S/390: Set the preferred mode for float vectors

gcc/ChangeLog:

2017-09-26  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>

	* config/s390/s390.c (s390_preferred_simd_mode): Return V4SFmode
	for SFmode.

From-SVN: r253196

gcc/ChangeLog

 2017-09-26  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
+	* config/s390/s390.c (s390_preferred_simd_mode): Return V4SFmode
+	for SFmode.
+
+2017-09-26  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
+
 	* config/s390/vector.md ("vec_unpacks_low_v16qi"): Rename to
 	vec_unpacks_lo_v16qi.
 	("vec_unpacku_low_v16qi"): Rename to vec_unpacku_lo_v16qi.

gcc/config/s390/s390.c

@@ -15859,6 +15859,14 @@ s390_atomic_assign_expand_fenv (tree *hold, tree *clear, tree *update)
 static machine_mode
 s390_preferred_simd_mode (scalar_mode mode)
 {
+  if (TARGET_VXE)
+    switch (mode)
+      {
+      case E_SFmode:
+	return V4SFmode;
+      default:;
+      }
+
   if (TARGET_VX)
     switch (mode)
       {