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To: David Howells <dhowells@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>,
       Christoph Hellwig <hch@infradead.org>,
       "Adam J. Richter" <adam@yggdrasil.com>, linux-kernel@vger.kernel.org
Subject: Re: Patch: linux-2.5.29 __downgrade_write() for CONFIG_RWSEM_GENERIC_SPINLOCK 
In-Reply-To: Message from David Howells <dhowells@redhat.com> 
   of "Mon, 29 Jul 2002 09:31:55 BST." <20869.1027931515@warthog.cambridge.redhat.com> 
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> Roman Zippel <zippel@linux-m68k.org> wrote:
> > Did you look at the code? gcc should be able to optimize that itself.
> 
> Maybe... gcc should also optimise my version to the same extent, I think
> (the result of one of the additional tests is known at compile time, and the
> other one is the same as the next test down). What I'm unsure about is how
> gcc will handle the variable being stored in memory not marked volatile and
> then retrieved again; whether it'll actually issue a read, or just assume
> it's got it cached.

It doesn't appear to make any difference which way it is done. The i386 code
from both looks the same.

David
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