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Simplify RegisterCoalescer::copyCoalesceInMBB().

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It is no longer necessary to separate VirtCopies, PhysCopies, and
ImpDefCopies. Implicitly defined copies are extremely rare after we
added the ProcessImplicitDefs pass, and physical register copies are not
joined any longer.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157059 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2012-05-18 18:21:48 +00:00
parent 7397b2c751
commit 846b183a9e
1 changed files with 15 additions and 48 deletions
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63
lib/CodeGen/RegisterCoalescer.cpp
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@ -1533,58 +1533,25 @@ RegisterCoalescer::copyCoalesceInMBB(MachineBasicBlock *MBB,
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++;
MII != E; ++MII)
if (MII->isCopyLike())
TryAgain.push_back(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;
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 the collected copies immediately.
// Null out the successful joins.
for (unsigned i = PrevSize, e = TryAgain.size(); i != e; ++i) {
bool Again = false;
if (joinCopy(TryAgain[i], Again) || !Again)
TryAgain[i] = 0;
}
// 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];
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);
}
// Remove the nulls from TryAgain.
TryAgain.erase(std::remove(TryAgain.begin() + PrevSize, TryAgain.end(),
(MachineInstr*)0), TryAgain.end());
}
void RegisterCoalescer::joinAllIntervals() {