poly_int: two-operation SLP

This patch makes two-operation SLP handle but reject variable-length
vectors.  Adding support for this is a post-GCC8 thing.

2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* tree-vect-slp.c (vect_build_slp_tree_1): Handle polynomial
	numbers of units.
	(vect_schedule_slp_instance): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>
From-SVN: r256141

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c25eb15242cb6f84e06e040df3fb02d48bac7b46..992ad1d9bf8b275c93e3788cef2cf86927026fbc 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,11 @@
+2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
+           Alan Hayward  <alan.hayward@arm.com>
+           David Sherwood  <david.sherwood@arm.com>
+
+       * tree-vect-slp.c (vect_build_slp_tree_1): Handle polynomial
+       numbers of units.
+       (vect_schedule_slp_instance): Likewise.
+
 2018-01-03  Richard Sandiford  <richard.sandiford@linaro.org>
            Alan Hayward  <alan.hayward@arm.com>
            David Sherwood  <david.sherwood@arm.com>

diff --git a/gcc/tree-vect-slp.c b/gcc/tree-vect-slp.c
index 4aa816f7886305e103c7807219003ce38613c5f3..391b3ea1d8836fe31a1b80bc3ef7b74c173b96ed 100644 (file)
--- a/gcc/tree-vect-slp.c
+++ b/gcc/tree-vect-slp.c
@@ -905,10 +905,19 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
 
   /* If we allowed a two-operation SLP node verify the target can cope
      with the permute we are going to use.  */
+  poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vectype);
   if (alt_stmt_code != ERROR_MARK
       && TREE_CODE_CLASS (alt_stmt_code) != tcc_reference)
     {
-      unsigned int count = TYPE_VECTOR_SUBPARTS (vectype);
+      unsigned HOST_WIDE_INT count;
+      if (!nunits.is_constant (&count))
+       {
+         if (dump_enabled_p ())
+           dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+                            "Build SLP failed: different operations "
+                            "not allowed with variable-length SLP.\n");
+         return false;
+       }
       vec_perm_builder sel (count, count, 1);
       for (i = 0; i < count; ++i)
        {
@@ -3824,6 +3833,7 @@ vect_schedule_slp_instance (slp_tree node, slp_instance instance,
 
   /* VECTYPE is the type of the destination.  */
   vectype = STMT_VINFO_VECTYPE (stmt_info);
+  poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vectype);
   group_size = SLP_INSTANCE_GROUP_SIZE (instance);
 
   if (!SLP_TREE_VEC_STMTS (node).exists ())
@@ -3886,13 +3896,16 @@ vect_schedule_slp_instance (slp_tree node, slp_instance instance,
          unsigned k = 0, l;
          for (j = 0; j < v0.length (); ++j)
            {
-             unsigned int nunits = TYPE_VECTOR_SUBPARTS (vectype);
-             tree_vector_builder melts (mvectype, nunits, 1);
-             for (l = 0; l < nunits; ++l)
+             /* Enforced by vect_build_slp_tree, which rejects variable-length
+                vectors for SLP_TREE_TWO_OPERATORS.  */
+             unsigned int const_nunits = nunits.to_constant ();
+             tree_vector_builder melts (mvectype, const_nunits, 1);
+             for (l = 0; l < const_nunits; ++l)
                {
                  if (k >= group_size)
                    k = 0;
-                 tree t = build_int_cst (meltype, mask[k++] * nunits + l);
+                 tree t = build_int_cst (meltype,
+                                         mask[k++] * const_nunits + l);
                  melts.quick_push (t);
                }
              tmask = melts.build ();