From: "H. Peter Anvin" <hpa@zytor.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Jim Kukunas <james.t.kukunas@linux.intel.com>,
Linux Raid <linux-raid@vger.kernel.org>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Neil Brown <neilb@suse.de>
Subject: Re: [PATCH] lib/raid6: Add AVX2 optimized recovery functions
Date: Thu, 29 Nov 2012 14:28:10 -0800 [thread overview]
Message-ID: <50B7E17A.2020609@zytor.com> (raw)
In-Reply-To: <20121129211828.GZ16230@one.firstfloor.org>
On 11/29/2012 01:18 PM, Andi Kleen wrote:
>
>> Either way, this implementatin technique was used for the MMX/SSE
>> implementations without any problems for 9 years now.
>
> It's still wrong.
>
> Lying to the compiler usually bites you at some point.
>
It's not lying to the compiler. It is telling the compiler "do
something that you have no way of knowing about".
It would be lying to the compiler if the compiler was allowed to touch
the FPU state, but it's not.
-hpa
prev parent reply other threads:[~2012-11-29 22:28 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-08 21:47 [PATCH] lib/raid6: Add AVX2 optimized recovery functions Jim Kukunas
2012-11-09 11:35 ` Paul Menzel
2012-11-09 11:39 ` H. Peter Anvin
2012-11-09 11:46 ` Paul Menzel
2012-11-09 11:50 ` NeilBrown
2012-11-09 12:24 ` H. Peter Anvin
2012-11-09 19:56 ` Jim Kukunas
2012-11-19 0:57 ` NeilBrown
2012-11-29 20:09 ` Andi Kleen
2012-11-29 21:13 ` H. Peter Anvin
2012-11-29 21:18 ` Andi Kleen
2012-11-29 22:27 ` H. Peter Anvin
2012-11-29 22:28 ` H. Peter Anvin [this message]
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