src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/ValueNode.java

*** 20,35 ****
--- 20,38 ----
   * or visit www.oracle.com if you need additional information or have any
   * questions.
   */
  package org.graalvm.compiler.nodes;
  
+ import java.util.function.Predicate;
+ 
  import org.graalvm.compiler.core.common.type.Stamp;
  import org.graalvm.compiler.graph.Node;
  import org.graalvm.compiler.graph.NodeClass;
  import org.graalvm.compiler.graph.iterators.NodePredicate;
  import org.graalvm.compiler.nodeinfo.InputType;
  import org.graalvm.compiler.nodeinfo.NodeInfo;
+ import org.graalvm.compiler.nodeinfo.Verbosity;
  import org.graalvm.compiler.nodes.spi.NodeValueMap;
  
  import jdk.vm.ci.meta.Constant;
  import jdk.vm.ci.meta.JavaConstant;
  import jdk.vm.ci.meta.JavaKind;
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          } else {
              return null;
          }
      }
  
+     public final boolean isJavaConstant() {
+         return isConstant() && asConstant() instanceof JavaConstant;
+     }
+ 
      public final JavaConstant asJavaConstant() {
          Constant value = asConstant();
          if (value instanceof JavaConstant) {
              return (JavaConstant) value;
          } else {
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              }
          }
          return false;
      }
  
+     @Override
+     protected void replaceAtUsages(Node other, Predicate<Node> filter, Node toBeDeleted) {
+         super.replaceAtUsages(other, filter, toBeDeleted);
+         assert checkReplaceAtUsagesInvariants(other);
+     }
+ 
+     private boolean checkReplaceAtUsagesInvariants(Node other) {
+         assert other == null || other instanceof ValueNode;
+         if (this.hasUsages() && !this.stamp().isEmpty() && !(other instanceof PhiNode) && other != null) {
+             assert ((ValueNode) other).stamp().getClass() == stamp().getClass() : "stamp have to be of same class";
+             boolean morePrecise = ((ValueNode) other).stamp().join(stamp()).equals(((ValueNode) other).stamp());
+             assert morePrecise : "stamp can only get more precise " + toString(Verbosity.All) + " " +
+                             other.toString(Verbosity.All);
+         }
+         return true;
+     }
  }