[Bug target/32593] Missed optimization of 'y = constant - x' operation

[astrange at ithinksw dot com]

------- Comment #4 from astrange at ithinksw dot com  2008-12-17 22:10 -------
Causes silly code on i386 with this:
void pred8x8l_vertical_add_c(unsigned char *pix, const short *block, int
stride){
    int i;
    for(i=0; i<8; i++){
        int j;
        for (j=0; j<8; j++){
            pix[j] = pix[j-stride] + block[j];
        }
        pix+= stride;
        block+= 8;
    }
}

where it calculates and then spills each of [0-7] - stride to the stack,
instead of just being able to keep -stride in a register and incrementing it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32593