From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on yquem.inria.fr X-Spam-Level: X-Spam-Status: No, score=0.3 required=5.0 tests=AWL autolearn=disabled version=3.1.3 X-Original-To: caml-list@yquem.inria.fr Delivered-To: caml-list@yquem.inria.fr Received: from mail1-relais-roc.national.inria.fr (mail1-relais-roc.national.inria.fr [192.134.164.82]) by yquem.inria.fr (Postfix) with ESMTP id BA54EBBAF for ; Tue, 5 May 2009 16:15:35 +0200 (CEST) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AscFAEDn/0lQDPKXYmdsb2JhbACNRokmFwoLBRIEqToIj2iCLhoIgTEF X-IronPort-AV: E=Sophos;i="4.38,431,1233529200"; d="scan'208";a="28780909" Received: from smtp2f.orange.fr ([80.12.242.151]) by mail1-smtp-roc.national.inria.fr with ESMTP; 05 May 2009 16:15:34 +0200 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf2f14.orange.fr (SMTP Server) with ESMTP id 85FD080000F6; Tue, 5 May 2009 16:15:33 +0200 (CEST) Received: from [192.168.1.58] (APuteaux-154-1-7-142.w83-199.abo.wanadoo.fr [83.199.4.142]) by mwinf2f14.orange.fr (SMTP Server) with ESMTP id 4B17680000F5; Tue, 5 May 2009 16:15:33 +0200 (CEST) X-ME-UUID: 20090505141533307.4B17680000F5@mwinf2f14.orange.fr Message-ID: <4A004A05.6040204@lexifi.com> Date: Tue, 05 May 2009 16:15:33 +0200 From: Jean-Marc Eber User-Agent: Thunderbird 2.0.0.21 (Windows/20090302) MIME-Version: 1.0 To: Dmitry Bely Cc: Caml List Subject: Re: [Caml-list] Ocamlopt code generator question References: <90823c940904281236x61204451nac149ee15b5df73a@mail.gmail.com> <4A0005C8.8010609@inria.fr> <90823c940905050241y11f012e5xee8316e3e4337ff9@mail.gmail.com> In-Reply-To: <90823c940905050241y11f012e5xee8316e3e4337ff9@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam: no; 0.00; lexifi:01 ocamlopt:01 lexifi:01 xavier's:01 ocaml:01 predictable:01 bytecode:01 ocamlopt:01 sqrt:01 ocaml:01 cvs:01 beginner's:01 bug:01 donate:98 eliminates:98 Hi Dimitry, LexiFi for instance _is_ clearly interested by a sse2 32bit code generator. One should probably have the following in mind and/or ask the following questions: - it is probably not a good idea to support both backends (sse2 and old stack fp i386 architecture). It will be necessary to make a choice (especially taking in account the limited INRIA resources and the burden of already supporting different windows ports). - would INRIA be ok to switch to a sse2 code generator (based on Dimitry's patch - supposing that he is ok to donate it to INRIA - or Xavier's work or whatever)? - I also guess that a sse2 code generator would be simpler than the current one (that has to support this horrible fp stack architecture) and would therefore be a better candidate for further enhancements. - what is the opinion on this list, as a switch to a sse2 backend would exclude "old" processors from being OCaml compatible (I don't have a precise list at hand for now) ? My opinion is that this support of legacy hardware is not important, but I guess others are arguing in opposite directions... :-) But again, having better floating point performance (and predictable behaviour, compared to the bytecode version) would be a big plus for some applications. Best regards, Jean-Marc Dmitry Bely a écrit : > > I see. Why I asked this: trying to improve floating-point performance > on 32-bit x86 platform I have merged floating-point SSE2 code > generator from amd64 ocamlopt back end to i386 one, making ia32sse2 > architecture. It also inlines sqrt() via -ffast-math flag and slightly > optimizes emit_float_test (usually eliminates an extra jump) - > features that are missed in the original amd64 code generator. All > this seems to work OK: beyond my own code all tests found in Ocaml CVS > test directory are passed. Of course this is idea is not new - you had > working IA32+SSE2 back end several years ago [1] but unfortunately > never released it to the public. > > Is this of any interest to anybody? > > - Dmitry Bely > > [1] http://caml.inria.fr/pub/ml-archives/caml-list/2003/03/e0db2f3f54ce19e4bad589ffbb082484.fr.html > > _______________________________________________ > Caml-list mailing list. Subscription management: > http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list > Archives: http://caml.inria.fr > Beginner's list: http://groups.yahoo.com/group/ocaml_beginners > Bug reports: http://caml.inria.fr/bin/caml-bugs