From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Stefan Monnier Newsgroups: gmane.emacs.bugs Subject: bug#766: 23.0.60; interesting warning during compilation Date: Wed, 03 Sep 2008 14:47:14 -0400 Message-ID: References: <4762603A-B23E-454E-A43C-422DE5036DC4@Freenet.DE> Reply-To: Stefan Monnier , 766@emacsbugs.donarmstrong.com NNTP-Posting-Host: lo.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1220468939 26613 80.91.229.12 (3 Sep 2008 19:08:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 3 Sep 2008 19:08:59 +0000 (UTC) Cc: Andreas Schwab , 766@emacsbugs.donarmstrong.com, Peter_Dyballa@Freenet.DE, bug-gnu-emacs@gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Sep 03 21:09:53 2008 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([199.232.76.165]) by lo.gmane.org with esmtp (Exim 4.50) id 1Kaxjl-0004MF-HL for geb-bug-gnu-emacs@m.gmane.org; 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Wed, 03 Sep 2008 14:47:42 -0400 Original-Received: from [199.232.76.173] (port=39630 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KaxOH-0001gR-6X for bug-gnu-emacs@gnu.org; Wed, 03 Sep 2008 14:47:41 -0400 Original-Received: from pruche.dit.umontreal.ca ([132.204.246.22]:51359) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1KaxO9-00050E-2g; Wed, 03 Sep 2008 14:47:33 -0400 Original-Received: from alfajor.home (vpn-132-204-232-121.acd.umontreal.ca [132.204.232.121]) by pruche.dit.umontreal.ca (8.14.1/8.14.1) with ESMTP id m83Ilh5d030089; Wed, 3 Sep 2008 14:47:43 -0400 Original-Received: by alfajor.home (Postfix, from userid 20848) id 4AA861C971; Wed, 3 Sep 2008 14:47:14 -0400 (EDT) In-Reply-To: (Eli Zaretskii's message of "Sat, 23 Aug 2008 21:18:19 +0300") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) X-NAI-Spam-Score: 0 X-NAI-Spam-Rules: 1 Rules triggered RV3096=0 X-detected-kernel: by monty-python.gnu.org: Linux 2.6 (newer, 3) X-CrossAssassin-Score: 2 X-detected-kernel: by monty-python.gnu.org: Linux 2.6 (newer, 3) Resent-Date: Wed, 03 Sep 2008 15:07:36 -0400 X-BeenThere: bug-gnu-emacs@gnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:20106 Archived-At: >> > If someone has suggestions how to avoid this warning without making >> > code ugly and unreadable, and preferably without system-dependent >> > #ifdef's, I'm all ears. >> >> EMACS_INT high_ino = s.st_ino >> 31 >> 1; > Thanks. Can we be reasonably sure that GCC will not become smart > enough some day to flag this as well? I don't think anybody can guarantee it, but usually it's a bad idea to output warnings about post-optimization code, so you may hope that GCC will optimize "x >> 31 >> 1" to "x >> 32" without ever outputing a warning about the silliness of the end result. Then again, the present code shows that even outputting a warning about "x >> 32" is already borderline annoying, so there's no guarantee gcc won't become more annoying in the future. Stefan