From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Floating-point constant folding in Emacs byte compiler Date: Fri, 23 Mar 2018 11:15:46 +0300 Message-ID: <83lgeji4wd.fsf@gnu.org> References: <2ce39e5c-cd1b-65d6-b125-719caad67932@cs.ucla.edu> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1521792836 9401 195.159.176.226 (23 Mar 2018 08:13:56 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 23 Mar 2018 08:13:56 +0000 (UTC) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Fri Mar 23 09:13:52 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1ezHpc-0002Hx-9r for ged-emacs-devel@m.gmane.org; Fri, 23 Mar 2018 09:13:49 +0100 Original-Received: from localhost ([::1]:36512 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezHrf-0008VA-KA for ged-emacs-devel@m.gmane.org; Fri, 23 Mar 2018 04:15:55 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:54082) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezHrY-0008Uc-SB for emacs-devel@gnu.org; Fri, 23 Mar 2018 04:15:49 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ezHrV-0003xi-Mm for emacs-devel@gnu.org; Fri, 23 Mar 2018 04:15:48 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:38039) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ezHrV-0003xU-JA; Fri, 23 Mar 2018 04:15:45 -0400 Original-Received: from [176.228.60.248] (port=1528 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1ezHrV-0003FL-1R; Fri, 23 Mar 2018 04:15:45 -0400 In-reply-to: (message from Stefan Monnier on Thu, 22 Mar 2018 21:26:00 -0400) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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:223939 Archived-At: > From: Stefan Monnier > Date: Thu, 22 Mar 2018 21:26:00 -0400 > > > These discrepancies mean that .elc files containing floating-point constants > > might not be platform-independent, in that byte-compiling a file on one > > machine X and running it on another machine Y can yield different results > > than byte-compiling and running the same file on Y. Is this sort of > > discrepancy intended? > > I'm pretty sure those runtime differences are not on-purpose, so whether > they show up at run-time or compile-time doesn't matter. > IOW we can keep optimizing those. I don't understand your conclusion: if this is unintended, then IMO we should stop optimizing these, so that byte code is more portable. Or am I missing something?