--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/type/StampPair.java	2019-03-12 08:08:45.643248773 +0100
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/type/StampPair.java	2019-03-12 08:08:45.271246353 +0100
@@ -24,6 +24,8 @@
 
 package org.graalvm.compiler.core.common.type;
 
+import java.util.Objects;
+
 /**
  * A pair of stamp with one being the stamp that can be trusted and the other one being a guess that
  * needs a dynamic check to be used.
@@ -63,4 +65,22 @@
             return trustedStamp + " (unchecked=" + uncheckedStamp + ")";
         }
     }
+
+    @Override
+    public int hashCode() {
+        return trustedStamp.hashCode() + 11 + (uncheckedStamp != null ? uncheckedStamp.hashCode() : 0);
+
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (obj == this) {
+            return true;
+        }
+        if (obj instanceof StampPair) {
+            StampPair other = (StampPair) obj;
+            return trustedStamp.equals(other.trustedStamp) && Objects.equals(uncheckedStamp, other.uncheckedStamp);
+        }
+        return false;
+    }
 }