From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28062 invoked by alias); 11 Jan 2015 22:10:02 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org Received: (qmail 28010 invoked by uid 55); 11 Jan 2015 22:09:57 -0000 From: "joona.kiiski at gmail dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug middle-end/64491] [5 Regression] incorrect warning: loop exit may only be reached after undefined behavior Date: Sun, 11 Jan 2015 22:10:00 -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: 5.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: minor X-Bugzilla-Who: joona.kiiski at gmail dot com X-Bugzilla-Status: NEW 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: 7bit X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated MIME-Version: 1.0 X-SW-Source: 2015-01/txt/msg00720.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64491 --- Comment #5 from joona.kiiski at gmail dot com --- Thanks for confirming the problem, Joost! * The original reporter stated that also 4.9 branch is affected, but I haven't tested this myself. No idea about 4.8 branch. * Latest gcc stable releases (4.7.4, 4.8.4, 4.9.2) compile Stockfish without this warning, so I assume that they are not affected. * For Stockfish, the generated code is correct (despite the wrong analysis by GCC). However I'm aware that GCC can do some aggressive optimizations in this area, so in other cases, who knows... On Sat, Jan 10, 2015 at 4:49 PM, Joost.VandeVondele at mat dot ethz.ch < gcc-bugzilla@gcc.gnu.org> wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64491 > > Joost VandeVondele changed: > > What |Removed |Added > > ---------------------------------------------------------------------------- > Status|WAITING |NEW > Last reconfirmed|2015-01-04 00:00:00 |2015-1-10 > CC| |Joost.VandeVondele at mat > dot ethz > | |.ch > Summary|warning: loop exit may only |[5 Regression] incorrect > |be reached after undefined |warning: loop exit may > only > |behavior |be reached after undefined > | |behavior > Known to fail| |5.0 > > --- Comment #4 from Joost VandeVondele ethz.ch> --- > The incorrect warning is confirmed. > > I wonder if this incorrect analysis could lead to wrong code generation. > > -- > You are receiving this mail because: > You are on the CC list for the bug. >