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

*** 89,96 ****
--- 89,108 ----
       *
       * @param thisNegated whether this condition should be considered as false.
       * @param other the other condition.
       */
      public TriState implies(boolean thisNegated, LogicNode other) {
+         if (this == other) {
+             return TriState.get(!thisNegated);
+         }
+         if (other instanceof LogicNegationNode) {
+             return flip(this.implies(thisNegated, ((LogicNegationNode) other).getValue()));
+         }
          return TriState.UNKNOWN;
      }
+ 
+     private static TriState flip(TriState triState) {
+         return triState.isUnknown()
+                         ? triState
+                         : TriState.get(!triState.toBoolean());
+     }
  }