Use vector_operand on SSE with 16b memory operand

Add vector_operand, which is vector_memory_operand or register_operand,
and use it, instead of nonimmediate_operand, in SSE patterns with 16-byte
memory operand.

gcc/

	PR target/68991
	* config/i386/i386.c (ix86_expand_vector_logical_operator):
	Replace nonimmediate_operand with vector_operand.
	* config/i386/predicates.md (vector_operand): New predicate.
	(general_vector_operand): Replace nonimmediate_operand with
	vector_operand.
	* config/i386/sse.md: Replace nonimmediate_operand with
	vector_operand and m constraint with Bm constraint on SSE
	patterns with 16-byte memory operand.
	* config/i386/subst.md (round_nimm_predicate): Replace
	nonimmediate_operand with vector_operand.
	(round_saeonly_nimm_predicate): Likewise.
	(round_saeonly_nimm_scalar_predicate): New.

gcc/testsuite/

	PR target/68991
	* gcc.target/i386/pr68991.c: New test.

From-SVN: r232088