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Re: [PATCH x86_64][BZ #20139] Don't allow configure with not supporting AVX512 assembler w/o --disable-avx512.
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Andrew Senkevich <andrew dot n dot senkevich at gmail dot com>
- Cc: libc-alpha <libc-alpha at sourceware dot org>, Florian Weimer <fweimer at redhat dot com>, Joseph Myers <joseph at codesourcery dot com>
- Date: Mon, 27 Jun 2016 15:46:27 -0700
- Subject: Re: [PATCH x86_64][BZ #20139] Don't allow configure with not supporting AVX512 assembler w/o --disable-avx512.
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On Mon, Jun 27, 2016 at 1:59 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Mon, Jun 27, 2016 at 1:49 PM, Andrew Senkevich
> <andrew.n.senkevich@gmail.com> wrote:
>> 27 ÐÑÐ 2016 Ð. 22:07 ÐÐÐÑÐÐÐÐÑÐÐÑ "H.J. Lu" <hjl.tools@gmail.com> ÐÐÐÐÑÐÐ:
>>>
>>> On Mon, Jun 27, 2016 at 12:04 PM, Florian Weimer <fweimer@redhat.com>
>>> wrote:
>>> > On 06/27/2016 08:36 PM, Andrew Senkevich wrote:
>>> >>
>>> >> 2016-06-27 20:53 GMT+03:00 Joseph Myers <joseph@codesourcery.com>:
>>> >>>
>>> >>> On Mon, 27 Jun 2016, Andrew Senkevich wrote:
>>> >>>
>>> >>>> Hi,
>>> >>>>
>>> >>>> this patch adds new configure option --enable-avx512 and defaults it
>>> >>>> for
>>> >>>> x86_64.
>>> >>>>
>>> >>>> To fix BZ #20139 we need don't let to configure with not supporting
>>> >>>> AVX512 assembler w/o --disable-avx512.
>>> >>>
>>> >>>
>>> >>> What assembler version is required to support AVX512, and when was
>>> >>> that
>>> >>> version released? It might be better to increase the minimum binutils
>>> >>> version for building glibc (generally, or for x86_64).
>>> >>
>>> >>
>>> >> 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.
>>
>> Yes, but not all required. There were some with ZMM registers supported
>> from 2.25. According configure check defining HAVE_AVX512_ASM_SUPPORT was
>> changed for that reason.
>
> Will binutils 2.24 able to save/restore ZMM registers?
>
The additional check is for SVML. We can require binutils 2.24
for x86-64 glibc and use HAVE_AVX512_ASM_SUPPORT only
for SVML.
--
H.J.