From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 1666) id CC240385742E; Tue, 5 Jul 2022 14:06:12 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org CC240385742E MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="utf-8" From: Richard Biener To: gcc-cvs@gcc.gnu.org Subject: [gcc r13-1505] tree-optimization/106198 - CFG cleanup vs LC SSA X-Act-Checkin: gcc X-Git-Author: Richard Biener X-Git-Refname: refs/heads/master X-Git-Oldrev: 1cc08ceb5baa4e4d6ade6de3a82d22d8fc2cc2a0 X-Git-Newrev: 07dd0f7ba27d1fe9f0ce5b049ac5735dc5d361ad Message-Id: <20220705140612.CC240385742E@sourceware.org> Date: Tue, 5 Jul 2022 14:06:12 +0000 (GMT) X-BeenThere: gcc-cvs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-cvs mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 05 Jul 2022 14:06:12 -0000 https://gcc.gnu.org/g:07dd0f7ba27d1fe9f0ce5b049ac5735dc5d361ad commit r13-1505-g07dd0f7ba27d1fe9f0ce5b049ac5735dc5d361ad Author: Richard Biener Date: Tue Jul 5 14:14:49 2022 +0200 tree-optimization/106198 - CFG cleanup vs LC SSA This is another case like PR106182 where for the 2nd testcase in the bug there are no removed or discovered loops but still changing loop exits invalidates LC SSA and it is not enough to just scan for uses in the blocks that changed loop depth. One might argue that if we'd include former exit destinations we'd pick up the original LC SSA use but for virtuals on block merging we'd have propagated those out (while for regular uses we insert copies). CFG cleanup can also be entered with loops needing fixup so any heuristics based on loop structure are bound to fail. PR tree-optimization/106198 * tree-cfgcleanup.cc (repair_loop_structures): Always do a full LC SSA rewrite but only if any blocks changed loop depth. * gcc.dg/pr106198.c: New testcase. Diff: --- gcc/testsuite/gcc.dg/pr106198.c | 22 ++++++++++++++++++++++ gcc/tree-cfgcleanup.cc | 6 +++--- 2 files changed, 25 insertions(+), 3 deletions(-) diff --git a/gcc/testsuite/gcc.dg/pr106198.c b/gcc/testsuite/gcc.dg/pr106198.c new file mode 100644 index 00000000000..00d2758efa7 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr106198.c @@ -0,0 +1,22 @@ +/* { dg-do compile } */ +/* { dg-options "-O3" } */ + +int printf(const char *, ...); +long a; +int b; +volatile int c; +int main() { + long e = a; + int f = a; + L: + if (b > 0) { + printf("0"); + goto L; + } + if (f) { + printf("%ld", (long)b); + goto L; + } + e >= b && c; + return 0; +} diff --git a/gcc/tree-cfgcleanup.cc b/gcc/tree-cfgcleanup.cc index 3b24e021b6b..b9ff6896ce6 100644 --- a/gcc/tree-cfgcleanup.cc +++ b/gcc/tree-cfgcleanup.cc @@ -1183,9 +1183,9 @@ repair_loop_structures (void) become unreachable by back edges from latch). Also a former irreducible loop can become reducible - in this case force a full rewrite into loop-closed SSA form. */ - if (loops_state_satisfies_p (LOOP_CLOSED_SSA)) - rewrite_into_loop_closed_ssa (n_new_or_deleted_loops ? NULL : changed_bbs, - TODO_update_ssa); + if (loops_state_satisfies_p (LOOP_CLOSED_SSA) + && (!bitmap_empty_p (changed_bbs) || n_new_or_deleted_loops)) + rewrite_into_loop_closed_ssa (NULL, TODO_update_ssa); BITMAP_FREE (changed_bbs);