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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/103860] [9/10/11/12 Regression] wrong code at -O3 with -fPIC on x86_64-linux-gnu Date: Wed, 29 Dec 2021 18:10:46 +0000 [thread overview] Message-ID: <bug-103860-4-BCdss9tsFX@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-103860-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103860 --- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> --- In the: while (!vec.is_empty () && pro != entry) { while (pro != entry && !can_get_prologue (pro, prologue_clobbered)) { pro = get_immediate_dominator (CDI_DOMINATORS, pro); if (bitmap_set_bit (bb_with, pro->index)) vec.quick_push (pro); } basic_block bb = vec.pop (); if (!can_dup_for_shrink_wrapping (bb, pro, max_grow_size)) while (!dominated_by_p (CDI_DOMINATORS, bb, pro)) { gcc_assert (pro != entry); pro = get_immediate_dominator (CDI_DOMINATORS, pro); if (bitmap_set_bit (bb_with, pro->index)) vec.quick_push (pro); } FOR_EACH_EDGE (e, ei, bb->succs) if (e->dest != EXIT_BLOCK_PTR_FOR_FN (cfun) && bitmap_set_bit (bb_with, e->dest->index)) vec.quick_push (e->dest); } loop, initially we try as pro bb 7 for which can_get_prologue (pro, prologue_clobbered) is true. We iterate for a while, until bb_with is 3, 4, 5, 6, 7, 8, pro still 7, and we pop bb 6, for which can_dup_for_shrink_wrapping is false. vec at this point is empty. As bb 6 isn't dominated by pro 7, we change pro to the immediate dominator of bb 7 which is bb 5, and as it already is in bb_with bitmap, we don't push anything. bb 6 also has no successors (it traps at the end), so we don't push there anything either. And because vec.is_empty () is true, the outer loop doesn't iterate any longer and so nothing checks if can_get_prologue (pro, prologue_clobbered) (which is false for bb 5).
next prev parent reply other threads:[~2021-12-29 18:10 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-29 16:08 [Bug tree-optimization/103860] New: " zhendong.su at inf dot ethz.ch 2021-12-29 17:17 ` [Bug rtl-optimization/103860] [9/10/11/12 Regression] " jakub at gcc dot gnu.org 2021-12-29 17:32 ` jakub at gcc dot gnu.org 2021-12-29 18:10 ` jakub at gcc dot gnu.org [this message] 2021-12-29 18:23 ` jakub at gcc dot gnu.org 2021-12-29 19:43 ` segher at gcc dot gnu.org 2021-12-29 19:58 ` jakub at gcc dot gnu.org 2021-12-29 20:30 ` segher at gcc dot gnu.org 2021-12-30 13:24 ` cvs-commit at gcc dot gnu.org 2021-12-30 13:39 ` [Bug rtl-optimization/103860] [9/10/11 " jakub at gcc dot gnu.org 2022-01-04 9:13 ` cvs-commit at gcc dot gnu.org 2022-01-04 13:59 ` rguenth at gcc dot gnu.org 2022-01-24 9:20 ` cvs-commit at gcc dot gnu.org 2022-01-24 9:30 ` [Bug rtl-optimization/103860] [9/10 " jakub at gcc dot gnu.org 2022-05-10 8:22 ` cvs-commit at gcc dot gnu.org 2022-05-11 6:23 ` cvs-commit at gcc dot gnu.org 2022-05-11 6:36 ` jakub at gcc dot gnu.org
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