/// the source, and if the source value is preserved as a sub-register of
/// the result, then replace all reachable uses of the source with the subreg
/// of the result.
+/// Do not generate an EXTRACT that is used only in a debug use, as this
+/// changes the code. Since this code does not currently share EXTRACTs, just
+/// ignore all debug uses.
bool OptimizeExts::OptimizeInstr(MachineInstr *MI, MachineBasicBlock *MBB,
SmallPtrSet<MachineInstr*, 8> &LocalMIs) {
bool Changed = false;
TargetRegisterInfo::isPhysicalRegister(SrcReg))
return false;
- MachineRegisterInfo::use_iterator UI = MRI->use_begin(SrcReg);
- if (++UI == MRI->use_end())
+ MachineRegisterInfo::use_nodbg_iterator UI = MRI->use_nodbg_begin(SrcReg);
+ if (++UI == MRI->use_nodbg_end())
// No other uses.
return false;
// Ok, the source has other uses. See if we can replace the other uses
// with use of the result of the extension.
SmallPtrSet<MachineBasicBlock*, 4> ReachedBBs;
- UI = MRI->use_begin(DstReg);
- for (MachineRegisterInfo::use_iterator UE = MRI->use_end(); UI != UE;
- ++UI)
+ UI = MRI->use_nodbg_begin(DstReg);
+ for (MachineRegisterInfo::use_nodbg_iterator UE = MRI->use_nodbg_end();
+ UI != UE; ++UI)
ReachedBBs.insert(UI->getParent());
bool ExtendLife = true;
// Uses that the result of the instruction can reach.
SmallVector<MachineOperand*, 8> ExtendedUses;
- UI = MRI->use_begin(SrcReg);
- for (MachineRegisterInfo::use_iterator UE = MRI->use_end(); UI != UE;
- ++UI) {
+ UI = MRI->use_nodbg_begin(SrcReg);
+ for (MachineRegisterInfo::use_nodbg_iterator UE = MRI->use_nodbg_end();
+ UI != UE; ++UI) {
MachineOperand &UseMO = UI.getOperand();
MachineInstr *UseMI = &*UI;
if (UseMI == MI)
continue;
+ if (UseMI->isPHI()) {
+ ExtendLife = false;
+ continue;
+ }
+
MachineBasicBlock *UseMBB = UseMI->getParent();
if (UseMBB == MBB) {
// Local uses that come after the extension.
Uses.push_back(&UseMO);
} else if (ReachedBBs.count(UseMBB))
// Non-local uses where the result of extension is used. Always
- // replace these.
+ // replace these unless it's a PHI.
Uses.push_back(&UseMO);
else if (Aggressive && DT->dominates(MBB, UseMBB))
// We may want to extend live range of the extension result in order
// Now replace all uses.
if (!Uses.empty()) {
+ SmallPtrSet<MachineBasicBlock*, 4> PHIBBs;
+ // Look for PHI uses of the extended result, we don't want to extend the
+ // liveness of a PHI input. It breaks all kinds of assumptions down
+ // stream. A PHI use is expected to be the kill of its source values.
+ UI = MRI->use_nodbg_begin(DstReg);
+ for (MachineRegisterInfo::use_nodbg_iterator UE = MRI->use_nodbg_end();
+ UI != UE; ++UI)
+ if (UI->isPHI())
+ PHIBBs.insert(UI->getParent());
+
const TargetRegisterClass *RC = MRI->getRegClass(SrcReg);
for (unsigned i = 0, e = Uses.size(); i != e; ++i) {
MachineOperand *UseMO = Uses[i];
MachineInstr *UseMI = UseMO->getParent();
MachineBasicBlock *UseMBB = UseMI->getParent();
+ if (PHIBBs.count(UseMBB))
+ continue;
unsigned NewVR = MRI->createVirtualRegister(RC);
BuildMI(*UseMBB, UseMI, UseMI->getDebugLoc(),
- TII->get(TargetInstrInfo::EXTRACT_SUBREG), NewVR)
+ TII->get(TargetOpcode::EXTRACT_SUBREG), NewVR)
.addReg(DstReg).addImm(SubIdx);
UseMO->setReg(NewVR);
++NumReuse;