From: Jan Beulich <jbeulich@suse.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: "binutils@sourceware.org" <binutils@sourceware.org>
Subject: Re: [committed, PATCH] x86: Don't disable SSE4a when disabling SSE4
Date: Mon, 17 Feb 2020 15:32:00 -0000 [thread overview]
Message-ID: <70b8fc74-e036-1064-ab65-5e0cfe5ec401@suse.com> (raw)
In-Reply-To: <CAMe9rOrUhF63akiVo9Ae=amKa6=tw4FuJknM97OQqXrHdBZpnQ@mail.gmail.com>
On 17.02.2020 16:30, H.J. Lu wrote:
> On Mon, Feb 17, 2020 at 7:27 AM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> 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.
>>
>
> SSE4 refers to SSE4 from Intel, which includes SSE4.1 and SSE4.2.
> SSE4a from AMD is unrelated from Intel SSE4.
Repeating my question then: Where is this being said? (Best imo
would be to delete ".arch .nosse4" support then, eliminating
the ambiguity.)
Jan
next prev parent reply other threads:[~2020-02-17 15:32 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-12 17:08 [PATCH] x86: fix SSE4a dependencies of ".arch .nosse*" Jan Beulich
2020-02-12 17:19 ` H.J. Lu
2020-02-16 16:48 ` [committed, PATCH] x86: Don't disable SSE4a when disabling SSE4 H.J. Lu
2020-02-17 1:06 ` Alan Modra
2020-02-17 1:20 ` H.J. Lu
2020-02-17 1:32 ` Alan Modra
2020-02-17 3:12 ` Alan Modra
2020-02-17 4:16 ` [committed, PATCH] Don't disable SSE3 when disabling SSE4a H.J. Lu
2020-02-17 15:27 ` [committed, PATCH] x86: Don't disable SSE4a when disabling SSE4 Jan Beulich
2020-02-17 15:30 ` H.J. Lu
2020-02-17 15:32 ` Jan Beulich [this message]
2020-02-17 15:45 ` H.J. Lu
2020-02-17 15:49 ` Jan Beulich
2020-02-17 16:53 ` H.J. Lu
2020-02-17 17:01 ` Jan Beulich
2020-02-17 17:05 ` H.J. Lu
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