Date: Wed, 11 Nov 2015 21:46:23 -0800 (PST)
From: David Rientjes <rientjes@google.com>
To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>, Pekka Enberg <penberg@kernel.org>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] tools/vm/page-types: suppress gcc warnings
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On Thu, 12 Nov 2015, Sergey Senozhatsky wrote:

> > This can't possibly be correct, the warnings are legitimate and the result
> > of the sigsetjmp() in the function.  You may be interested in
> > returns_twice rather than marking random automatic variables as volatile.
> 
> Hm, ok. I saw no probs with `int first' and `end' being volatile
> 

This will only happen with the undocumented change in your first patch 
which adds -O2.

I don't know what version of gcc you're using, but only "first" and "end" 
being marked volatile isn't sufficient since mere code inspection would 
show that "off" will also be clobbered -- it's part of the loop.
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