Few MVE intrinsics like vldrbq_s32, vldrhq_s32 etc., the assembler instructions
generated by current compiler are wrong.
eg: vldrbq_s32 generates an assembly instructions `vldrb.s32 q0,[ip]`.
But as per Arm-arm second argument in above instructions must also be a low
register (<= r7). This patch fixes this issue by creating a new predicate
"mve_memory_operand" and constraint "Ux" which allows low registers as arguments
to the generated instructions depending on the mode of the argument. A new constraint
"Ul" is created to handle loading to PC-relative addressing modes for vector
store/load intrinsiscs.
All the corresponding MVE intrinsic generating wrong code-gen as vldrbq_s32
are modified in this patch.

	Backported from mainline
	2020-05-20  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

gcc/
	PR target/94959
	* config/arm/arm-protos.h (arm_mode_base_reg_class): Function
	declaration.
	(mve_vector_mem_operand): Likewise.
	* config/arm/arm.c (thumb2_legitimate_address_p): For MVE target check
	the load from memory to a core register is legitimate for give mode.
	(mve_vector_mem_operand): Define function.
	(arm_print_operand): Modify comment.
	(arm_mode_base_reg_class): Define.
	* config/arm/arm.h (MODE_BASE_REG_CLASS): Modify to add check for
	TARGET_HAVE_MVE and expand to arm_mode_base_reg_class on TRUE.
	* config/arm/constraints.md (Ux): Likewise.
	(Ul): Likewise.
	* config/arm/mve.md (mve_mov): Replace constraint Us with Ux and also
	add support for missing Vector Store Register and Vector Load Register.
	Add a new alternative to support load from memory to PC (or label) in
	vector store/load.
	(mve_vstrbq_<supf><mode>): Modify constraint Us to Ux.
	(mve_vldrbq_<supf><mode>): Modify constriant Us to Ux, predicate to
	mve_memory_operand and also modify the MVE instructions to emit.
	(mve_vldrbq_z_<supf><mode>): Modify constraint Us to Ux.
	(mve_vldrhq_fv8hf): Modify constriant Us to Ux, predicate to
	mve_memory_operand and also modify the MVE instructions to emit.
	(mve_vldrhq_<supf><mode>): Modify constriant Us to Ux, predicate to
	mve_memory_operand and also modify the MVE instructions to emit.
	(mve_vldrhq_z_fv8hf): Likewise.
	(mve_vldrhq_z_<supf><mode>): Likewise.
	(mve_vldrwq_fv4sf): Likewise.
	(mve_vldrwq_<supf>v4si): Likewise.
	(mve_vldrwq_z_fv4sf): Likewise.
	(mve_vldrwq_z_<supf>v4si): Likewise.
	(mve_vld1q_f<mode>): Modify constriant Us to Ux.
	(mve_vld1q_<supf><mode>): Likewise.
	(mve_vstrhq_fv8hf): Modify constriant Us to Ux, predicate to
	mve_memory_operand.
	(mve_vstrhq_p_fv8hf): Modify constriant Us to Ux, predicate to
	mve_memory_operand and also modify the MVE instructions to emit.
	(mve_vstrhq_p_<supf><mode>): Likewise.
	(mve_vstrhq_<supf><mode>): Modify constriant Us to Ux, predicate to
	mve_memory_operand.
	(mve_vstrwq_fv4sf): Modify constriant Us to Ux.
	(mve_vstrwq_p_fv4sf): Modify constriant Us to Ux and also modify the MVE
	instructions to emit.
	(mve_vstrwq_p_<supf>v4si): Likewise.
	(mve_vstrwq_<supf>v4si): Likewise.Modify constriant Us to Ux.
	* config/arm/predicates.md (mve_memory_operand): Define.

gcc/testsuite/
	PR target/94959
	* gcc.target/arm/mve/intrinsics/mve_vector_float2.c: Modify.
	* gcc.target/arm/mve/intrinsics/mve_vldr.c: New test.
	* gcc.target/arm/mve/intrinsics/mve_vldr_z.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vstr.c: Likewise.
	* gcc.target/arm/mve/intrinsics/mve_vstr_p.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_f16.c: Modify.
	* gcc.target/arm/mve/intrinsics/vld1q_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_f16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vld1q_z_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_s8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrbq_z_u8.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrdq_gather_base_wb_s64.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrdq_gather_base_wb_u64.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrdq_gather_base_wb_z_s64.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrdq_gather_base_wb_z_u64.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_f16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_z_f16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_z_s16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_z_u16.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrhq_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_z_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_gather_base_wb_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_z_f32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_z_s32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vldrwq_z_u32.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vuninitializedq_float.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vuninitializedq_float1.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vuninitializedq_int.c: Likewise.
	* gcc.target/arm/mve/intrinsics/vuninitializedq_int1.c: Likewise.

Co-Authored-By: Andre Vieira  <andre.simoesdiasvieira@arm.com>