std::vector<MachineInstr*> &TryAgain) {
DEBUG(dbgs() << MBB->getName() << ":\n");
- SmallVector<MachineInstr*, 8> VirtCopies;
- SmallVector<MachineInstr*, 8> PhysCopies;
- SmallVector<MachineInstr*, 8> ImpDefCopies;
+ // Collect all copy-like instructions in MBB. Don't start coalescing anything
+ // yet, it might invalidate the iterator.
+ const unsigned PrevSize = TryAgain.size();
for (MachineBasicBlock::iterator MII = MBB->begin(), E = MBB->end();
- MII != E;) {
- MachineInstr *Inst = MII++;
-
- // If this isn't a copy nor a extract_subreg, we can't join intervals.
- unsigned SrcReg, DstReg;
- if (Inst->isCopy()) {
- DstReg = Inst->getOperand(0).getReg();
- SrcReg = Inst->getOperand(1).getReg();
- } else if (Inst->isSubregToReg()) {
- DstReg = Inst->getOperand(0).getReg();
- SrcReg = Inst->getOperand(2).getReg();
- } else
- continue;
+ MII != E; ++MII)
+ if (MII->isCopyLike())
+ TryAgain.push_back(MII);
- bool SrcIsPhys = TargetRegisterInfo::isPhysicalRegister(SrcReg);
- bool DstIsPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
- if (LIS->hasInterval(SrcReg) && LIS->getInterval(SrcReg).empty())
- ImpDefCopies.push_back(Inst);
- else if (SrcIsPhys || DstIsPhys)
- PhysCopies.push_back(Inst);
- else
- VirtCopies.push_back(Inst);
- }
-
- // Try coalescing implicit copies and insert_subreg <undef> first,
- // followed by copies to / from physical registers, then finally copies
- // from virtual registers to virtual registers.
- for (unsigned i = 0, e = ImpDefCopies.size(); i != e; ++i) {
- MachineInstr *TheCopy = ImpDefCopies[i];
+ // Try coalescing the collected copies immediately.
+ // Null out the successful joins.
+ for (unsigned i = PrevSize, e = TryAgain.size(); i != e; ++i) {
bool Again = false;
- if (!joinCopy(TheCopy, Again))
- if (Again)
- TryAgain.push_back(TheCopy);
- }
- for (unsigned i = 0, e = PhysCopies.size(); i != e; ++i) {
- MachineInstr *TheCopy = PhysCopies[i];
- bool Again = false;
- if (!joinCopy(TheCopy, Again))
- if (Again)
- TryAgain.push_back(TheCopy);
- }
- for (unsigned i = 0, e = VirtCopies.size(); i != e; ++i) {
- MachineInstr *TheCopy = VirtCopies[i];
- bool Again = false;
- if (!joinCopy(TheCopy, Again))
- if (Again)
- TryAgain.push_back(TheCopy);
+ if (joinCopy(TryAgain[i], Again) || !Again)
+ TryAgain[i] = 0;
}
+
+ // Remove the nulls from TryAgain.
+ TryAgain.erase(std::remove(TryAgain.begin() + PrevSize, TryAgain.end(),
+ (MachineInstr*)0), TryAgain.end());
}
void RegisterCoalescer::joinAllIntervals() {