From owner-freebsd-current@FreeBSD.ORG Thu Jul 9 16:39:47 2009 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A8B781065670; Thu, 9 Jul 2009 16:39:47 +0000 (UTC) (envelope-from xcllnt@mac.com) Received: from asmtpout026.mac.com (asmtpout026.mac.com [17.148.16.101]) by mx1.freebsd.org (Postfix) with ESMTP id 89E098FC14; Thu, 9 Jul 2009 16:39:47 +0000 (UTC) (envelope-from xcllnt@mac.com) MIME-version: 1.0 Content-transfer-encoding: 7BIT Content-type: text/plain; charset=us-ascii; format=flowed Received: from macbook-pro.jnpr.net (natint3.juniper.net [66.129.224.36]) by asmtp026.mac.com (Sun Java(tm) System Messaging Server 6.3-8.01 (built Dec 16 2008; 32bit)) with ESMTPSA id <0KMI0035BWXKFG20@asmtp026.mac.com>; Thu, 09 Jul 2009 09:39:22 -0700 (PDT) From: Marcel Moolenaar In-reply-to: <20090709085014.GE43264@mech-cluster238.men.bris.ac.uk> Date: Thu, 09 Jul 2009 09:39:20 -0700 Message-id: <8B6FE903-10E5-4A32-8E2E-482595D8F495@mac.com> References: <20090707094808.GA93317@mech-cluster238.men.bris.ac.uk> <20090707095058.GC7827@rink.nu> <20090707124405.GA46091@mech-cluster238.men.bris.ac.uk> <20090707133611.GA66072@rink.nu> <93B562A8-9FE7-44D5-91E4-C9AB1A25BD2A@mac.com> <20090708114019.GA19781@mech-cluster238.men.bris.ac.uk> <650DC54B-5FA6-49CB-8A9C-58461289778F@mac.com> <20090709085014.GE43264@mech-cluster238.men.bris.ac.uk> To: Anton Shterenlikht X-Mailer: Apple Mail (2.1068) Cc: Rink Springer , freebsd-current@freebsd.org, freebsd-ia64@freebsd.org Subject: Re: buildworld panic on ia64 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Jul 2009 16:39:50 -0000 On Jul 9, 2009, at 1:50 AM, Anton Shterenlikht wrote: >> By all means: experiment. But be very careful not to make >> the assumption that if the code compiles, it'll also run. >> The weirder the set of compiler options, the more likely >> you trip over optimization bugs and end up with an unstable >> system. And I'm not even talking about whether the set >> of options give you more optimal code in general. > > I see.. > > Is there any advice for compiler options on ia64? My advise at this time is to not change from the default. I haven't done any kind of experimentation or know of any- one else who did, to make any kind of claim as to the effectiveness or harm of various compiler options. I'm not talking cleanroom experiments here. I'm sure that there have been plenty of people looking at SPECcpu and who came up with a very creative set of compiler options that make SPECcpu perform "optimally" (for each program). This normally also includes fixing the compiler (and even adding special case code) to have correct code generated in that case. I'm talking about a safe set of options that people can use and that yields correct code 99.9% of the time and gives acceptable (if not good) code. I cannot stress the importance of having the toolchain generate correct code when working on a FreeBSD port to a different architecture. > I'm sorry if I'm asking obvious questions. > Perhaps this is documented/disucced somewhere > already? I'm new to ia64, most of my FBSD > experience is from alpha and i386. These aren't obvious questions. Compiler options, if they are being discussed, are primarily discussed for i386 or amd64. -- Marcel Moolenaar xcllnt@mac.com