* tree-cfg.c (execute_warn_function_return): Break out noreturn
	warning too..
	(execute_warn_function_noreturn): ... here.
	(pass_warn_function_noreturn): New pass.
	* tree-pass.h (pass_warn_function_noreturn): Declare
	* tree-optimize.c (init_tree_optimization_passes): Move return
	warnings early and add noreturn warnings at place of previous
	return warnings.

From-SVN: r99696