From: Jan Beulich <jbeulich@suse.com>
To: "H.J. Lu" <hjl.tools@gmail.com>
Cc: Binutils <binutils@sourceware.org>
Subject: Re: [PATCH] x86: Replace CpuABM with CpuPOPCNT
Date: Mon, 17 Feb 2020 15:46:00 -0000 [thread overview]
Message-ID: <0c6ac813-e0f2-3d7f-040d-b94409f7f837@suse.com> (raw)
In-Reply-To: <CAMe9rOr09cY5WPDwgMo55pGZd9x15pgzJy_8KCTxJnf9QQsLdw@mail.gmail.com>
On 17.02.2020 16:42, H.J. Lu wrote:
> On Mon, Feb 17, 2020 at 7:40 AM Jan Beulich <jbeulich@suse.com> wrote:
>>
>> On 17.02.2020 16:27, H.J. Lu wrote:
>>> AMD ABM has 2 instructions: popcnt and lzcnt. ABM CPUID feature bit has
>>> been reused for lzcnt and a POPCNT CPUID feature bit is added for popcnt.
>>> This patch removes CpuABM and adds CpuPOPCNT. It changes ABM to enable
>>> both lzcnt and popcnt, changes SSE4.2 to also enable popcnt.
>>
>> I don't think removing support for something may have in active and
>> working use is a good idea. Adding some better mechanism as
>> _suggested_ replacement is of course fine, but people would better
>> not be forced to change their _correct_ code because of gas side
>> change.
>
> No assembly code changes are needed. The .abm directive still works
> as before. My patch only changes assembler internal implementation.
Oh, I'm sorry for the noise then. I apparently didn't look closely
enough.
Jan
prev parent reply other threads:[~2020-02-17 15:46 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 15:27 H.J. Lu
2020-02-17 15:40 ` Jan Beulich
2020-02-17 15:43 ` H.J. Lu
2020-02-17 15:46 ` Jan Beulich [this message]
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