From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753532AbaIDPft (ORCPT ); Thu, 4 Sep 2014 11:35:49 -0400 Received: from mail-lb0-f180.google.com ([209.85.217.180]:45359 "EHLO mail-lb0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750980AbaIDPfq (ORCPT ); Thu, 4 Sep 2014 11:35:46 -0400 From: Rasmus Villemoes To: Cyrill Gorcunov Cc: Andrew Morton , "Eric W. Biederman" , linux-kernel@vger.kernel.org, stable@vger.kernel.org, "H. Peter Anvin" , Pavel Emelyanov Subject: Re: [PATCH] kcmp: Fix standard comparison bug Organization: D03 References: <1409827206-4199-1-git-send-email-linux@rasmusvillemoes.dk> <20140904132912.GL16395@moon> X-Hashcash: 1:20:140904:stable@vger.kernel.org::fsiXAi+2hypDA7Rf:00000000000000000000000000000000000000005OH X-Hashcash: 1:20:140904:ebiederm@xmission.com::wfoLzpiQALZtbK64:00000000000000000000000000000000000000001Aaj X-Hashcash: 1:20:140904:gorcunov@gmail.com::Ig3j0DOclmZZB+zi:00000000000000000000000000000000000000000001gdY X-Hashcash: 1:20:140904:akpm@linux-foundation.org.openvz.org::73fKkPzicVZAEcKi:00000000000000000000000001hi2 X-Hashcash: 1:20:140904:hpa@zytor.com::epiC6Kb7o1ilhzXr:00002YCm X-Hashcash: 1:20:140904:xemul@parallels.com::XSa8aW/Pgsxrvw7r:00000000000000000000000000000000000000000049UB X-Hashcash: 1:20:140904:linux-kernel@vger.kernel.org::dqcFvHRrgPCXtGEY:0000000000000000000000000000000007HCf Date: Thu, 04 Sep 2014 17:35:43 +0200 In-Reply-To: <20140904132912.GL16395@moon> (Cyrill Gorcunov's message of "Thu, 4 Sep 2014 17:29:12 +0400") Message-ID: <87sik7tn3k.fsf@rasmusvillemoes.dk> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 04 2014, Cyrill Gorcunov 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