From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Newsgroups: gmane.emacs.bugs Subject: bug#42147: 28.0.50; pure vs side-effect-free, missing optimizations? Date: Thu, 2 Jul 2020 12:26:51 +0200 Message-ID: References: <3A9CC2A3-8307-47B2-8D80-795C0AF020E1@acm.org> <0433A879-C98D-4B1A-B85C-A15DA9289099@acm.org> <1621669100.2102667.1593639091621@mail.yahoo.com> Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="32335"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Paul Eggert , Stefan Monnier , 42147@debbugs.gnu.org To: Andrea Corallo Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Jul 02 12:28:11 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jqwRu-0008JA-H4 for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 02 Jul 2020 12:28:10 +0200 Original-Received: from localhost ([::1]:33130 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jqwRt-0004zr-JQ for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 02 Jul 2020 06:28:09 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:40780) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jqwRm-0004zE-Uv for bug-gnu-emacs@gnu.org; Thu, 02 Jul 2020 06:28:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:42881) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jqwRm-0000YN-Lu for bug-gnu-emacs@gnu.org; Thu, 02 Jul 2020 06:28:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jqwRm-0000iq-Hq for bug-gnu-emacs@gnu.org; Thu, 02 Jul 2020 06:28:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 02 Jul 2020 10:28:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 42147 X-GNU-PR-Package: emacs Original-Received: via spool by 42147-submit@debbugs.gnu.org id=B42147.15936856342716 (code B ref 42147); Thu, 02 Jul 2020 10:28:02 +0000 Original-Received: (at 42147) by debbugs.gnu.org; 2 Jul 2020 10:27:14 +0000 Original-Received: from localhost ([127.0.0.1]:54427 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jqwQz-0000hi-Ek for submit@debbugs.gnu.org; Thu, 02 Jul 2020 06:27:14 -0400 Original-Received: from mail233c50.megamailservers.eu ([91.136.10.243]:50142 helo=mail37c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jqwQv-0000hV-8O for 42147@debbugs.gnu.org; Thu, 02 Jul 2020 06:27:11 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1593685616; bh=vp6P+uJ6Q/54Jsq6L3hDjFY1ooflN2+0znTdz9qSjbw=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=LShFtcq5lIh05UHzqEZsz3HlFPeF/zb+lIAn8W6eM8kicsv3l7KXVMK/eQ+smMGMJ jeFQXDGb6l/FlCVyONMtW1kwOwoN9oeIX0DXwCbypf0cM+WG9JcF70BpmVIhr8gXbl 5kEL2C0wDe0rV6neu0l3PmBsWQf/RuLEikpaIttU= Feedback-ID: mattiase@acm.or Original-Received: from [192.168.0.4] (c188-150-171-71.bredband.comhem.se [188.150.171.71]) (authenticated bits=0) by mail37c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 062AQpRG007802; Thu, 2 Jul 2020 10:26:53 +0000 In-Reply-To: <1621669100.2102667.1593639091621@mail.yahoo.com> X-Mailer: Apple Mail (2.3445.104.14) X-CTCH-RefID: str=0001.0A782F22.5EFDB5C5.0094, ss=1, re=0.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: 0.000 X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-CSC: 0 X-CHA: v=2.3 cv=bJNo382Z c=1 sm=1 tr=0 a=SF+I6pRkHZhrawxbOkkvaA==:117 a=SF+I6pRkHZhrawxbOkkvaA==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=vQ39kIYf1yTL1eD7LZIA:9 a=fuH0C7_SlnkRor91:21 a=XcD88_b8t1jAXqHb:21 a=CjuIK1q_8ugA:10 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:182627 Archived-At: 1 juli 2020 kl. 23.31 skrev Andrea Corallo : > Another reason why I'm interested is that I reuse these > definitions in the native compiler. In that case there are probably more functions you may want to consider = for purity -- what about: < > <=3D >=3D =3D /=3D string< string=3D string-equal eq eql equal proper-list-p identity memq memql member assq assql assoc > I guess for the most part I can just include the one I've missed. By all means, but do not take my word for the correctness of my list -- = think it through yourself. We mustn't err here. > I'm not only sure about the one operating on lists like `length' given = the > list may be modified in the runtime (?). Not sure why this would be an obstacle, but I could have overlooked = something important! Could you explain your thinking in greater detail, = and if possible provide an example of code that you think might be = miscompiled if 'length' or 'safe-length' were marked pure? I still wonder if there is any reason to limit arithmetic constant = folding to the portable fixnum range. Given that we don't evaluate = fixnump or bignump at compile-time, what observable effects would = constant-folding, say, (ash 1 32) have? Advice from deeper thinkers = solicited!