arm: [MVE intrinsics] rework vstr?q_scatter_offset

This patch implements vstr?q_scatter_offset using the new MVE builtins
framework.

It uses a similar approach to a previous patch which grouped
truncating and non-truncating stores in two sets of patterns, rather
than having groups of patterns depending on the destination size.

We need to add the 'integer_64' types of suffixes in order to support
vstrdq_scatter_offset.

The patch introduces the MVE_VLD_ST_scatter iterator, similar to
MVE_VLD_ST but which also includes V2DI (again, for
vstrdq_scatter_offset).

The new MVE_scatter_offset mode attribute is used to map the
destination type to the offset type (both are usually equal, except
when the destination is floating-point).

We end up with four sets of patterns:
- vector scatter stores with offset (non-truncating)
- predicated vector scatter stores with offset (non-truncating)
- truncating vector scatter stores with offset
- predicated truncating vector scatter stores with offset

gcc/ChangeLog:

	* config/arm/arm-mve-builtins-base.cc (class vstrq_scatter_impl):
	New.
	(vstrbq_scatter, vstrhq_scatter, vstrwq_scatter, vstrdq_scatter):
	New.
	* config/arm/arm-mve-builtins-base.def (vstrbq_scatter)
	(vstrhq_scatter, vstrwq_scatter, vstrdq_scatter): New.
	* config/arm/arm-mve-builtins-base.h (vstrbq_scatter)
	(vstrhq_scatter, vstrwq_scatter, vstrdq_scatter): New.
	* config/arm/arm-mve-builtins.cc (integer_64): New.
	* config/arm/arm_mve.h (vstrbq_scatter_offset): Delete.
	(vstrbq_scatter_offset_p): Delete.
	(vstrhq_scatter_offset): Delete.
	(vstrhq_scatter_offset_p): Delete.
	(vstrdq_scatter_offset_p): Delete.
	(vstrdq_scatter_offset): Delete.
	(vstrwq_scatter_offset_p): Delete.
	(vstrwq_scatter_offset): Delete.
	(vstrbq_scatter_offset_s8): Delete.
	(vstrbq_scatter_offset_u8): Delete.
	(vstrbq_scatter_offset_u16): Delete.
	(vstrbq_scatter_offset_s16): Delete.
	(vstrbq_scatter_offset_u32): Delete.
	(vstrbq_scatter_offset_s32): Delete.
	(vstrbq_scatter_offset_p_s8): Delete.
	(vstrbq_scatter_offset_p_s32): Delete.
	(vstrbq_scatter_offset_p_s16): Delete.
	(vstrbq_scatter_offset_p_u8): Delete.
	(vstrbq_scatter_offset_p_u32): Delete.
	(vstrbq_scatter_offset_p_u16): Delete.
	(vstrhq_scatter_offset_s32): Delete.
	(vstrhq_scatter_offset_s16): Delete.
	(vstrhq_scatter_offset_u32): Delete.
	(vstrhq_scatter_offset_u16): Delete.
	(vstrhq_scatter_offset_p_s32): Delete.
	(vstrhq_scatter_offset_p_s16): Delete.
	(vstrhq_scatter_offset_p_u32): Delete.
	(vstrhq_scatter_offset_p_u16): Delete.
	(vstrdq_scatter_offset_p_s64): Delete.
	(vstrdq_scatter_offset_p_u64): Delete.
	(vstrdq_scatter_offset_s64): Delete.
	(vstrdq_scatter_offset_u64): Delete.
	(vstrhq_scatter_offset_f16): Delete.
	(vstrhq_scatter_offset_p_f16): Delete.
	(vstrwq_scatter_offset_f32): Delete.
	(vstrwq_scatter_offset_p_f32): Delete.
	(vstrwq_scatter_offset_p_s32): Delete.
	(vstrwq_scatter_offset_p_u32): Delete.
	(vstrwq_scatter_offset_s32): Delete.
	(vstrwq_scatter_offset_u32): Delete.
	(__arm_vstrbq_scatter_offset_s8): Delete.
	(__arm_vstrbq_scatter_offset_s32): Delete.
	(__arm_vstrbq_scatter_offset_s16): Delete.
	(__arm_vstrbq_scatter_offset_u8): Delete.
	(__arm_vstrbq_scatter_offset_u32): Delete.
	(__arm_vstrbq_scatter_offset_u16): Delete.
	(__arm_vstrbq_scatter_offset_p_s8): Delete.
	(__arm_vstrbq_scatter_offset_p_s32): Delete.
	(__arm_vstrbq_scatter_offset_p_s16): Delete.
	(__arm_vstrbq_scatter_offset_p_u8): Delete.
	(__arm_vstrbq_scatter_offset_p_u32): Delete.
	(__arm_vstrbq_scatter_offset_p_u16): Delete.
	(__arm_vstrhq_scatter_offset_s32): Delete.
	(__arm_vstrhq_scatter_offset_s16): Delete.
	(__arm_vstrhq_scatter_offset_u32): Delete.
