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Re: [committed, PATCH] x86: Don't disable SSE4a when disabling SSE4


On 16.02.2020 17:47, H.J. Lu wrote:
> On Wed, Feb 12, 2020 at 9:18 AM H.J. Lu <hjl.tools@gmail.com> wrote:
>>
>> On Wed, Feb 12, 2020 at 9:08 AM Jan Beulich <jbeulich@suse.com> wrote:
>>>
>>> Since ".arch sse4a" enables SSE3 and earlier, disabling SSE3 should also
>>> disable SSE4a. And as per its name, ".arch .nosse4" should also do so.
>>>
>>> gas/
>>> 2020-02-XX  Jan Beulich  <jbeulich@suse.com>
>>>
>>>         * config/tc-i386.c (cpu_noarch): Use CPU_ANY_SSE4_FLAGS in
>>>         "nosse4" entry.
>>>
>>> opcodes/
>>> 2020-02-XX  Jan Beulich  <jbeulich@suse.com>
>>>
>>>         * i386-gen.c (cpu_flag_init): Move CpuSSE4a from
>>>         CPU_ANY_SSE_FLAGS entry to CPU_ANY_SSE3_FLAGS one. Add
>>>         CPU_ANY_SSE4_FLAGS entry.
>>>         * i386-init.h: Re-generate.
>>>
>>
>> OK.
>>
>> Thanks.
> 
> commit 7deea9aad8 changed nosse4 to include CpuSSE4a.  But AMD SSE4a is
> a superset of SSE3 and Intel SSE4 is a superset of SSSE3.  Disable Intel
> SSE4 shouldn't disable AMD SSE4a.  This patch restores nosse4.  It also
> adds .sse4a and nosse4a.

And where is it said that "nosse4" means only the Intel flavors? As
said in the commit message of said change, to me the clear implication
is that anything called SSE4* will get disabled.

Jan


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