From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 13426 invoked by alias); 8 May 2015 17:46:23 -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 13416 invoked by uid 89); 8 May 2015 17:46:23 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.9 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,T_RP_MATCHES_RCVD autolearn=no version=3.3.2 X-HELO: mail.zytor.com Received: from terminus.zytor.com (HELO mail.zytor.com) (198.137.202.10) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Fri, 08 May 2015 17:46:22 +0000 Received: from tazenda.hos.anvin.org (c-24-130-130-177.hsd1.ca.comcast.net [24.130.130.177]) (authenticated bits=0) by mail.zytor.com (8.14.8/8.14.5) with ESMTP id t48HkImG026551 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO); Fri, 8 May 2015 10:46:18 -0700 Message-ID: <554CF665.7070901@zytor.com> Date: Fri, 08 May 2015 17:46:00 -0000 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Richard Henderson , gcc-patches@gcc.gnu.org CC: law@redhat.com, peterz@infradead.org, torvalds@linux-foundation.org, jakub@redhat.com Subject: Re: [RFC 0/6] Flags outputs for asms References: <1431034740-5375-1-git-send-email-rth@redhat.com> <554C0E31.5070509@zytor.com> <554CDC30.1080903@redhat.com> In-Reply-To: <554CDC30.1080903@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-SW-Source: 2015-05/txt/msg00712.txt.bz2 On 05/08/2015 08:54 AM, Richard Henderson wrote: > > Anyway, I'll look into whether the branch around alpha can be optimized, but > I'd be shocked if I'd be able to do anything about the branch around beta. > True, there's nothing in between that will clobber the flags so it would be an > excellent improvement, but combine doesn't work across basic blocks and > changing that would be a major task. > Either way... optimization is something that can be done gradually. Once we start using the feature we can figure out where it makes sense to do further optimizations. 0hpa