predicates.md (easy_fp_constant): Discount decimal float modes.

predicates.md (easy_fp_constant): Discount decimal float modes.

	* config/rs6000/predicates.md (easy_fp_constant): Discount decimal
	float modes.
	* config/rs6000/rs6000.c (rs6000_scalar_mode_supported_p): New.
	(TARGET_SCALAR_MODE_SUPPORTED_P): Define.
	(USE_FP_FOR_ARG): Reject decimal float modes.
	(function_arg_advance): Likewise.
	(output_toc): Handle emitting TDmode, DDmode and SDmode constants.
	(rs6000_handle_altivec_attribute): Do not permit decimal floating
	point types in AltiVec vectors.
	(rs6000_function_value): Use GP_ARG_RETURN for decimal floats.
	(rs6000_libcall_value): Likewise.

From-SVN: r109533