From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-2.9 required=5.0 tests=BAYES_00,MAILING_LIST_MULTI autolearn=unavailable autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 103376,a00006d3c4735d70 X-Google-Attributes: gid103376,public X-Google-ArrivalTime: 2004-02-29 05:47:42 PST Path: archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news.tele.dk!news.tele.dk!small.news.tele.dk!newsfeed.icl.net!newsfeed.fjserv.net!feed.news.tiscali.de!tiscali!newsfeed1.ip.tiscali.net!proxad.net!usenet-fr.net!enst.fr!melchior!cuivre.fr.eu.org!melchior.frmug.org!not-for-mail From: Stephen Leake Newsgroups: comp.lang.ada Subject: Re: left-to-right (was In-Out Parameters for functions) Date: 29 Feb 2004 08:44:19 -0500 Organization: Cuivre, Argent, Or Message-ID: References: <1075851506.238480@master.nyc.kbcfp.com> <4020C947.81A6D703@0.0> <1075907239.138068@master.nyc.kbcfp.com> <402232E9.3EE15B4B@0.0> <1075987360.225622@master.nyc.kbcfp.com> <40236C0B.E988E003@0.0> <1077634311.254581@master.nyc.kbcfp.com> NNTP-Posting-Host: lovelace.ada-france.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: melchior.cuivre.fr.eu.org 1078062272 68755 212.85.156.195 (29 Feb 2004 13:44:32 GMT) X-Complaints-To: usenet@melchior.cuivre.fr.eu.org NNTP-Posting-Date: Sun, 29 Feb 2004 13:44:32 +0000 (UTC) To: comp.lang.ada@ada-france.org Return-Path: In-Reply-To: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.3 X-Virus-Scanned: by amavisd-new-20030616-p7 (Debian) at ada-france.org X-BeenThere: comp.lang.ada@ada-france.org X-Mailman-Version: 2.1.4 Precedence: list List-Id: "Gateway to the comp.lang.ada Usenet newsgroup" List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Xref: archiver1.google.com comp.lang.ada:5946 Date: 2004-02-29T08:44:19-05:00 "Robert I. Eachus" writes: > Stephen Leake wrote: > > > But you haven't answered my question. Is there, in actual fact, any > > compiler that actually does these optimizations? > > Sure, lots of them, but that is not really the interesting question. Well, it was interesting to _me_, because I didn't know the answer. I suspect any question to which you know the answer is "uninteresting" :). > The interesting experiment is to find a way to turn off just the > optimizations that take advantage of the reordering freedoms, then > see what effect it has on the performance of the compiled code on > some set of benchmarks. Yes. Maybe one of your students will take up the challenge? > Well years go the same > sort of thing was done by hardware and language architects both in > academia and in industry. The conclusion AT THAT TIME, was that the > freedom to reorder, and the compiler code to take advantage of it, was > very worthwhile. Ok. That explains Ada's choice. > With OoO superscaler machines, it is not clear that there would be > any advantage to requiring "more predictable" semantics in > programming languages given what happens during execution. But it > could be that the "optimization freedoms" don't buy much in the way > of performance anymore. Right. Until someone does that, we cannot fairly evaluate the issue of whether changing to requiring left-to-right parameter evaluation would gain more than it loses. But I'm satisfied for now that it is not worth it. -- -- Stephe