diff --git a/lib/CodeGen/RegAllocLocal.cpp b/lib/CodeGen/RegAllocLocal.cpp index 3e1038daa9c..c3d4442a27b 100644 --- a/lib/CodeGen/RegAllocLocal.cpp +++ b/lib/CodeGen/RegAllocLocal.cpp @@ -589,20 +589,24 @@ void RALocal::ComputeLocalLiveness(MachineBasicBlock& MBB) { std::map >::iterator last = LastUseDef.find(MO.getReg()); if (last != LastUseDef.end()) { - - // If this is a two address instr, then we don't mark the def - // as killing the use. - if (last->second.first == I && - I->getDesc().getOperandConstraint(last->second.second, - TOI::TIED_TO) == (signed)i) { - LastUseDef[MO.getReg()] = std::make_pair(I, i); - continue; + // Check if this is a two address instruction. If so, then + // the def does not kill the use. + if (last->second.first == I) { + bool isTwoAddr = false; + for (unsigned j = i+1, je = I->getDesc().getNumOperands(); + j < je; ++j) { + const MachineOperand &MO2 = I->getOperand(j); + if (MO2.isRegister() && MO2.isUse() && + MO2.getReg() == MO.getReg() && + I->getDesc().getOperandConstraint(j, TOI::TIED_TO) == (int)i) + isTwoAddr = true; + } + + if (isTwoAddr) continue; } - MachineOperand& lastUD = last->second.first->getOperand(last->second.second); - if (lastUD.isDef()) lastUD.setIsDead(true); else if (lastUD.isUse())