Replace mode_for_int_vector with related_int_vector_mode

mode_for_int_vector, like mode_for_vector, can sometimes return
an integer mode or an unsupported vector mode.  But no callers
are interested in that case, and only want supported vector modes.
This patch therefore replaces mode_for_int_vector with
related_int_vector_mode, which gives the target a chance to pick
its preferred vector mode for the given element mode and size.

2019-11-14  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* machmode.h (mode_for_int_vector): Delete.
	(related_int_vector_mode): Declare.
	* stor-layout.c (mode_for_int_vector): Delete.
	(related_int_vector_mode): New function.
	* optabs.c (expand_vec_perm_1): Use related_int_vector_mode
	instead of mode_for_int_vector.
	(expand_vec_perm_const): Likewise.
	* config/aarch64/aarch64.c (aarch64_emit_approx_sqrt): Likewise.
	(aarch64_evpc_sve_tbl): Likewise.
	* config/s390/s390.c (s390_expand_vec_compare_cc): Likewise.
	(s390_expand_vcond): Likewise.

From-SVN: r278230

6 files changed, 42 insertions, 37 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 54f2449..3131af7 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,19 @@
 2019-11-14  Richard Sandiford  <richard.sandiford@arm.com>
 
+	* machmode.h (mode_for_int_vector): Delete.
+	(related_int_vector_mode): Declare.
+	* stor-layout.c (mode_for_int_vector): Delete.
+	(related_int_vector_mode): New function.
+	* optabs.c (expand_vec_perm_1): Use related_int_vector_mode
+	instead of mode_for_int_vector.
+	(expand_vec_perm_const): Likewise.
+	* config/aarch64/aarch64.c (aarch64_emit_approx_sqrt): Likewise.
+	(aarch64_evpc_sve_tbl): Likewise.
+	* config/s390/s390.c (s390_expand_vec_compare_cc): Likewise.
+	(s390_expand_vcond): Likewise.
+
+2019-11-14  Richard Sandiford  <richard.sandiford@arm.com>
+
 	* target.def (related_mode): New hook.
 	* doc/tm.texi.in (TARGET_VECTORIZE_RELATED_MODE): New hook.
 	* doc/tm.texi: Regenerate.
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 9a5f27f..b6c8d77 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -1816,7 +1816,7 @@ aarch64_sve_element_int_mode (machine_mode mode)
 }
 
 /* Return the integer vector mode associated with SVE mode MODE.
-   Unlike mode_for_int_vector, this can handle the case in which
+   Unlike related_int_vector_mode, this can handle the case in which
    MODE is a predicate (and thus has a different total size).  */
 
 machine_mode
@@ -12537,7 +12537,7 @@ aarch64_emit_approx_sqrt (rtx dst, rtx src, bool recp)
     gcc_assert (use_rsqrt_p (mode));
 
   machine_mode mmsk = (VECTOR_MODE_P (mode)
-		       ? mode_for_int_vector (mode).require ()
+		       ? related_int_vector_mode (mode).require ()
 		       : int_mode_for_mode (mode).require ());
   rtx xmsk = gen_reg_rtx (mmsk);
   if (!recp)
@@ -19068,7 +19068,7 @@ aarch64_evpc_sve_tbl (struct expand_vec_perm_d *d)
   if (d->testing_p)
     return true;
 
-  machine_mode sel_mode = mode_for_int_vector (d->vmode).require ();
+  machine_mode sel_mode = related_int_vector_mode (d->vmode).require ();
   rtx sel = vec_perm_indices_to_rtx (sel_mode, d->perm);
   if (d->one_vector_p)
     emit_unspec2 (d->target, UNSPEC_TBL, d->op0, force_reg (sel_mode, sel));
diff --git a/gcc/config/s390/s390.c b/gcc/config/s390/s390.c
index c761158..8cb19ea 100644
--- a/gcc/config/s390/s390.c
+++ b/gcc/config/s390/s390.c
@@ -6653,7 +6653,7 @@ s390_expand_vec_compare_cc (rtx target, enum rtx_code code,
 	case LE:   cc_producer_mode = CCVFHEmode; code = GE; swap_p = true; break;
 	default: gcc_unreachable ();
 	}
-      scratch_mode = mode_for_int_vector (GET_MODE (cmp1)).require ();
+      scratch_mode = related_int_vector_mode (GET_MODE (cmp1)).require ();
 
       if (inv_p)
 	all_p = !all_p;
@@ -6759,7 +6759,7 @@ s390_expand_vcond (rtx target, rtx then, rtx els,
 
