LiveIntervalAnalysis.cpp

  LiveInterval& Interval = getOrCreateInterval(reg);
  VNInfo* VN = Interval.getNextValue(
            getInstructionIndex(startInst) + InstrSlots::DEF,
            startInst, getVNInfoAllocator());
  VN->hasPHIKill = true;
  VN->kills.push_back(getMBBEndIdx(startInst->getParent()));
  LiveRange LR(getInstructionIndex(startInst) + InstrSlots::DEF,
               getMBBEndIdx(startInst->getParent()) + 1, VN);
  Interval.addRange(LR);
  
  return LR;
}