S/390: Remove code duplication in vec_* comparison expanders

S/390: Remove code duplication in vec_* comparison expanders

s390.md uses a lot of near-identical expanders that perform dispatching
to other expanders based on operand types. Since the following patch
would require even more of these, avoid copy-pasting the code by
generating these expanders using an iterator.

gcc/ChangeLog:

2019-10-01  Ilya Leoshkevich  <iii@linux.ibm.com>

	PR target/77918
	* config/s390/s390.c (s390_expand_vec_compare): Use
	gen_vec_cmpordered and gen_vec_cmpunordered.
	* config/s390/vector.md (vec_cmpuneq, vec_cmpltgt, vec_ordered,
	vec_unordered): Delete.
	(vec_ordered<mode>): Rename to vec_cmpordered<mode>.
	(vec_unordered<mode>): Rename to vec_cmpunordered<mode>.
	(VEC_CMP_EXPAND): New iterator for the generic dispatcher.
	(vec_cmp<code>): Generic dispatcher.

From-SVN: r276409