fix PR5827 by disabling the phi slicing transformation in a case
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
diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index a6e0eef..4f4296f 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11234,6 +11234,23 @@
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 @@
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)]) {