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//===- InstructionSimplify.cpp - Fold instruction operands ----------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements routines for folding instructions into simpler forms
// that do not require creating new instructions. For example, this does
// constant folding, and can handle identities like (X&0)->0.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/InstructionSimplify.h"
#include "llvm/Analysis/ConstantFolding.h"
#include "llvm/Instructions.h"
using namespace llvm;
/// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
/// fold the result. If not, this returns null.
Value *llvm::SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
const TargetData *TD) {
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
Constant *COps[] = {CLHS, CRHS};
return ConstantFoldInstOperands(Opcode, LHS->getType(), COps, 2, TD);
}
return 0;
}
/// SimplifyCompare - Given operands for a CmpInst, see if we can
/// fold the result.
Value *llvm::SimplifyCompare(unsigned Predicate, Value *LHS, Value *RHS,
const TargetData *TD) {
CmpInst::Predicate Pred = (CmpInst::Predicate)Predicate;
if (Constant *CLHS = dyn_cast<Constant>(LHS))
if (Constant *CRHS = dyn_cast<Constant>(RHS)) {
Constant *COps[] = {CLHS, CRHS};
return ConstantFoldCompareInstOperands(Pred, COps, 2, TD);
}
// If this is an integer compare and the LHS and RHS are the same, fold it.
if (LHS == RHS)
if (isa<IntegerType>(LHS->getType()) || isa<PointerType>(LHS->getType())) {
if (ICmpInst::isTrueWhenEqual(Pred))
return ConstantInt::getTrue(LHS->getContext());
else
return ConstantInt::getFalse(LHS->getContext());
}
return 0;
}
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