Force compiler to not optimize side-effect-less statements

Question

I was reading some old game programming books and as some of you might know, back in that day it was usually faster to do bit hacks than do things the standard way. (Convert

Answer 1

Return the value?

int float_to_int(float f)
{
    return static_cast(f); // has no side-effects
}

and then at the call site, you can sum all the return values up, and print out the result when the benchmark is done. The usual way to do this is to somehow make sure you depend on the result.

You could use a global variable instead, but it seems like that'd generate more cache misses. Usually, simply returning the value to the caller (and making sure the caller actually does something with it) does the trick.