--- /dev/null	2017-01-22 10:16:57.869617664 -0800
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/cfg/Loop.java	2017-02-15 16:57:05.527658243 -0800
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2012, 2012, 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.core.common.cfg;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public abstract class Loop<T extends AbstractBlockBase<T>> {
+
+    private final Loop<T> parent;
+    private final List<Loop<T>> children;
+
+    private final int depth;
+    private final int index;
+    private final T header;
+    private final List<T> blocks;
+    private final List<T> exits;
+
+    protected Loop(Loop<T> parent, int index, T header) {
+        this.parent = parent;
+        if (parent != null) {
+            this.depth = parent.getDepth() + 1;
+            parent.getChildren().add(this);
+        } else {
+            this.depth = 1;
+        }
+        this.index = index;
+        this.header = header;
+        this.blocks = new ArrayList<>();
+        this.children = new ArrayList<>();
+        this.exits = new ArrayList<>();
+    }
+
+    public abstract long numBackedges();
+
+    @Override
+    public String toString() {
+        return "loop " + index + " depth " + getDepth() + (parent != null ? " outer " + parent.index : "");
+    }
+
+    public Loop<T> getParent() {
+        return parent;
+    }
+
+    public List<Loop<T>> getChildren() {
+        return children;
+    }
+
+    public int getDepth() {
+        return depth;
+    }
+
+    public int getIndex() {
+        return index;
+    }
+
+    public T getHeader() {
+        return header;
+    }
+
+    public List<T> getBlocks() {
+        return blocks;
+    }
+
+    public List<T> getExits() {
+        return exits;
+    }
+
+    /**
+     * Determines if one loop is a transitive parent of another loop.
+     *
+     * @param childLoop The loop for which parentLoop might be a transitive parent loop.
+     * @param parentLoop The loop which might be a transitive parent loop of child loop.
+     * @return {@code true} if parentLoop is a (transitive) parent loop of childLoop, {@code false}
+     *         otherwise
+     */
+    public static <T extends AbstractBlockBase<T>> boolean transitiveParentLoop(Loop<T> childLoop, Loop<T> parentLoop) {
+        Loop<T> curr = childLoop;
+        while (curr != null) {
+            if (curr == parentLoop) {
+                return true;
+            }
+            curr = curr.getParent();
+        }
+        return false;
+    }
+}