re PR middle-end/20991 (ICE in cgraph_mark_reachable_node)

re PR middle-end/20991 (ICE in cgraph_mark_reachable_node)

	* cgraph.c (cgraph_clone_node): Do not handle vtable_method
	* cgraph.h (struct cgraph_local_info): Drop vtable_method.
	* cgraphunit.c (cgraph_copy_node_for_versioning): Drop vtable_method.
	* lto-cgraph.c (lto_output_node, input_overwrite_node): Drop vtable method.
	* gimple-fold.c (can_refer_decl_in_current_unit_p): Mention PR20991 in
	gimple-fold.c
	* varasm.c (mark_decl_referenced): Drop vtable_method handling code.
	* cp/class.c (cp_fold_obj_type_ref): Drop vtable_method.

From-SVN: r172613