https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82004
--- Comment #28 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Ah, I can actually reproduce the failure with the #c27 testcase with -Ofast -fno-tree-pre. So, to workaround this issue with SPEC, either we need to find out why PRE peels off the first iteration on this small testcase and not on the original 628.pop2_s and see if we can convince it to do so, or we need some pattern match to handle the -Ofast -fno-tree-pre #c27 testcase the way I've outlined in #c18.
