Add MachineRegisterInfo::constrainRegClass and use it in MachineCSE.

This function is intended to be used when inserting a machine instruction that
trivially restricts the legal registers, like LEA requiring a GR32_NOSP
argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115875 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2010-10-06 23:54:39 +00:00
parent 893ab5d701
commit bf4699c561
3 changed files with 24 additions and 7 deletions

View File

@ -120,17 +120,12 @@ bool MachineCSE::PerformTrivialCoalescing(MachineInstr *MI,
continue;
if (DefMI->getOperand(0).getSubReg() || DefMI->getOperand(1).getSubReg())
continue;
const TargetRegisterClass *SRC = MRI->getRegClass(SrcReg);
const TargetRegisterClass *RC = MRI->getRegClass(Reg);
const TargetRegisterClass *NewRC = getCommonSubClass(RC, SRC);
if (!NewRC)
if (!MRI->constrainRegClass(SrcReg, MRI->getRegClass(Reg)))
continue;
DEBUG(dbgs() << "Coalescing: " << *DefMI);
DEBUG(dbgs() << "*** to: " << *MI);
DEBUG(dbgs() << "*** to: " << *MI);
MO.setReg(SrcReg);
MRI->clearKillFlags(SrcReg);
if (NewRC != SRC)
MRI->setRegClass(SrcReg, NewRC);
DefMI->eraseFromParent();
++NumCoalesces;
Changed = true;