| //===- 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/Constants.h" |
| #include "llvm/IR/ConstantFold.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 *FoldICmp(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 ConstantExpr::getCompare(P, LC, RC); |
| return nullptr; |
| } |
| |
| Value *FoldGEP(Type *Ty, Value *Ptr, ArrayRef<Value *> IdxList, |
| bool IsInBounds = false) 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; |
| |
| if (IsInBounds) |
| return ConstantExpr::getInBoundsGetElementPtr(Ty, PC, IdxList); |
| else |
| return ConstantExpr::getGetElementPtr(Ty, PC, IdxList); |
| } |
| 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; |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // 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); |
| } |
| |
| //===--------------------------------------------------------------------===// |
| // Compare Instructions |
| //===--------------------------------------------------------------------===// |
| |
| Constant *CreateFCmp(CmpInst::Predicate P, Constant *LHS, |
| Constant *RHS) const override { |
| return ConstantExpr::getCompare(P, LHS, RHS); |
| } |
| }; |
| |
| } // end namespace llvm |
| |
| #endif // LLVM_IR_CONSTANTFOLDER_H |