LiveIntervalAnalysis.cpp

  LiveInterval& Interval = getOrCreateInterval(reg);
  VNInfo* VN = Interval.getNextValue(
    SlotIndex(getInstructionIndex(startInst).getDefIndex()),
    startInst, getVNInfoAllocator());
  VN->setHasPHIKill(true);
  LiveRange LR(
     SlotIndex(getInstructionIndex(startInst).getDefIndex()),
     getMBBEndIdx(startInst->getParent()), VN);
  Interval.addRange(LR);

  return LR;
}