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: Making 'eq' == 'eql' in bignum branch Date: Tue, 31 Jul 2018 05:38:37 +0300 Message-ID: <83d0v4p1si.fsf@gnu.org> References: <29f933ac-a6bf-8742-66a7-0a9d6d3e5a88@disroot.org> <87tvpdnzgy.fsf@tromey.com> <4c2a814f-c254-29e5-39cf-11b5f2e5c9c8@cs.ucla.edu> <49d8ba62-c9a5-9203-d882-8e900b441ff3@cs.ucla.edu> <8e0320d9-e0d0-2b57-57cc-2df4399f133c@cs.ucla.edu> <87lgaio7xd.fsf@tromey.com> <877em1cb0i.fsf@tromey.com> <765767b2-d2e5-a9a6-f724-d58ecf4847bb@cs.ucla.edu> <76081b5d-8c10-0a37-2c97-d4864c0faa80@cs.ucla.edu> <09153aed-361d-4f82-d9ac-b502314769ae@cs.ucla.edu> <83600yt8ih.fsf@gnu.org> <83h8kgpnir.fsf@gnu.org> <7dd71d44-69bc-3adf-576b-8b9e31184a24@cs.ucla.edu> NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1533004597 11915 195.159.176.226 (31 Jul 2018 02:36:37 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 31 Jul 2018 02:36:37 +0000 (UTC) Cc: monnier@iro.umontreal.ca, emacs-devel@gnu.org To: Paul Eggert Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue Jul 31 04:36:33 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 1fkKWW-000319-SN for ged-emacs-devel@m.gmane.org; Tue, 31 Jul 2018 04:36:32 +0200 Original-Received: from localhost ([::1]:56727 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkKYd-0001ym-DZ for ged-emacs-devel@m.gmane.org; Mon, 30 Jul 2018 22:38:43 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:41383) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkKYT-0001yf-SP for emacs-devel@gnu.org; Mon, 30 Jul 2018 22:38:34 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fkKYP-0003qw-86 for emacs-devel@gnu.org; Mon, 30 Jul 2018 22:38:33 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:43126) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkKYP-0003qs-3o; Mon, 30 Jul 2018 22:38:29 -0400 Original-Received: from [176.228.60.248] (port=3144 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1fkKYO-0001xT-Ik; Mon, 30 Jul 2018 22:38:28 -0400 In-reply-to: <7dd71d44-69bc-3adf-576b-8b9e31184a24@cs.ucla.edu> (message from Paul Eggert on Mon, 30 Jul 2018 14:58:15 -0700) 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:228029 Archived-At: > Cc: emacs-devel@gnu.org > From: Paul Eggert > Date: Mon, 30 Jul 2018 14:58:15 -0700 > > Not at all. In practice, floating point computations favor values like 0.0 and > 100.0 where the bottom 3 bits of the representation are zero. True, computations > involving random floating-point numbers will get such values only 1/8 of the > time; but Emacs computations are not typically random. > > Any changes in this area should be aimed at typical Emacs usage. If we can get a > performance win when Emacs compiles itself, that'd be a good sign, though of > course not conclusive. Emacs compiling itself is not a typical use of floats in Emacs, IMO. It's a very specialized use case, which is very rare in normal usage of Emacs. I typically build a production release of Emacs just once, and then use it for many moons. If we want to claim that typical usage of floats in Emacs favors round values, we need to back that up by some data.