PR bootstrap/48327
	* tree-ssa-threadupdate.c (struct redirection_data): Remove
	do_not_duplicate field.
	(lookup_redirection_data): Corresponding changes.
	(create_duplicates): Always create a template block.
	(redirect_edges): Remove code which reused the original block
	when it was going to become unreachable code.
	(thread_block): Don't set do_not_duplicate field.

From-SVN: r171703