re PR libstdc++/71181 (Reserving in unordered_map doesn't reserve enough)

re PR libstdc++/71181 (Reserving in unordered_map doesn't reserve enough)

2016-06-20  François Dumont  <fdumont@gcc.gnu.org>

	PR libstdc++/71181
	* include/tr1/hashtable_policy.h
	(_Prime_rehash_policy::_M_next_bkt): Make past-the-end iterator
	dereferenceable to avoid check on lower_bound result.
	(_Prime_rehash_policy::_M_bkt_for_elements): Call latter.
	(_Prime_rehash_policy::_M_need_rehash): Likewise.
	* src/c++11/hashtable_c++0x.cc (_Prime_rehash_policy::_M_next_bkt):
	Always return a value greater than input value. Set _M_next_resize to
	max value when reaching highest prime number.
	* src/shared/hashtable-aux.cc (__prime_list): Add comment about sentinel
	being now useless.
	* testsuite/23_containers/unordered_set/hash_policy/71181.cc: New.
	* testsuite/23_containers/unordered_set/hash_policy/power2_rehash.cc
	(test02): New.
	* testsuite/23_containers/unordered_set/hash_policy/prime_rehash.cc: New.
	* testsuite/23_containers/unordered_set/hash_policy/rehash.cc:
	Fix indentation.

From-SVN: r237617