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From: "pinskia at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/108997] New: GCC prediction on bool comparisons seems wrong Date: Thu, 02 Mar 2023 22:51:37 +0000 [thread overview] Message-ID: <bug-108997-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108997 Bug ID: 108997 Summary: GCC prediction on bool comparisons seems wrong Product: gcc Version: 13.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: pinskia at gcc dot gnu.org Target Milestone: --- I noticed this while looking into 108992. I suspect we look into this but I am not 100% sure this is a bug. Testcase: void use(int *); void use2(int *); void foo(bool cond, int * p) { if (cond) { use(p); } use2(p); } GCC predicts the branch to be taken 66% of the time, but I would have assume it should be 50% as it is a bool and there is no other information. I suspect this is due to prediction when comparing against 0.
next reply other threads:[~2023-03-02 22:51 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-03-02 22:51 pinskia at gcc dot gnu.org [this message] 2023-03-02 23:26 ` [Bug tree-optimization/108997] " nok.raven at gmail dot com 2023-03-02 23:35 ` pinskia at gcc dot gnu.org 2023-03-03 0:05 ` nok.raven at gmail dot com 2023-03-03 0:10 ` pinskia at gcc dot gnu.org 2023-03-03 8:43 ` rguenth at gcc dot gnu.org 2023-03-07 14:49 ` marxin at gcc dot gnu.org
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