Empty the redirect_edge_var_map after each pass

Empty the redirect_edge_var_map after each pass

	Alan Lawrence  <alan.lawrence@arm.com>
	Richard Biener  <richard.guenther@gmail.com>

	* cfgexpand.c (pass_expand::execute): Replace call to
	redirect_edge_var_map_destroy with redirect_edge_var_map_empty.
	* tree-ssa.c (delete_tree_ssa): Likewise.
	* function.c (set_cfun): Call redirect_edge_var_map_empty.
	* passes.c (execute_one_ipa_transform_pass, execute_one_pass): Likewise.
	* tree-ssa.h (redirect_edge_var_map_destroy): Remove.
	(redirect_edge_var_map_empty): New.
	* tree-ssa.c (redirect_edge_var_map_destroy): Remove.
	(redirect_edge_var_map_empty): New.

Co-Authored-By: Richard Biener <richard.guenther@gmail.com>
From-SVN: r231232