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From: "Simon.Richter at hogyros dot de" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug rtl-optimization/109930] New: transform atomic exchange to unconditional store when old value is unused? Date: Mon, 22 May 2023 10:49:12 +0000 [thread overview] Message-ID: <bug-109930-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109930 Bug ID: 109930 Summary: transform atomic exchange to unconditional store when old value is unused? Product: gcc Version: 13.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: rtl-optimization Assignee: unassigned at gcc dot gnu.org Reporter: Simon.Richter at hogyros dot de Target Milestone: --- I'm not sure if that is a valid substitution, but... I have a state machine that has a few transitions where I already know the old state, so I can simply do an unconditional store, but I'd also like to have an assertion on the old state in my debug version: std::atomic<uint32_t> x; /* ... */ auto old_value = x.exchange(5); assert(old_value == 3); with NDEBUG set, the assert is omitted, and no one is interested in the old value, so the load-with-reserve can be omitted and the store-conditional replaced with a regular store, and this should still be semantically equivalent.
next reply other threads:[~2023-05-22 10:49 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2023-05-22 10:49 Simon.Richter at hogyros dot de [this message] 2023-05-22 12:38 ` [Bug rtl-optimization/109930] " rguenth at gcc dot gnu.org 2023-05-22 15:31 ` pinskia at gcc dot gnu.org 2023-05-22 17:55 ` Simon.Richter at hogyros dot de 2023-05-31 17:29 ` wilco at gcc dot gnu.org 2023-06-01 1:40 ` Simon.Richter at hogyros dot de
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