And there you have it. Purists claim C or C++ can't do X because it's UBH in the standard. Pragmatists know that C and (especially) C++ aren't languages on their own, while "gcc" and "MSVC++" are complete (and very similar) languages.
You also need to know the exact implementation of your compiler's optimizer, otherwise you don't know whether it's safe to change your program. Any change might give the optimizer enough information to unleash the nasal demons in previously cromulent code.
