S/390: vec_init improvements

S/390: vec_init improvements

This enables the vec_init pattern also for V4SF, V1TI, and V1TF.

gcc/testsuite/ChangeLog:

2017-03-24  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* gcc.target/s390/vector/vec-init-2.c: New test.

gcc/ChangeLog:

2017-03-24  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/s390/s390.c (s390_expand_vec_init): Enable vector load
	pair for all vector types with 64 bit elements.
	* config/s390/vx-builtins.md (V_HW_64): Move mode iterator to ...
	* config/s390/vector.md (V_HW_64): ... here.
	(V_128_NOSINGLE): New mode iterator.
	("vec_init<V_HW:mode>"): Use V_128 as mode iterator.
	("*vec_splat<mode>"): Use V_128_NOSINGLE mode iterator.
	("*vec_tf_to_v1tf", "*vec_ti_to_v1ti"): New pattern definitions.
	("*vec_load_pairv2di"): Change to ...
	("*vec_load_pair<mode>"): ... this one.

From-SVN: r246446