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From: Alexandre Oliva <>
To: Jonathan Wakely via Gcc-patches <>
Cc:, Jonathan Wakely <>,
Subject: Re: [PATCH] libstdc++: Optimize operator+(string/char*, string/char*) equally
Date: Wed, 24 Aug 2022 19:39:02 -0300	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <> (Jonathan Wakely via Gcc-patches's message of "Wed, 24 Aug 2022 15:24:11 +0100")

On Aug 24, 2022, Jonathan Wakely via Gcc-patches <> wrote:

>            * 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.

ISTM this requires the following additional tweak:

diff --git a/libstdc++-v3/src/c++11/ b/libstdc++-v3/src/c++11/
index bfae6d902a1dd..2ec0e9d85f947 100644
--- a/libstdc++-v3/src/c++11/
+++ b/libstdc++-v3/src/c++11/
   template class basic_string<C>;
   template S operator+(const C*, const S&);
+  template S operator+(const S&, const C*);
   template S operator+(C, const S&);
   template S operator+(const S&, const S&);

Without this, I'm getting undefined references to this specialization in, that I tracked down to a std::system_error ctor in
cxx11-ios_failure.o.  I got this while testing another patch that might
be the reason why the template instantiation doesn't get inlined, but...
we can't depend on its being inlined, can we?

Alexandre Oliva, happy hacker      
   Free Software Activist                       GNU Toolchain Engineer
Disinformation flourishes because many people care deeply about injustice
but very few check the facts.  Ask me about <>

  reply	other threads:[~2022-08-24 22:39 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
2022-08-24 22:39         ` Alexandre Oliva [this message]
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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