+
+ // Mark is isKill if it's there no other uses of the same virtual
+ // register and it's not a two-address operand. IsKill will be
+ // unset if reg is reused.
+ if (!isTied && KilledMIRegs.count(VirtReg) == 0) {
+ MI.getOperand(i).setIsKill();
+ KilledMIRegs.insert(VirtReg);
+ }
+
+ continue;
+ } // CanReuse
+
+ // Otherwise we have a situation where we have a two-address instruction
+ // whose mod/ref operand needs to be reloaded. This reload is already
+ // available in some register "PhysReg", but if we used PhysReg as the
+ // operand to our 2-addr instruction, the instruction would modify
+ // PhysReg. This isn't cool if something later uses PhysReg and expects
+ // to get its initial value.
+ //
+ // To avoid this problem, and to avoid doing a load right after a store,
+ // we emit a copy from PhysReg into the designated register for this
+ // operand.
+ //
+ // This case also applies to an earlyclobber'd PhysReg.
+ unsigned DesignatedReg = VRM->getPhys(VirtReg);
+ assert(DesignatedReg && "Must map virtreg to physreg!");
+
+ // Note that, if we reused a register for a previous operand, the
+ // register we want to reload into might not actually be
+ // available. If this occurs, use the register indicated by the
+ // reuser.
+ if (ReusedOperands.hasReuses())
+ DesignatedReg = ReusedOperands.
+ GetRegForReload(VirtReg, DesignatedReg, &MI, Spills,
+ MaybeDeadStores, RegKills, KillOps, *VRM);
+
+ // If the mapped designated register is actually the physreg we have
+ // incoming, we don't need to inserted a dead copy.
+ if (DesignatedReg == PhysReg) {
+ // If this stack slot value is already available, reuse it!
+ if (ReuseSlot > VirtRegMap::MAX_STACK_SLOT)
+ DEBUG(dbgs() << "Reusing RM#"
+ << ReuseSlot-VirtRegMap::MAX_STACK_SLOT-1);
+ else
+ DEBUG(dbgs() << "Reusing SS#" << ReuseSlot);
+ DEBUG(dbgs() << " from physreg " << TRI->getName(PhysReg)
+ << " for vreg" << VirtReg
+ << " instead of reloading into same physreg.\n");
+ unsigned RReg = SubIdx ? TRI->getSubReg(PhysReg, SubIdx) : PhysReg;
+ MI.getOperand(i).setReg(RReg);
+ MI.getOperand(i).setSubReg(0);
+ ReusedOperands.markClobbered(RReg);
+ ++NumReused;
+ continue;
+ }
+
+ MRI->setPhysRegUsed(DesignatedReg);
+ ReusedOperands.markClobbered(DesignatedReg);
+
+ // Back-schedule reloads and remats.
+ MachineBasicBlock::iterator InsertLoc =
+ ComputeReloadLoc(&MI, MBB->begin(), PhysReg, TRI, DoReMat,
+ SSorRMId, TII, *MBB->getParent());
+ MachineInstr *CopyMI = BuildMI(*MBB, InsertLoc, MI.getDebugLoc(),
+ TII->get(TargetOpcode::COPY),
+ DesignatedReg).addReg(PhysReg);
+ CopyMI->setAsmPrinterFlag(MachineInstr::ReloadReuse);
+ UpdateKills(*CopyMI, TRI, RegKills, KillOps);
+
+ // This invalidates DesignatedReg.
+ Spills.ClobberPhysReg(DesignatedReg);
+
+ Spills.addAvailable(ReuseSlot, DesignatedReg);
+ unsigned RReg =
+ SubIdx ? TRI->getSubReg(DesignatedReg, SubIdx) : DesignatedReg;
+ MI.getOperand(i).setReg(RReg);
+ MI.getOperand(i).setSubReg(0);
+ DEBUG(dbgs() << '\t' << *prior(InsertLoc));
+ ++NumReused;
+ continue;
+ } // if (PhysReg)
+
+ // Otherwise, reload it and remember that we have it.
+ PhysReg = VRM->getPhys(VirtReg);
+ assert(PhysReg && "Must map virtreg to physreg!");
+
+ // Note that, if we reused a register for a previous operand, the
+ // register we want to reload into might not actually be
+ // available. If this occurs, use the register indicated by the
+ // reuser.
+ if (ReusedOperands.hasReuses())
+ PhysReg = ReusedOperands.GetRegForReload(VirtReg, PhysReg, &MI,
+ Spills, MaybeDeadStores, RegKills, KillOps, *VRM);
+
+ MRI->setPhysRegUsed(PhysReg);
+ ReusedOperands.markClobbered(PhysReg);
+ if (AvoidReload)
+ ++NumAvoided;
+ else {
+ // Back-schedule reloads and remats.
+ MachineBasicBlock::iterator InsertLoc =
+ ComputeReloadLoc(MI, MBB->begin(), PhysReg, TRI, DoReMat,
+ SSorRMId, TII, *MBB->getParent());
+
+ if (DoReMat) {
+ ReMaterialize(*MBB, InsertLoc, PhysReg, VirtReg, TII, TRI, *VRM);