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Re: [RFC] How to add vector math functions to Glibc
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Andrew Senkevich <andrew dot n dot senkevich at gmail dot com>
- Cc: "Joseph S. Myers" <joseph at codesourcery dot com>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Thu, 25 Sep 2014 08:40:29 -0700
- Subject: Re: [RFC] How to add vector math functions to Glibc
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On Thu, Sep 25, 2014 at 8:17 AM, Andrew Senkevich
<andrew.n.senkevich@gmail.com> wrote:
>> If consensus ends up being to have such a library (libmvec or libmvect?),
>> then the installation rules for libm.so as a linker script should go in
>> math/Makefile, not the toplevel Makerules. (I don't know what if any
>> changes might be needed to allow subdirectories to provide libraries as
>> linker scripts.)
>
> There were three options about the place where to add vectorized math functions:
>
> 1. GLIBC (libm)
> 2. GLIBC (additional library)
> 3. GCC
>
> In GLIBC cases build of vectorized functions can be conditional, no
> additional -lmvec required because of libm.so installed as linked
> script in case of vectorized functions available, so it seems not very
> important whether functions located in additional library or in libm.
>
I don't think they should be in libm since most of applications
won't use those vector functions, which increase libm size
unnecessarily. A separate library is better.
--
H.J.