- if (*RegInfo->getImmediateSubRegisters(Reg) == 0) {
- // No sub-registers, just check if reg is killed by RefMI.
- if (PhysRegInfo[Reg] == RefMI)
- return true;
- } else if (SubKills.empty())
- // None of the sub-registers are killed elsewhere...
- return true;
- return false;
-}
-
-void LiveVariables::addRegisterKills(unsigned Reg, MachineInstr *MI,
- SmallSet<unsigned, 4> &SubKills) {
- if (SubKills.count(Reg) == 0)
- addRegisterKilled(Reg, MI, true);
- else {
- for (const unsigned *SubRegs = RegInfo->getImmediateSubRegisters(Reg);
- unsigned SubReg = *SubRegs; ++SubRegs)
- addRegisterKills(SubReg, MI, SubKills);
- }
+ if (LastRefOrPartRef == PhysRegDef[Reg] && LastRefOrPartRef != MI) {
+ if (LastPartDef)
+ // The last partial def kills the register.
+ LastPartDef->addOperand(MachineOperand::CreateReg(Reg, false/*IsDef*/,
+ true/*IsImp*/, true/*IsKill*/));
+ else {
+ MachineOperand *MO =
+ LastRefOrPartRef->findRegisterDefOperand(Reg, false, TRI);
+ bool NeedEC = MO->isEarlyClobber() && MO->getReg() != Reg;
+ // If the last reference is the last def, then it's not used at all.
+ // That is, unless we are currently processing the last reference itself.
+ LastRefOrPartRef->addRegisterDead(Reg, TRI, true);
+ if (NeedEC) {
+ // If we are adding a subreg def and the superreg def is marked early
+ // clobber, add an early clobber marker to the subreg def.
+ MO = LastRefOrPartRef->findRegisterDefOperand(Reg);
+ if (MO)
+ MO->setIsEarlyClobber();
+ }
+ }
+ } else if (!PhysRegUse[Reg]) {
+ // Partial uses. Mark register def dead and add implicit def of
+ // sub-registers which are used.
+ // EAX<dead> = op AL<imp-def>
+ // That is, EAX def is dead but AL def extends pass it.
+ PhysRegDef[Reg]->addRegisterDead(Reg, TRI, true);
+ for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
+ unsigned SubReg = *SubRegs; ++SubRegs) {
+ if (!PartUses.count(SubReg))
+ continue;
+ bool NeedDef = true;
+ if (PhysRegDef[Reg] == PhysRegDef[SubReg]) {
+ MachineOperand *MO = PhysRegDef[Reg]->findRegisterDefOperand(SubReg);
+ if (MO) {
+ NeedDef = false;
+ assert(!MO->isDead());
+ }
+ }
+ if (NeedDef)
+ PhysRegDef[Reg]->addOperand(MachineOperand::CreateReg(SubReg,
+ true/*IsDef*/, true/*IsImp*/));
+ LastRefOrPartRef->addRegisterKilled(SubReg, TRI, true);
+ for (const unsigned *SS = TRI->getSubRegisters(SubReg); *SS; ++SS)
+ PartUses.erase(*SS);
+ }
+ } else
+ LastRefOrPartRef->addRegisterKilled(Reg, TRI, true);
+ return true;