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fix PR5827 by disabling the phi slicing transformation in a case

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where instcombine would have to split a critical edge due to a
phi node of an invoke.  Since instcombine can't change the CFG,
it has to bail out from doing the transformation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91763 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-12-19 07:01:15 +00:00
parent e88728d757
commit 0ebc6ce974
2 changed files with 77 additions and 2 deletions
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21
lib/Transforms/Scalar/InstructionCombining.cpp
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@@ -11234,6 +11234,23 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) {
for (unsigned PHIId = 0; PHIId != PHIsToSlice.size(); ++PHIId) {
PHINode *PN = PHIsToSlice[PHIId];
// Scan the input list of the PHI. If any input is an invoke, and if the
// input is defined in the predecessor, then we won't be split the critical
// edge which is required to insert a truncate. Because of this, we have to
// bail out.
for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
InvokeInst *II = dyn_cast<InvokeInst>(PN->getIncomingValue(i));
if (II == 0) continue;
if (II->getParent() != PN->getIncomingBlock(i))
continue;
// If we have a phi, and if it's directly in the predecessor, then we have
// a critical edge where we need to put the truncate. Since we can't
// split the edge in instcombine, we have to bail out.
return 0;
}
for (Value::use_iterator UI = PN->use_begin(), E = PN->use_end();
UI != E; ++UI) {
Instruction *User = cast<Instruction>(*UI);
@@ -11316,7 +11333,9 @@ Instruction *InstCombiner::SliceUpIllegalIntegerPHI(PHINode &FirstPhi) {
PredVal = EltPHI;
EltPHI->addIncoming(PredVal, Pred);
continue;
} else if (PHINode *InPHI = dyn_cast<PHINode>(PN)) {
}
if (PHINode *InPHI = dyn_cast<PHINode>(PN)) {
// If the incoming value was a PHI, and if it was one of the PHIs we
// already rewrote it, just use the lowered value.
if (Value *Res = ExtractedVals[LoweredPHIRecord(InPHI, Offset, Ty)]) {