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Re: Thoughts on memcmp expansion (PR43052)

From: Bernd Schmidt <bschmidt at redhat dot com>
To: Florian Weimer <fweimer at redhat dot com>, GCC Patches <gcc-patches at gcc dot gnu dot org>, Nick Clifton <nickc at redhat dot com>
Date: Tue, 31 May 2016 16:09:41 +0200
Subject: Re: Thoughts on memcmp expansion (PR43052)
Authentication-results: sourceware.org; auth=none
References: <56992541 dot 3090402 at redhat dot com> <55238d87-b52b-b743-5a5f-5afb43355b26 at redhat dot com>

On 05/30/2016 11:37 AM, Florian Weimer wrote:

 * Expand __memcmp_eq for small constant sizes with loads and
   comparison, fall back to a memcmp call.


Should we export such a function from glibc?  I expect it's fairly
common.  Computing the tail difference costs a few cycles.

At the moment the patch ensures that no actual memcmp_eq function iscalled, it's either expanded inline or we fall back to memcmp. Butthere's no reason why it couldn't be added under some appropriate name.



Bernd

References:
- Re: Thoughts on memcmp expansion (PR43052)
  - From: Florian Weimer

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