Test 253.perlbmk from SPEC CPU2000 gets wrong answers with current trunk on powerpc64-unknown-linux-gnu when compiled with "-m64 -Os" due to wrong code generated for this loop:
while (--count) *dst-- = *src--; where dst and src are of type "struct sv **". I'll attach a simplified testcase in which dst and src are of type "long long *". The failure begins with this patch: http://gcc.gnu.org/viewcvs?view=rev&rev=133102 r133102 | rguenth | 2008-03-11 09:36:51 +0000 (Tue, 11 Mar 2008) -- Summary: miscompiled loop in perlbmk for -Os Product: gcc Version: 4.4.0 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: janis at gcc dot gnu dot org GCC target triplet: powerpc64-unknown-linux-gnu http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36038