re PR libstdc++/54296 (using the object in the map to erase element from the map crashes)

2012-09-05  François Dumont  <fdumont@gcc.gnu.org>

	PR libstdc++/54296
	* include/bits/hashtable.h (_M_erase(size_type, __node_base*,
	__node_type*)): New.
	(erase(const_iterator)): Use latter.
	(_M_erase(std::true_type, const key_type&)): New, likewise.
	(_M_erase(std::false_type, const key_type&)): New. Find all nodes
	matching the key before deallocating them so that the key doesn't
	get invalidated.
	(erase(const key_type&)): Use the new member functions.
	* testsuite/23_containers/unordered_map/erase/54296.cc: New.
	* testsuite/23_containers/unordered_multimap/erase/54296.cc: New.

From-SVN: r190991