--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.graal.virtual/src/com/oracle/graal/virtual/phases/ea/EffectsBlockState.java	Fri Jun 07 16:43:35 2013 +0200
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2011, 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 com.oracle.graal.virtual.phases.ea;
+
+import java.util.*;
+
+import com.oracle.graal.nodes.*;
+
+public abstract class EffectsBlockState<T extends EffectsBlockState<T>> {
+
+    protected final IdentityHashMap<ValueNode, ValueNode> scalarAliases;
+
+    protected EffectsBlockState() {
+        scalarAliases = new IdentityHashMap<>();
+    }
+
+    protected EffectsBlockState(EffectsBlockState<T> other) {
+        scalarAliases = new IdentityHashMap<>(other.scalarAliases);
+    }
+
+    public void addScalarAlias(ValueNode alias, ValueNode value) {
+        scalarAliases.put(alias, value);
+    }
+
+    public ValueNode getScalarAlias(ValueNode alias) {
+        ValueNode result = scalarAliases.get(alias);
+        return result == null ? alias : result;
+    }
+
+    @Override
+    public String toString() {
+        return "Scalar Aliases: " + scalarAliases.toString();
+    }
+
+    public void meetAliases(List<T> states) {
+        scalarAliases.putAll(states.get(0).scalarAliases);
+        for (int i = 1; i < states.size(); i++) {
+            EffectsBlockState<T> state = states.get(i);
+            meetMaps(scalarAliases, state.scalarAliases);
+        }
+    }
+
+    public boolean equivalentTo(T other) {
+        if (this == other) {
+            return true;
+        }
+        return scalarAliases.equals(other.scalarAliases);
+    }
+
+    protected static <K, V> boolean compareMaps(Map<K, V> left, Map<K, V> right) {
+        if (left.size() != right.size()) {
+            return false;
+        }
+        return compareMapsNoSize(left, right);
+    }
+
+    protected static <K, V> boolean compareMapsNoSize(Map<K, V> left, Map<K, V> right) {
+        if (left == right) {
+            return true;
+        }
+        for (Map.Entry<K, V> entry : right.entrySet()) {
+            K key = entry.getKey();
+            V value = entry.getValue();
+            assert value != null;
+            V otherValue = left.get(key);
+            if (otherValue != value && !value.equals(otherValue)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    protected static <U, V> void meetMaps(Map<U, V> target, Map<U, V> source) {
+        Iterator<Map.Entry<U, V>> iter = target.entrySet().iterator();
+        while (iter.hasNext()) {
+            Map.Entry<U, V> entry = iter.next();
+            if (source.containsKey(entry.getKey())) {
+                assert source.get(entry.getKey()) == entry.getValue();
+            } else {
+                iter.remove();
+            }
+        }
+    }
+
+}