--- old/src/hotspot/share/opto/compile.cpp	2018-07-13 16:28:32.043666612 +0200
+++ new/src/hotspot/share/opto/compile.cpp	2018-07-13 16:28:31.763666616 +0200
@@ -4650,7 +4650,7 @@
 Node* Compile::optimize_acmp(PhaseGVN* phase, Node* a, Node* b) {
   if (a->is_ValueType() || b->is_ValueType()) {
     // Return constant false because one operand is a non-null value type
-    return phase->intcon(1);
+    return new CmpINode(phase->intcon(0), phase->intcon(1)); // We need to return a new node
   }
   const TypeInstPtr* ta = phase->type(a)->isa_instptr();
   const TypeInstPtr* tb = phase->type(b)->isa_instptr();
@@ -4663,7 +4663,7 @@
     if ((ta != NULL && !TypePtr::NULL_PTR->higher_equal(ta)) ||
         (tb != NULL && !TypePtr::NULL_PTR->higher_equal(tb))) {
       // One operand is never NULL, fold to constant false
-      return phase->intcon(1);
+      return new CmpINode(phase->intcon(0), phase->intcon(1)); // We need to return a new node
     } else {
       // Check if both operands are null by or'ing the oops
       a = phase->transform(new CastP2XNode(NULL, a));