RISC-V: Finish all integer C/C++ intrinsics

RISC-V: Finish all integer C/C++ intrinsics

gcc/ChangeLog:

	* config/riscv/predicates.md: Refine codes.
	* config/riscv/riscv-protos.h (RVV_VUNDEF): New macro.
	* config/riscv/riscv-v.cc: Refine codes.
	* config/riscv/riscv-vector-builtins-bases.cc (enum ternop_type): New
	enum.
	(class imac): New class.
	(enum widen_ternop_type): New enum.
	(class iwmac): New class.
	(BASE): New class.
	* config/riscv/riscv-vector-builtins-bases.h: Ditto.
	* config/riscv/riscv-vector-builtins-functions.def (vmacc): Ditto.
	(vnmsac): Ditto.
	(vmadd): Ditto.
	(vnmsub): Ditto.
	(vwmacc): Ditto.
	(vwmaccu): Ditto.
	(vwmaccsu): Ditto.
	(vwmaccus): Ditto.
	* config/riscv/riscv-vector-builtins.cc
	(function_builder::apply_predication): Adjust for multiply-add support.
	(function_expander::add_vundef_operand): Refine codes.
	(function_expander::use_ternop_insn): New function.
	(function_expander::use_widen_ternop_insn): Ditto.
	* config/riscv/riscv-vector-builtins.h: New function.
	* config/riscv/vector.md (@pred_mul_<optab><mode>): New pattern.
	(pred_mul_<optab><mode>_undef_merge): Ditto.
	(*pred_<madd_nmsub><mode>): Ditto.
	(*pred_<macc_nmsac><mode>): Ditto.
	(*pred_mul_<optab><mode>): Ditto.
	(@pred_mul_<optab><mode>_scalar): Ditto.
	(*pred_mul_<optab><mode>_undef_merge_scalar): Ditto.
	(*pred_<madd_nmsub><mode>_scalar): Ditto.
	(*pred_<macc_nmsac><mode>_scalar): Ditto.
	(*pred_mul_<optab><mode>_scalar): Ditto.
	(*pred_mul_<optab><mode>_undef_merge_extended_scalar): Ditto.
	(*pred_<madd_nmsub><mode>_extended_scalar): Ditto.
	(*pred_<macc_nmsac><mode>_extended_scalar): Ditto.
	(*pred_mul_<optab><mode>_extended_scalar): Ditto.
	(@pred_widen_mul_plus<su><mode>): Ditto.
	(@pred_widen_mul_plus<su><mode>_scalar): Ditto.
	(@pred_widen_mul_plussu<mode>): Ditto.
	(@pred_widen_mul_plussu<mode>_scalar): Ditto.
	(@pred_widen_mul_plusus<mode>_scalar): Ditto.