https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111601
--- Comment #25 from GCC 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:9582538cf07d83d7e80553827de8b0f91e4705d8 commit r14-5955-g9582538cf07d83d7e80553827de8b0f91e4705d8 Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Nov 29 09:14:03 2023 +0100 fold-mem-offsets: Fix powerpc64le-linux profiledbootstrap [PR111601] The introduction of the fold-mem-offsets pass breaks profiledbootstrap on powerpc64le-linux. From what I can see, the pass works one basic block at a time and will punt on any non-DEBUG_INSN uses outside of the current block (I believe because of the /* This use affects instructions outside of CAN_FOLD_INSNS. */ if (!bitmap_bit_p (&can_fold_insns, INSN_UID (use))) return 0; test and can_fold_insns only set in do_analysis (when processing insns in current bb, cleared at the end) or results of get_single_def_in_bb (which are checked to be in the same bb). But, while get_single_def_in_bb checks for if (DF_INSN_LUID (def) > DF_INSN_LUID (insn)) return NULL; The basic block in the PR in question has: ... (insn 212 210 215 25 (set (mem/f:DI (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) [2 *last_viable_336+0 S8 A64]) (reg/f:DI 9 9 [orig:155 _342 ] [155])) "pr111601.ii":50:17 683 {*movdi_internal64} (expr_list:REG_DEAD (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) (nil))) (insn 215 212 484 25 (set (reg:DI 5 5 [226]) (const_int 0 [0])) "pr111601.ii":52:12 683 {*movdi_internal64} (expr_list:REG_EQUIV (const_int 0 [0]) (nil))) (insn 484 215 218 25 (set (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) (reg/f:DI 9 9 [orig:155 _342 ] [155])) "pr111601.ii":52:12 683 {*movdi_internal64} (nil)) ... (insn 564 214 216 25 (set (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) (plus:DI (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) (const_int 96 [0x60]))) "pr111601.ii":52:12 66 {*adddi3} (nil)) (insn 216 564 219 25 (set (mem/f:DI (reg/v/f:DI 10 10 [orig:152 last_viable ] [152]) [2 _343->next+0 S8 A64]) (reg:DI 5 5 [226])) "pr111601.ii":52:12 683 {*movdi_internal64} (expr_list:REG_DEAD (reg:DI 5 5 [226]) (nil))) ... and when asking for all uses of %r10 from def 564, it will see uses in 216 and 212; the former is after the += 96 addition and gets changed to load from %r10+96 with the addition being dropped, but there is the other store which is a use across the backedge and when reached from other edges certainly doesn't have the + 96 addition anywhere, so the pass doesn't actually change that location. This patch adds checks from get_single_def_in_bb to get_uses as well, in particular check that the (regular non-debug) use only appears in the same basic block as the definition and that it doesn't appear before it (i.e. use across backedge). 2023-11-29 Jakub Jelinek <ja...@redhat.com> PR bootstrap/111601 * fold-mem-offsets.cc (get_uses): Ignore DEBUG_INSN uses. Otherwise, punt if use is in a different basic block from INSN or appears before INSN in the same basic block. Formatting fixes. (get_single_def_in_bb): Formatting fixes. (fold_offsets_1, pass_fold_mem_offsets::execute): Comment formatting fixes. * g++.dg/opt/pr111601.C: New test.
