Subversion Repositories QNX 8.QNX8 LLVM/Clang compiler suite

//====- 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 *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 Fold(ConstantExpr::getCompare(P, LC, RC));

    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,

                 bool IsInBounds = false) const override {

    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 Fold(ConstantExpr::getInBoundsGetElementPtr(Ty, PC, IdxList));

      else

        return Fold(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 Fold(ConstantExpr::getSelect(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;

  }

  //===--------------------------------------------------------------------===//

  // Cast/Conversion Operators

  //===--------------------------------------------------------------------===//

  Constant *CreateCast(Instruction::CastOps Op, Constant *C,

                       Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getCast(Op, C, DestTy));

  }

  Constant *CreateIntCast(Constant *C, Type *DestTy,

                          bool isSigned) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getIntegerCast(C, DestTy, isSigned));

  }

  Constant *CreatePointerCast(Constant *C, Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getPointerCast(C, DestTy));

  }

  Constant *CreateFPCast(Constant *C, Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getFPCast(C, DestTy));

  }

  Constant *CreateBitCast(Constant *C, Type *DestTy) const override {

    return CreateCast(Instruction::BitCast, C, DestTy);

  }

  Constant *CreateIntToPtr(Constant *C, Type *DestTy) const override {

    return CreateCast(Instruction::IntToPtr, C, DestTy);

  }

  Constant *CreatePtrToInt(Constant *C, Type *DestTy) const override {

    return CreateCast(Instruction::PtrToInt, C, DestTy);

  }

  Constant *CreateZExtOrBitCast(Constant *C, Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getZExtOrBitCast(C, DestTy));

  }

  Constant *CreateSExtOrBitCast(Constant *C, Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getSExtOrBitCast(C, DestTy));

  }

  Constant *CreateTruncOrBitCast(Constant *C, Type *DestTy) const override {

    if (C->getType() == DestTy)

      return C; // avoid calling Fold

    return Fold(ConstantExpr::getTruncOrBitCast(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));

  }

  //===--------------------------------------------------------------------===//

  // Compare Instructions

  //===--------------------------------------------------------------------===//

  Constant *CreateFCmp(CmpInst::Predicate P, Constant *LHS,

                       Constant *RHS) const override {

    return Fold(ConstantExpr::getCompare(P, LHS, RHS));

  }

};

}

#endif