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Subject: Re: New x86-64 micro-architecture levels
To: Florian Weimer <fweimer@redhat.com>
Cc: Richard Biener <richard.guenther@gmail.com>, "H.J. Lu"
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From: Jan Beulich <jbeulich@suse.com>
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Date: Mon, 13 Jul 2020 09:47:59 +0200
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On 13.07.2020 09:40, Florian Weimer wrote:
> * Richard Biener:
>>> 2. I have a library with AVX2 and FMA, which directory should it go?
>>
>> Eventually GCC/gas can annotate objects with the lowest architecture
>> level that is applicable?
> 
> H.J. has patches for ELF program properties.  I think
> GNU_PROPERTY_X86_ISA_1_NEEDED would convey this information.  This
> proposal and the glibc patches are independent of that.

>From (partly just halfway) recent discussions with H.J. I gained
the understanding that the piece we're aiming at getting to work
properly is the recording of GNU_PROPERTY_X86_FEATURE_2_*, not
so much GNU_PROPERTY_X86_ISA_1_*. If the ISA one is to be used as
a basis here, a lot of new flags will need adding (and properly
setting) first, I think.

Jan