- DEBUG(dbgs() << "Deleting dead def " << Idx << '\t' << *MI);
-
- // Check for live intervals that may shrink
- for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
- MOE = MI->operands_end(); MOI != MOE; ++MOI) {
- if (!MOI->isReg())
- continue;
- unsigned Reg = MOI->getReg();
- if (!TargetRegisterInfo::isVirtualRegister(Reg))
- continue;
- LiveInterval &LI = LIS.getInterval(Reg);
-
- // Shrink read registers, unless it is likely to be expensive and
- // unlikely to change anything. We typically don't want to shrink the
- // PIC base register that has lots of uses everywhere.
- // Always shrink COPY uses that probably come from live range splitting.
- if (MI->readsVirtualRegister(Reg) &&
- (MI->isCopy() || MOI->isDef() || MRI.hasOneNonDBGUse(Reg) ||
- LI.killedAt(Idx)))
- ToShrink.insert(&LI);
-
- // Remove defined value.
- if (MOI->isDef()) {
- if (VNInfo *VNI = LI.getVNInfoAt(Idx)) {
- if (delegate_)
- delegate_->LRE_WillShrinkVirtReg(LI.reg);
- LI.removeValNo(VNI);
- if (LI.empty()) {
- ToShrink.remove(&LI);
- eraseVirtReg(Reg);
- }
+ // Collect virtual registers to be erased after MI is gone.
+ SmallVector<unsigned, 8> RegsToErase;
+ bool ReadsPhysRegs = false;
+
+ // Check for live intervals that may shrink
+ for (MachineInstr::mop_iterator MOI = MI->operands_begin(),
+ MOE = MI->operands_end(); MOI != MOE; ++MOI) {
+ if (!MOI->isReg())
+ continue;
+ unsigned Reg = MOI->getReg();
+ if (!TargetRegisterInfo::isVirtualRegister(Reg)) {
+ // Check if MI reads any unreserved physregs.
+ if (Reg && MOI->readsReg() && !MRI.isReserved(Reg))
+ ReadsPhysRegs = true;
+ else if (MOI->isDef()) {
+ for (MCRegUnitIterator Units(Reg, MRI.getTargetRegisterInfo());
+ Units.isValid(); ++Units) {
+ if (LiveRange *LR = LIS.getCachedRegUnit(*Units)) {
+ if (VNInfo *VNI = LR->getVNInfoAt(Idx))
+ LR->removeValNo(VNI);