From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Alejandro Colomar <alx.manpages@gmail.com>,
"linux-man@vger.kernel.org" <linux-man@vger.kernel.org>
Cc: Alejandro Colomar <alx@kernel.org>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>
Subject: Re: [PATCH] memchr.3: Deprecate rawmemchr(3)
Date: Fri, 6 Jan 2023 12:57:03 +0000 [thread overview]
Message-ID: <PAWPR08MB898270B26F1A5776B87DE3F883FB9@PAWPR08MB8982.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <20230105190246.17819-1-alx@kernel.org>
Hi Alex,
> It is not optimized, and it calls either strlen(3) or memchr(3), so the
> caller can do it directly, and it will be better.
>
> Suggested-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
> Signed-off-by: Alejandro Colomar <alx@kernel.org>
This looks good to me. Btw in the codesearch there are about 800
uses, the majority looks like prototypes etc, so there are few actual
uses. Interestingly GLIBC still contains this:
#ifdef _LIBC
p = __rawmemchr (p, '\0');
#else
p = strchr (p, '\0');
#endif
The strchr (p, 0) is optimized by compilers into strlen (since that's
obviously the right optimization) so adding rawmemchr was not
only wasted effort, but it made things slower as well. So we should
remove these uses from GLIBC.
Cheers,
Wilco
prev parent reply other threads:[~2023-01-06 12:57 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-05 19:02 Alejandro Colomar
2023-01-06 12:57 ` Wilco Dijkstra [this message]
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