[alexti]

Originally posted by Arryn:
BTW, AFAIK, there aren't any C/C++ keywords that affect the sort of optimizations that can cause these troubles. The best way to avoid them is understanding how functions pass back values, most importantly, what all the various optimization switches do (and which ones you have turned "on"), and how the compiler actually optimizes the code (which is done at the assembly-code level, not source-code level).

The idea of the standards is to be able to write code which will work correctly (meaning that as programmer specified in the source code - as opposite to what the programmer wants ) if compiled by any standard-compliant compiler. Optimizer should meet all criteria defined in the language standard concerning the produced binary code, so the only case when it is allowed to alter the results is when the programmer is using constructs which behaviour is undefined by the standard. And the programmer should not be using such constructs.

If one had to examing the code and switches for each particular optimizer, he'd better just optimize the source code.

Of course, if one needs to compile something with particular compiler and that compiler is broken, that's bad luck

And if using MSVC5/6 one can optimize for size, it often produces faster code then optimization for speed (even if speed-optimized executable is sort of working).