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Message-ID: <48DBE8C3.2060708@ct.jp.nec.com>
Date: Thu, 25 Sep 2008 12:38:43 -0700
From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
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To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
       linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH v2 -tip 0/4] x86: signal handler improvement
References: <48DBD396.5020103@ct.jp.nec.com> <48DBD519.6030204@zytor.com> <48DBD8A6.8060900@ct.jp.nec.com> <48DBD96F.6090309@zytor.com>
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H. Peter Anvin wrote:
> Hiroshi Shimamoto wrote:
>>> This is a gcc failure, and should be reported to the gcc people.
>> Does this gcc failure mean unnecessary storing into stack?
>>
> 
> Yes, it should be able to process this in a register, instead of storing 
> to the stack and then merging later.
> 
> It's possible it's trying to do that to hide latency, but that's clearly 
> a lose in this case.

OK, I'll test with some gcc versions.
It's necessary to check outputs of the latest gcc, I think.

thanks,
Hiroshi Shimamoto