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Date: Tue, 3 Mar 2009 09:33:15 +0000
Message-ID: <87a5b0800903030133y7bd22204y4995657cfd75950f@mail.gmail.com>
Subject: Re: [PATCH] crc32: remove useless __pure modifier from functions
From: Will Newton <will.newton@gmail.com>
To: Thiago Galesi <thiagogalesi@gmail.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>, akpm@linux-foundation.org,
       linux-kernel@vger.kernel.org
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On Mon, Mar 2, 2009 at 5:42 PM, Thiago Galesi <thiagogalesi@gmail.com> wrote:
>>
>> Hmm. They're not marked as pure in the header files. Does GCC look it up
>> from the object file or something for this...?
>
> I just tested this, the answer is No :(
>
> It only works if it's marked in the header. But when it's marked, it
> works, and redundant calls are optimized.

Did you see any change in size of your kernel with this annotation? It
didn't seem to have any effect as far as I could tell.

There are a number of functions in lib/ code that could be marked
__pure or __attribute_const__ but I'm not sure if it's worth the
effort, for my compiler (gcc 4.2) at least.
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