From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by yquem.inria.fr (Postfix) with ESMTP id BF503BB81 for ; Tue, 27 Sep 2005 17:22:04 +0200 (CEST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j8RFM3m6002941 for ; Tue, 27 Sep 2005 17:22:04 +0200 Received: from nez-perce.inria.fr (nez-perce.inria.fr [192.93.2.78]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id RAA31281 for ; Tue, 27 Sep 2005 17:22:03 +0200 (MET DST) Received: from mercure.iro.umontreal.ca (mercure.iro.umontreal.ca [132.204.24.67]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j8RFM2oD002933 for ; Tue, 27 Sep 2005 17:22:03 +0200 Received: from hidalgo.iro.umontreal.ca (hidalgo.iro.umontreal.ca [132.204.27.50]) by mercure.iro.umontreal.ca (Postfix) with ESMTP id 35E492CF5FE; Tue, 27 Sep 2005 11:21:39 -0400 (EDT) Received: from asado.iro.umontreal.ca (asado.iro.umontreal.ca [132.204.24.84]) by hidalgo.iro.umontreal.ca (Postfix) with ESMTP id 806414AC00D; Tue, 27 Sep 2005 11:21:24 -0400 (EDT) Received: by asado.iro.umontreal.ca (Postfix, from userid 20848) id 64847F69C4; Tue, 27 Sep 2005 11:21:24 -0400 (EDT) Message-ID: To: skaller Cc: caml-list@inria.fr Subject: Re: [Caml-list] Re: Ant: Efficiency of let/and References: <20050926043240.24009.qmail@web26809.mail.ukl.yahoo.com> <87hdc724wo.fsf-monnier+gmane.comp.lang.caml.inria@gnu.org> <1127799169.31518.154.camel@rosella> From: Stefan Monnier Date: Tue, 27 Sep 2005 11:21:24 -0400 In-Reply-To: <1127799169.31518.154.camel@rosella> (skaller@users.sourceforge.net's message of "Tue, 27 Sep 2005 15:32:49 +1000") User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.0.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-DIRO-MailScanner-Information: Please contact the ISP for more information X-DIRO-MailScanner: Found to be clean X-DIRO-MailScanner-SpamCheck: n'est pas un polluriel, SpamAssassin (score=-4.847, requis 5, autolearn=not spam, AWL 0.05, BAYES_00 -4.90) X-MailScanner-From: monnier@iro.umontreal.ca X-Miltered: at nez-perce with ID 4339639C.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 4339639A.001 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; caml-list:01 umontreal:01 compiler:01 parallelism:01 parallelism:01 pipelines:01 compilers:01 let':01 integer:01 rarely:02 let:03 imagined:95 parallel:04 processors:04 indeed:05 X-Spam-Checker-Version: SpamAssassin 3.0.3 (2005-04-27) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.0 required=5.0 tests=none autolearn=disabled version=3.0.3 >> If someone tries to use such things as `and' or >> unspecified-argument-evaluation-order in the hopes that the compiler will >> extract some imagined parallelism is simply deluding himself. >> In some cases, the freedom to execute in any order does lead to better >> code, but that code rarely if ever uses any kind of parallelism. > This is not so at all. Limited Parallelism is indeed found in all > modern processors, which can, for example, distribute multiple > instructions on several pipelines, decode in parallel with > computing values, or perform several integer and/or floating > operations simultaneously. This has nothing to do with what I said. Compilers can equally take advantage of ILP with a `let' or with a specified evaluation order. Stefan