[PATCH] Remove unnecessary invalidation support in threading

2015-10-29  Jeff Law  <law@redhat.com>

	* tree-ssa-scopedtables.h (const_and_copies): Remove invalidate
	method.
	* tree-ssa-scopedtables.h (const_and_copies::invalidate): Remove.
	* tree-ssa-threadedge.c
	(record_temporary_equivalences_from_stmts_at_dest): Remove
	backedge_seen argument and associated code which invalidated
	equivalences based on the value of that argument.
	(thread_through_normal_block): Corresponding changes.

From-SVN: r229559