* function.c (assign_parms): Handle frontend-directed pass by
        invisible reference.
cp/
        * call.c (build_over_call): Likewise.
        (cp_convert_parm_for_inlining): New fn.
        (convert_for_arg_passing): New fn.
        (convert_default_arg, build_over_call): Use it.
        (type_passed_as): New fn.
        * pt.c (tsubst_decl): Use it.
        * decl2.c (cp_build_parm_decl): New fn.
        (build_artificial_parm): Use it.
        (start_static_storage_duration_function): Likewise.
        * decl.c (start_cleanup_fn, grokdeclarater): Likewise.
        (grokparms): Don't mess with DECL_ARG_TYPE.
        * typeck.c (convert_arguments): Use convert_for_arg_passing.
        * cp-lang.c (LANG_HOOKS_TREE_INLINING_CONVERT_PARM_FOR_INLINING):
        Define.
        * cp-tree.h: Declare new fns.

From-SVN: r55781