[ARM][GCC][2/5x]: MVE load intrinsics.

[ARM][GCC][2/5x]: MVE load intrinsics.

This patch supports the following MVE ACLE load intrinsics.

vldrbq_gather_offset_u8, vldrbq_gather_offset_s8, vldrbq_s8, vldrbq_u8, vldrbq_gather_offset_u16, vldrbq_gather_offset_s16, vldrbq_s16, vldrbq_u16, vldrbq_gather_offset_u32, vldrbq_gather_offset_s32, vldrbq_s32, vldrbq_u32, vldrwq_gather_base_s32, vldrwq_gather_base_u32.

Please refer to M-profile Vector Extension (MVE) intrinsics [1]  for more details.
[1]  https://developer.arm.com/architectures/instruction-sets/simd-isas/helium/mve-intrinsics

2020-03-18  Andre Vieira  <andre.simoesdiasvieira@arm.com>
            Mihail Ionescu  <mihail.ionescu@arm.com>
            Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* config/arm/arm-builtins.c (LDRGU_QUALIFIERS): Define builtin
	qualifier.
	(LDRGS_QUALIFIERS): Likewise.
	(LDRS_QUALIFIERS): Likewise.
	(LDRU_QUALIFIERS): Likewise.
	(LDRGBS_QUALIFIERS): Likewise.
	(LDRGBU_QUALIFIERS): Likewise.
	* config/arm/arm_mve.h (vldrbq_gather_offset_u8): Define macro.
	(vldrbq_gather_offset_s8): Likewise.
	(vldrbq_s8): Likewise.
	(vldrbq_u8): Likewise.
	(vldrbq_gather_offset_u16): Likewise.
	(vldrbq_gather_offset_s16): Likewise.
	(vldrbq_s16): Likewise.
	(vldrbq_u16): Likewise.
	(vldrbq_gather_offset_u32): Likewise.
	(vldrbq_gather_offset_s32): Likewise.
	(vldrbq_s32): Likewise.
	(vldrbq_u32): Likewise.
	(vldrwq_gather_base_s32): Likewise.
	(vldrwq_gather_base_u32): Likewise.
	(__arm_vldrbq_gather_offset_u8): Define intrinsic.
	(__arm_vldrbq_gather_offset_s8): Likewise.
	(__arm_vldrbq_s8): Likewise.
	(__arm_vldrbq_u8): Likewise.
	(__arm_vldrbq_gather_offset_u16): Likewise.
	(__arm_vldrbq_gather_offset_s16): Likewise.
	(__arm_vldrbq_s16): Likewise.
	(__arm_vldrbq_u16): Likewise.
	(__arm_vldrbq_gather_offset_u32): Likewise.
	(__arm_vldrbq_gather_offset_s32): Likewise.
	(__arm_vldrbq_s32): Likewise.
	(__arm_vldrbq_u32): Likewise.
	(__arm_vldrwq_gather_base_s32): Likewise.
	(__arm_vldrwq_gather_base_u32): Likewise.
	(vldrbq_gather_offset): Define polymorphic variant.
	* config/arm/arm_mve_builtins.def (LDRGU_QUALIFIERS): Use builtin
	qualifier.
	(LDRGS_QUALIFIERS): Likewise.
	(LDRS_QUALIFIERS): Likewise.
	(LDRU_QUALIFIERS): Likewise.
	(LDRGBS_QUALIFIERS): Likewise.
	(LDRGBU_QUALIFIERS): Likewise.
	* config/arm/mve.md (VLDRBGOQ): Define iterator.
	(VLDRBQ): Likewise.
	(VLDRWGBQ): Likewise.
	(mve_vldrbq_gather_offset_<supf><mode>): Define RTL pattern.
	(mve_vldrbq_<supf><mode>): Likewise.
	(mve_vldrwq_gather_base_<supf>v4si): Likewise.

gcc/testsuite/ChangeLog:

2020-03-18  Andre Vieira  <andre.simoesdiasvieira@arm.com>
            Mihail Ionescu  <mihail.ionescu@arm.com>
            Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_s16.c: New test.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_u32.c: Likewise.