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Re: [PATCH] Make strcmp optimized for SSE2 with unaligned load/store as default
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Roland McGrath <roland at hack dot frob dot com>
- Cc: OndÅej BÃlka <neleai at seznam dot cz>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Tue, 25 Aug 2015 12:23:49 -0700
- Subject: Re: [PATCH] Make strcmp optimized for SSE2 with unaligned load/store as default
- Authentication-results: sourceware.org; auth=none
- References: <CAMe9rOqgek-2_GfDeFYdHpHvvt0RodUCOBrb-0nKMiCEd62ycg at mail dot gmail dot com> <20150825185920 dot 2DF5A2C3A73 at topped-with-meat dot com> <CAMe9rOr0_GpATYS8cYYZups3ti8eke9HCoiCpY3H6wXz5Y8WBw at mail dot gmail dot com> <20150825192103 dot 768822C3A73 at topped-with-meat dot com>
On Tue, Aug 25, 2015 at 12:21 PM, Roland McGrath <firstname.lastname@example.org> wrote:
>> ld.so and libc use the same code in sysdeps/x86_64/strcmp.S. When we
>> move sysdeps/x86_64/multiarch/strcmp-sse2-unaligned.S to
>> sysdeps/x86_64/strcmp.S to make it the default in libc, it is used by ld.so.
>> To make ld.so not to use it requires extra work, which doesn't make any
>> senses. If it is OK for libc, it should be OK for ld.so.
> The first change is to eliminate any explicit difference between libc and
Here is the patch:
> ld.so. There is no controversy about that. The second change is which
Here is the controversy :
> strcmp implementation is used by everybody, which needs the same kind of
> rationale made explicit as does every other performance-motivated change.