// AValNo is the value number in A that defines the copy, A3 in the example.
LiveInterval::iterator ALR = IntA.FindLiveRangeContaining(CopyIdx-1);
VNInfo *AValNo = ALR->valno;
- if (AValNo->def == ~0U || AValNo->def == ~1U)
+ // If other defs can reach uses of this def, then it's not safe to perform
+ // the optimization.
+ if (AValNo->def == ~0U || AValNo->def == ~1U || AValNo->hasPHIKill)
return false;
MachineInstr *DefMI = li_->getInstructionFromIndex(AValNo->def);
const TargetInstrDesc &TID = DefMI->getDesc();
MachineOperand &UseMO = UI.getOperand();
++UI;
MachineInstr *UseMI = UseMO.getParent();
+ if (JoinedCopies.count(UseMI))
+ continue;
unsigned UseIdx = li_->getInstructionIndex(UseMI);
LiveInterval::iterator ULR = IntA.FindLiveRangeContaining(UseIdx);
if (ULR->valno != AValNo)