unsigned Dst = MI->getOperand(0).getReg();
unsigned Src = MI->getOperand(1).getReg();
- // FIXME: If "B = X" kills X, we have to move the kill back to its
- // previous use. For now we just avoid the optimization in that case.
- LiveInterval &SrcInt = li.getInterval(Src);
- if (SrcInt.killedAt(VNI->def))
- return false;
-
if (!TargetRegisterInfo::isVirtualRegister(Src) ||
!TargetRegisterInfo::isVirtualRegister(Dst))
return false;
// If the copies use two different value numbers of X, we cannot merge
// A and B.
+ LiveInterval &SrcInt = li.getInterval(Src);
if (SrcInt.getVNInfoAt(Other->def) != SrcInt.getVNInfoAt(VNI->def))
return false;
if (RHSValNoAssignments.empty())
RHSValNoAssignments.push_back(-1);
+ SmallVector<unsigned, 8> SourceRegisters;
for (SmallVector<MachineInstr*, 8>::iterator I = DupCopies.begin(),
E = DupCopies.end(); I != E; ++I) {
MachineInstr *MI = *I;
// X = X
// and mark the X as coalesced to keep the illusion.
unsigned Src = MI->getOperand(1).getReg();
+ SourceRegisters.push_back(Src);
MI->getOperand(0).substVirtReg(Src, 0, *tri_);
markAsJoined(MI);
}
+ // If B = X was the last use of X in a liverange, we have to shrink it now
+ // that B = X is gone.
+ for (SmallVector<unsigned, 8>::iterator I = SourceRegisters.begin(),
+ E = SourceRegisters.end(); I != E; ++I) {
+ li_->shrinkToUses(&li_->getInterval(*I));
+ }
+
// If we get here, we know that we can coalesce the live ranges. Ask the
// intervals to coalesce themselves now.
LHS.join(RHS, &LHSValNoAssignments[0], &RHSValNoAssignments[0], NewVNInfo,