From: Andi Kleen <ak@novell.com>
Organization: SUSE Linux Products GmbH, Nuernberg, GF: Markus Rex, HRB 16746 (AG Nuernberg)
To: "linux-os (Dick Johnson)" <linux-os@analogic.com>
Subject: Re: Is gcc thread-unsafe?
Date: Thu, 25 Oct 2007 14:16:19 +0200
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Cc: "Nick Piggin" <nickpiggin@yahoo.com.au>,
       "Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
       "Linus Torvalds" <torvalds@linux-foundation.org>
References: <200710251324.49888.nickpiggin@yahoo.com.au> <200710250915.50675.ak@suse.de> <Pine.LNX.4.61.0710250753350.22665@chaos.analogic.com>
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On Thursday 25 October 2007 13:58:56 linux-os (Dick Johnson) wrote:
> 
> On Thu, 25 Oct 2007, Andi Kleen wrote:
> 
> > On Thursday 25 October 2007 05:24, Nick Piggin wrote:
> >
> >> Basically, what the gcc developers are saying is that gcc is
> >> free to load and store to any memory location, so long as it
> >> behaves as if the instructions were executed in sequence.
> >
> > This case is clearly a bug, a very likely code pessimization.
> > I guess it wasn't intentional, just an optimization that is useful
> > for local register values doing too much.
> 
> 
> I don't think it is a BUG,

Bug as in an optimization that makes the code slower than it was
before. That is clearly a bug in a compiler.

-Andi
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