From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3131 invoked by alias); 8 Mar 2007 15:01:45 -0000 Received: (qmail 3118 invoked by uid 22791); 8 Mar 2007 15:01:43 -0000 X-Spam-Check-By: sourceware.org Received: from mr4.cc.ic.ac.uk (HELO mr4.cc.ic.ac.uk) (155.198.5.114) by sourceware.org (qpsmtpd/0.31) with ESMTP; Thu, 08 Mar 2007 15:01:34 +0000 Received: from icexp2.cc.ic.ac.uk ([155.198.3.42] helo=icex.imperial.ac.uk) by mr4.cc.ic.ac.uk with smtp (Exim 4.63) (envelope-from ) id 1HPK7U-00088R-7b; Thu, 08 Mar 2007 15:01:28 +0000 Received: from icex1.ic.ac.uk ([155.198.3.1]) by icex.imperial.ac.uk with Microsoft SMTPSVC(6.0.3790.1830); Thu, 8 Mar 2007 15:01:05 +0000 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Subject: RE: Linux c++ opmization--- linux runs at half the speed of windows? Date: Thu, 08 Mar 2007 16:10:00 -0000 Message-ID: <2CB39EAF0E0EFF498ADEDA636B8C999F04C392B3@icex1.ic.ac.uk> In-Reply-To: From: "Atwood, Robert C" To: "Shane R" Cc: X-IsSubscribed: yes Mailing-List: contact gcc-help-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-help-owner@gcc.gnu.org X-SW-Source: 2007-03/txt/msg00109.txt.bz2 =20 > On another note does anyone have any experience with the=20 > Intel drop in=20 > replacement for GCC? >=20 > Thanks in advance for any help, >=20 > Shane Yes but not very good experience, perhaps mediocre. I had very annoying problems with a bug in the intel optimizer .. It seemed like my code was way faster, until I noticed that it was not giving the correct results, and observed that the optimizer was reducing precision when it should not. There was also some case where it kept optimizing a=3Db; b=3Dc; into effectively a=3Db=3Dc; not the same thing at all! THe recommended workaround was to reduce the optimization level , at which point it was no longer faster and I had lost my own time faffing about with it. Since then that bug was supposedly fixed in later release, but they lost my confidence and convinced me further that free software is the way to go, not only for political, but also practical reasons.