--- a/src/hotspot/share/opto/phaseX.cpp	Tue Nov 06 10:10:18 2018 -0800
+++ b/src/hotspot/share/opto/phaseX.cpp	Tue Nov 06 23:03:05 2018 +0100
@@ -769,6 +769,22 @@
 
 
 //=============================================================================
+Node* PhaseGVN::apply_ideal(Node* k, bool can_reshape) {
+  Node* i = BarrierSet::barrier_set()->barrier_set_c2()->ideal_node(this, k, can_reshape);
+  if (i == NULL) {
+    i = k->Ideal(this, can_reshape);
+  }
+  return i;
+}
+
+Node* PhaseGVN::apply_identity(Node* k) {
+  Node* i = BarrierSet::barrier_set()->barrier_set_c2()->identity_node(this, k);
+  if (i == k) {
+    i = k->Identity(this);
+  }
+  return i;
+}
+
 //------------------------------transform--------------------------------------
 // Return a node which computes the same function as this node, but in a
 // faster or cheaper fashion.
@@ -786,7 +802,7 @@
   Node *k = n;
   NOT_PRODUCT( uint loop_count = 0; )
   while( 1 ) {
-    Node *i = k->Ideal(this, /*can_reshape=*/false);
+    Node *i = apply_ideal(k, /*can_reshape=*/false);
     if( !i ) break;
     assert( i->_idx >= k->_idx, "Idealize should return new nodes, use Identity to return old nodes" );
     k = i;
@@ -823,7 +839,7 @@
   }
 
   // Now check for Identities
-  Node *i = k->Identity(this);  // Look for a nearby replacement
+  Node *i = apply_identity(k);  // Look for a nearby replacement
   if( i != k ) {                // Found? Return replacement!
     NOT_PRODUCT( set_progress(); )
     return i;
@@ -1213,7 +1229,7 @@
   DEBUG_ONLY(dead_loop_check(k);)
   DEBUG_ONLY(bool is_new = (k->outcnt() == 0);)
   C->remove_modified_node(k);
-  Node* i = k->Ideal(this, /*can_reshape=*/true);
+  Node* i = apply_ideal(k, /*can_reshape=*/true);
   assert(i != k || is_new || i->outcnt() > 0, "don't return dead nodes");
 #ifndef PRODUCT
   verify_step(k);
@@ -1255,7 +1271,7 @@
     // Try idealizing again
     DEBUG_ONLY(is_new = (k->outcnt() == 0);)
     C->remove_modified_node(k);
-    i = k->Ideal(this, /*can_reshape=*/true);
+    i = apply_ideal(k, /*can_reshape=*/true);
     assert(i != k || is_new || (i->outcnt() > 0), "don't return dead nodes");
 #ifndef PRODUCT
     verify_step(k);
@@ -1297,7 +1313,7 @@
   }
 
   // Now check for Identities
-  i = k->Identity(this);      // Look for a nearby replacement
+  i = apply_identity(k);      // Look for a nearby replacement
   if (i != k) {                // Found? Return replacement!
     NOT_PRODUCT(set_progress();)
     add_users_to_worklist(k);