From owner-freebsd-current@FreeBSD.ORG Tue Sep 11 15:12:34 2012 Return-Path: Delivered-To: current@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 25BB21065680; Tue, 11 Sep 2012 15:12:34 +0000 (UTC) (envelope-from sgk@troutmask.apl.washington.edu) Received: from troutmask.apl.washington.edu (troutmask.apl.washington.edu [128.95.76.21]) by mx1.freebsd.org (Postfix) with ESMTP id F3A858FC0A; Tue, 11 Sep 2012 15:12:33 +0000 (UTC) Received: from troutmask.apl.washington.edu (localhost.apl.washington.edu [127.0.0.1]) by troutmask.apl.washington.edu (8.14.5/8.14.5) with ESMTP id q8BFCUFD087712; Tue, 11 Sep 2012 08:12:30 -0700 (PDT) (envelope-from sgk@troutmask.apl.washington.edu) Received: (from sgk@localhost) by troutmask.apl.washington.edu (8.14.5/8.14.5/Submit) id q8BFCUS7087711; Tue, 11 Sep 2012 08:12:30 -0700 (PDT) (envelope-from sgk) Date: Tue, 11 Sep 2012 08:12:30 -0700 From: Steve Kargl To: Tijl Coosemans Message-ID: <20120911151230.GB87526@troutmask.apl.washington.edu> References: <20120910211207.GC64920@lor.one-eyed-alien.net> <20120911104518.GF37286@deviant.kiev.zoral.com.ua> <20120911120649.GA52235@freebsd.org> <20120911132410.GA87126@troutmask.apl.washington.edu> <504F4645.4070900@FreeBSD.org> <504F4A6B.4010001@coosemans.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <504F4A6B.4010001@coosemans.org> User-Agent: Mutt/1.4.2.3i Cc: toolchain@FreeBSD.org, Dimitry Andric , current@FreeBSD.org Subject: Re: Clang as default compiler November 4th 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: Tue, 11 Sep 2012 15:12:34 -0000 On Tue, Sep 11, 2012 at 04:27:55PM +0200, Tijl Coosemans wrote: > On 11-09-2012 16:10, Dimitry Andric wrote: > > On 2012-09-11 15:24, Steve Kargl wrote: > >> What is important is whether software built with clang functions > >> correctly. See for example, > >> > >> http://math-atlas.sourceforge.net/errata.html#WhatComp > > > > Yes, maths support, specifically precision, is admittedly still one of > > clang's (really llvm's) weaker points. It is currently not really a > > high priority item for upstream. > > > > This is obviously something that a certain part of our userbase will > > care a lot about, while most of the time they won't care so much about > > licensing or politics. So those people are probably better off using > > gcc for the time being. > > Does it affect the accuracy of libm functions? > I'm not sure if anyone has done any extensive testing. I've started to run some of my test codes to compare certain functions in a clang-compiled libm, gcc-compiled libm, and reference solutions generated from math/mpfr. For a locally patched j0f, I found that clang gave much worse accuracy. If I revert the local patch, clang and gcc are to give the same results. Unfortnately, an unpatched j0f gives 500000 ULP errors. -- Steve