From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 50172 invoked by alias); 24 Oct 2017 10:48:46 -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 49771 invoked by uid 89); 24 Oct 2017 10:48:45 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-0.7 required=5.0 tests=AWL,BAYES_00,RCVD_IN_BRBL_LASTEXT,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=no version=3.3.2 spammy=discipline X-HELO: smtp.eu.adacore.com Received: from mel.act-europe.fr (HELO smtp.eu.adacore.com) (194.98.77.210) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 24 Oct 2017 10:48:44 +0000 Received: from localhost (localhost [127.0.0.1]) by filtered-smtp.eu.adacore.com (Postfix) with ESMTP id A2D3381DD3; Tue, 24 Oct 2017 12:48:42 +0200 (CEST) Received: from smtp.eu.adacore.com ([127.0.0.1]) by localhost (smtp.eu.adacore.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id o1w_5RgyQZoM; Tue, 24 Oct 2017 12:48:42 +0200 (CEST) Received: from polaris.localnet (bon31-6-88-161-99-133.fbx.proxad.net [88.161.99.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.eu.adacore.com (Postfix) with ESMTPSA id 8333A81396; Tue, 24 Oct 2017 12:48:42 +0200 (CEST) From: Eric Botcazou To: Richard Sandiford Cc: gcc-patches@gcc.gnu.org Subject: Re: [000/nnn] poly_int: representation of runtime offsets and sizes Date: Tue, 24 Oct 2017 10:53:00 -0000 Message-ID: <10524871.8B8OuvVQlb@polaris> User-Agent: KMail/4.14.10 (Linux/3.16.7-53-desktop; KDE/4.14.9; x86_64; ; ) In-Reply-To: <87o9owq35v.fsf@linaro.org> References: <871sltvm7r.fsf@linaro.org> <4728974.295PUQgt1k@polaris> <87o9owq35v.fsf@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-SW-Source: 2017-10/txt/msg01672.txt.bz2 > Yeah. E.g. for ==, the two options would be: > > a) must_eq (a, b) -> a == b > must_ne (a, b) -> a != b > > which has the weird property that (a == b) != (!(a != b)) > > b) must_eq (a, b) -> a == b > may_ne (a, b) -> a != b > > which has the weird property that a can be equal to b when a != b Yes, a) was the one I had in mind, i.e. the traditional operators are the must variants and you use an outer ! in order to express the may. Of course this would require a bit of discipline but, on the other hand, if most of the cases fall in the must category, that could be less ugly. > Sorry about that. It's the best I could come up with without losing > the may/must distinction. Which variant is known_zero though? Must or may? -- Eric Botcazou