From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 112586 invoked by alias); 3 Aug 2015 16:29:35 -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 112570 invoked by uid 89); 3 Aug 2015 16:29:34 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.4 required=5.0 tests=AWL,BAYES_00,KAM_LAZY_DOMAIN_SECURITY,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=no version=3.3.2 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, 03 Aug 2015 16:29:33 +0000 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (Postfix) with ESMTPS id 7BD30341AD8; Mon, 3 Aug 2015 16:29:32 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-21.phx2.redhat.com [10.3.113.21]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t73GTVAO014956; Mon, 3 Aug 2015 12:29:32 -0400 Subject: Re: [PATCH][RTL-ifcvt] Improve conditional select ops on immediates To: Ilya Enkovich , Uros Bizjak References: <55BF666A.5000008@arm.com> Cc: Kyrill Tkachov , "gcc-patches@gcc.gnu.org" , "H.J. Lu" From: Jeff Law Message-ID: <55BF96EB.20802@redhat.com> Date: Mon, 03 Aug 2015 16:29:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.1.0 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: 2015-08/txt/msg00097.txt.bz2 On 08/03/2015 09:50 AM, Ilya Enkovich wrote: > > The original code looks better, tree height is just 2 and therefore it > can be executed in 2 cycles. New code has more dependencies and tree > height becomes 5. It is always hard to say for all x86 targets but as > a generic code the original version is better. Agreed. Reducing tree height is definitely a good thing as a general rule. jeff