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/include/llvm/CodeGen/LiveInterval.h b/include/llvm/CodeGen/LiveInterval.h
index 7bcc4c7..fb74486 100644
--- a/include/llvm/CodeGen/LiveInterval.h
+++ b/include/llvm/CodeGen/LiveInterval.h
@@ -276,7 +276,7 @@
/// are found to be equivalent. This eliminates V1, replacing all
/// LiveRanges with the V1 value number with the V2 value number. This can
/// cause merging of V1/V2 values numbers and compaction of the value space.
- void MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
+ VNInfo* MergeValueNumberInto(VNInfo *V1, VNInfo *V2);
/// MergeInClobberRanges - For any live ranges that are not defined in the
/// current interval, but are defined in the Clobbers interval, mark them
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index 6341b9c..40f8cd4 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -591,7 +591,7 @@
/// are found to be equivalent. This eliminates V1, replacing all
/// LiveRanges with the V1 value number with the V2 value number. This can
/// cause merging of V1/V2 values numbers and compaction of the value space.
-void LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
+VNInfo* LiveInterval::MergeValueNumberInto(VNInfo *V1, VNInfo *V2) {
assert(V1 != V2 && "Identical value#'s are always equivalent!");
// This code actually merges the (numerically) larger value number into the
@@ -652,6 +652,8 @@
} else {
V1->def = ~1U;
}
+
+ return V2;
}
void LiveInterval::Copy(const LiveInterval &RHS,
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.