http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50489
--- Comment #4 from Gary Funck <gary at intrepid dot com> 2011-09-23 17:38:18 UTC --- (In reply to comment #3) > Does the problem vanish if you add -fno-strict-aliasing? > > One more thing, you mention -O2 in the flags, but then refer to selective > scheduler, which is only enabled at -O3. Perhaps you meant Haifa scheduler. The tests still fail with "-O3 -fno-strict-aliasing". They pass with "-O3 -fno-schedule-insns2". We mentioned -O2 in the bug report, because it helped rule out other optimizations that -O3 might imply. Then we selectively added "-ftree-vectorize" and "-fschedule-insns2" to demonstrate that the combination of those additional optimizations will demonstrate the mis-scheduling. If there are additional tests that you suggest that we can run to help narrow this down, let us know, and we'll try to provide that additional information. Also, we can provide a script to run gdb on "cc1upc", if that helps. Thanks.