https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110590
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jan Hubicka <hubi...@gcc.gnu.org>: https://gcc.gnu.org/g:15bbf1826a01f5beb2d7c0f74d6270bbc94ece91 commit r14-2396-g15bbf1826a01f5beb2d7c0f74d6270bbc94ece91 Author: Jan Hubicka <j...@suse.cz> Date: Sat Jul 8 17:38:09 2023 +0200 Fix tree-ssa/update-cunroll.c In this testcase the profile is misupdated before loop has two exits. The first exit is one eliminated by complete unrolling while second exit remains. We remove first exit but forget about fact that the source BB of other exit will then have higher frequency making other exit more likely. This patch fixes that in duplicate_loop_body_to_header_edge. While looking into resulting profiles I also noticed that in some cases scale_loop_profile may drop probabilities to 0 incorrectly either when trying to update exit from nested loop (which has similar problem) or when the profile was inconsistent as described in coment bellow. gcc/ChangeLog: PR middle-end/110590 * cfgloopmanip.cc (scale_loop_profile): Avoid scaling exits within inner loops and be more careful about inconsistent profiles. (duplicate_loop_body_to_header_edge): Fix profile update when eliminated exit is followed by other exit. gcc/testsuite/ChangeLog: PR middle-end/110590 * gcc.dg/tree-prof/update-cunroll-2.c: Remove xfail. * gcc.dg/tree-ssa/update-cunroll.c: Likewise.
