RISC-V: Add RVV reduction C/C++ intrinsics support

RISC-V: Add RVV reduction C/C++ intrinsics support

gcc/ChangeLog:

	* config/riscv/riscv-vector-builtins-bases.cc (class reducop): New class.
	(class widen_reducop): Ditto.
	(class freducop): Ditto.
	(class widen_freducop): Ditto.
	(BASE): Ditto.
	* config/riscv/riscv-vector-builtins-bases.h: Ditto.
	* config/riscv/riscv-vector-builtins-functions.def (vredsum): Add reduction support.
	(vredmaxu): Ditto.
	(vredmax): Ditto.
	(vredminu): Ditto.
	(vredmin): Ditto.
	(vredand): Ditto.
	(vredor): Ditto.
	(vredxor): Ditto.
	(vwredsum): Ditto.
	(vwredsumu): Ditto.
	(vfredusum): Ditto.
	(vfredosum): Ditto.
	(vfredmax): Ditto.
	(vfredmin): Ditto.
	(vfwredosum): Ditto.
	(vfwredusum): Ditto.
	* config/riscv/riscv-vector-builtins-shapes.cc (struct reduc_alu_def): Ditto.
	(SHAPE): Ditto.
	* config/riscv/riscv-vector-builtins-shapes.h: Ditto.
	* config/riscv/riscv-vector-builtins-types.def (DEF_RVV_WI_OPS): New macro.
	(DEF_RVV_WU_OPS): Ditto.
	(DEF_RVV_WF_OPS): Ditto.
	(vint8mf8_t): Ditto.
	(vint8mf4_t): Ditto.
	(vint8mf2_t): Ditto.
	(vint8m1_t): Ditto.
	(vint8m2_t): Ditto.
	(vint8m4_t): Ditto.
	(vint8m8_t): Ditto.
	(vint16mf4_t): Ditto.
	(vint16mf2_t): Ditto.
	(vint16m1_t): Ditto.
	(vint16m2_t): Ditto.
	(vint16m4_t): Ditto.
	(vint16m8_t): Ditto.
	(vint32mf2_t): Ditto.
	(vint32m1_t): Ditto.
	(vint32m2_t): Ditto.
	(vint32m4_t): Ditto.
	(vint32m8_t): Ditto.
	(vuint8mf8_t): Ditto.
	(vuint8mf4_t): Ditto.
	(vuint8mf2_t): Ditto.
	(vuint8m1_t): Ditto.
	(vuint8m2_t): Ditto.
	(vuint8m4_t): Ditto.
	(vuint8m8_t): Ditto.
	(vuint16mf4_t): Ditto.
	(vuint16mf2_t): Ditto.
	(vuint16m1_t): Ditto.
	(vuint16m2_t): Ditto.
	(vuint16m4_t): Ditto.
	(vuint16m8_t): Ditto.
	(vuint32mf2_t): Ditto.
	(vuint32m1_t): Ditto.
	(vuint32m2_t): Ditto.
	(vuint32m4_t): Ditto.
	(vuint32m8_t): Ditto.
	(vfloat32mf2_t): Ditto.
	(vfloat32m1_t): Ditto.
	(vfloat32m2_t): Ditto.
	(vfloat32m4_t): Ditto.
	(vfloat32m8_t): Ditto.
	* config/riscv/riscv-vector-builtins.cc (DEF_RVV_WI_OPS): Ditto.
	(DEF_RVV_WU_OPS): Ditto.
	(DEF_RVV_WF_OPS): Ditto.
	(required_extensions_p): Add reduction support.
	(rvv_arg_type_info::get_base_vector_type): Ditto.
	(rvv_arg_type_info::get_tree_type): Ditto.
	* config/riscv/riscv-vector-builtins.h (enum rvv_base_type): Ditto.
	* config/riscv/riscv.md: Ditto.
	* config/riscv/vector-iterators.md (minu): Ditto.
	* config/riscv/vector.md (@pred_reduc_<reduc><mode><vlmul1>): New patern.
	(@pred_reduc_<reduc><mode><vlmul1_zve32>): Ditto.
	(@pred_widen_reduc_plus<v_su><mode><vwlmul1>): Ditto.
	(@pred_widen_reduc_plus<v_su><mode><vwlmul1_zve32>):Ditto.
	(@pred_reduc_plus<order><mode><vlmul1>): Ditto.
	(@pred_reduc_plus<order><mode><vlmul1_zve32>): Ditto.
	(@pred_widen_reduc_plus<order><mode><vwlmul1>): Ditto.