[Bug libstdc++/115799] ranges::find's optimized branching for memchr is not quite right

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115799

--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:

https://gcc.gnu.org/g:762ee55d369a3257997092ef7853cf9dd4d5cc4f

commit r15-1879-g762ee55d369a3257997092ef7853cf9dd4d5cc4f
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Jul 5 18:58:00 2024 +0100

    libstdc++: Fix memchr path in std::ranges::find for non-common range
[PR115799]

    The memchr optimization introduced in r15-1857 needs to advance the
    start iterator instead of returning the sentinel.

    libstdc++-v3/ChangeLog:

            PR libstdc++/115799
            * include/bits/ranges_util.h (__find_fn): Return iterator
            instead of sentinel.
            * testsuite/25_algorithms/find/constrained.cc: Check non-common
            contiguous sized range of char.