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Re: [PATCH x86_64][BZ #20139] Don't allow configure with not supporting AVX512 assembler w/o --disable-avx512.


2016-06-30 0:45 GMT+03:00 H.J. Lu <hjl.tools@gmail.com>:
> On Tue, Jun 28, 2016 at 6:04 AM, Andrew Senkevich
> <andrew.n.senkevich@gmail.com> wrote:
>> 2016-06-27 23:22 GMT+03:00 Joseph Myers <joseph@codesourcery.com>:
>>> On Mon, 27 Jun 2016, H.J. Lu wrote:
>>>
>>>> >> May be it will be the best way.  Needed version is 2.25 and it was
>>>> >> released at Mon, 5 Jan 2015.
>>>> >
>>>> >
>>>> > It's a fairly recent version.
>>>> >
>>>>
>>>> Binutils 2.24 released in Dec., 2013 supports AVX512.
>>>
>>> Time-based updates to the binutils requirements would indicate moving to
>>> requiring binutils 2.24 for building glibc 2.25 and later rather than
>>> requiring it now for building glibc 2.24, but given a clear reason for the
>>> requirement I wouldn't object to bringing it forward.
>>>
>>> Note: if we require a version with AVX512 support, we should also remove
>>> all the configure / preprocessor / makefile conditionals on such support,
>>> and all places where .byte directives are used for instruction encoding
>>> because of instructions not supported in older versions.
>>
>> If current issue is enough reason for requiring binutils 2.24 now for
>> building Glibc 2.24 I can prepare this patch.
>>
>
> Here is a patch to require binutils 2.24 to build x86-64 glibc.  Tested
> with binutils 2.24 and 2.27.  Verified with binutils 2.23 which fails to
> configure glibc.  OK for master?

> Since mathvec library
> needs assembler support for AVX512DQ,  we disable mathvec if assembler
> doesn't support AVX512DQ.

It is not mathvec disabling, it is disabling only some
implementations, they are as wrappers in this case.


--
WBR,
Andrew


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