Re: [072/nnn] poly_int: vectorizable_live_operation

[Jeff Law]

On 10/23/2017 11:29 AM, Richard Sandiford wrote:
> This patch makes vectorizable_live_operation cope with variable-length
> vectors.  For now we just handle cases in which we can tell at compile
> time which vector contains the final result.
> 
> 
> 2017-10-23  Richard Sandiford  
>   Alan Hayward  
>   David Sherwood  
> 
> gcc/
>   * tree-vect-loop.c (vectorizable_live_operation): Treat the number
>   of units as polynomial.  Punt if we can't tell at compile time
>   which vector contains the final result.
OK.
jeff

[072/nnn] poly_int: vectorizable_live_operation

[Richard Sandiford]

This patch makes vectorizable_live_operation cope with variable-length
vectors.  For now we just handle cases in which we can tell at compile
time which vector contains the final result.


2017-10-23  Richard Sandiford  
Alan Hayward  
David Sherwood  

gcc/
* tree-vect-loop.c (vectorizable_live_operation): Treat the number
of units as polynomial.  Punt if we can't tell at compile time
which vector contains the final result.

Index: gcc/tree-vect-loop.c
===
--- gcc/tree-vect-loop.c2017-10-23 17:22:36.904793787 +0100
+++ gcc/tree-vect-loop.c2017-10-23 17:22:37.879692661 +0100
@@ -7132,10 +7132,12 @@ vectorizable_live_operation (gimple *stm
   imm_use_iterator imm_iter;
   tree lhs, lhs_type, bitsize, vec_bitsize;
   tree vectype = STMT_VINFO_VECTYPE (stmt_info);
-  int nunits = TYPE_VECTOR_SUBPARTS (vectype);
+  poly_uint64 nunits = TYPE_VECTOR_SUBPARTS (vectype);
   int ncopies;
   gimple *use_stmt;
   auto_vec vec_oprnds;
+  int vec_entry = 0;
+  poly_uint64 vec_index = 0;
 
   gcc_assert (STMT_VINFO_LIVE_P (stmt_info));
 
@@ -7164,6 +7166,30 @@ vectorizable_live_operation (gimple *stm
   else
 ncopies = vect_get_num_copies (loop_vinfo, vectype);
 
+  if (slp_node)
+{
+  gcc_assert (slp_index >= 0);
+
+  int num_scalar = SLP_TREE_SCALAR_STMTS (slp_node).length ();
+  int num_vec = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node);
+
+  /* Get the last occurrence of the scalar index from the concatenation of
+all the slp vectors. Calculate which slp vector it is and the index
+within.  */
+  poly_uint64 pos = (num_vec * nunits) - num_scalar + slp_index;
+
+  /* Calculate which vector contains the result, and which lane of
+that vector we need.  */
+  if (!can_div_trunc_p (pos, nunits, _entry, _index))
+   {
+ if (dump_enabled_p ())
+   dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
+"Cannot determine which vector holds the"
+" final result.\n");
+ return false;
+   }
+}
+
   if (!vec_stmt)
 /* No transformation required.  */
 return true;
@@ -7185,18 +7211,6 @@ vectorizable_live_operation (gimple *stm
   tree vec_lhs, bitstart;
   if (slp_node)
 {
-  gcc_assert (slp_index >= 0);
-
-  int num_scalar = SLP_TREE_SCALAR_STMTS (slp_node).length ();
-  int num_vec = SLP_TREE_NUMBER_OF_VEC_STMTS (slp_node);
-
-  /* Get the last occurrence of the scalar index from the concatenation of
-all the slp vectors. Calculate which slp vector it is and the index
-within.  */
-  int pos = (num_vec * nunits) - num_scalar + slp_index;
-  int vec_entry = pos / nunits;
-  int vec_index = pos % nunits;
-
   /* Get the correct slp vectorized stmt.  */
   vec_lhs = gimple_get_lhs (SLP_TREE_VEC_STMTS (slp_node)[vec_entry]);