From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 02C73385AC38; Sat, 14 Aug 2021 22:30:20 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 02C73385AC38 From: "eggert at cs dot ucla.edu" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/101913] -Wstrict-overflow -O3 false alarm on tzdb localtime.c Date: Sat, 14 Aug 2021 22:30:20 +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: 11.2.1 X-Bugzilla-Keywords: diagnostic X-Bugzilla-Severity: normal X-Bugzilla-Who: eggert at cs dot ucla.edu 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 X-BeenThere: gcc-bugs@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc-bugs mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Aug 2021 22:30:21 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D101913 --- Comment #3 from eggert at cs dot ucla.edu --- (In reply to Andrew Pinski from comment #1) > >-1L << 63 is LONG_MIN > No it is undefined and has an overflow bit on it. > You want (long)(-1UL << 63) for it be correct. > But the warning is still there. I updated the attachment to avoid any undefined behavior, by replacing -1L<= <63 with -1-9223372036854775807L. As you say, the bug is still there. > I thought -fsanitize=3Dundefined enabled -fwrapv too ... It doesn't. (Perhaps you meant -ftrapv?)=