From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: [Emacs-diffs] master 3b48f99: Tune pseudovector allocation assuming Qnil == 0 Date: Mon, 19 Jan 2015 01:03:48 -0800 Organization: UCLA Computer Science Department Message-ID: <54BCC874.4020401@cs.ucla.edu> References: <20150116091337.18580.48119@vcs.savannah.gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1421658269 508 80.91.229.3 (19 Jan 2015 09:04:29 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 19 Jan 2015 09:04:29 +0000 (UTC) Cc: Dmitry Antipov To: Stefan Monnier , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Jan 19 10:04:22 2015 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1YD8Fx-00017k-3S for ged-emacs-devel@m.gmane.org; Mon, 19 Jan 2015 10:04:21 +0100 Original-Received: from localhost ([::1]:36173 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YD8Fw-0000fg-6y for ged-emacs-devel@m.gmane.org; Mon, 19 Jan 2015 04:04:20 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:44510) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YD8Fo-0000bM-7a for emacs-devel@gnu.org; Mon, 19 Jan 2015 04:04:16 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YD8Fj-00022B-Ta for emacs-devel@gnu.org; Mon, 19 Jan 2015 04:04:12 -0500 Original-Received: from smtp.cs.ucla.edu ([131.179.128.62]:47830) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YD8Fj-000225-NR for emacs-devel@gnu.org; Mon, 19 Jan 2015 04:04:07 -0500 Original-Received: from localhost (localhost.localdomain [127.0.0.1]) by smtp.cs.ucla.edu (Postfix) with ESMTP id E477139E801F; Mon, 19 Jan 2015 01:04:06 -0800 (PST) X-Virus-Scanned: amavisd-new at smtp.cs.ucla.edu Original-Received: from smtp.cs.ucla.edu ([127.0.0.1]) by localhost (smtp.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Kb3BTvASXqf0; Mon, 19 Jan 2015 01:04:06 -0800 (PST) Original-Received: from [192.168.1.9] (pool-173-55-11-52.lsanca.fios.verizon.net [173.55.11.52]) by smtp.cs.ucla.edu (Postfix) with ESMTPSA id 5C77339E801E; Mon, 19 Jan 2015 01:04:06 -0800 (PST) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 In-Reply-To: X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6.x X-Received-From: 131.179.128.62 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:181429 Archived-At: Stefan Monnier wrote: > Is Qnil==0 true for all builds? Yes, that's been true since Jan 10. I looked, and there are some other places where we can profitably prefer memset to assigning Qnil by hand; I did this in commit b7f83adda5a32140811e8e7decc4394d64cada3d just now. > Maybe it's better to do > > if (Qnil == 0) > > else > It's a bit simpler to verify that Qnil is zero, as in the abovementioned commit.