--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/AbstractBeginNode.java	2017-02-15 17:06:28.791202619 -0800
@@ -0,0 +1,145 @@
+/*
+ * Copyright (c) 2011, 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.nodes;
+
+import java.util.Iterator;
+import java.util.NoSuchElementException;
+
+import org.graalvm.compiler.core.common.type.Stamp;
+import org.graalvm.compiler.core.common.type.StampFactory;
+import org.graalvm.compiler.graph.IterableNodeType;
+import org.graalvm.compiler.graph.Node;
+import org.graalvm.compiler.graph.NodeClass;
+import org.graalvm.compiler.graph.iterators.NodeIterable;
+import org.graalvm.compiler.nodeinfo.InputType;
+import org.graalvm.compiler.nodeinfo.NodeInfo;
+import org.graalvm.compiler.nodes.extended.AnchoringNode;
+import org.graalvm.compiler.nodes.extended.GuardingNode;
+import org.graalvm.compiler.nodes.spi.LIRLowerable;
+import org.graalvm.compiler.nodes.spi.NodeLIRBuilderTool;
+
+@NodeInfo(allowedUsageTypes = {InputType.Guard, InputType.Anchor})
+public abstract class AbstractBeginNode extends FixedWithNextNode implements LIRLowerable, GuardingNode, AnchoringNode, IterableNodeType {
+
+    public static final NodeClass<AbstractBeginNode> TYPE = NodeClass.create(AbstractBeginNode.class);
+
+    protected AbstractBeginNode(NodeClass<? extends AbstractBeginNode> c) {
+        this(c, StampFactory.forVoid());
+    }
+
+    protected AbstractBeginNode(NodeClass<? extends AbstractBeginNode> c, Stamp stamp) {
+        super(c, stamp);
+    }
+
+    public static AbstractBeginNode prevBegin(FixedNode from) {
+        Node next = from;
+        while (next != null) {
+            if (next instanceof AbstractBeginNode) {
+                AbstractBeginNode begin = (AbstractBeginNode) next;
+                return begin;
+            }
+            next = next.predecessor();
+        }
+        return null;
+    }
+
+    private void evacuateGuards(FixedNode evacuateFrom) {
+        if (!hasNoUsages()) {
+            AbstractBeginNode prevBegin = prevBegin(evacuateFrom);
+            assert prevBegin != null;
+            for (Node anchored : anchored().snapshot()) {
+                anchored.replaceFirstInput(this, prevBegin);
+            }
+        }
+    }
+
+    public void prepareDelete() {
+        prepareDelete((FixedNode) predecessor());
+    }
+
+    public void prepareDelete(FixedNode evacuateFrom) {
+        evacuateGuards(evacuateFrom);
+    }
+
+    @Override
+    public boolean verify() {
+        assertTrue(predecessor() != null || this == graph().start() || this instanceof AbstractMergeNode, "begin nodes must be connected");
+        return super.verify();
+    }
+
+    @Override
+    public void generate(NodeLIRBuilderTool gen) {
+        // nop
+    }
+
+    public NodeIterable<GuardNode> guards() {
+        return usages().filter(GuardNode.class);
+    }
+
+    public NodeIterable<Node> anchored() {
+        return usages();
+    }
+
+    public NodeIterable<FixedNode> getBlockNodes() {
+        return new NodeIterable<FixedNode>() {
+
+            @Override
+            public Iterator<FixedNode> iterator() {
+                return new BlockNodeIterator(AbstractBeginNode.this);
+            }
+        };
+    }
+
+    private class BlockNodeIterator implements Iterator<FixedNode> {
+
+        private FixedNode current;
+
+        BlockNodeIterator(FixedNode next) {
+            this.current = next;
+        }
+
+        @Override
+        public boolean hasNext() {
+            return current != null;
+        }
+
+        @Override
+        public FixedNode next() {
+            FixedNode ret = current;
+            if (ret == null) {
+                throw new NoSuchElementException();
+            }
+            if (!(current instanceof FixedWithNextNode) || (current instanceof AbstractBeginNode && current != AbstractBeginNode.this)) {
+                current = null;
+            } else {
+                current = ((FixedWithNextNode) current).next();
+            }
+            return ret;
+        }
+
+        @Override
+        public void remove() {
+            throw new UnsupportedOperationException();
+        }
+    }
+}