From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 2288 invoked by alias); 22 Aug 2008 13:33:17 -0000 Received: (qmail 29839 invoked by uid 48); 22 Aug 2008 13:31:31 -0000 Date: Fri, 22 Aug 2008 13:33:00 -0000 Message-ID: <20080822133131.29837.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/37194] Autovectorization of small constant iteration loop degrades performance In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "dorit at gcc dot gnu dot org" 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: 2008-08/txt/msg01619.txt.bz2 ------- Comment #3 from dorit at gcc dot gnu dot org 2008-08-22 13:31 ------- (In reply to comment #2) > The x86_64 generated code looks like ... > I wonder why we do not use movups instead. > t.i:3: note: Alignment of access forced using peeling. > t.i:3: note: Peeling for alignment will be applied. because the vectorizer doesn't support misaligned stores. I think it should be easy to add - see this old patch: http://gcc.gnu.org/ml/gcc-patches/2007-01/msg00604.html (and also on http://gcc.gnu.org/wiki/VectorizationTasks, under "todo"). -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37194