From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 9D3F93858426; Mon, 23 Jan 2023 17:45:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 9D3F93858426 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gcc.gnu.org; s=default; t=1674495903; bh=Ub5ETmgwbtSpkxQoT5Z1pm3g1IFLIsSr58/OWBipfGk=; h=From:To:Subject:Date:In-Reply-To:References:From; b=gDHIugZ/ppRGk3JMntv7OBQJhR4KW05Wx71nRKmEyPovUylIFzypK2wIrlukDsuoB HnA5PVjNQ+J+OSf2720p2wBFf+9Zo+hA9LLUNoEV8NcUvoX6DE3tD6mIkrGxTSml+l jt7J/3F1A3z0dku6sohS81s3/r1QY61BQLZ8vRR0= From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/108498] ppc64 big endian generates uninitialized reads with -fstore-merging Date: Mon, 23 Jan 2023 17:45:03 +0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: middle-end X-Bugzilla-Version: 12.0 X-Bugzilla-Keywords: wrong-code 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=3D108498 --- Comment #12 from Andrew Pinski --- (In reply to Adam Stylinski from comment #11)=20 > It's possible's a glibc bug and clang avoids it by simply not needing it = but > it seems doubtful a small memcpy like this would have an issue that didn't > show up until now. It seems like if it did need a memcpy, GCC would invo= ke > it's builtin for a struct like like this rather than call into a library > function. Is there a compilation flag I can invoke to rule that out? Li= ke > some sort of "only builtins"? No I misread the generated code. I missed there is a store missing. store to offset 124 is missing I think.=