From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: by sourceware.org (Postfix, from userid 48) id 337CB385840A; Tue, 28 Sep 2021 05:23:34 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 337CB385840A From: "pinskia at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/102511] [12 Regression] GCC produces incorrect code for -O3: first element of the array is skipped Date: Tue, 28 Sep 2021 05:23:34 +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-Version: 12.0 X-Bugzilla-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: pinskia at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Resolution: X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 12.0 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: Tue, 28 Sep 2021 05:23:34 -0000 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102511 --- Comment #4 from Andrew Pinski --- So the difference between -O2 and -O3 that matters here is -ftree-vectorize= but it is not the vectorizer that is making the difference but rather ch_vect. But I can't figure out what is going wrong. Also adding -fwrapv fixes it too.=