From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 113612 invoked by alias); 1 Aug 2016 09:09:31 -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 113602 invoked by uid 89); 1 Aug 2016 09:09:30 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 spammy=clue, Hx-languages-length:1617, HTo:U*law, opportunity X-HELO: mail-ua0-f171.google.com Received: from mail-ua0-f171.google.com (HELO mail-ua0-f171.google.com) (209.85.217.171) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES128-GCM-SHA256 encrypted) ESMTPS; Mon, 01 Aug 2016 09:09:28 +0000 Received: by mail-ua0-f171.google.com with SMTP id l32so101915535ual.2 for ; Mon, 01 Aug 2016 02:09:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=+0CX9PGXyyOlqaTRkWDD/KaXqJGBp7C3pF0P2WAxOFw=; b=CdULaJ2mj3n/ZQvYNEgV92WcQt5k5/+Wt4USeLvaFgENNP3TlW+XtL/epXx0ayNT6v rSgddSmTGz6L+byyj9xwOW3z/jZ25IBj93+dcBFe9bKI5MGLWbD/xPgUNDqoHEGUznxi XPFftQG2s+0tUnCz3tF/VKWdEzeZTcHnN9B9LcCSNTAtZJggHBnXWXzCyF17eiVWUOOq qzElaYBvnGNbBPqTcTtAjiVkWYQV6rHMnJ7fODGEdvrUMmQ6QLav8nZM3gVSRhI9S133 HmT95Y0OtzOIFOnVOWRciVtMHuEI62usBWrWe1LpF+te5WYl0FnAR82zFg/+jf/tp8e0 t6uQ== X-Gm-Message-State: AEkooutt/eMZ1OUThGwz2YQH5uKuXqyQkbz/HBVR5+uGp2jH9raegmnO8JPTjNAZ18aSH+NOr3pd6sFmtP5h1g== X-Received: by 10.176.1.8 with SMTP id 8mr25728508uak.93.1470042566572; Mon, 01 Aug 2016 02:09:26 -0700 (PDT) MIME-Version: 1.0 Received: by 10.176.2.244 with HTTP; Mon, 1 Aug 2016 02:09:25 -0700 (PDT) In-Reply-To: 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> <4bb744cb-92df-ca29-54e2-82162216e88c@redhat.com> <5cacdc29-e916-f460-3c44-5fa6450a24a9@redhat.com> <37fbe5e6-6e44-ffff-5467-21e162919586@redhat.com> From: Ilya Enkovich Date: Mon, 01 Aug 2016 09:09:00 -0000 Message-ID: Subject: Re: [PATCH, vec-tails 07/10] Support loop epilogue combining To: Jeff Law Cc: Richard Biener , gcc-patches , Yuri Rumyantsev , Igor Zamyatin Content-Type: text/plain; charset=UTF-8 X-IsSubscribed: yes X-SW-Source: 2016-08/txt/msg00025.txt.bz2 2016-07-26 18:38 GMT+03:00 Ilya Enkovich : > 2016-07-26 18:26 GMT+03:00 Jeff Law : >> On 07/26/2016 03:57 AM, Ilya Enkovich wrote: >>>> >>>> >>>> Ilya, what's the fundamental reason why we need to run >>>> if-conversion again? Yes, I know you want to if-convert the >>>> epilogue, but why? >>>> >>>> What are the consequences of not doing if-conversion on the >>>> epilogue? Presumably we miss a vectorization opportunity on the >>>> tail. But that may be a reasonable limitation to allow the >>>> existing work to move forward while you go back and revamp things a >>>> little. >>> >>> >>> If we have some control-flow in a loop then we have to if-convert it >>> for vectorizer. We need to preserve both versions: if-converted one >>> for vectorizer and the original one to be used if vectorization >>> fails. For epilogues we have similar situation and need two >>> versions. I do it by running if-conversion on a copy of original >>> loop. Note that it doesn't run full if-conversion pass. If-conversion >>> is called for epilogue loop only. >> >> Right. So what I think Richi wants you to try is to use the if-converted >> loop to construct the if-converted epilogue. It seems conceptually simple >> and low cost -- the question is on the implementation side. I have no clue >> how painful that would be. > > Probably another part of if-conversion may be re-used to build required > epilogue. I'll have a look. Hi, Yuri will continue my work from this point. Thanks, Ilya > > Thanks, > Ilya > >> >> jeff >>