while (P != FirstNonPHI && P->getOpcode() == TargetInstrInfo::PHI) {
unsigned DestReg = P->getOperand(0).getReg();
+ // Don't both doing PHI elimination for dead PHI's.
+ if (P->registerDefIsDead(DestReg)) {
+ ++P;
+ continue;
+ }
+
LiveInterval& PI = LI.getOrCreateInterval(DestReg);
unsigned pIdx = LI.getInstructionIndex(FirstNonPHI);
VNInfo* PVN = PI.getLiveRangeContaining(pIdx)->valno;
for (std::vector<MachineInstr*>::iterator I = phis.begin(), E = phis.end();
I != E; ++I) {
+ // If this is a dead PHI node, then remove it from LiveIntervals.
+ unsigned DestReg = (*I)->getOperand(0).getReg();
+ if ((*I)->registerDefIsDead(DestReg)) {
+ LiveInterval& PI = LI.getInterval(DestReg);
+
+ if (PI.containsOneValue()) {
+ LI.removeInterval(DestReg);
+ } else {
+ MachineBasicBlock::iterator PIter = *I;
+ while (PIter->getOpcode() == TargetInstrInfo::PHI) ++PIter;
+ unsigned idx = LI.getInstructionIndex(PIter);
+
+ PI.removeRange(*PI.getLiveRangeContaining(idx), true);
+ }
+ }
+
LI.RemoveMachineInstrFromMaps(*I);
(*I)->eraseFromParent();
}