--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.word/src/org/graalvm/compiler/word/nodes/WordCastNode.java	2016-12-09 00:57:32.236599989 -0800
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2013, 2015, 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.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package org.graalvm.compiler.word.nodes;
+
+import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;
+import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;
+
+import org.graalvm.compiler.core.common.LIRKind;
+import org.graalvm.compiler.core.common.type.AbstractPointerStamp;
+import org.graalvm.compiler.core.common.type.ObjectStamp;
+import org.graalvm.compiler.core.common.type.Stamp;
+import org.graalvm.compiler.core.common.type.StampFactory;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeClass;
+import org.graalvm.compiler.graph.spi.Canonicalizable;
+import org.graalvm.compiler.graph.spi.CanonicalizerTool;
+import org.graalvm.compiler.nodeinfo.NodeInfo;
+import org.graalvm.compiler.nodes.ConstantNode;
+import org.graalvm.compiler.nodes.FixedWithNextNode;
+import org.graalvm.compiler.nodes.ValueNode;
+import org.graalvm.compiler.nodes.spi.LIRLowerable;
+import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
+import org.graalvm.compiler.word.Word.Opcode;
+
+import jdk.vm.ci.meta.AllocatableValue;
+import jdk.vm.ci.meta.JavaConstant;
+import jdk.vm.ci.meta.JavaKind;
+import jdk.vm.ci.meta.Value;
+import jdk.vm.ci.meta.ValueKind;
+
+/**
+ * Casts between Word and Object exposed by the {@link Opcode#FROM_ADDRESS},
+ * {@link Opcode#OBJECT_TO_TRACKED}, {@link Opcode#OBJECT_TO_UNTRACKED} and {@link Opcode#TO_OBJECT}
+ * operations. It has an impact on the pointer maps for the GC, so it must not be scheduled or
+ * optimized away.
+ */
+@NodeInfo(cycles = CYCLES_1, size = SIZE_1)
+public final class WordCastNode extends FixedWithNextNode implements LIRLowerable, Canonicalizable {
+
+    public static final NodeClass<WordCastNode> TYPE = NodeClass.create(WordCastNode.class);
+
+    @Input ValueNode input;
+    public final boolean trackedPointer;
+
+    public static WordCastNode wordToObject(ValueNode input, JavaKind wordKind) {
+        assert input.getStackKind() == wordKind;
+        return new WordCastNode(StampFactory.object(), input);
+    }
+
+    public static WordCastNode addressToWord(ValueNode input, JavaKind wordKind) {
+        assert input.stamp() instanceof AbstractPointerStamp;
+        return new WordCastNode(StampFactory.forKind(wordKind), input);
+    }
+
+    public static WordCastNode objectToTrackedPointer(ValueNode input, JavaKind wordKind) {
+        assert input.stamp() instanceof ObjectStamp;
+        return new WordCastNode(StampFactory.forKind(wordKind), input, true);
+    }
+
+    public static WordCastNode objectToUntrackedPointer(ValueNode input, JavaKind wordKind) {
+        assert input.stamp() instanceof ObjectStamp;
+        return new WordCastNode(StampFactory.forKind(wordKind), input, false);
+    }
+
+    protected WordCastNode(Stamp stamp, ValueNode input) {
+        this(stamp, input, true);
+    }
+
+    protected WordCastNode(Stamp stamp, ValueNode input, boolean trackedPointer) {
+        super(TYPE, stamp);
+        this.input = input;
+        this.trackedPointer = trackedPointer;
+    }
+
+    public ValueNode getInput() {
+        return input;
+    }
+
+    @Override
+    public Node canonical(CanonicalizerTool tool) {
+        if (tool.allUsagesAvailable() && hasNoUsages()) {
+            /* If the cast is unused, it can be eliminated. */
+            return input;
+        }
+
+        assert !stamp().isCompatible(input.stamp());
+        if (input.isConstant()) {
+            /* Null pointers are uncritical for GC, so they can be constant folded. */
+            if (input.asJavaConstant().isNull()) {
+                return ConstantNode.forIntegerStamp(stamp(), 0);
+            } else if (input.asJavaConstant().getJavaKind().isNumericInteger() && input.asJavaConstant().asLong() == 0) {
+                return ConstantNode.forConstant(stamp(), JavaConstant.NULL_POINTER, tool.getMetaAccess());
+            }
+        }
+
+        return this;
+    }
+
+    @Override
+    public void generate(NodeLIRBuilderTool generator) {
+        Value value = generator.operand(input);
+        ValueKind<?> kind = generator.getLIRGeneratorTool().getLIRKind(stamp());
+        assert kind.getPlatformKind().getSizeInBytes() == value.getPlatformKind().getSizeInBytes();
+
+        if (trackedPointer && LIRKind.isValue(kind) && !LIRKind.isValue(value)) {
+            // just change the PlatformKind, but don't drop reference information
+            kind = value.getValueKind().changeType(kind.getPlatformKind());
+        }
+
+        if (kind.equals(value.getValueKind())) {
+            generator.setResult(this, value);
+        } else {
+            AllocatableValue result = generator.getLIRGeneratorTool().newVariable(kind);
+            generator.getLIRGeneratorTool().emitMove(result, value);
+            generator.setResult(this, result);
+        }
+    }
+}