MachineInstr.cpp

      RemoveOperand(OpIdx);
    else
      getOperand(OpIdx).setIsDead(false);
    DeadOps.pop_back();
  }

  // If not found, this means an alias of one of the operands is dead. Add a
  // new implicit operand if required.
  if (!Found && AddIfNotFound) {
    addOperand(MachineOperand::CreateReg(IncomingReg,
                                         true  /*IsDef*/,
                                         true  /*IsImp*/,
                                         false /*IsKill*/,
                                         true  /*IsDead*/));
    return true;
  }
  return Found;
}