--- /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/DominatorOptimizationProblem.java	2016-12-09 00:47:10.624200435 -0800
@@ -0,0 +1,153 @@
+/*
+ * 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.Arrays;
+import java.util.BitSet;
+import java.util.EnumMap;
+import java.util.Set;
+import java.util.stream.Stream;
+
+/**
+ * This class represents a dominator tree problem, i.e. a problem which can be solved by traversing
+ * the dominator (sub-)tree.
+ *
+ * @param <E> An enum that describes the flags that can be associated with a block.
+ * @param <C> An arbitrary cost type that is associated with a block. It is intended to carry
+ *            information needed to calculate the solution. Note that {@code C} should not contain
+ *            boolean flags. Use an enum entry in {@code E} instead.
+ */
+public abstract class DominatorOptimizationProblem<E extends Enum<E>, C> {
+
+    private AbstractBlockBase<?>[] blocks;
+    private EnumMap<E, BitSet> flags;
+    private BlockMap<C> costs;
+
+    protected DominatorOptimizationProblem(Class<E> flagType, AbstractControlFlowGraph<?> cfg) {
+        this.blocks = cfg.getBlocks();
+        flags = new EnumMap<>(flagType);
+        costs = new BlockMap<>(cfg);
+        assert verify(blocks);
+    }
+
+    private static boolean verify(AbstractBlockBase<?>[] blocks) {
+        for (int i = 0; i < blocks.length; i++) {
+            AbstractBlockBase<?> block = blocks[i];
+            if (i != block.getId()) {
+                assert false : String.format("Id index mismatch @ %d vs. %s.getId()==%d", i, block, block.getId());
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public final AbstractBlockBase<?>[] getBlocks() {
+        return blocks;
+    }
+
+    public final AbstractBlockBase<?> getBlockForId(int id) {
+        AbstractBlockBase<?> block = blocks[id];
+        assert block.getId() == id : "wrong block-to-id mapping";
+        return block;
+    }
+
+    /**
+     * Sets a flag for a block.
+     */
+    public final void set(E flag, AbstractBlockBase<?> block) {
+        BitSet bitSet = flags.get(flag);
+        if (bitSet == null) {
+            bitSet = new BitSet(blocks.length);
+            flags.put(flag, bitSet);
+        }
+        bitSet.set(block.getId());
+    }
+
+    /**
+     * Checks whether a flag is set for a block.
+     */
+    public final boolean get(E flag, AbstractBlockBase<?> block) {
+        BitSet bitSet = flags.get(flag);
+        return bitSet == null ? false : bitSet.get(block.getId());
+    }
+
+    /**
+     * Returns a {@linkplain Stream} of blocks for which {@code flag} is set.
+     */
+    public final Stream<? extends AbstractBlockBase<?>> stream(E flag) {
+        return Arrays.asList(getBlocks()).stream().filter(block -> get(flag, block));
+    }
+
+    /**
+     * Returns the cost object associated with {@code block}. Might return {@code null} if not set.
+     */
+    public final C getCost(AbstractBlockBase<?> block) {
+        C cost = costs.get(block);
+        return cost;
+    }
+
+    /**
+     * Sets the cost for a {@code block}.
+     */
+    public final void setCost(AbstractBlockBase<?> block, C cost) {
+        costs.put(block, cost);
+    }
+
+    /**
+     * Sets {@code flag} for all blocks along the dominator path from {@code block} to the root
+     * until a block it finds a block where {@code flag} is already set.
+     */
+    public final void setDominatorPath(E flag, AbstractBlockBase<?> block) {
+        BitSet bitSet = flags.get(flag);
+        if (bitSet == null) {
+            bitSet = new BitSet(blocks.length);
+            flags.put(flag, bitSet);
+        }
+        for (AbstractBlockBase<?> b = block; b != null && !bitSet.get(b.getId()); b = b.getDominator()) {
+            // mark block
+            bitSet.set(b.getId());
+        }
+    }
+
+    /**
+     * Returns a {@link Stream} of flags associated with {@code block}.
+     */
+    public final Stream<E> getFlagsForBlock(AbstractBlockBase<?> block) {
+        return getFlags().stream().filter(flag -> get(flag, block));
+    }
+
+    /**
+     * Returns the {@link Set} of flags that can be set for this
+     * {@linkplain DominatorOptimizationProblem problem}.
+     */
+    public final Set<E> getFlags() {
+        return flags.keySet();
+    }
+
+    /**
+     * Returns the name of a flag.
+     */
+    public String getName(E flag) {
+        return flag.toString();
+    }
+}