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Rewrite previous patch to suit Chris's preference.

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llvm-svn: 50174
This commit is contained in:
Dale Johannesen 2008-04-23 18:34:37 +00:00
parent 74178d02d1
commit d70ea13581
1 changed files with 31 additions and 21 deletions
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52
lib/Transforms/Scalar/InstructionCombining.cpp
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@ -8694,6 +8694,31 @@ Instruction *InstCombiner::visitInvokeInst(InvokeInst &II) {
return visitCallSite(&II);
}
// If this cast does not affect the value passed through the varargs
// area, we can eliminate the use of the cast.
static bool isSafeToEliminateVarargsCast(const CallSite CS,
const CastInst * const CI,
const TargetData * const TD,
const int ix) {
if (!CI->isLosslessCast())
return false;
// The size of ByVal arguments is derived from the type, so we
// can't change to a type with a different size. If the size were
// passed explicitly we could avoid this check.
if (!CS.paramHasAttr(ix, ParamAttr::ByVal))
return true;
const Type* SrcTy =
cast<PointerType>(CI->getOperand(0)->getType())->getElementType();
const Type* DstTy = cast<PointerType>(CI->getType())->getElementType();
if (!SrcTy->isSized() || !DstTy->isSized())
return false;
if (TD->getABITypeSize(SrcTy) != TD->getABITypeSize(DstTy))
return false;
return true;
}
// visitCallSite - Improvements for call and invoke instructions.
//
Instruction *InstCombiner::visitCallSite(CallSite CS) {
@ -8752,28 +8777,13 @@ Instruction *InstCombiner::visitCallSite(CallSite CS) {
// See if we can optimize any arguments passed through the varargs area of
// the call.
for (CallSite::arg_iterator I = CS.arg_begin()+FTy->getNumParams(),
E = CS.arg_end(); I != E; ++I, ++ix)
if (CastInst *CI = dyn_cast<CastInst>(*I)) {
// If this cast does not affect the value passed through the varargs
// area, we can eliminate the use of the cast.
const PointerType* SrcPTy, *DstPTy;
if (CI->isLosslessCast()) {
// The size of ByVal arguments is derived from the type, so we
// can't change to a type with a different size. If the size were
// passed explicitly we could avoid this check.
if (CS.paramHasAttr(ix, ParamAttr::ByVal) &&
(SrcPTy = cast<PointerType>(CI->getOperand(0)->getType())) &&
(DstPTy = cast<PointerType>(CI->getType()))) {
const Type* SrcTy = SrcPTy->getElementType();
const Type* DstTy = DstPTy->getElementType();
if (!SrcTy->isSized() || !DstTy->isSized() ||
TD->getABITypeSize(SrcTy) != TD->getABITypeSize(DstTy))
continue;
}
*I = CI->getOperand(0);
Changed = true;
}
E = CS.arg_end(); I != E; ++I, ++ix) {
CastInst *CI = dyn_cast<CastInst>(*I);
if (CI && isSafeToEliminateVarargsCast(CS, CI, TD, ix)) {
*I = CI->getOperand(0);
Changed = true;
}
}
}
if (isa<InlineAsm>(Callee) && !CS.doesNotThrow()) {