/// reMaterializeAll - Try to rematerialize as many uses of li_ as possible,
/// and trim the live ranges after.
void InlineSpiller::reMaterializeAll() {
// Do a quick scan of the interval values to find if any are remattable.
reMattable_.clear();
usedValues_.clear();
for (LiveInterval::const_vni_iterator I = li_->vni_begin(),
E = li_->vni_end(); I != E; ++I) {
VNInfo *VNI = *I;
if (VNI->isUnused() || !VNI->isDefAccurate())
continue;
MachineInstr *DefMI = lis_.getInstructionFromIndex(VNI->def);
if (!DefMI || !tii_.isTriviallyReMaterializable(DefMI))
continue;
reMattable_.insert(VNI);
}
// Often, no defs are remattable.
if (reMattable_.empty())
return;
// Try to remat before all uses of li_->reg.
bool anyRemat = false;
for (MachineRegisterInfo::use_nodbg_iterator
RI = mri_.use_nodbg_begin(li_->reg);
MachineInstr *MI = RI.skipInstruction();)
anyRemat |= reMaterializeFor(MI);
if (!anyRemat)
return;
// Remove any values that were completely rematted.
bool anyRemoved = false;
for (SmallPtrSet<VNInfo*, 8>::iterator I = reMattable_.begin(),
E = reMattable_.end(); I != E; ++I) {
VNInfo *VNI = *I;
if (VNI->hasPHIKill() || usedValues_.count(VNI))
continue;
MachineInstr *DefMI = lis_.getInstructionFromIndex(VNI->def);
DEBUG(dbgs() << "\tremoving dead def: " << VNI->def << '\t' << *DefMI);
lis_.RemoveMachineInstrFromMaps(DefMI);
vrm_.RemoveMachineInstrFromMaps(DefMI);
DefMI->eraseFromParent();
VNI->setIsDefAccurate(false);
anyRemoved = true;
}
if (!anyRemoved)
return;
// Removing values may cause debug uses where li_ is not live.
for (MachineRegisterInfo::use_iterator RI = mri_.use_begin(li_->reg);
MachineInstr *MI = RI.skipInstruction();) {
if (!MI->isDebugValue())
continue;
// Try to preserve the debug value if li_ is live immediately after it.
MachineBasicBlock::iterator NextMI = MI;
++NextMI;
if (NextMI != MI->getParent()->end() && !lis_.isNotInMIMap(NextMI)) {
VNInfo *VNI = li_->getVNInfoAt(lis_.getInstructionIndex(NextMI));
if (VNI && (VNI->hasPHIKill() || usedValues_.count(VNI)))
continue;
}
DEBUG(dbgs() << "Removing debug info due to remat:" << "\t" << *MI);
MI->eraseFromParent();
}
}
