Message-ID: <4A490D00.4020908@zytor.com>
Date: Mon, 29 Jun 2009 11:50:40 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Petr Tesarik <ptesarik@suse.cz>
CC: "Robert P. J. Day" <rpjday@crashcourse.ca>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Andrew Morton <akpm@osdl.org>
Subject: Re: [PATCH] Introduce a boolean "single_bit_set" function.
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Petr Tesarik wrote:
> 
> Ok, then my only concern is that the hweight* functions return the exact
> weight, which might be much less efficient if all we need is to know
> whether it's 1.
> 
> Theoretically, gcc should be able to optimize things out, but I'm not
> all that optimistic about how well it does it.
> 

I can almost guarantee it won't in this case.

	-hpa
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