Refactor SLP reduction group discovery

The following refactors a bit how we perform SLP reduction group
discovery possibly making it easier to have multiple reduction
groups later, esp. with single-lane SLP.

	* tree-vect-slp.cc (vect_analyze_slp_instance): Remove
	slp_inst_kind_reduc_group handling.
	(vect_analyze_slp): Add the meat here.

diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 8c18f5308e2e16bc90d5f4e8b7ce9b1b4345707d..f34ed54a70b0343637a6a04fd363b96d30f9b579 100644 (file)
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -3586,7 +3586,6 @@ vect_analyze_slp_instance (vec_info *vinfo,
                           slp_instance_kind kind,
                           unsigned max_tree_size, unsigned *limit)
 {
-  unsigned int i;
   vec<stmt_vec_info> scalar_stmts;
 
   if (is_a <bb_vec_info> (vinfo))
@@ -3620,35 +3619,6 @@ vect_analyze_slp_instance (vec_info *vinfo,
       STMT_VINFO_REDUC_DEF (vect_orig_stmt (stmt_info))
        = STMT_VINFO_REDUC_DEF (vect_orig_stmt (scalar_stmts.last ()));
     }
-  else if (kind == slp_inst_kind_reduc_group)
-    {
-      /* Collect reduction statements.  */
-      const vec<stmt_vec_info> &reductions
-       = as_a <loop_vec_info> (vinfo)->reductions;
-      scalar_stmts.create (reductions.length ());
-      for (i = 0; reductions.iterate (i, &next_info); i++)
-       {
-         gassign *g;
-         next_info = vect_stmt_to_vectorize (next_info);
-         if ((STMT_VINFO_RELEVANT_P (next_info)
-              || STMT_VINFO_LIVE_P (next_info))
-             /* ???  Make sure we didn't skip a conversion around a reduction
-                path.  In that case we'd have to reverse engineer that
-                conversion stmt following the chain using reduc_idx and from
-                the PHI using reduc_def.  */
-             && STMT_VINFO_DEF_TYPE (next_info) == vect_reduction_def
-             /* Do not discover SLP reductions for lane-reducing ops, that
-                will fail later.  */
-             && (!(g = dyn_cast <gassign *> (STMT_VINFO_STMT (next_info)))
-                 || (gimple_assign_rhs_code (g) != DOT_PROD_EXPR
-                     && gimple_assign_rhs_code (g) != WIDEN_SUM_EXPR
-                     && gimple_assign_rhs_code (g) != SAD_EXPR)))
-           scalar_stmts.quick_push (next_info);
-       }
-      /* If less than two were relevant/live there's nothing to SLP.  */
-      if (scalar_stmts.length () < 2)
-       return false;
-    }
   else
     gcc_unreachable ();
 
@@ -3740,9 +3710,40 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size)
 
       /* Find SLP sequences starting from groups of reductions.  */
       if (loop_vinfo->reductions.length () > 1)
-       vect_analyze_slp_instance (vinfo, bst_map, loop_vinfo->reductions[0],
-                                  slp_inst_kind_reduc_group, max_tree_size,
-                                  &limit);
+       {
+         /* Collect reduction statements.  */
+         vec<stmt_vec_info> scalar_stmts;
+         scalar_stmts.create (loop_vinfo->reductions.length ());
+         for (auto next_info : loop_vinfo->reductions)
+           {
+             gassign *g;
+             next_info = vect_stmt_to_vectorize (next_info);
+             if ((STMT_VINFO_RELEVANT_P (next_info)
+                  || STMT_VINFO_LIVE_P (next_info))
+                 /* ???  Make sure we didn't skip a conversion around a
+                    reduction path.  In that case we'd have to reverse
+                    engineer that conversion stmt following the chain using
+                    reduc_idx and from the PHI using reduc_def.  */
+                 && STMT_VINFO_DEF_TYPE (next_info) == vect_reduction_def
+                 /* Do not discover SLP reductions for lane-reducing ops, that
+                    will fail later.  */
+                 && (!(g = dyn_cast <gassign *> (STMT_VINFO_STMT (next_info)))
+                     || (gimple_assign_rhs_code (g) != DOT_PROD_EXPR
+                         && gimple_assign_rhs_code (g) != WIDEN_SUM_EXPR
+                         && gimple_assign_rhs_code (g) != SAD_EXPR)))
+               scalar_stmts.quick_push (next_info);
+           }
+         if (scalar_stmts.length () > 1)
+           {
+             vec<stmt_vec_info> roots = vNULL;
+             vec<tree> remain = vNULL;
+             vect_build_slp_instance (loop_vinfo, slp_inst_kind_reduc_group,
+                                      scalar_stmts, roots, remain,
+                                      max_tree_size, &limit, bst_map, NULL);
+           }
+         else
+           scalar_stmts.release ();
+       }
     }
 
   hash_set<slp_tree> visited_patterns;