[ARM][GCC][4/5x]: MVE load intrinsics with zero(_z) suffix.

[ARM][GCC][4/5x]: MVE load intrinsics with zero(_z) suffix.

This patch supports the following MVE ACLE load intrinsics with zero(_z) suffix.
* ``_z`` (zero) which indicates false-predicated lanes are filled with zeroes, these are only used for load instructions.

vldrbq_gather_offset_z_s16, vldrbq_gather_offset_z_u8, vldrbq_gather_offset_z_s32, vldrbq_gather_offset_z_u16, vldrbq_gather_offset_z_u32, vldrbq_gather_offset_z_s8, vldrbq_z_s16, vldrbq_z_u8, vldrbq_z_s8, vldrbq_z_s32, vldrbq_z_u16, vldrbq_z_u32, vldrwq_gather_base_z_u32, vldrwq_gather_base_z_s32.

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 (LDRGBS_Z_QUALIFIERS): Define builtin
	qualifier.
	(LDRGBU_Z_QUALIFIERS): Likewise.
	(LDRGS_Z_QUALIFIERS): Likewise.
	(LDRGU_Z_QUALIFIERS): Likewise.
	(LDRS_Z_QUALIFIERS): Likewise.
	(LDRU_Z_QUALIFIERS): Likewise.
	* config/arm/arm_mve.h (vldrbq_gather_offset_z_s16): Define macro.
	(vldrbq_gather_offset_z_u8): Likewise.
	(vldrbq_gather_offset_z_s32): Likewise.
	(vldrbq_gather_offset_z_u16): Likewise.
	(vldrbq_gather_offset_z_u32): Likewise.
	(vldrbq_gather_offset_z_s8): Likewise.
	(vldrbq_z_s16): Likewise.
	(vldrbq_z_u8): Likewise.
	(vldrbq_z_s8): Likewise.
	(vldrbq_z_s32): Likewise.
	(vldrbq_z_u16): Likewise.
	(vldrbq_z_u32): Likewise.
	(vldrwq_gather_base_z_u32): Likewise.
	(vldrwq_gather_base_z_s32): Likewise.
	(__arm_vldrbq_gather_offset_z_s8): Define intrinsic.
	(__arm_vldrbq_gather_offset_z_s32): Likewise.
	(__arm_vldrbq_gather_offset_z_s16): Likewise.
	(__arm_vldrbq_gather_offset_z_u8): Likewise.
	(__arm_vldrbq_gather_offset_z_u32): Likewise.
	(__arm_vldrbq_gather_offset_z_u16): Likewise.
	(__arm_vldrbq_z_s8): Likewise.
	(__arm_vldrbq_z_s32): Likewise.
	(__arm_vldrbq_z_s16): Likewise.
	(__arm_vldrbq_z_u8): Likewise.
	(__arm_vldrbq_z_u32): Likewise.
	(__arm_vldrbq_z_u16): Likewise.
	(__arm_vldrwq_gather_base_z_s32): Likewise.
	(__arm_vldrwq_gather_base_z_u32): Likewise.
	(vldrbq_gather_offset_z): Define polymorphic variant.
	* config/arm/arm_mve_builtins.def (LDRGBS_Z_QUALIFIERS): Use builtin
	qualifier.
	(LDRGBU_Z_QUALIFIERS): Likewise.
	(LDRGS_Z_QUALIFIERS): Likewise.
	(LDRGU_Z_QUALIFIERS): Likewise.
	(LDRS_Z_QUALIFIERS): Likewise.
	(LDRU_Z_QUALIFIERS): Likewise.
	* config/arm/mve.md (mve_vldrbq_gather_offset_z_<supf><mode>): Define
	RTL pattern.
	(mve_vldrbq_z_<supf><mode>): Likewise.
	(mve_vldrwq_gather_base_z_<supf>v4si): Likewise.

gcc/testsuite/ChangeLog: Likewise.

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_z_s16.c: New test.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_z_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_z_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_gather_offset_z_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_z_u32.c: Likewise.