------- Comment #16 from pinskia at gcc dot gnu dot org 2006-03-10 04:41 ------- Hmm, I see a missed optimization here (I want to say a PRE one too). D.1521_32 = k_4 * 4; D.1525_37 = (long int *) D.1521_32; D.1526_38 = D.1525_37 + array_9; D.1527_39 = D.1526_38 + 4B; # VUSE <SMT.4_42>; D.1528_40 = *D.1527_39; if (prephitmp.27_35 < D.1528_40) goto <L2>; else goto <L3>;
<L2>:; k_41 = k_4 + 1; pretmp.22_23 = k_41 * 4; pretmp.24_6 = (long int *) pretmp.22_23; prephitmp.25_48 = pretmp.24_6 + array_9; # VUSE <SMT.4_42>; prephitmp.27_51 = *prephitmp.25_48; prephitmp.27_51 here is also the same as D.1528_40. Though I don't know how to figure this out in PRE or any other optimization. I almost want to say this is the real cause. Looking at 3.4's asm, you don't have the extra load but for 4.0 and above you do. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21485
