[PATCH v2 5/5] vect: Cost niter conditions.

From: Robin Dapp <[email protected]>

This patch adjusts niter-condition costing.  Instead of just one
vector statements, it counts the number of ANDed terms and costs
that many scalar statements.

gcc/ChangeLog:

	* tree-vect-loop.cc (vect_estimate_min_profitable_iters): Adjust
	niter condition costing.
---
 gcc/tree-vect-loop.cc | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/gcc/tree-vect-loop.cc b/gcc/tree-vect-loop.cc
index 54f8912b894..410bf7aca4b 100644
--- a/gcc/tree-vect-loop.cc
+++ b/gcc/tree-vect-loop.cc
@@ -4128,8 +4128,23 @@ vect_estimate_min_profitable_iters (loop_vec_info loop_vinfo,
   /* Requires loop versioning with niter checks.  */
   if (LOOP_REQUIRES_VERSIONING_FOR_NITERS (loop_vinfo))
     {
+      tree assum = LOOP_VINFO_NITERS_ASSUMPTIONS (loop_vinfo);
+
+      /* Count the ANDs and comparisons in the assumption tree.  */
+      auto count_conditions = [] (tree *t, int *, void *nconditions) -> tree
+	{
+	  if (EXPR_P (*t)
+	      && (TREE_CODE (*t) == BIT_AND_EXPR
+		  || TREE_CODE_CLASS (TREE_CODE (*t)) == tcc_comparison))
+	    (*(int *) nconditions)++;
+	  return NULL_TREE;
+	};
+
+      int nconditions = 0;
+      walk_tree_without_duplicates (&assum, count_conditions, &nconditions);
+
       /*  FIXME: Make cost depend on complexity of individual check.  */
-      (void) add_stmt_cost (target_cost_data, 1, vector_stmt,
+      (void) add_stmt_cost (target_cost_data, nconditions, scalar_stmt,
 			    NULL, NULL, NULL_TREE, 0, vect_prologue);
       if (dump_enabled_p ())
 	dump_printf (MSG_NOTE,
-- 
2.54.0