From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 55310 invoked by alias); 18 Aug 2015 18:14:28 -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 55297 invoked by uid 89); 18 Aug 2015 18:14:27 -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; Tue, 18 Aug 2015 18:14:27 +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 0EE619239C; Tue, 18 Aug 2015 18:14:26 +0000 (UTC) Received: from localhost.localdomain (ovpn-113-201.phx2.redhat.com [10.3.113.201]) by int-mx13.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t7IIEPK4021413; Tue, 18 Aug 2015 14:14:25 -0400 Subject: Re: [PATCH GCC]Improve bound information in loop niter analysis To: "Bin.Cheng" , Richard Biener References: <000401d0c918$d7a2e780$86e8b680$@arm.com> Cc: Bin Cheng , GCC Patches From: Jeff Law Message-ID: <55D37601.6060200@redhat.com> Date: Tue, 18 Aug 2015 18:38:00 -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=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2015-08/txt/msg01019.txt.bz2 On 08/17/2015 04:01 AM, Bin.Cheng wrote: >> >> + c0 = fold_convert (type, c0); >> + c1 = fold_convert (type, c1); >> + >> + if (operand_equal_p (var, c0, 0)) >> >> I believe if c0 is not already of type type operand-equal_p will never succeed. > It's quite specific case targeting comparison between var and it's > range bounds. Given c0 is in form of "var + offc0", then the > comparison "var + offc0 != range bounds" doesn't have any useful > information. Maybe useless type conversion can be handled here > though, it might be even corner case. My comment about useless type conversions was more about a deficiency in operand_equal_p's implementation. It wasn't something I felt needed to be addressed in your patch. I think using operand_equal_p is fine here. Jeff