2019-10-02  Kwok Cheung Yeung  <kcy@codesourcery.com>

        gcc/fortran/
        * f95-lang.c (LANG_HOOKS_OMP_IS_OPTIONAL_ARGUMENT): Define to
        gfc_omp_is_optional_argument.
        * trans-decl.c (create_function_arglist): Set
        GFC_DECL_OPTIONAL_ARGUMENT in the generated decl if the parameter is
        optional.
        * trans-openmp.c (gfc_omp_is_optional_argument): New.
        (gfc_omp_privatize_by_reference): Return true if the decl is an
        optional pass-by-reference argument.
        * trans.h (gfc_omp_is_optional_argument): New declaration.
        (lang_decl): Add new optional_arg field.
        (GFC_DECL_OPTIONAL_ARGUMENT): New macro.

        gcc/
        * langhooks-def.h (LANG_HOOKS_OMP_IS_OPTIONAL_ARGUMENT): Default to
        false.
        (LANG_HOOKS_DECLS): Add LANG_HOOKS_OMP_IS_OPTIONAL_ARGUMENT.
        * langhooks.h (omp_is_optional_argument): New hook.
        * omp-general.c (omp_is_optional_argument): New.
        * omp-general.h (omp_is_optional_argument): New declaration.
        * omp-low.c (lower_omp_target): Create temporary for received value
        and take the address for new_var if the original variable was a
        DECL_BY_REFERENCE.  Use size of referenced object when a
        pass-by-reference optional argument used as argument to firstprivate.

From-SVN: r276444