MergeValueInto is too smart: it might choose to do the merge the opposite direction.
Live interval reconstruction needs to account for this, and scour its maps to
prevent dangling references.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63558 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/PreAllocSplitting.cpp b/lib/CodeGen/PreAllocSplitting.cpp
index a538db8..99fdb84 100644
--- a/lib/CodeGen/PreAllocSplitting.cpp
+++ b/lib/CodeGen/PreAllocSplitting.cpp
@@ -654,8 +654,24 @@
}
if (MBB->pred_size() == 1 && !RetVNI->hasPHIKill) {
- LI->MergeValueNumberInto(RetVNI, IncomingVNs.begin()->second);
- Phis[MBB] = RetVNI = IncomingVNs.begin()->second;
+ VNInfo* OldVN = RetVNI;
+ VNInfo* NewVN = IncomingVNs.begin()->second;
+ VNInfo* MergedVN = LI->MergeValueNumberInto(OldVN, NewVN);
+ if (MergedVN == OldVN) std::swap(OldVN, NewVN);
+
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator LOI = LiveOut.begin(),
+ LOE = LiveOut.end(); LOI != LOE; ++LOI)
+ if (LOI->second == OldVN)
+ LOI->second = MergedVN;
+ for (DenseMap<MachineInstr*, VNInfo*>::iterator NVI = NewVNs.begin(),
+ NVE = NewVNs.end(); NVI != NVE; ++NVI)
+ if (NVI->second == OldVN)
+ NVI->second = MergedVN;
+ for (DenseMap<MachineBasicBlock*, VNInfo*>::iterator PI = Phis.begin(),
+ PE = Phis.end(); PI != PE; ++PI)
+ if (PI->second == OldVN)
+ PI->second = MergedVN;
+ RetVNI = MergedVN;
} else {
// Otherwise, merge the incoming VNInfos with a phi join. Create a new
// VNInfo to represent the joined value.