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: Mon, 30 Jul 2018 21:49:16 +0300 Message-ID: <83h8kgpnir.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> NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1532976476 15230 195.159.176.226 (30 Jul 2018 18:47:56 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 30 Jul 2018 18:47:56 +0000 (UTC) Cc: emacs-devel@gnu.org To: Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Jul 30 20:47:52 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 1fkDCu-0003js-8M for ged-emacs-devel@m.gmane.org; Mon, 30 Jul 2018 20:47:48 +0200 Original-Received: from localhost ([::1]:55384 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkDF0-00013p-NR for ged-emacs-devel@m.gmane.org; Mon, 30 Jul 2018 14:49:58 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:38718) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkDEJ-00012Z-1V for emacs-devel@gnu.org; Mon, 30 Jul 2018 14:49:15 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fkDEE-00030L-37 for emacs-devel@gnu.org; Mon, 30 Jul 2018 14:49:15 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:35907) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkDED-00030H-Va; Mon, 30 Jul 2018 14:49:10 -0400 Original-Received: from [176.228.60.248] (port=2182 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1fkDED-0006VK-EF; Mon, 30 Jul 2018 14:49:09 -0400 In-reply-to: (message from Stefan Monnier on Mon, 30 Jul 2018 13:07:35 -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:228011 Archived-At: > From: Stefan Monnier > Date: Mon, 30 Jul 2018 13:07:35 -0400 > > > How likely is it to see a floating-point number with 4 low-order bits > > of mantissa zero? > > For floating point values read from Elisp source code, the probability > is not bad at all. OTOH for code performing any non-trivial > calculation, of course, the probably should hover around 1/2^4, so > pretty low. That's what I thought. So given this, aren't we optimizing a rare situation, and OTOH making the code more complex and perhaps less efficient for the majority of use cases?