From: "H. Peter Anvin" <hpa@zytor.com>
To: Uros Bizjak <ubizjak@gmail.com>
Cc: Uros Bizjak <uros_bizjak1@t-2.net>,
linux-kernel@vger.kernel.org, "x86@kernel.org" <x86@kernel.org>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: ASM flags in general
Date: Mon, 27 Jul 2015 14:14:21 -0700 [thread overview]
Message-ID: <55B69F2D.3070603@zytor.com> (raw)
In-Reply-To: <CAFULd4avNv-betLaxzx1s-7ED3UDUuKnaNj-D0CsjEZWCL-twA@mail.gmail.com>
On 07/27/2015 01:01 PM, Uros Bizjak wrote:
> On Mon, Jul 27, 2015 at 9:04 PM, H. Peter Anvin <hpa@zytor.com> wrote:
>
>> I wonder if using "set" would be a performance regression over "sbb" for
>> the existing bitops, in which case it would slot quite nicely into this
>> scheme.
>
> As far as I have looked into the compiled code, following sequence was
> produced when the value was directly used as bool
>
[...]
>
> vs. new sequence:
>
You misunderstood me: I was referring to *old* versions of gcc (≤ 5); in
order words: can we use the macros I proposed instead of #ifdef? For
gcc 6+ we obviously want to use the flags output.
-hpa
next prev parent reply other threads:[~2015-07-27 21:14 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-27 17:48 [PATCH v2] x86: Introduce ASM flags to bitops Uros Bizjak
2015-07-27 19:04 ` ASM flags in general H. Peter Anvin
2015-07-27 20:01 ` Uros Bizjak
2015-07-27 21:14 ` H. Peter Anvin [this message]
2015-07-27 20:38 ` Andy Lutomirski
2015-07-27 21:04 ` H. Peter Anvin
2015-07-27 22:43 ` Andy Lutomirski
[not found] ` <BFA94A6B-8E68-4990-8737-F1F470D47F6A@zytor.com>
2015-07-27 23:36 ` Andy Lutomirski
[not found] ` <E2EE4512-30B2-4E73-B91A-DC1A9AA0AF6C@zytor.com>
2015-07-27 23:49 ` Andy Lutomirski
2015-07-27 23:56 ` H. Peter Anvin
2015-07-27 23:58 ` Andy Lutomirski
2015-07-28 0:03 ` H. Peter Anvin
2015-07-28 0:35 ` H. Peter Anvin
2015-07-28 0:41 ` Andy Lutomirski
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