+ SmallVector<unsigned, 4> Kills;
+ if (mi->getOperand(ti).isDead() &&
+ isSafeToDelete(mi, regB, TII, Kills)) {
+ SmallVector<std::pair<std::pair<unsigned, bool>
+ ,MachineInstr*>, 4> NewKills;
+ bool ReallySafe = true;
+ // If this instruction kills some virtual registers, we need
+ // update the kill information. If it's not possible to do so,
+ // then bail out.
+ while (!Kills.empty()) {
+ unsigned Kill = Kills.back();
+ Kills.pop_back();
+ if (TargetRegisterInfo::isPhysicalRegister(Kill)) {
+ ReallySafe = false;
+ break;
+ }
+ MachineInstr *LastKill = FindLastUseInMBB(Kill, &*mbbi, Dist);
+ if (LastKill) {
+ bool isModRef = LastKill->modifiesRegister(Kill);
+ NewKills.push_back(std::make_pair(std::make_pair(Kill,isModRef),
+ LastKill));
+ } else {
+ ReallySafe = false;
+ break;
+ }
+ }
+
+ if (ReallySafe) {
+ if (LV) {
+ while (!NewKills.empty()) {
+ MachineInstr *NewKill = NewKills.back().second;
+ unsigned Kill = NewKills.back().first.first;
+ bool isDead = NewKills.back().first.second;
+ NewKills.pop_back();
+ if (LV->removeVirtualRegisterKilled(Kill, mi)) {
+ if (isDead)
+ LV->addVirtualRegisterDead(Kill, NewKill);
+ else
+ LV->addVirtualRegisterKilled(Kill, NewKill);
+ }
+ }
+ }
+
+ // We're really going to nuke the old inst. If regB was marked
+ // as a kill we need to update its Kills list.
+ if (mi->getOperand(si).isKill())
+ LV->removeVirtualRegisterKilled(regB, mi);
+
+ mbbi->erase(mi); // Nuke the old inst.
+ mi = nmi;
+ ++NumDeletes;
+ break; // Done with this instruction.
+ }