From: Stefan Kangas <stefankangas@gmail.com>
To: "Eli Zaretskii" <eliz@gnu.org>,
"Mattias Engdegård" <mattias.engdegard@gmail.com>
Cc: pipcet@protonmail.com, acorallo@gnu.org, emacs-devel@gnu.org
Subject: Re: master b0ba0d42b0f: * src/lisp.h (EQ): Improve generated code.
Date: Thu, 28 Nov 2024 14:46:55 -0800 [thread overview]
Message-ID: <CADwFkmn+0G55u80r7NEpQs8z0vOUZuBNfy_p9FPg+a4F_ZG20Q@mail.gmail.com> (raw)
In-Reply-To: <867c8ncdx4.fsf@gnu.org>
Eli Zaretskii <eliz@gnu.org> writes:
>> From: Mattias Engdegård <mattias.engdegard@gmail.com>
>> Date: Thu, 28 Nov 2024 18:53:46 +0100
>> Cc: Andrea Corallo <acorallo@gnu.org>,
>> Emacs Devel <emacs-devel@gnu.org>
>>
>> We should probably define some variant of likely/unlikely because those cover most needs of __builtin_expect, rather than using it directly. Then portability wouldn't be a problem.
>
> Portability is already not a problem, so I see no need for inventing
> new macros for this purpose.
Right, since this is already done for us by Gnulib. But the other
reason to having such macros is readability.
To be clear, the proposed macros would look something like this (copied
here from the Linux kernel):
#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
Andrea's code would then read like so:
- return BASE_EQ ((__builtin_expect (symbols_with_pos_enabled, false)
+ return BASE_EQ ((unlikely (symbols_with_pos_enabled)
next prev parent reply other threads:[~2024-11-28 22:46 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <173279015204.1017853.4020802222494409378@vcs3.savannah.gnu.org>
[not found] ` <20241128103552.86CC34F4FDB@vcs3.savannah.gnu.org>
2024-11-28 13:53 ` master b0ba0d42b0f: * src/lisp.h (EQ): Improve generated code Pip Cet via Emacs development discussions.
2024-11-28 14:44 ` Eli Zaretskii
2024-11-28 14:55 ` Andrea Corallo
2024-11-28 15:00 ` Eli Zaretskii
2024-11-28 15:02 ` Andrea Corallo
2024-11-28 17:53 ` Mattias Engdegård
2024-11-28 20:14 ` Pip Cet via Emacs development discussions.
2024-11-28 20:16 ` Eli Zaretskii
2024-11-28 22:46 ` Stefan Kangas [this message]
2024-11-29 8:21 ` Andrea Corallo
2024-11-29 1:10 ` Björn Lindqvist
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