[ILUG] gcc optimizations

[Caolan McNamara]

I was wondering about strlen and string literals with gcc earlier on.
so i decided to do a little test. 

with gcc i.c where i.c is 
int main(void)
    {
    int i = strlen("test");
    return(i);
    }

with no optimization gcc calls strlen, but with optimization turned on
gcc converts the strlen call on the literal "test" directly into the
value 4, which made my day, coz it was what i hoped to see. cute eh..
main:
    pushl %ebp
    movl %esp,%ebp
    movl $4,%eax
    movl %ebp,%esp
    popl %ebp
    ret

But what i wondered was, if there was a list of what gcc does to optimize
anywhere, or it is just a hodgepodge of magic rules that you have to trawl
through experimentation or the gcc source to determine.

C.

Real Life: Caolan McNamara           *  Doing: MSc in HCI
Work: Caolan.McNamara at ul.ie          *  Phone: +353-86-8790257
URL: http://www.csn.ul.ie/~caolan    *  Sig: an oblique strategy
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