From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1QcSB1-0006TM-Ha for garchives@archives.gentoo.org; Fri, 01 Jul 2011 01:05:47 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 515D71C0ED; Fri, 1 Jul 2011 01:04:36 +0000 (UTC) Received: from qmta08.emeryville.ca.mail.comcast.net (qmta08.emeryville.ca.mail.comcast.net [76.96.30.80]) by pigeon.gentoo.org (Postfix) with ESMTP id 074861C0A4 for ; Fri, 1 Jul 2011 01:04:35 +0000 (UTC) Received: from omta01.emeryville.ca.mail.comcast.net ([76.96.30.11]) by qmta08.emeryville.ca.mail.comcast.net with comcast id 2R4Z1h0020EPchoA8R4ZTl; Fri, 01 Jul 2011 01:04:33 +0000 Received: from ajax ([24.11.47.14]) by omta01.emeryville.ca.mail.comcast.net with comcast id 2R4m1h0160JMh7c8MR4oc9; Fri, 01 Jul 2011 01:04:50 +0000 Date: Thu, 30 Jun 2011 21:04:29 -0400 From: Frank Peters To: gentoo-amd64@lists.gentoo.org Subject: Re: [gentoo-amd64] Re: GCC-4.5.2 Has Serious Problems Message-Id: <20110630210429.fbcd8904.frank.peters@comcast.net> In-Reply-To: References: <20110630174530.9bcbcd47.frank.peters@comcast.net> X-Mailer: Sylpheed 3.1.1 (GTK+ 2.24.5; x86_64-unknown-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-amd64@lists.gentoo.org Reply-to: gentoo-amd64@lists.gentoo.org Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Archives-Salt: X-Archives-Hash: 22909ecfc1d4ee7c05a66c9715a40807 On Fri, 01 Jul 2011 02:44:36 +0300 Nikos Chantziaras wrote: > > And here you can read more thorough information about strict aliasing: > > http://labs.qt.nokia.com/2011/06/10/type-punning-and-strict-aliasing > You've saved the day in more ways than one. A few days ago I posted about a possible problem with a floating point test called the UCBTEST. After examining the source code of this test, I see violations of aliasing rules throughout. It's hard to efficiently manipulate variables without them. Of course, this code was written before the C99 standard and so is exempt. But the use of "-fno-strict-aliasing" will apply with the UCBTEST as well. Thanks again for the information. Frank Peters