MemCpyOptimizer.cpp

  bool MadeChange = false;
  MD = &getAnalysis<MemoryDependenceAnalysis>();
  TD = getAnalysisIfAvailable<DataLayout>();
  TLI = &getAnalysis<TargetLibraryInfo>();

  // If we don't have at least memset and memcpy, there is little point of doing
  // anything here.  These are required by a freestanding implementation, so if
  // even they are disabled, there is no point in trying hard.
  if (!TLI->has(LibFunc::memset) || !TLI->has(LibFunc::memcpy))
    return false;

  while (1) {
    if (!iterateOnFunction(F))
      break;
    MadeChange = true;
  }

  MD = 0;
  return MadeChange;
}