
if (any_of(IdxList, [](Value *V) { return !isa<Constant>(V); }))
return nullptr;
return ConstantExpr::getGetElementPtr(Ty, PC, IdxList, NW);
}
return nullptr;
}
Value *FoldSelect(Value *C, Value *True, Value *False) const override {
auto *CC = dyn_cast<Constant>(C);
auto *TC = dyn_cast<Constant>(True);
auto *FC = dyn_cast<Constant>(False);
if (CC && TC && FC)
return ConstantFoldSelectInstruction(CC, TC, FC);
return nullptr;
}
Value *FoldExtractValue(Value *Agg,
ArrayRef<unsigned> IdxList) const override {
if (auto *CAgg = dyn_cast<Constant>(Agg))
return ConstantFoldExtractValueInstruction(CAgg, IdxList);
return nullptr;
};
Value *FoldInsertValue(Value *Agg, Value *Val,
ArrayRef<unsigned> IdxList) const override {
auto *CAgg = dyn_cast<Constant>(Agg);
auto *CVal = dyn_cast<Constant>(Val);
if (CAgg && CVal)
return ConstantFoldInsertValueInstruction(CAgg, CVal, IdxList);
return nullptr;
}
Value *FoldExtractElement(Value *Vec, Value *Idx) const override {
auto *CVec = dyn_cast<Constant>(Vec);
auto *CIdx = dyn_cast<Constant>(Idx);
if (CVec && CIdx)
return ConstantExpr::getExtractElement(CVec, CIdx);
return nullptr;
}
Value *FoldInsertElement(Value *Vec, Value *NewElt,
Value *Idx) const override {
auto *CVec = dyn_cast<Constant>(Vec);
auto *CNewElt = dyn_cast<Constant>(NewElt);
auto *CIdx = dyn_cast<Constant>(Idx);
if (CVec && CNewElt && CIdx)
return ConstantExpr::getInsertElement(CVec, CNewElt, CIdx);
return nullptr;
}
Value *FoldShuffleVector(Value *V1, Value *V2,
ArrayRef<int> Mask) const override {
auto *C1 = dyn_cast<Constant>(V1);
auto *C2 = dyn_cast<Constant>(V2);
if (C1 && C2)
return ConstantExpr::getShuffleVector(C1, C2, Mask);
return nullptr;
}
Value *FoldCast(Instruction::CastOps Op, Value *V,
Type *DestTy) const override {
if (auto *C = dyn_cast<Constant>(V)) {
if (ConstantExpr::isDesirableCastOp(Op))
return ConstantExpr::getCast(Op, C, DestTy);
return ConstantFoldCastInstruction(Op, C, DestTy);
}
return nullptr;
}
Value *FoldBinaryIntrinsic(Intrinsic::ID ID, Value *LHS, Value *RHS, Type *Ty,
Instruction *FMFSource) const override {
// Use TargetFolder or InstSimplifyFolder instead.
return nullptr;
}
//===--------------------------------------------------------------------===//
// Cast/Conversion Operators
//===--------------------------------------------------------------------===//
Constant *CreatePointerCast(Constant *C, Type *DestTy) const override {
return ConstantExpr::getPointerCast(C, DestTy);
}
Constant *CreatePointerBitCastOrAddrSpaceCast(Constant *C,
Type *DestTy) const override {
return ConstantExpr::getPointerBitCastOrAddrSpaceCast(C, DestTy);
}
};
} // end namespace llvm
#endif // LLVM_IR_CONSTANTFOLDER_H
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