RISC-V: Support 128 bit vector chunk

RISC-V has provide different VLEN configuration by different ISA
extension like `zve32x`, `zve64x` and `v`
zve32x just guarantee the minimal VLEN is 32 bits,
zve64x guarantee the minimal VLEN is 64 bits,
and v guarantee the minimal VLEN is 128 bits,

Current status (without this patch):

Zve32x: Mode for one vector register mode is VNx1SImode and VNx1DImode
is invalid mode
 - one vector register could hold 1 + 1x SImode where x is 0~n, so it
might hold just one SI

Zve64x: Mode for one vector register mode is VNx1DImode or VNx2SImode
 - one vector register could hold 1 + 1x DImode where x is 0~n, so it
might hold just one DI.
 - one vector register could hold 2 + 2x SImode where x is 0~n, so it
might hold just two SI.

However `v` extension guarantees the minimal VLEN is 128 bits.

We introduce another type/mode mapping for this configure:

v: Mode for one vector register mode is VNx2DImode or VNx4SImode
 - one vector register could hold 2 + 2x DImode where x is 0~n, so it
will hold at least two DI
 - one vector register could hold 4 + 4x SImode where x is 0~n, so it
will hold at least four DI

This patch model the mode more precisely for the RVV, and help some
middle-end optimization that assume number of element must be a
multiple of two.

gcc/ChangeLog:

	* config/riscv/riscv-modes.def (FLOAT_MODE): Add chunk 128 support.
	(VECTOR_BOOL_MODE): Ditto.
	(ADJUST_NUNITS): Ditto.
	(ADJUST_ALIGNMENT): Ditto.
	(ADJUST_BYTESIZE): Ditto.
	(ADJUST_PRECISION): Ditto.
	(RVV_MODES): Ditto.
	(VECTOR_MODE_WITH_PREFIX): Ditto.
	* config/riscv/riscv-v.cc (ENTRY): Ditto.
	(get_vlmul): Ditto.
	(get_ratio): Ditto.
	* config/riscv/riscv-vector-builtins.cc (DEF_RVV_TYPE): Ditto.
	* config/riscv/riscv-vector-builtins.def (DEF_RVV_TYPE): Ditto.
	(vbool64_t): Ditto.
	(vbool32_t): Ditto.
	(vbool16_t): Ditto.
	(vbool8_t): Ditto.
	(vbool4_t): Ditto.
	(vbool2_t): Ditto.
	(vbool1_t): Ditto.
	(vint8mf8_t): Ditto.
	(vuint8mf8_t): Ditto.
	(vint8mf4_t): Ditto.
	(vuint8mf4_t): Ditto.
	(vint8mf2_t): Ditto.
	(vuint8mf2_t): Ditto.
	(vint8m1_t): Ditto.
	(vuint8m1_t): Ditto.
	(vint8m2_t): Ditto.
	(vuint8m2_t): Ditto.
	(vint8m4_t): Ditto.
	(vuint8m4_t): Ditto.
	(vint8m8_t): Ditto.
	(vuint8m8_t): Ditto.
	(vint16mf4_t): Ditto.
	(vuint16mf4_t): Ditto.
	(vint16mf2_t): Ditto.
	(vuint16mf2_t): Ditto.
	(vint16m1_t): Ditto.
	(vuint16m1_t): Ditto.
	(vint16m2_t): Ditto.
	(vuint16m2_t): Ditto.
	(vint16m4_t): Ditto.
	(vuint16m4_t): Ditto.
	(vint16m8_t): Ditto.
	(vuint16m8_t): Ditto.
	(vint32mf2_t): Ditto.
	(vuint32mf2_t): Ditto.
	(vint32m1_t): Ditto.
	(vuint32m1_t): Ditto.
	(vint32m2_t): Ditto.
	(vuint32m2_t): Ditto.
	(vint32m4_t): Ditto.
	(vuint32m4_t): Ditto.
	(vint32m8_t): Ditto.
	(vuint32m8_t): Ditto.
	(vint64m1_t): Ditto.
	(vuint64m1_t): Ditto.
	(vint64m2_t): Ditto.
	(vuint64m2_t): Ditto.
	(vint64m4_t): Ditto.
	(vuint64m4_t): Ditto.
	(vint64m8_t): Ditto.
	(vuint64m8_t): Ditto.
	(vfloat32mf2_t): Ditto.
	(vfloat32m1_t): Ditto.
	(vfloat32m2_t): Ditto.
	(vfloat32m4_t): Ditto.
	(vfloat32m8_t): Ditto.
	(vfloat64m1_t): Ditto.
	(vfloat64m2_t): Ditto.
	(vfloat64m4_t): Ditto.
	(vfloat64m8_t): Ditto.
	* config/riscv/riscv-vector-switch.def (ENTRY): Ditto.
	* config/riscv/riscv.cc (riscv_legitimize_poly_move): Ditto.
	(riscv_convert_vector_bits): Ditto.
	* config/riscv/riscv.md:
	* config/riscv/vector-iterators.md:
	* config/riscv/vector.md
	(@pred_indexed_<order>store<VNX32_QH:mode><VNX32_QHI:mode>): Ditto.
	(@pred_indexed_<order>store<VNX32_QHS:mode><VNX32_QHSI:mode>): Ditto.
	(@pred_indexed_<order>store<VNX64_Q:mode><VNX64_Q:mode>): Ditto.
	(@pred_indexed_<order>store<VNX64_QH:mode><VNX64_QHI:mode>): Ditto.
	(@pred_indexed_<order>store<VNX128_Q:mode><VNX128_Q:mode>): Ditto.
	(@pred_reduc_<reduc><mode><vlmul1_zve64>): Ditto.
	(@pred_widen_reduc_plus<v_su><mode><vwlmul1_zve64>): Ditto.
	(@pred_reduc_plus<order><mode><vlmul1_zve64>): Ditto.
	(@pred_widen_reduc_plus<order><mode><vwlmul1_zve64>): Ditto.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pr108185-4.c: Adapt testcase.
	* gcc.target/riscv/rvv/base/spill-1.c: Ditto.
	* gcc.target/riscv/rvv/base/spill-11.c: Ditto.
	* gcc.target/riscv/rvv/base/spill-2.c: Ditto.
	* gcc.target/riscv/rvv/base/spill-3.c: Ditto.
	* gcc.target/riscv/rvv/base/spill-5.c: Ditto.
	* gcc.target/riscv/rvv/base/spill-9.c: Ditto.