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diff --git a/Source/JavaScriptCore/b3/B3PureCSE.cpp b/Source/JavaScriptCore/b3/B3PureCSE.cpp
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+++ b/Source/JavaScriptCore/b3/B3PureCSE.cpp
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+/*
+ * Copyright (C) 2016 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
+ */
+
+#include "config.h"
+#include "B3PureCSE.h"
+
+#if ENABLE(B3_JIT)
+
+#include "B3Dominators.h"
+#include "B3Value.h"
+
+namespace JSC { namespace B3 {
+
+PureCSE::PureCSE()
+{
+}
+
+PureCSE::~PureCSE()
+{
+}
+
+void PureCSE::clear()
+{
+    m_map.clear();
+}
+
+Value* PureCSE::findMatch(const ValueKey& key, BasicBlock* block, Dominators& dominators)
+{
+    if (!key)
+        return nullptr;
+
+    auto iter = m_map.find(key);
+    if (iter == m_map.end())
+        return nullptr;
+
+    for (Value* match : iter->value) {
+        if (dominators.dominates(match->owner, block))
+            return match;
+    }
+
+    return nullptr;
+}
+
+bool PureCSE::process(Value* value, Dominators& dominators)
+{
+    if (value->opcode() == Identity)
+        return false;
+
+    ValueKey key = value->key();
+    if (!key)
+        return false;
+
+    Matches& matches = m_map.add(key, Matches()).iterator->value;
+
+    for (Value* match : matches) {
+        if (dominators.dominates(match->owner, value->owner)) {
+            value->replaceWithIdentity(match);
+            return true;
+        }
+    }
+
+    matches.append(value);
+    return false;
+}
+
+} } // namespace JSC::B3
+
+#endif // ENABLE(B3_JIT)
+