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the NumCastsRemoved argument to CanEvaluateSExtd is dead, remove it.

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llvm-svn: 93110
This commit is contained in:
Chris Lattner 2010-01-10 07:42:21 +00:00
parent e68d6e61b1
commit fa864affbc
1 changed files with 13 additions and 26 deletions
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39
lib/Transforms/InstCombine/InstCombineCasts.cpp
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@ -783,8 +783,7 @@ Instruction *InstCombiner::visitZExt(ZExtInst &CI) {
/// This function works on both vectors and scalars. For vectors, the result is
/// the number of bits known sign extended in each element.
///
static unsigned CanEvaluateSExtd(Value *V, const Type *Ty,
unsigned &NumCastsRemoved, TargetData *TD) {
static unsigned CanEvaluateSExtd(Value *V, const Type *Ty, TargetData *TD) {
assert(V->getType()->getScalarSizeInBits() < Ty->getScalarSizeInBits() &&
"Can't sign extend type to a smaller type");
// If this is a constant, return the number of sign bits the extended version
@ -795,16 +794,9 @@ static unsigned CanEvaluateSExtd(Value *V, const Type *Ty,
Instruction *I = dyn_cast<Instruction>(V);
if (!I) return 0;
// If this is a truncate from the destination type, we can trivially eliminate
// it, and this will remove a cast overall.
if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty) {
// If the operand of the truncate is itself a cast, and is eliminable, do
// not count this as an eliminable cast. We would prefer to eliminate those
// two casts first.
if (!isa<CastInst>(I->getOperand(0)) && I->hasOneUse())
++NumCastsRemoved;
// If this is a truncate from the dest type, we can trivially eliminate it.
if (isa<TruncInst>(I) && I->getOperand(0)->getType() == Ty)
return ComputeNumSignBits(I->getOperand(0), TD);
}
// We can't extend or shrink something that has multiple uses: doing so would
// require duplicating the instruction in general, which isn't profitable.
@ -819,23 +811,23 @@ static unsigned CanEvaluateSExtd(Value *V, const Type *Ty,
case Instruction::Or:
case Instruction::Xor:
// These operators can all arbitrarily be extended or truncated.
Tmp1 = CanEvaluateSExtd(I->getOperand(0), Ty, NumCastsRemoved, TD);
Tmp1 = CanEvaluateSExtd(I->getOperand(0), Ty, TD);
if (Tmp1 == 0) return 0;
Tmp2 = CanEvaluateSExtd(I->getOperand(1), Ty, NumCastsRemoved, TD);
Tmp2 = CanEvaluateSExtd(I->getOperand(1), Ty, TD);
return std::min(Tmp1, Tmp2);
case Instruction::Add:
case Instruction::Sub:
// Add/Sub can have at most one carry/borrow bit.
Tmp1 = CanEvaluateSExtd(I->getOperand(0), Ty, NumCastsRemoved, TD);
Tmp1 = CanEvaluateSExtd(I->getOperand(0), Ty, TD);
if (Tmp1 == 0) return 0;
Tmp2 = CanEvaluateSExtd(I->getOperand(1), Ty, NumCastsRemoved, TD);
Tmp2 = CanEvaluateSExtd(I->getOperand(1), Ty, TD);
if (Tmp2 == 0) return 0;
return std::min(Tmp1, Tmp2)-1;
case Instruction::Mul:
// These operators can all arbitrarily be extended or truncated.
if (!CanEvaluateSExtd(I->getOperand(0), Ty, NumCastsRemoved, TD))
if (!CanEvaluateSExtd(I->getOperand(0), Ty, TD))
return 0;
if (!CanEvaluateSExtd(I->getOperand(1), Ty, NumCastsRemoved, TD))
if (!CanEvaluateSExtd(I->getOperand(1), Ty, TD))
return 0;
return 1; // IMPROVE?
@ -856,9 +848,9 @@ static unsigned CanEvaluateSExtd(Value *V, const Type *Ty,
}
case Instruction::Select: {
SelectInst *SI = cast<SelectInst>(I);
Tmp1 = CanEvaluateSExtd(SI->getTrueValue(), Ty, NumCastsRemoved, TD);
Tmp1 = CanEvaluateSExtd(SI->getTrueValue(), Ty, TD);
if (Tmp1 == 0) return 0;
Tmp2 = CanEvaluateSExtd(SI->getFalseValue(), Ty, NumCastsRemoved,TD);
Tmp2 = CanEvaluateSExtd(SI->getFalseValue(), Ty, TD);
return std::min(Tmp1, Tmp2);
}
case Instruction::PHI: {
@ -869,8 +861,7 @@ static unsigned CanEvaluateSExtd(Value *V, const Type *Ty,
unsigned Result = ~0U;
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
Result = std::min(Result,
CanEvaluateSExtd(PN->getIncomingValue(i), Ty,
NumCastsRemoved, TD));
CanEvaluateSExtd(PN->getIncomingValue(i), Ty, TD));
if (Result == 0) return 0;
}
return Result;
@ -911,11 +902,7 @@ Instruction *InstCombiner::visitSExt(SExtInst &CI) {
// expression tree to something weird like i93 unless the source is also
// strange.
if (isa<VectorType>(DestTy) || ShouldChangeType(SrcTy, DestTy)) {
unsigned NumCastsRemoved = 0;
// Check to see if we can do this transformation, and if so, how many bits
// of the promoted expression will be known copies of the sign bit in the
// result.
unsigned NumBitsSExt = CanEvaluateSExtd(Src, DestTy, NumCastsRemoved, TD);
unsigned NumBitsSExt = CanEvaluateSExtd(Src, DestTy, TD);
if (NumBitsSExt == 0)
return 0;