2012-01-13  François Dumont  <fdumont@gcc.gnu.org>

	* include/bits/hashtable_policy.h (_Hash_node_base): New, use it as
	base class of ...
	(_Hash_node<Value, true>, _Hash_node<Value, false>): ... those.
	* include/bits/hashtable.h (_Hashtable): Replace _M_begin_bucket_index
	by _M_before_begin. Review implementation so that we do not need to
	look for previous non-empty bucket when inserting nodes.

From-SVN: r183164