* tree-ssa-threadupdate.c (redirection_data): Record two
	duplicated blocks instead of just one.
	(local_info): Explain why we don't create a template for the
	second duplicated block in a thread path.
	(create_block_for_threading): Accept argument indicating array
	index into redirection_data to store its result.
	(lookup_redirection_data): Initialize both duplicate blocks.
	(ssa_create_duplicates): If a jump threading path needs multiple
	blocks duplicated, then duplicate them.
	(ssa_fix_duplicate_block_edges): Corresponding changes.
	(ssa_fixup_template_block, thread_single_edge):  Likewise.

From-SVN: r204982