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Date: Wed, 11 May 2016 13:24:09 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Brian Gerst <brgerst@gmail.com>
Cc: Borislav Petkov <bp@suse.de>, "H. Peter Anvin" <hpa@zytor.com>,
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Subject: Re: [PATCH -v2] x86/hweight: Get rid of the special calling
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On Wed, May 11, 2016 at 07:15:19AM -0400, Brian Gerst wrote:

> I think he meant the out of line version would be asm, so you could
> control what registers were clobbered.

Yeah, it might save a few cycles on the call, but given that most
machines should have popcnt these days is it worth the hassle/cost of
duplicating the lib/hweight.c magic in asm (and remember, twice, once
for 32bit and once for 64bit) ?