--- /dev/null	2016-05-31 09:42:47.975716356 -0700
+++ new/src/jdk.vm.compiler/share/classes/org.graalvm.compiler.core.common/src/org/graalvm/compiler/core/common/cfg/AbstractControlFlowGraph.java	2016-12-09 00:47:09.822165092 -0800
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2014, 2014, 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.Collection;
+
+public interface AbstractControlFlowGraph<T extends AbstractBlockBase<T>> {
+
+    int BLOCK_ID_INITIAL = -1;
+    int BLOCK_ID_VISITED = -2;
+
+    /**
+     * Returns the list blocks contained in this control flow graph.
+     *
+     * It is {@linkplain CFGVerifier guaranteed} that the blocks are numbered and ordered according
+     * to a reverse post order traversal of the control flow graph.
+     *
+     * @see CFGVerifier
+     */
+    T[] getBlocks();
+
+    Collection<Loop<T>> getLoops();
+
+    T getStartBlock();
+
+    /**
+     * True if block {@code a} is dominated by block {@code b}.
+     */
+    static boolean isDominatedBy(AbstractBlockBase<?> a, AbstractBlockBase<?> b) {
+        int domNumberA = a.getDominatorNumber();
+        int domNumberB = b.getDominatorNumber();
+        return domNumberA >= domNumberB && domNumberA <= b.getMaxChildDominatorNumber();
+    }
+
+    /**
+     * True if block {@code a} dominates block {@code b} and {@code a} is not identical block to
+     * {@code b}.
+     */
+    static boolean strictlyDominates(AbstractBlockBase<?> a, AbstractBlockBase<?> b) {
+        return a != b && dominates(a, b);
+    }
+
+    /**
+     * True if block {@code a} dominates block {@code b}.
+     */
+    static boolean dominates(AbstractBlockBase<?> a, AbstractBlockBase<?> b) {
+        assert a != null && b != null;
+        return isDominatedBy(b, a);
+    }
+
+    /**
+     * Calculates the common dominator of two blocks.
+     *
+     * Note that this algorithm makes use of special properties regarding the numbering of blocks.
+     *
+     * @see #getBlocks()
+     * @see CFGVerifier
+     */
+    static AbstractBlockBase<?> commonDominator(AbstractBlockBase<?> a, AbstractBlockBase<?> b) {
+        if (a == null) {
+            return b;
+        } else if (b == null) {
+            return a;
+        } else {
+            int aDomDepth = a.getDominatorDepth();
+            int bDomDepth = b.getDominatorDepth();
+            AbstractBlockBase<?> aTemp;
+            AbstractBlockBase<?> bTemp;
+            if (aDomDepth > bDomDepth) {
+                aTemp = a;
+                bTemp = b;
+            } else {
+                aTemp = b;
+                bTemp = a;
+            }
+            return commonDominatorHelper(aTemp, bTemp);
+        }
+    }
+
+    static AbstractBlockBase<?> commonDominatorHelper(AbstractBlockBase<?> a, AbstractBlockBase<?> b) {
+        int domNumberA = a.getDominatorNumber();
+        AbstractBlockBase<?> result = b;
+        while (domNumberA < result.getDominatorNumber()) {
+            result = result.getDominator();
+        }
+        while (domNumberA > result.getMaxChildDominatorNumber()) {
+            result = result.getDominator();
+        }
+        return result;
+    }
+
+    /**
+     * @see AbstractControlFlowGraph#commonDominator(AbstractBlockBase, AbstractBlockBase)
+     */
+    @SuppressWarnings("unchecked")
+    static <T extends AbstractBlockBase<T>> T commonDominatorTyped(T a, T b) {
+        return (T) commonDominator(a, b);
+    }
+}