	(__arm_vstrhq_scatter_offset_u16): Delete.
	(__arm_vstrhq_scatter_offset_p_s32): Delete.
	(__arm_vstrhq_scatter_offset_p_s16): Delete.
	(__arm_vstrhq_scatter_offset_p_u32): Delete.
	(__arm_vstrhq_scatter_offset_p_u16): Delete.
	(__arm_vstrdq_scatter_offset_p_s64): Delete.
	(__arm_vstrdq_scatter_offset_p_u64): Delete.
	(__arm_vstrdq_scatter_offset_s64): Delete.
	(__arm_vstrdq_scatter_offset_u64): Delete.
	(__arm_vstrwq_scatter_offset_p_s32): Delete.
	(__arm_vstrwq_scatter_offset_p_u32): Delete.
	(__arm_vstrwq_scatter_offset_s32): Delete.
	(__arm_vstrwq_scatter_offset_u32): Delete.
	(__arm_vstrhq_scatter_offset_f16): Delete.
	(__arm_vstrhq_scatter_offset_p_f16): Delete.
	(__arm_vstrwq_scatter_offset_f32): Delete.
	(__arm_vstrwq_scatter_offset_p_f32): Delete.
	(__arm_vstrbq_scatter_offset): Delete.
	(__arm_vstrbq_scatter_offset_p): Delete.
	(__arm_vstrhq_scatter_offset): Delete.
	(__arm_vstrhq_scatter_offset_p): Delete.
	(__arm_vstrdq_scatter_offset_p): Delete.
	(__arm_vstrdq_scatter_offset): Delete.
	(__arm_vstrwq_scatter_offset_p): Delete.
	(__arm_vstrwq_scatter_offset): Delete.
	* config/arm/arm_mve_builtins.def (vstrbq_scatter_offset_s)
	(vstrbq_scatter_offset_u, vstrbq_scatter_offset_p_s)
	(vstrbq_scatter_offset_p_u, vstrhq_scatter_offset_p_u)
	(vstrhq_scatter_offset_u, vstrhq_scatter_offset_p_s)
	(vstrhq_scatter_offset_s, vstrdq_scatter_offset_s)
	(vstrhq_scatter_offset_f, vstrwq_scatter_offset_f)
	(vstrwq_scatter_offset_s, vstrdq_scatter_offset_p_s)
	(vstrhq_scatter_offset_p_f, vstrwq_scatter_offset_p_f)
	(vstrwq_scatter_offset_p_s, vstrdq_scatter_offset_u)
	(vstrwq_scatter_offset_u, vstrdq_scatter_offset_p_u)
	(vstrwq_scatter_offset_p_u) Delete.
	* config/arm/iterators.md (MVE_VLD_ST_scatter): New.
	(MVE_scatter_offset): New.
	(MVE_elem_ch): Add entry for V2DI.
	(supf): Remove VSTRBQSO_S, VSTRBQSO_U, VSTRHQSO_S, VSTRHQSO_U,
	VSTRDQSO_S, VSTRDQSO_U, VSTRWQSO_U, VSTRWQSO_S.
	(VSTRBSOQ, VSTRHSOQ, VSTRDSOQ, VSTRWSOQ): Delete.
	* config/arm/mve.md (mve_vstrbq_scatter_offset_<supf><mode>):
	Delete.
	(mve_vstrbq_scatter_offset_<supf><mode>_insn): Delete.
	(mve_vstrbq_scatter_offset_p_<supf><mode>): Delete.
	(mve_vstrbq_scatter_offset_p_<supf><mode>_insn): Delete.
	(mve_vstrhq_scatter_offset_p_<supf><mode>): Delete.
	(mve_vstrhq_scatter_offset_p_<supf><mode>_insn): Delete.
	(mve_vstrhq_scatter_offset_<supf><mode>): Delete.
	(mve_vstrhq_scatter_offset_<supf><mode>_insn): Delete.
	(mve_vstrdq_scatter_offset_p_<supf>v2di): Delete.
	(mve_vstrdq_scatter_offset_p_<supf>v2di_insn): Delete.
	(mve_vstrdq_scatter_offset_<supf>v2di): Delete.
	(mve_vstrdq_scatter_offset_<supf>v2di_insn): Delete.
	(mve_vstrhq_scatter_offset_fv8hf): Delete.
	(mve_vstrhq_scatter_offset_fv8hf_insn): Delete.
	(mve_vstrhq_scatter_offset_p_fv8hf): Delete.
	(mve_vstrhq_scatter_offset_p_fv8hf_insn): Delete.
	(mve_vstrwq_scatter_offset_fv4sf): Delete.
	(mve_vstrwq_scatter_offset_fv4sf_insn): Delete.
	(mve_vstrwq_scatter_offset_p_fv4sf): Delete.
	(mve_vstrwq_scatter_offset_p_fv4sf_insn): Delete.
	(mve_vstrwq_scatter_offset_p_<supf>v4si): Delete.
	(mve_vstrwq_scatter_offset_p_<supf>v4si_insn): Delete.
	(mve_vstrwq_scatter_offset_<supf>v4si): Delete.
	(mve_vstrwq_scatter_offset_<supf>v4si_insn): Delete.
	(@mve_vstrq_scatter_offset_<mode>): New.
	(@mve_vstrq_scatter_offset_p_<mode>): New.
	(@mve_vstrq_truncate_scatter_offset_<mode>): New.
	(@mve_vstrq_truncate_scatter_offset_p_<mode>): New.
	* config/arm/unspecs.md (VSTRBQSO_S, VSTRBQSO_U, VSTRHQSO_S)
	(VSTRDQSO_S, VSTRDQSO_U, VSTRWQSO_S, VSTRWQSO_U, VSTRHQSO_F)
	(VSTRWQSO_F, VSTRHQSO_U): Delete.
	(VSTRQSO, VSTRQSO_P, VSTRQSO_TRUNC, VSTRQSO_TRUNC_P): New.