From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 81376 invoked by alias); 11 May 2018 10:35:46 -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 80926 invoked by uid 89); 11 May 2018 10:35:45 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.3 required=5.0 tests=AWL,BAYES_00,SPF_PASS autolearn=ham version=3.3.2 spammy= X-HELO: smtp.ispras.ru Received: from bran.ispras.ru (HELO smtp.ispras.ru) (83.149.199.196) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Fri, 11 May 2018 10:35:43 +0000 Received: from monopod.intra.ispras.ru (monopod.intra.ispras.ru [10.10.3.121]) by smtp.ispras.ru (Postfix) with ESMTP id 5966B203CC; Fri, 11 May 2018 13:35:40 +0300 (MSK) Date: Fri, 11 May 2018 10:44:00 -0000 From: Alexander Monakov To: Segher Boessenkool cc: Richard Biener , gcc-patches@gcc.gnu.org Subject: Re: [PATCH 0/2] Introduce gcc_qsort In-Reply-To: <20180511102905.GC17342@gate.crashing.org> Message-ID: References: <20180510155641.2950-1-amonakov@ispras.ru> <82E69EBE-92EB-41AB-8E1B-ADBD65516D73@gmail.com> <20180511102905.GC17342@gate.crashing.org> User-Agent: Alpine 2.20.13 (LNX 116 2015-12-14) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII X-SW-Source: 2018-05/txt/msg00547.txt.bz2 On Fri, 11 May 2018, Segher Boessenkool wrote: > For example from reload1.c: No, this example is not relevant, because ... > static int > reload_reg_class_lower (const void *r1p, const void *r2p) > { > int r1 = *(const short *) r1p, r2 = *(const short *) r2p; > > // ... > > return r1 - r2; this subtracts integers, not pointers. In general such address-based comparisons steps are invalid; they lack anti-reflexivity. So comparators are not actually allowed to do that. Alexander