https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94618
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:c41884a09206be0e21cad7eea71b9754daa969d4 commit r10-7769-gc41884a09206be0e21cad7eea71b9754daa969d4 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Apr 17 10:33:27 2020 +0200 Fix -fcompare-debug issue in delete_insn_and_edges [PR94618] delete_insn_and_edges calls purge_dead_edges whenever deleting the last insn in a bb, whatever it is. If it called it only for mandatory last insns in the basic block (that may not be followed by DEBUG_INSNs, dunno if that is control_flow_insn_p or something more complex), that wouldn't be a problem, but as it calls it on any last insn and can actually do something in the bb, if such an insn is followed by one more more DEBUG_INSNs and nothing else in the same bb, we don't call purge_dead_edges with -g and do call it with -g0. On the testcase, there are two reg-to-reg moves with REG_EH_REGION notes (previously memory accesses but simplified and yet not optimized), and the second is followed by DEBUG_INSNs; the second move is delete_insn_and_edges and after removing it, for -g0 purge_dead_edges removes the REG_EH_REGION from the now last insn in the bb (the first reg-to-reg move), while for -g it isn't called and things diverge from that quickly on. Fixed by calling purdge_dead_edges even if we remove the last real insn followed only by DEBUG_INSNs in the same bb. 2020-04-17 Jakub Jelinek <ja...@redhat.com> PR rtl-optimization/94618 * cfgrtl.c (delete_insn_and_edges): Set purge not just when insn is the BB_END of its block, but also when it is only followed by DEBUG_INSNs in its block. * g++.dg/opt/pr94618.C: New test.
