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move a trunc-specific transform out of commonIntCastTransforms into visitTrunc. 

llvm-svn: 92773
This commit is contained in:
Chris Lattner 2010-01-05 21:11:17 +00:00
parent c3f2137c06
commit b82a840eb2
1 changed files with 34 additions and 32 deletions
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66
llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
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@ -625,28 +625,6 @@ Instruction *InstCombiner::commonIntCastTransforms(CastInst &CI) {
}
}
Value *Op0 = SrcI->getNumOperands() > 0 ? SrcI->getOperand(0) : 0;
Value *Op1 = SrcI->getNumOperands() > 1 ? SrcI->getOperand(1) : 0;
switch (SrcI->getOpcode()) {
case Instruction::Add:
case Instruction::Mul:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
// If we are discarding information, rewrite.
if (DestBitSize < SrcBitSize && DestBitSize != 1) {
// Don't insert two casts unless at least one can be eliminated.
if (!ValueRequiresCast(CI.getOpcode(), Op1, DestTy) ||
!ValueRequiresCast(CI.getOpcode(), Op0, DestTy)) {
Value *Op0c = Builder->CreateTrunc(Op0, DestTy, Op0->getName());
Value *Op1c = Builder->CreateTrunc(Op1, DestTy, Op1->getName());
return BinaryOperator::Create(
cast<BinaryOperator>(SrcI)->getOpcode(), Op0c, Op1c);
}
}
break;
}
return 0;
}
@ -656,8 +634,8 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
return Result;
Value *Src = CI.getOperand(0);
const Type *Ty = CI.getType();
uint32_t DestBitWidth = Ty->getScalarSizeInBits();
const Type *DestTy = CI.getType();
uint32_t DestBitWidth = DestTy->getScalarSizeInBits();
uint32_t SrcBitWidth = Src->getType()->getScalarSizeInBits();
// Canonicalize trunc x to i1 -> (icmp ne (and x, 1), 0)
@ -679,12 +657,12 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
APInt Mask(APInt::getLowBitsSet(SrcBitWidth, ShAmt).shl(DestBitWidth));
if (MaskedValueIsZero(ShiftOp, Mask)) {
if (ShAmt >= DestBitWidth) // All zeros.
return ReplaceInstUsesWith(CI, Constant::getNullValue(Ty));
return ReplaceInstUsesWith(CI, Constant::getNullValue(DestTy));
// Okay, we can shrink this. Truncate the input, then return a new
// shift.
Value *V1 = Builder->CreateTrunc(ShiftOp, Ty, ShiftOp->getName());
Value *V2 = ConstantExpr::getTrunc(ShAmtV, Ty);
Value *V1 = Builder->CreateTrunc(ShiftOp, DestTy, ShiftOp->getName());
Value *V2 = ConstantExpr::getTrunc(ShAmtV, DestTy);
return BinaryOperator::CreateLShr(V1, V2);
}
}
@ -694,15 +672,39 @@ Instruction *InstCombiner::visitTrunc(TruncInst &CI) {
match(Src, m_Shl(m_Value(ShiftOp), m_ConstantInt(ShAmtV)))) {
uint32_t ShAmt = ShAmtV->getLimitedValue(SrcBitWidth);
if (ShAmt >= DestBitWidth) // All zeros.
return ReplaceInstUsesWith(CI, Constant::getNullValue(Ty));
return ReplaceInstUsesWith(CI, Constant::getNullValue(DestTy));
// Okay, we can shrink this. Truncate the input, then return a new
// shift.
Value *V1 = Builder->CreateTrunc(ShiftOp, Ty, ShiftOp->getName());
Value *V2 = ConstantExpr::getTrunc(ShAmtV, Ty);
Value *V1 = Builder->CreateTrunc(ShiftOp, DestTy, ShiftOp->getName());
Value *V2 = ConstantExpr::getTrunc(ShAmtV, DestTy);
return BinaryOperator::CreateShl(V1, V2);
}
// If we are discarding information from a simple binop, rewrite.
if (Src->hasOneUse() && isa<Instruction>(Src)) {
Instruction *SrcI = cast<Instruction>(Src);
switch (SrcI->getOpcode()) {
default: break;
case Instruction::Add:
// TODO: SUB?
case Instruction::Mul:
case Instruction::And:
case Instruction::Or:
case Instruction::Xor:
Value *Op0 = SrcI->getOperand(0);
Value *Op1 = SrcI->getOperand(1);
// Don't insert two casts unless at least one can be eliminated.
if (!ValueRequiresCast(Instruction::Trunc, Op1, DestTy) ||
!ValueRequiresCast(Instruction::Trunc, Op0, DestTy)) {
Op0 = Builder->CreateTrunc(Op0, DestTy, Op0->getName());
Op1 = Builder->CreateTrunc(Op1, DestTy, Op1->getName());
return BinaryOperator::Create(cast<BinaryOperator>(SrcI)->getOpcode(),
Op0, Op1);
}
}
}
return 0;
}
@ -925,8 +927,8 @@ Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
// zext (xor i1 X, true) to i32 --> xor (zext i1 X to i32), 1
Value *X;
if (SrcI && SrcI->getType()->isInteger(1) &&
match(SrcI, m_Not(m_Value(X))) &&
if (SrcI && SrcI->hasOneUse() && SrcI->getType()->isInteger(1) &&
match(SrcI, m_Not(m_Value(X))) &&
(!X->hasOneUse() || !isa<CmpInst>(X))) {
Value *New = Builder->CreateZExt(X, CI.getType());
return BinaryOperator::CreateXor(New, ConstantInt::get(CI.getType(), 1));