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: Mon, 02 Apr 2018 16:30:31 +0300 Message-ID: <83y3i568i0.fsf@gnu.org> References: <2ce39e5c-cd1b-65d6-b125-719caad67932@cs.ucla.edu> <83vadmgfbz.fsf@gnu.org> <87d0zr2n1u.fsf@gmail.com> <83h8p2g99p.fsf@gnu.org> <87370m3k4y.fsf@gmail.com> <838taeg6z5.fsf@gnu.org> <7a49cbdf-f2c3-0803-2ee8-3d9f55e405a5@cs.ucla.edu> <7a4f10ec-c1b9-953d-7a95-b2f1ff762735@cs.ucla.edu> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1522675777 24057 195.159.176.226 (2 Apr 2018 13:29:37 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 2 Apr 2018 13:29:37 +0000 (UTC) Cc: rpluim@gmail.com, eggert@cs.ucla.edu, pipcet@gmail.com, emacs-devel@gnu.org To: Noam Postavsky Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Apr 02 15:29:32 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 1f2zWd-00067q-TV for ged-emacs-devel@m.gmane.org; Mon, 02 Apr 2018 15:29:32 +0200 Original-Received: from localhost ([::1]:35001 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f2zYh-0005zu-F9 for ged-emacs-devel@m.gmane.org; Mon, 02 Apr 2018 09:31:39 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40522) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f2zXa-0005yi-VC for emacs-devel@gnu.org; Mon, 02 Apr 2018 09:30:31 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f2zXX-000529-Fr for emacs-devel@gnu.org; Mon, 02 Apr 2018 09:30:30 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:41910) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f2zXX-00051v-BY; Mon, 02 Apr 2018 09:30:27 -0400 Original-Received: from [176.228.60.248] (port=2411 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1f2zXW-0000V1-L5; Mon, 02 Apr 2018 09:30:27 -0400 In-reply-to: (message from Noam Postavsky on Mon, 2 Apr 2018 08:57:30 -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:224241 Archived-At: > From: Noam Postavsky > Date: Mon, 2 Apr 2018 08:57:30 -0400 > Cc: Robert Pluim , Paul Eggert , > Emacs developers > > On 30 March 2018 at 12:26, Pip Cet wrote: > > > It's easy to fix this by merging the constvec based on eql rather than > > eq, but that makes the byte compiler inconsistent: with optimization, > > (lambda () (eq 1024.0 1024.0)) will still be false, but without > > optimization, it will turn into bytecode that always returns true. > > The byte-compiler is already inconsistent in this way for string literals: Yes, because strings share the same EQ issue with floats. And because we sometimes try to "optimize" that. For example, in make_pure_string.