[Bug libstdc++/100387] ranges::minmax compares moved-out value

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100387

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Patrick Palka
<ppa...@gcc.gnu.org>:

https://gcc.gnu.org/g:927548b42c4850094eb41c7ae882cbe219b24231

commit r11-8728-g927548b42c4850094eb41c7ae882cbe219b24231
Author: Patrick Palka <ppa...@redhat.com>
Date:   Fri Jun 18 19:33:39 2021 -0400

    libstdc++: Reduce ranges::minmax/minmax_element comparison complexity

    This rewrites ranges::minmax and ranges::minmax_element so that it
    performs at most 3*N/2 many comparisons, as required by the standard.
    In passing, this also fixes PR100387 by avoiding a premature std::move
    in ranges::minmax and in std::shift_right.

            PR libstdc++/100387

    libstdc++-v3/ChangeLog:

            * include/bits/ranges_algo.h (__minmax_fn::operator()): Rewrite
            to limit comparison complexity to 3*N/2.
            (__minmax_element_fn::operator()): Likewise.
            (shift_right): Avoid premature std::move of __result.
            * testsuite/25_algorithms/minmax/constrained.cc (test04, test05):
            New tests.
            * testsuite/25_algorithms/minmax_element/constrained.cc (test02):
            Likewise.

    (cherry picked from commit cc9c94d43dcfa98436152af9c00f011e9dab25f6)