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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/102221] Missed optimizations for algorithms over std::unique_ptr
Date: Wed, 08 Sep 2021 20:21:34 +0000	[thread overview]
Message-ID: <bug-102221-4-d0h3u7c0Vu@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-102221-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102221

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #1)
> This comes from the construction of a local unique_ptr<int> variable in:
> 
>   template<typename _RandomAccessIterator, typename _Compare>
>     _GLIBCXX20_CONSTEXPR
>     void
>     __unguarded_linear_insert(_RandomAccessIterator __last,
> 			      _Compare __comp)

Actually, even if we eliminate the temporary here, there's another in the
__make_heap routine:

      while (true)
        {
          _ValueType __value = _GLIBCXX_MOVE(*(__first + __parent));
          std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__value),
                             __comp);
          if (__parent == 0)
            return;
          __parent--;
        }

  parent reply	other threads:[~2021-09-08 20:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-06 17:34 [Bug c++/102221] New: " dangelog at gmail dot com
2021-09-08  9:37 ` [Bug libstdc++/102221] " redi at gcc dot gnu.org
2021-09-08 15:08 ` dangelog at gmail dot com
2021-09-08 20:00 ` redi at gcc dot gnu.org
2021-09-08 20:21 ` redi at gcc dot gnu.org [this message]
2021-09-09 15:06 ` dangelog at gmail dot com
2021-12-09 16:31 ` dangelog at gmail dot com
2021-12-23  9:18 ` pinskia at gcc dot gnu.org

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