From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 6cd5678: Clarify compiler-pacifier in frame.c Date: Tue, 27 Aug 2019 11:02:21 +0300 Message-ID: <83lfvfdoj6.fsf@gnu.org> References: <835zmnjdjm.fsf@gnu.org> <227db16b-17d1-b44b-97b3-e80211415eef@cs.ucla.edu> <831rx9iupo.fsf@gnu.org> <32f9db09-0c04-df03-4bb7-76fe2aa9a88f@cs.ucla.edu> <83tva4fjkz.fsf@gnu.org> <87cb5a0c-bdd8-726c-80ed-92e9f3518a58@cs.ucla.edu> <83o90cfecf.fsf@gnu.org> <87lfvg3qbi.fsf@telefonica.net> <83imqjgb1g.fsf@gnu.org> <87ftln4wm0.fsf@telefonica.net> <83a7bvg4a2.fsf@gnu.org> <87blwb4u2i.fsf@telefonica.net> <835zmjg1re.fsf@gnu.org> <831rx7f863.fsf@gnu.org> <834b9308-5235-be47-1cf8-136bb6f35e48@cs.ucla.edu> Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="61077"; mail-complaints-to="usenet@blaine.gmane.org" Cc: emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Aug 27 10:02:30 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1i2WQv-000Fjj-0Y for ged-emacs-devel@m.gmane.org; Tue, 27 Aug 2019 10:02:29 +0200 Original-Received: from localhost ([::1]:47850 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2WQt-0003OB-Vi for ged-emacs-devel@m.gmane.org; Tue, 27 Aug 2019 04:02:28 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33386) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i2WQl-0003No-2G for emacs-devel@gnu.org; Tue, 27 Aug 2019 04:02:21 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:54234) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1i2WQk-0007XB-Ji; Tue, 27 Aug 2019 04:02:18 -0400 Original-Received: from [176.228.60.248] (port=1729 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1i2WQi-0002ga-QE; Tue, 27 Aug 2019 04:02:17 -0400 In-reply-to: <834b9308-5235-be47-1cf8-136bb6f35e48@cs.ucla.edu> (message from Paul Eggert on Tue, 27 Aug 2019 00:28:58 -0700) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:239610 Archived-At: > Cc: emacs-devel@gnu.org > From: Paul Eggert > Date: Tue, 27 Aug 2019 00:28:58 -0700 > > 5342 int geometry = XParseGeometry (SSDATA (string), > 5343 &x, &y, &width, &height); > 5344 Lisp_Object result = Qnil; > 5345 if (geometry & XValue) > 5346 { > 5347 Lisp_Object element; > 5348 > 5349 if (x >= 0 && (geometry & XNegative)) > > ... then GCC is giving a false alarm: x must be initialized in line 5349 if > (geometry & XValue) is nonzero in line 5345. How do you know whether (geometry & XValue) is nonzero in each relevant use case? And how should GCC know that?