When all defs of a vr are implicit_def, delete all of the defs.

llvm-svn: 89905
This commit is contained in:
Evan Cheng 2009-11-26 00:32:36 +00:00
parent 2d4ff12da9
commit 595a16300c
1 changed files with 6 additions and 2 deletions

View File

@ -183,19 +183,23 @@ bool ProcessImplicitDefs::runOnMachineFunction(MachineFunction &fn) {
// is not an implicit_def, do not insert implicit_def's before the
// uses.
bool Skip = false;
SmallVector<MachineInstr*, 4> DeadImpDefs;
for (MachineRegisterInfo::def_iterator DI = mri_->def_begin(Reg),
DE = mri_->def_end(); DI != DE; ++DI) {
if (DI->getOpcode() != TargetInstrInfo::IMPLICIT_DEF) {
MachineInstr *DeadImpDef = &*DI;
if (DeadImpDef->getOpcode() != TargetInstrInfo::IMPLICIT_DEF) {
Skip = true;
break;
}
DeadImpDefs.push_back(DeadImpDef);
}
if (Skip)
continue;
// The only implicit_def which we want to keep are those that are live
// out of its block.
MI->eraseFromParent();
for (unsigned j = 0, ee = DeadImpDefs.size(); j != ee; ++j)
DeadImpDefs[j]->eraseFromParent();
Changed = true;
// Process each use instruction once.