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: Sat, 4 Jul 2020 16:58:13 +0200 Message-ID: References: <3A9CC2A3-8307-47B2-8D80-795C0AF020E1@acm.org> <0433A879-C98D-4B1A-B85C-A15DA9289099@acm.org> <1621669100.2102667.1593639091621@mail.yahoo.com> <775819003.2516724.1593687594435@mail.yahoo.com> <5F2B4684-34D1-4474-8909-9F435369FE54@acm.org> <705260433.2731607.1593698199171@mail.yahoo.com> <6CF8EE58-9A49-40E7-AA86-48AB39BF94BA@acm.org> <28B19D86-343C-4126-B95F-1F38735F73F2@acm.org> <1288c6a5-545b-f68c-ff6b-7683db3e54c1@cs.ucla.edu> <1374652931.3977142.1593803140551@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="17042"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Paul Eggert , Stefan Monnier , 42147@debbugs.gnu.org To: Andrea Corallo , Philipp Stephani Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat Jul 04 17:06:19 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 1jrjkB-0004Kv-3d for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 04 Jul 2020 17:06:19 +0200 Original-Received: from localhost ([::1]:38844 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jrjkA-0005Qa-4X for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 04 Jul 2020 11:06:18 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:59792) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jrjd8-0001np-Lj for bug-gnu-emacs@gnu.org; Sat, 04 Jul 2020 10:59:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:47830) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jrjd8-0005H7-9e for bug-gnu-emacs@gnu.org; Sat, 04 Jul 2020 10:59:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jrjd8-0005Wk-8x for bug-gnu-emacs@gnu.org; Sat, 04 Jul 2020 10:59:02 -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: Sat, 04 Jul 2020 14:59:02 +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=B42147.159387471321209 (code B ref 42147); Sat, 04 Jul 2020 14:59:02 +0000 Original-Received: (at 42147) by debbugs.gnu.org; 4 Jul 2020 14:58:33 +0000 Original-Received: from localhost ([127.0.0.1]:59376 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jrjcf-0005W1-AQ for submit@debbugs.gnu.org; Sat, 04 Jul 2020 10:58:33 -0400 Original-Received: from mail200c50.megamailservers.eu ([91.136.10.210]:39408 helo=mail193c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jrjcc-0005Vq-4W for 42147@debbugs.gnu.org; Sat, 04 Jul 2020 10:58:32 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1593874698; bh=c6u82rFySUawC1S2o0vkyhBe0yoUeFjiLHeiFmUbDfk=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=qsNMpVYbBUhWecpUqvFzSgWc7N1bXalB6WWTjPeAZ3DGecSq5avDuBD0e/lDNOVb0 Y9VILMx700xrOBtvMWgYltHVYsgZRX9DaMiIipWS5YpRVXUdJe7iH9lHWWwb7dKEZE nOufO8bdA/qgIHwm4yI1glFaniUf0j4GbahN78ZQ= 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 mail193c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 064EwE4g024063; Sat, 4 Jul 2020 14:58:15 +0000 In-Reply-To: <1374652931.3977142.1593803140551@mail.yahoo.com> X-Mailer: Apple Mail (2.3445.104.14) X-CTCH-RefID: str=0001.0A782F19.5F00990A.0037, 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=cM2eTWWN c=1 sm=1 tr=0 a=SF+I6pRkHZhrawxbOkkvaA==:117 a=SF+I6pRkHZhrawxbOkkvaA==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=mQlE-r5yVJJReojE4i0A:9 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:182694 Archived-At: 3 juli 2020 kl. 21.05 skrev Andrea Corallo : > attached the updated version of the patch updating the pure function > classification. Thanks Andrea! Philipp Stephani raised the interesting question of = (essentially) whether 'car' is pure. For the purposes of the current = constant folding in the byte compiler the answer is yes, but perhaps you = have wider ambitions in your work? Clearly, (car X) cannot be moved past some operations with side-effects = if X is aliased: (let* ((x (list 'a)) (y (car x))) (f x) y) Here, (car x) cannot be sunk past the call to f despite x remaining = unchanged (assuming lexical binding). It would be useful to know more exactly what notion of purity you = require.