[koyote]

I ran into a similarish issue in C++ (MSVC++) where a small change that improved an error message led to a 10% slowdown.

The function was something like:

  int ReturnAnswerIfCharIsValid(char* c)
  {
    if(c == nullptr)
      throw std::exception("ERROR!");

    return 42;
  }

The exception line was changed to something like:

  throw std::exception("Char is not valid, please fix it!"); // String is now longer

The performance of this hot-path function went down the drain.

I fixed it by replacing the exception call with yet another function call:

  if(c == nullptr)
     ThrowException();

Other fixes might have included something like __forceinline in the function signature.

[hinkley]

It’s weird that something that should be in a constants pool would hit the inlining threshold.