src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.graph/src/org/graalvm/compiler/graph/spi/Canonicalizable.java

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  /*
!  * Copyright (c) 2011, 2018, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
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  /*
!  * Copyright (c) 2011, 2019, Oracle and/or its affiliates. All rights reserved.
   * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   *
   * This code is free software; you can redistribute it and/or modify it
   * under the terms of the GNU General Public License version 2 only, as
   * published by the Free Software Foundation.
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           *
           * @return the original node or another node with the same input ordering
           */
          Node maybeCommuteInputs();
      }
+ 
+     /**
+      * This sub-interface of {@link Canonicalizable} is intended for nodes that have exactly three
+      * inputs. It has an additional {@link #canonical(CanonicalizerTool, Node, Node, Node)} method
+      * that looks at the given inputs instead of the current inputs of the node - which can be used
+      * to ask "what if this input is changed to this node" - questions.
+      *
+      * @param <T> the common supertype of all inputs of this node
+      */
+     public interface Ternary<T extends Node> extends Canonicalizable {
+ 
+         /**
+          * Similar to {@link Canonicalizable#canonical(CanonicalizerTool)}, except that
+          * implementations should act as if the current input of the node was the given one, i.e.,
+          * they should never look at the inputs via the this pointer.
+          */
+         Node canonical(CanonicalizerTool tool, T forX, T forY, T forZ);
+ 
+         /**
+          * Gets the current value of the input, so that calling
+          * {@link #canonical(CanonicalizerTool, Node, Node, Node)} with the value returned from this
+          * method should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+          */
+         T getX();
+ 
+         /**
+          * Gets the current value of the input, so that calling
+          * {@link #canonical(CanonicalizerTool, Node, Node, Node)} with the value returned from this
+          * method should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+          */
+         T getY();
+ 
+         /**
+          * Gets the current value of the input, so that calling
+          * {@link #canonical(CanonicalizerTool, Node, Node, Node)} with the value returned from this
+          * method should behave exactly like {@link Canonicalizable#canonical(CanonicalizerTool)}.
+          */
+         T getZ();
+ 
+         @SuppressWarnings("unchecked")
+         @Override
+         default T canonical(CanonicalizerTool tool) {
+             return (T) canonical(tool, getX(), getY(), getZ());
+         }
+     }
  }