2018-09-18 François Dumont <fdumont@gcc.gnu.org>
PR libstdc++/87135
* src/c++11/hashtable_c++0x.cc:
(_Prime_rehash_policy::_M_next_bkt): Return a prime no smaller than
requested size, but not necessarily greater.
(_Prime_rehash_policy::_M_need_rehash): Rehash only if target size is
strictly greater than next resize threshold.
* testsuite/23_containers/unordered_map/modifiers/reserve.cc: Adapt test
to validate that there is no rehash as long as number of insertion is
lower or equal to the reserved number of elements.
From-SVN: r264413
