From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 11460 invoked by alias); 11 May 2011 18:20:37 -0000 Received: (qmail 11432 invoked by uid 22791); 11 May 2011 18:20:36 -0000 X-SWARE-Spam-Status: No, hits=-1.2 required=5.0 tests=AWL,BAYES_00,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,RCVD_IN_DNSWL_NONE X-Spam-Check-By: sourceware.org Received: from mo-p00-ob.rzone.de (HELO mo-p00-ob.rzone.de) (81.169.146.162) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Wed, 11 May 2011 18:20:20 +0000 X-RZG-AUTH: :LXoWVUeid/7A29J/hMvvT2k715jHQaJercGOZE+TiTS5oCK9h49H+/Q= X-RZG-CLASS-ID: mo00 Received: from [192.168.2.100] (dslb-084-058-210-188.pools.arcor-ip.net [84.58.210.188]) by post.strato.de (cohen mo32) (RZmta 25.18) with ESMTPA id V03f4fn4BHertv ; Wed, 11 May 2011 20:20:03 +0200 (MEST) Message-ID: <4DCAD237.3010008@gjlay.de> Date: Wed, 11 May 2011 19:39:00 -0000 From: Georg-Johann Lay User-Agent: Mozilla Thunderbird 1.0.7 (Windows/20050923) MIME-Version: 1.0 To: Denis Chertykov CC: gcc-patches@gcc.gnu.org, Anatoly Sokolov , Eric Weddington Subject: Re: [Patch,AVR]: Fix PR27663 References: <4DBEC003.4050300@gjlay.de> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes 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 X-SW-Source: 2011-05/txt/msg00858.txt.bz2 Denis Chertykov schrieb: > 2011/5/2 Georg-Johann Lay : > >>This is a fix for an optimization flaw when a long value is composed >>from byte values. >> >>For -fsplit-wide-types (which is still default for avr) the code is >>worse than with -fno-split-wide-types. The code for the test case is >>better in either situations, i.e. compared to code without the patch, >>but it is still not optimal. >> >>Fixing this by some combine patterns is the only thing the BE can do. >>I did not write more complex patterns because things get too complex >>with little performance gain. >> >>Tested without regressions. >> >>Johann >> >>2011-05-02 Georg-Johann Lay >> >> PR target/27663 >> * config/avr/predicates.md (const_8_16_24_operand): New predicate. >> * config/avr/avr.md ("*iorqi.byte0", >> "*iorqi.byte1-3"): New define_insn_and_split patterns. >> > I'm sorry, but I dot'n like to have a both combiner related patches in > port because code improvement isn't much and your patterns are > difficult to understand and maintain. > > May be somebody else have a different oppinion ? > I'm open to discussion. > > Denis. Let me add that the patch is generic enough to also improve ORing HI against QI like described in http://gcc.gnu.org/PR41076 which is not uncommon on avr. Johann