From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 16193 invoked by alias); 12 May 2011 14:05:49 -0000 Received: (qmail 16181 invoked by uid 22791); 12 May 2011 14:05:47 -0000 X-SWARE-Spam-Status: No, hits=-2.7 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 12 May 2011 14:05:00 +0000 From: "irar at il dot ibm.com" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/48172] [4.5/4.6/4.7 Regression] incorrect vectorization of loop in GCC 4.5.* with -O3 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: wrong-code X-Bugzilla-Severity: critical X-Bugzilla-Who: irar at il dot ibm.com X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.5.4 X-Bugzilla-Changed-Fields: 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 Date: Thu, 12 May 2011 14:06:00 -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 X-SW-Source: 2011-05/txt/msg01025.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48172 --- Comment #13 from Ira Rosen 2011-05-12 13:02:39 UTC --- (In reply to comment #12) > Like this? > Yes, looks good to me. > > I also think that the re-alignment adjustment needs to be multiplied > by DR_STEP (maybe we only support it for DR_STEP == 1 at the moment). The realignment adjustment is for the case when we load two consecutive aligned vectors and extract the relevant elements from them (in Altivec): for a[1:4] we load a[0:3] and a[4:7]. So, the adjustment adds one more vector size to cover that additional loaded vector. I don't see why it needs to be multiplied by DR_STEP. Thanks, Ira