   /* We always use an integral type vector to hold the comparison
      result.  */
-  result_mode = mode_for_int_vector (cmp_mode).require ();
+  result_mode = related_int_vector_mode (cmp_mode).require ();
   result_target = gen_reg_rtx (result_mode);
 
   /* We allow vector immediates as comparison operands that
diff --git a/gcc/machmode.h b/gcc/machmode.h
index 906b216..6750833 100644
--- a/gcc/machmode.h
+++ b/gcc/machmode.h
@@ -879,22 +879,9 @@ smallest_int_mode_for_size (poly_uint64 size)
 extern opt_scalar_int_mode int_mode_for_mode (machine_mode);
 extern opt_machine_mode bitwise_mode_for_mode (machine_mode);
 extern opt_machine_mode mode_for_vector (scalar_mode, poly_uint64);
-extern opt_machine_mode mode_for_int_vector (unsigned int, poly_uint64);
 extern opt_machine_mode related_vector_mode (machine_mode, scalar_mode,
 					     poly_uint64 = 0);
-
-/* 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));
-}
+extern opt_machine_mode related_int_vector_mode (machine_mode);
 
 /* A class for iterating through possible bitfield modes.  */
 class bit_field_mode_iterator
diff --git a/gcc/optabs.c b/gcc/optabs.c
index d6701df..3c3dd9e 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -5542,7 +5542,7 @@ expand_vec_perm_1 (enum insn_code icode, rtx target,
   class expand_operand ops[4];
 
   gcc_assert (GET_MODE_CLASS (smode) == MODE_VECTOR_INT
-	      || mode_for_int_vector (tmode).require () == smode);
+	      || related_int_vector_mode (tmode).require () == smode);
   create_output_operand (&ops[0], target, tmode);
   create_input_operand (&ops[3], sel, smode);
 
@@ -5679,8 +5679,7 @@ expand_vec_perm_const (machine_mode mode, rtx v0, rtx v1,
   /* The optabs are only defined for selectors with the same width
      as the values being permuted.  */
   machine_mode required_sel_mode;
-  if (!mode_for_int_vector (mode).exists (&required_sel_mode)
-      || !VECTOR_MODE_P (required_sel_mode))
+  if (!related_int_vector_mode (mode).exists (&required_sel_mode))
     {
       delete_insns_since (last);
       return NULL_RTX;
diff --git a/gcc/stor-layout.c b/gcc/stor-layout.c
index c1b724f..7d00364 100644
--- a/gcc/stor-layout.c
+++ b/gcc/stor-layout.c
@@ -515,21 +515,6 @@ mode_for_vector (scalar_mode innermode, poly_uint64 nunits)
   return opt_machine_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, poly_uint64 nunits)
-{
-  scalar_int_mode int_mode;
-  machine_mode vec_mode;
-  if (int_mode_for_size (int_bits, 0).exists (&int_mode)
-      && mode_for_vector (int_mode, nunits).exists (&vec_mode))
-    return vec_mode;
-  return opt_machine_mode ();
-}
-
 /* If a piece of code is using vector mode VECTOR_MODE and also wants
    to operate on elements of mode ELEMENT_MODE, return the vector mode
    it should use for those elements.  If NUNITS is nonzero, ensure that
@@ -550,6 +535,26 @@ related_vector_mode (machine_mode vector_mode, scalar_mode element_mode,
   return targetm.vectorize.related_mode (vector_mode, element_mode, nunits);
 }
 
+/* If a piece of code is using vector mode VECTOR_MODE and also wants
+   to operate on integer vectors with the same element size and number
+   of elements, return the vector mode it should use.  Return an empty
+   opt_machine_mode if there is no supported vector mode with the
+   required properties.
+
+   Unlike mode_for_vector. any returned mode is guaranteed to satisfy
+   both VECTOR_MODE_P and targetm.vector_mode_supported_p.  */
+
+opt_machine_mode
+related_int_vector_mode (machine_mode vector_mode)
+{
+  gcc_assert (VECTOR_MODE_P (vector_mode));
+  scalar_int_mode int_mode;
+  if (int_mode_for_mode (GET_MODE_INNER (vector_mode)).exists (&int_mode))
+    return related_vector_mode (vector_mode, int_mode,
+				GET_MODE_NUNITS (vector_mode));
+  return opt_machine_mode ();
+}
+
 /* Return the alignment of MODE. This will be bounded by 1 and
    BIGGEST_ALIGNMENT.  */