Re: [078/nnn] poly_int: two-operation SLP

[Jeff Law]

On 10/23/2017 11:31 AM, Richard Sandiford wrote:
> This patch makes two-operation SLP handle but reject variable-length
> vectors.  Adding support for this is a post-GCC8 thing.
> 
> 
> 2017-10-23  Richard Sandiford  
>   Alan Hayward  
>   David Sherwood  
> 
> gcc/
>   * tree-vect-slp.c (vect_build_slp_tree_1): Handle polynomial
>   numbers of units.
>   (vect_schedule_slp_instance): Likewise.
OK.
jeff

[078/nnn] poly_int: two-operation SLP

[Richard Sandiford]

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


2017-10-23  Richard Sandiford  
Alan Hayward  
David Sherwood  

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

Index: gcc/tree-vect-slp.c
===
--- gcc/tree-vect-slp.c 2017-10-23 17:22:42.827179461 +0100
+++ gcc/tree-vect-slp.c 2017-10-23 17:22:43.865071801 +0100
@@ -903,10 +903,19 @@ vect_build_slp_tree_1 (vec_info *vinfo,
 
   /* 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 ())
+   {
+ 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;
+   }
   auto_vec_perm_indices sel (count);
   for (i = 0; i < count; ++i)
{
@@ -3796,6 +3805,7 @@ vect_schedule_slp_instance (slp_tree nod
 
   /* 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 ())
@@ -3858,13 +3868,16 @@ vect_schedule_slp_instance (slp_tree nod
  unsigned k = 0, l;
  for (j = 0; j < v0.length (); ++j)
{
- unsigned int nunits = TYPE_VECTOR_SUBPARTS (vectype);
- auto_vec melts (nunits);
- 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 ();
+ auto_vec melts (const_nunits);
+ 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 = build_vector (mvectype, melts);