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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
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D102221

--- 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:
>=20
>   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 =3D _GLIBCXX_MOVE(*(__first + __parent));
          std::__adjust_heap(__first, __parent, __len, _GLIBCXX_MOVE(__valu=
e),
                             __comp);
          if (__parent =3D=3D 0)
            return;
          __parent--;
        }=