From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 115561 invoked by alias); 25 Jul 2016 18:01:21 -0000 Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org Received: (qmail 115522 invoked by uid 89); 25 Jul 2016 18:01:20 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-3.2 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy= X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Mon, 25 Jul 2016 18:01:19 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9391E32A8B2; Mon, 25 Jul 2016 18:01:18 +0000 (UTC) Received: from localhost.localdomain (ovpn-116-144.phx2.redhat.com [10.3.116.144]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u6PI1HKc018830; Mon, 25 Jul 2016 14:01:18 -0400 Subject: Re: [PATCH, vec-tails 07/10] Support loop epilogue combining To: Richard Biener References: <20160519194450.GH40563@msticlxl57.ims.intel.com> <18ccae1a-30c3-c23c-e28f-287f9d41eaa0@redhat.com> <20160628122439.GB4143@msticlxl57.ims.intel.com> <20160720143705.GA2605@msticlxl57.ims.intel.com> Cc: Ilya Enkovich , gcc-patches From: Jeff Law Message-ID: <4bb744cb-92df-ca29-54e2-82162216e88c@redhat.com> Date: Mon, 25 Jul 2016 18:01:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2016-07/txt/msg01652.txt.bz2 On 07/22/2016 05:36 AM, Richard Biener wrote: > The thing that needs work I think is re-running of if-conversion. I wonder if we could revamp if-conversion to work on a subset of the CFG? I can see that potentially being useful in other contexts. Would that work for you Richi? We've already got Bin doing that for DOM... > Also I don't like at > all that we have many variants of vectorizing but somehow the decision which one > to choose is rather unclear. The way the epilogue vectorization code > is hooked in > is rather awkward and bound to be a maintainance burden (well, maybe a > small one). I think it's going to be a small one. I suspect that we really need another architecture with masking capabilities to really be able to see how the costing models ought to work and bring sanity to that decision. > > And last, I double there is a case for a masked vectorized loop - I can bet that > doing a non-masked vectorized loop plus a masked epilogue (with no iteration > then!) will be always faster unless you hit the window of very few iterations > (or optimizing for size - in which case vectorizing is questionable on > its own and > disabled IIRC). Ilya, does this case make a noticeable difference with the ICC implementation? Jeff