Hi,

This patch adds support for the MVE instructions VHCADD, VHADD, VHSUB 
and VRHADD.

gas/ChangeLog:

2019-05-01  Andre Vieira  <andre.simoesdiasvieira@arm.com>

	* config/tc-arm.c (enum operand_parse_code): New operand.
	(parse_operands): Handle new operand.
	(mve_encode_qqr): Change to support new instructions.
	(enum vfp_or_neon_is_neon_bits): Moved.
	(vfp_or_neon_is_neon): Moved.
	(check_simd_pred_availability): Moved.
	(do_neon_dyadic_i_su): Changed to support MVE variants.
	(neon_dyadic_misc): Changed mve_encode_qqr call.
	(do_mve_vbrsr): Likewise.
	(do_mve_vhcadd): New encoding function.
         (insns): Change existing to accept MVE variants and add new.
	* testsuite/gas/arm/mve-vhadd-vhsub-vrhadd-bad.d: New test.
	* testsuite/gas/arm/mve-vhadd-vhsub-vrhadd-bad.l: New test.
	* testsuite/gas/arm/mve-vhadd-vhsub-vrhadd-bad.s: New test.
	* testsuite/gas/arm/mve-vhcadd-bad.d: New test.
	* testsuite/gas/arm/mve-vhcadd-bad.l: New test.
	* testsuite/gas/arm/mve-vhcadd-bad.s: New test.