install location of math-vector-fortran.h

[Matthias Klose]

On 6/8/20 1:03 PM, Florian Weimer via Gcc wrote:
> * Matthias Klose:
> 
>> [not subscribed to the libc-alpha list]
>>
>> GCC and glibc need to agree on the install location for math-vector-fortran.h.
>> Currently it is installed into
>>
>>   /usr/include/finclude/math-vector-fortran.h
>>
>> However the file is architecture specific, currently only having
>> variants for x86_64-*-gnu, x86_64-*-gnux32, and a generic variant.
>> This creates problems when the file is contained in a Debian package
>> which is marked as Multi-Arch: same, also it should create problems
>> installing the i386 and amd64 rpm's on the the same system.  How to
>> solve this issue?
> 
> Uhm.  If you want an upstream solution, you need to upstream your
> multi-arch patches.

they are in GCC.  Please note that there is no patch yet for this header file,
so I can't upstream anything yet.

>>  - The header file currently seems to be completely conditionalized.
>>    Is it safe to assume that the x86 variant is still considered empty
>>    for any other architecture?  Will it stay this way?  In this case
>>    this variant could be installed everywhere, or better, glibc could
>>    stop maintaining the variant at all.
> 
> I do not understand these questions.  The Fortran header is the
> equivalent of the <bits/math-vector.h> C header.  Its contents depends
> on what is necessary to describe the libmvec ABI.  We will only know the
> ABI for libmvec once there is a port for other architectures, so future
> evolution of the header is impossible to predict.

this file currently only has lines like:

!GCC$ builtin (cos) attributes simd (notinbranch) if('x86_64')

so it shouldn't have any effect to other architectures?  Or are the conditionals
explicitly done to exclude the 32bit x86 configuration?

Matthias