[Bug libstdc++/97828] std::ranges::search_n does not work with counted_iterator<_List_iterator<...>>

[ensadc at mailnesia dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97828

--- Comment #2 from ensadc at mailnesia dot com ---
This seems to fix the bug (note: not thoroughly tested)

diff --git a/libstdc++-v3/include/bits/ranges_algo.h
b/libstdc++-v3/include/bits/ranges_algo.h
index f1a4cc24c0d..414ce0b1baa 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -579,21 +579,24 @@ namespace ranges
              }
          }

-       if constexpr (sized_sentinel_for<_Sent, _Iter>)
+       if constexpr (random_access_iterator<_Iter>
+                     && sized_sentinel_for<_Sent, _Iter>)
          {
            auto __tail_size = __last - __first;
            auto __remainder = __count;

            while (__remainder <= __tail_size)
              {
+               auto __t = __remainder;
                __first += __remainder;
                __tail_size -= __remainder;
                auto __backtrack = __first;
                while (__value_comp(std::__invoke(__proj, *--__backtrack)))
                  {
-                   if (--__remainder == 0)
+                   if (--__t == 0)
                      return {__first - __count, __first};
                  }
+               __remainder = __count - __remainder + __t;
              }
            auto __i = __first + __tail_size;
            return {__i, __i};