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

a function call incurs quite a bit of overhead, so I would remove this anyway.

adding a dummy += i; is no problem, as long as you keep this same bit of code in the alternate profile too. (So the code you are comparing it against).

Last but not least: generate asm code. Even if you can not code in asm, the generated code is typically understandable since it will have labels and commented C code behind it. So you know (sortoff) what happens, and which bits are kept.

R

p.s. found this too:

 inline float pslNegFabs32f(float x){
       __asm{
         fld  x //Push 'x' into st(0) of FPU stack
         fabs
         fchs   //change sign
         fstp x //Pop from st(0) of FPU stack
        }
       return x;
 } 

supposedly also very fast. You might want to profile this too. (although it is hardly portable code)