From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 661 invoked by alias); 7 Dec 2012 14:39:04 -0000 Received: (qmail 617 invoked by uid 48); 7 Dec 2012 14:38:48 -0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/55616] bogus warning about undefined overflow after overflow check Date: Fri, 07 Dec 2012 14:39:00 -0000 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: tree-optimization X-Bugzilla-Keywords: diagnostic X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Keywords Status Last reconfirmed Ever Confirmed Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 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 X-SW-Source: 2012-12/txt/msg00734.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55616 Richard Biener changed: What |Removed |Added ---------------------------------------------------------------------------- Keywords| |diagnostic Status|UNCONFIRMED |NEW Last reconfirmed| |2012-12-07 Ever Confirmed|0 |1 --- Comment #1 from Richard Biener 2012-12-07 14:38:48 UTC --- It's not VRP that warns here but we perform the simplification before reaching VRP, from forward-propagation which just sees long b = a + C; if (a > b) something (); and uses fold to simplify a > a + C. There it assumes that overflow does not occur.