https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103837
--- Comment #10 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-10 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:aa998156c69fcb70ed637f34fd86e47020254ce5 commit r10-10661-gaa998156c69fcb70ed637f34fd86e47020254ce5 Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Dec 28 17:40:17 2021 +0100 loop-invariant: Fix -fcompare-debug failure [PR103837] In the following testcase we have a -fcompare-debug failure, because can_move_invariant_reg doesn't ignore DEBUG_INSNs in its decisions. In the testcase we have due to uninitialized variable: loop_header debug_insn using pseudo84 pseudo84 = invariant insn using pseudo84 end loop and with -g decide not to move the pseudo84 = invariant before the loop header; in this case not resetting the debug insns might be fine. But, we could have also: pseudo84 = whatever loop_header debug_insn using pseudo84 pseudo84 = invariant insn using pseudo84 end loop and in that case not resetting the debug insns would result in wrong-debug. And, we don't really have generally a good substitution on what pseudo84 contains, it could inherit various values from different paths. So, the following patch ignores DEBUG_INSNs in the decisions, and if there are any that previously prevented the optimization, resets them before return true. 2021-12-28 Jakub Jelinek <ja...@redhat.com> PR rtl-optimization/103837 * loop-invariant.c (can_move_invariant_reg): Ignore DEBUG_INSNs in the decisions whether to return false or continue and right before returning true reset those debug insns that previously caused returning false. * gcc.dg/pr103837.c: New test. (cherry picked from commit 3c5fd3616f73fbcd241cc3a5e09275c2b0c49bd4)
