From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id D1E2D3858C60; Fri, 3 Feb 2023 17:20:17 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org D1E2D3858C60 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1675444817; bh=9G3/TAvIBBN9eELATijSs8dug2dlBNqqbAG7/nI/PvY=; h=From:To:Subject:Date:In-Reply-To:References:From; b=fjlnOQvecDI5aAd6rg7ddOkTSV/1o4ltAgULEY4vvM55Ay0jf2KKrbNVzz6AzmHeX bKpFoUS6q5Yep8AOk7px7b2Z8bNClPrZYwByalxCNJMMHszJGdqTglmEjDe1Ur7kmI ED07i04f2yEWD9nSLwlV+K0mt+NyYadRng+jw9os= From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug target/108659] Suboptimal 128 bit atomics codegen on AArch64 and x64 Date: Fri, 03 Feb 2023 17:20:17 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: target X-Bugzilla-Version: 12.2.1 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: pinskia at gcc dot gnu.org X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 List-Id: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D108659 --- Comment #4 from Andrew Pinski --- (In reply to Niall Douglas from comment #3)=20 > You may be interested in reading https://reviews.llvm.org/D110069. It wan= ted > to have LLVM generate a 128 bit AArch64 CAS for atomics. LLVM merged that > change, it'll be in the next release. Using CAS for atomic load is not valid thing to do ... Because atomic load from constant rodata needs to work. LLVM breaks this case as they don't care about it. GCC does though.=