From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Delivered-To: caml-list@yquem.inria.fr Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by yquem.inria.fr (Postfix) with ESMTP id 39A51BC88 for ; Wed, 9 Feb 2005 10:26:44 +0100 (CET) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.13.0/8.13.0) with ESMTP id j199Qhdk030215 for ; Wed, 9 Feb 2005 10:26:44 +0100 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 KAA27622 for ; Wed, 9 Feb 2005 10:26:43 +0100 (MET) Received: from qrnik.knm.org.pl (paf87.warszawa.sdi.tpnet.pl [217.96.225.87]) by nez-perce.inria.fr (8.13.0/8.13.0) with ESMTP id j199QeOH014637 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO) for ; Wed, 9 Feb 2005 10:26:43 +0100 Received: from qrczak by qrnik.knm.org.pl with local (Exim 3.36 #1) id 1Cyo7L-0002qG-00 for caml-list@inria.fr; Wed, 09 Feb 2005 10:26:39 +0100 To: caml-list@inria.fr Subject: Re: [Caml-list] ackermann test X-Face: OW>RV&gN+&b-aiNY|U)f=S%w+/rK!);f>/W9IXg})]&F>ht.1Up8@04+_!gOp(_/l_-+E^. 2\vI)1=D,%HWiq)r(M/V~dr^5T^KF/[w5YZ4<0Sus3+O>l3uA/&W_21m?.s,Po8{pb0@ References: <1107921472.5022.410.camel@pelican.wigram> <877e9a170502082009591db0b4@mail.gmail.com> <1107922403.5022.426.camel@pelican.wigram> From: "Marcin 'Qrczak' Kowalczyk" Mail-Followup-To: caml-list@inria.fr Date: Wed, 09 Feb 2005 10:26:39 +0100 In-Reply-To: <1107922403.5022.426.camel@pelican.wigram> (skaller@users.sourceforge.net's message of "09 Feb 2005 15:13:23 +1100") Message-ID: <87vf92qe28.fsf@qrnik.zagroda> User-Agent: Gnus/5.1006 (Gnus v5.10.6) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: "Marcin 'Qrczak' Kowalczyk" X-Miltered: at concorde with ID 4209D753.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Miltered: at nez-perce with ID 4209D750.000 by Joe's j-chkmail (http://j-chkmail.ensmp.fr)! X-Spam: no; 0.00; caml-list:01 ackermann:01 sourceforge:01 writes:01 tail:01 ack:01 ack:01 int:01 int:01 generates:08 using:15 test:15 then:17 code:17 code:17 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on yquem.inria.fr X-Spam-Status: No, score=0.1 required=5.0 tests=FORGED_RCVD_HELO autolearn=disabled version=3.0.2 X-Spam-Level: skaller writes: >> Where can I find the C code you are using? > > int ack(int x, int y) { > return x==0? y+1: (y==0? ack(x-1,1):ack(x-1,ack(x,y-1))); > } If you write it like this: int ack(int x, int y) { if (x==0) return y+1; if (y==0) return ack(x-1,1); return ack(x-1,ack(x,y-1)); } then gcc-3.4.3 generates better code (optimizes tail calls). -fomit-frame-pointer further speeds it up. -- __("< Marcin Kowalczyk \__/ qrczak@knm.org.pl ^^ http://qrnik.knm.org.pl/~qrczak/