LiveIntervalAnalysis.cpp

        std::string msg;
        raw_string_ostream Msg(msg);
        Msg << "Ran out of registers during register allocation!";
        if (MI->isInlineAsm()) {
          Msg << "\nPlease check your inline asm statement for invalid "
              << "constraints:\n";
          MI->print(Msg, tm_);
        }
        report_fatal_error(Msg.str());
      }
      for (const unsigned* AS = tri_->getSubRegisters(PReg); *AS; ++AS) {
        if (!hasInterval(*AS))
          continue;
        LiveInterval &spli = getInterval(*AS);
        if (spli.liveAt(Index))
          spli.removeRange(Index.getLoadIndex(),
                           Index.getNextIndex().getBaseIndex());
      }
    }
  }
  return Cut;
}

LiveRange LiveIntervals::addLiveRangeToEndOfBlock(unsigned reg,
                                                  MachineInstr* startInst) {
  LiveInterval& Interval = getOrCreateInterval(reg);
  VNInfo* VN = Interval.getNextValue(
    SlotIndex(getInstructionIndex(startInst).getDefIndex()),
    startInst, true, getVNInfoAllocator());
  VN->setHasPHIKill(true);
  VN->kills.push_back(indexes_->getTerminatorGap(startInst->getParent()));
  LiveRange LR(
     SlotIndex(getInstructionIndex(startInst).getDefIndex()),
     getMBBEndIdx(startInst->getParent()), VN);
  Interval.addRange(LR);
  
  return LR;
}