[AArch64] Vectorise bswap[16,32,64]

[AArch64] Vectorise bswap[16,32,64]

	* config/aarch64/aarch64-builtins.c
	(aarch64_builtin_vectorized_function): Handle BUILT_IN_BSWAP16,
	BUILT_IN_BSWAP32, BUILT_IN_BSWAP64.
	* config/aarch64/aarch64-simd.md (bswap<mode>): New pattern.
	* config/aarch64/aarch64-simd-builtins.def: Define vector bswap
	builtins.
	* config/aarch64/iterator.md (VDQHSD): New mode iterator.
	(Vrevsuff): New mode attribute.

	* lib/target-supports.exp (check_effective_target_vect_bswap): New.
	* gcc.dg/vect/vect-bswap16: New test.
	* gcc.dg/vect/vect-bswap32: Likewise.
	* gcc.dg/vect/vect-bswap64: Likewise.

From-SVN: r209736