Check if transitives need to be registered.

Whenever a relation is added, register_transitive is always called.
If neither operand was in a relation before, or this is not a new
relation, then there is no need to register transitives.

	PR tree-optimization/106280
	* value-relation.cc (dom_oracle::register_relation): Register
	transitives only when it is possible for there to be one.
	(dom_oracle::set_one_relation): Return NULL if this is an
	existing relation.

diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index 13ce441..bd34425 100644 (file)
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -967,8 +967,12 @@ dom_oracle::register_relation (basic_block bb, relation_kind k, tree op1,
     equiv_oracle::register_relation (bb, k, op1, op2);
   else
     {
+      // if neither op1 nor op2 are in a relation before this is registered,
+      // there will be no transitive.
+      bool check = bitmap_bit_p (m_relation_set, SSA_NAME_VERSION (op1))
+                  || bitmap_bit_p (m_relation_set, SSA_NAME_VERSION (op2));
       relation_chain *ptr = set_one_relation (bb, k, op1, op2);
-      if (ptr)
+      if (ptr && check)
        register_transitives (bb, *ptr);
     }
 }
@@ -1010,13 +1014,16 @@ dom_oracle::set_one_relation (basic_block bb, relation_kind k, tree op1,
       // Check into whether we can simply replace the relation rather than
       // intersecting it.  THis may help with some optimistic iterative
       // updating algorithms.
-      ptr->intersect (vr);
+      bool new_rel = ptr->intersect (vr);
       if (dump_file && (dump_flags & TDF_DETAILS))
        {
          fprintf (dump_file, " to produce ");
          ptr->dump (dump_file);
-         fprintf (dump_file, "\n");
+         fprintf (dump_file, " %s.\n", new_rel ? "Updated" : "No Change");
        }
+      // If there was no change, return no record..
+      if (!new_rel)
+       return NULL;
     }
   else
     {