Index: gcc/machmode.h
===================================================================
--- gcc/machmode.h	2017-09-04 12:18:50.674859598 +0100
+++ gcc/machmode.h	2017-09-04 12:18:53.153306182 +0100
@@ -706,6 +706,21 @@ extern machine_mode bitwise_mode_for_mod
 
 extern machine_mode mode_for_vector (scalar_mode, unsigned);
 
+extern opt_machine_mode mode_for_int_vector (unsigned int, unsigned int);
+
+/* Return the integer vector equivalent of MODE, if one exists.  In other
+   words, return the mode for an integer vector that has the same number
+   of bits as MODE and the same number of elements as MODE, with the
+   latter being 1 if MODE is scalar.  The returned mode can be either
+   an integer mode or a vector mode.  */
+
+inline opt_machine_mode
+mode_for_int_vector (machine_mode mode)
+{
+  return mode_for_int_vector (GET_MODE_UNIT_BITSIZE (mode),
+			      GET_MODE_NUNITS (mode));
+}
+
 /* A class for iterating through possible bitfield modes.  */
 class bit_field_mode_iterator
 {
Index: gcc/stor-layout.c
===================================================================
--- gcc/stor-layout.c	2017-09-04 12:18:50.675762071 +0100
+++ gcc/stor-layout.c	2017-09-04 12:18:53.153306182 +0100
@@ -517,6 +517,23 @@ mode_for_vector (scalar_mode innermode,
   return mode;
 }
 
+/* Return the mode for a vector that has NUNITS integer elements of
+   INT_BITS bits each, if such a mode exists.  The mode can be either
+   an integer mode or a vector mode.  */
+
+opt_machine_mode
+mode_for_int_vector (unsigned int int_bits, unsigned int nunits)
+{
+  scalar_int_mode int_mode;
+  if (int_mode_for_size (int_bits, 0).exists (&int_mode))
+    {
+      machine_mode vec_mode = mode_for_vector (int_mode, nunits);
+      if (vec_mode != BLKmode)
+	return vec_mode;
+    }
+  return opt_machine_mode ();
+}
+
 /* Return the alignment of MODE. This will be bounded by 1 and
    BIGGEST_ALIGNMENT.  */
 
Index: gcc/config/aarch64/aarch64.c
===================================================================
--- gcc/config/aarch64/aarch64.c	2017-09-04 12:18:44.874165502 +0100
+++ gcc/config/aarch64/aarch64.c	2017-09-04 12:18:53.144272229 +0100
@@ -8282,9 +8282,6 @@ aarch64_emit_approx_sqrt (rtx dst, rtx s
       return false;
     }
 
-  machine_mode mmsk
-    = mode_for_vector (int_mode_for_mode (GET_MODE_INNER (mode)).require (),
-		       GET_MODE_NUNITS (mode));
   if (!recp)
     {
       if (!(flag_mlow_precision_sqrt
@@ -8302,7 +8299,7 @@ aarch64_emit_approx_sqrt (rtx dst, rtx s
     /* Caller assumes we cannot fail.  */
     gcc_assert (use_rsqrt_p (mode));
 
-
+  machine_mode mmsk = mode_for_int_vector (mode).require ();
   rtx xmsk = gen_reg_rtx (mmsk);
   if (!recp)
     /* When calculating the approximate square root, compare the
Index: gcc/config/powerpcspe/powerpcspe.c
===================================================================
--- gcc/config/powerpcspe/powerpcspe.c	2017-09-04 12:18:44.919414816 +0100
+++ gcc/config/powerpcspe/powerpcspe.c	2017-09-04 12:18:53.148287319 +0100
@@ -38739,8 +38739,7 @@ rs6000_do_expand_vec_perm (rtx target, r
 
   imode = vmode;
   if (GET_MODE_CLASS (vmode) != MODE_VECTOR_INT)
-    imode = mode_for_vector
-      (int_mode_for_mode (GET_MODE_INNER (vmode)).require (), nelt);
+    imode = mode_for_int_vector (vmode).require ();
 
   x = gen_rtx_CONST_VECTOR (imode, gen_rtvec_v (nelt, perm));
   x = expand_vec_perm (vmode, op0, op1, x, target);
Index: gcc/config/rs6000/rs6000.c
===================================================================
--- gcc/config/rs6000/rs6000.c	2017-09-04 12:18:44.929470219 +0100
+++ gcc/config/rs6000/rs6000.c	2017-09-04 12:18:53.151298637 +0100
@@ -35584,8 +35584,7 @@ rs6000_do_expand_vec_perm (rtx target, r
 
   imode = vmode;
   if (GET_MODE_CLASS (vmode) != MODE_VECTOR_INT)
-    imode = mode_for_vector
-      (int_mode_for_mode (GET_MODE_INNER (vmode)).require (), nelt);
+    imode = mode_for_int_vector (vmode).require ();
 
   x = gen_rtx_CONST_VECTOR (imode, gen_rtvec_v (nelt, perm));
   x = expand_vec_perm (vmode, op0, op1, x, target);
Index: gcc/config/s390/s390.c
===================================================================
--- gcc/config/s390/s390.c	2017-09-04 11:50:24.561571751 +0100
+++ gcc/config/s390/s390.c	2017-09-04 12:18:53.153306182 +0100
@@ -6472,10 +6472,7 @@ s390_expand_vec_compare_cc (rtx target,
 	case LE:   cc_producer_mode = CCVFHEmode; code = GE; swap_p = true; break;
 	default: gcc_unreachable ();
 	}
-      scratch_mode = mode_for_vector
-	(int_mode_for_mode (GET_MODE_INNER (GET_MODE (cmp1))).require (),
-	 GET_MODE_NUNITS (GET_MODE (cmp1)));
-      gcc_assert (scratch_mode != BLKmode);
+      scratch_mode = mode_for_int_vector (GET_MODE (cmp1)).require ();
 
       if (inv_p)
 	all_p = !all_p;
@@ -6581,9 +6578,7 @@ s390_expand_vcond (rtx target, rtx then,
 
   /* We always use an integral type vector to hold the comparison
      result.  */
-  result_mode = mode_for_vector
-    (int_mode_for_mode (GET_MODE_INNER (cmp_mode)).require (),
-     GET_MODE_NUNITS (cmp_mode));
+  result_mode = mode_for_int_vector (cmp_mode).require ();
   result_target = gen_reg_rtx (result_mode);
 
   /* We allow vector immediates as comparison operands that
