TwoAddressInstructionPass.cpp

  while (VReg != -1) {
    if (MRI->use_empty(VReg)) {
      MachineInstr *DefMI = MRI->getVRegDef(VReg);
      DefMI->eraseFromParent();
    }
    VReg = ReMatRegs.find_next(VReg);
  }

  return MadeChange;
}