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From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
To: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org.openvz.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	"H. Peter Anvin" <hpa@zytor.com>,
	Pavel Emelyanov <xemul@parallels.com>
Subject: Re: [PATCH] kcmp: Fix standard comparison bug
Date: Thu, 04 Sep 2014 17:35:43 +0200	[thread overview]
Message-ID: <87sik7tn3k.fsf@rasmusvillemoes.dk> (raw)
In-Reply-To: <20140904132912.GL16395@moon> (Cyrill Gorcunov's message of "Thu, 4 Sep 2014 17:29:12 +0400")

On Thu, Sep 04 2014, Cyrill Gorcunov <gorcunov@gmail.com> wrote:

> On Thu, Sep 04, 2014 at 12:40:06PM +0200, Rasmus Villemoes wrote:
>> 
>> Note that it makes absolutely no difference that a transmogrying
                                                       ^^^^
                                                    transmogrifying

> It's more than that, I looked into disassembly code and
> found that compiler overoptimize obfuscation, instead of doing
> ^ and * sequently it substracts xor production of both operands
> first and only then multiplies the result.

...which it seems to be perfectly entitled to; xz - yz == (x-y)z holds
in any ring. 

Anyway, I'll stop beating the dead horse.

Rasmus

  reply	other threads:[~2014-09-04 15:35 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-04 10:40 [PATCH] kcmp: Fix standard comparison bug Rasmus Villemoes
2014-09-04 13:29 ` Cyrill Gorcunov
2014-09-04 15:35   ` Rasmus Villemoes [this message]
2014-09-05 17:50 ` Cyrill Gorcunov

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