From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 55974 invoked by alias); 8 Oct 2015 16:58:33 -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 55964 invoked by uid 89); 8 Oct 2015 16:58:33 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,T_RP_MATCHES_RCVD autolearn=ham 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; Thu, 08 Oct 2015 16:58:27 +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 B8CE08E69E; Thu, 8 Oct 2015 16:58:26 +0000 (UTC) Received: from localhost.localdomain (vpn1-6-126.ams2.redhat.com [10.36.6.126]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t98GwPkr009745; Thu, 8 Oct 2015 12:58:26 -0400 Subject: Re: Move some bit and binary optimizations in simplify and match To: "Hurugalawadi, Naveen" , "gcc-patches@gcc.gnu.org" References: From: Bernd Schmidt Message-ID: <5616A0B1.9050503@redhat.com> Date: Thu, 08 Oct 2015 16:58:00 -0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-10/txt/msg00883.txt.bz2 On 10/07/2015 11:54 AM, Hurugalawadi, Naveen wrote: > Move Fold X & (X ^ Y) as X & ~Y to match.pd. > Move Fold X & (Y ^ X) as ~Y & X to match.pd. I wonder if we shouldn't try to autogenerate patterns such as these. I did something like that for a different project a long time ago. Generate expressions up to a certain level of complexity, identify which ones are equivalent, and pick the one with the lowest cost for simplifications... Bernd