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//====- TargetFolder.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 TargetFolder class, a helper for IRBuilder.
// It provides IRBuilder with a set of methods for creating constants with
// target dependent folding, in addition to the same target-independent
// folding that the ConstantFolder class provides. For general constant
// creation and folding, use ConstantExpr and the routines in
// llvm/Analysis/ConstantFolding.h.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_TARGETFOLDER_H
#define LLVM_ANALYSIS_TARGETFOLDER_H
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/IRBuilderFolder.h"
#include "llvm/IR/Operator.h"
namespace llvm {
class Constant;
class DataLayout;
class Type;
/// TargetFolder - Create constants with target dependent folding.
class TargetFolder final : public IRBuilderFolder {
const DataLayout &DL;
/// Fold - Fold the constant using target specific information.
Constant *Fold(Constant *C) const {
return ConstantFoldConstant(C, DL);
}
virtual void anchor();
public:
explicit TargetFolder(const DataLayout &DL) : DL(DL) {}
//===--------------------------------------------------------------------===//
// 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 Fold(ConstantExpr::get(Opc, LC, RC));
return ConstantFoldBinaryOpOperands(Opc, LC, RC, DL);
}
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 Fold(ConstantExpr::get(
Opc, LC, RC, IsExact ? PossiblyExactOperator::IsExact : 0));
return ConstantFoldBinaryOpOperands(Opc, LC, RC, DL);
}
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 Fold(ConstantExpr::get(Opc, LC, RC, Flags));
}
return ConstantFoldBinaryOpOperands(Opc, LC, RC, DL);
}
return nullptr;
}
Value *FoldBinOpFMF(Instruction::BinaryOps Opc, Value *LHS, Value *RHS,
FastMathFlags FMF) const override {
return FoldBinOp(Opc, LHS, RHS);
}
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 ConstantFoldCompareInstOperands(P, LC, RC, DL);
return nullptr;
}
Value *FoldUnOpFMF(Instruction::UnaryOps Opc, Value *V,
FastMathFlags FMF) const override {
if (Constant *C = dyn_cast<Constant>(V))
return ConstantFoldUnaryOpOperand(Opc, C, DL);
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 Fold(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 Fold(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 Fold(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 Fold(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))
return ConstantFoldCastOperand(Op, C, DestTy, DL);
return nullptr;
}
Value *FoldBinaryIntrinsic(Intrinsic::ID ID, Value *LHS, Value *RHS, Type *Ty,
Instruction *FMFSource) const override {
auto *C1 = dyn_cast<Constant>(LHS);
auto *C2 = dyn_cast<Constant>(RHS);
if (C1 && C2)
return ConstantFoldBinaryIntrinsic(ID, C1, C2, Ty, FMFSource);
return nullptr;
}
//===--------------------------------------------------------------------===//
// Cast/Conversion Operators
//===--------------------------------------------------------------------===//
Constant *CreatePointerCast(Constant *C, Type *DestTy) const override {
if (C->getType() == DestTy)
return C; // avoid calling Fold
return Fold(ConstantExpr::getPointerCast(C, DestTy));
}
Constant *CreatePointerBitCastOrAddrSpaceCast(Constant *C,
Type *DestTy) const override {
if (C->getType() == DestTy)
return C; // avoid calling Fold
return Fold(ConstantExpr::getPointerBitCastOrAddrSpaceCast(C, DestTy));
}
};
}
#endif
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