From: Jonathan Wakely <jwakely@redhat.com>
To: whh8b@obs.cr
Cc: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Optimize operator+(string/char*, string/char*) equally
Date: Wed, 24 Aug 2022 15:24:11 +0100 [thread overview]
Message-ID: <CACb0b4n=MOL4muPH8XojL8qs5-ue3zJFoL4izOUsy+dtLajP7g@mail.gmail.com> (raw)
In-Reply-To: <20220824061648.1119635-2-whh8b@obs.cr>
On Wed, 24 Aug 2022 at 07:17, Will Hawkins wrote:
>
> Until now operator+(char*, string) and operator+(string, char*) had
> different performance characteristics. The former required a single
> memory allocation and the latter required two. This patch makes the
> performance equal.
>
> libstdc++-v3/ChangeLog:
There should be a blank line here.
> * libstdc++-v3/include/bits/basic_string.h (operator+(string, char*)):
The path should be relative to the ChangeLog, so should not include
the libstdc++-v3/ directory component. You can use the git gcc-verify
alias to check your commit msgs format before submitting. That runs
the same checks as will be used for the server-side hook that decides
whether to allow a push. See the customization script described at
https://gcc.gnu.org/gitwrite.html#vendor for the alaises.
Also, the overload you're changing is operator+(const string&, const
char*). The distinction matters, because there is also
operator+(string&&, const char*) and what you wrote looks more like
that one.
So I've committed it with this changelog:
libstdc++-v3/ChangeLog:
* include/bits/basic_string.h (operator+(const string&,
const char*)):
Remove naive implementation.
* include/bits/basic_string.tcc (operator+(const string&,
const char*)):
Add single-allocation implementation.
Thanks for the patch!
next prev parent reply other threads:[~2022-08-24 14:24 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-22 18:15 whh8b
2022-08-22 18:15 ` whh8b
2022-08-23 16:33 ` Jonathan Wakely
2022-08-24 6:18 ` Will Hawkins
2022-08-24 9:49 ` Jonathan Wakely
2022-08-24 6:16 ` [PATCH v2] libstdc++: Optimize operator+(string/char*,string/char*) whh8b
2022-08-24 6:16 ` [PATCH] libstdc++: Optimize operator+(string/char*,string/char*) equally whh8b
2022-08-24 6:16 ` [PATCH] libstdc++: Optimize operator+(string/char*, string/char*) equally whh8b
2022-08-24 14:24 ` Jonathan Wakely [this message]
2022-08-24 22:39 ` Alexandre Oliva
2022-08-24 22:47 ` Jonathan Wakely
2022-08-24 23:02 ` Jonathan Wakely
2022-08-25 5:52 ` Will Hawkins
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