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diff --git a/deps/v8/src/crankshaft/hydrogen-alias-analysis.h b/deps/v8/src/crankshaft/hydrogen-alias-analysis.h
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+++ b/deps/v8/src/crankshaft/hydrogen-alias-analysis.h
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+// Copyright 2013 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef V8_CRANKSHAFT_HYDROGEN_ALIAS_ANALYSIS_H_
+#define V8_CRANKSHAFT_HYDROGEN_ALIAS_ANALYSIS_H_
+
+#include "src/crankshaft/hydrogen.h"
+
+namespace v8 {
+namespace internal {
+
+enum HAliasing {
+  kMustAlias,
+  kMayAlias,
+  kNoAlias
+};
+
+
+// Defines the interface to alias analysis for the rest of the compiler.
+// A simple implementation can use only local reasoning, but a more powerful
+// analysis might employ points-to analysis.
+class HAliasAnalyzer : public ZoneObject {
+ public:
+  // Simple alias analysis distinguishes allocations, parameters,
+  // and constants using only local reasoning.
+  HAliasing Query(HValue* a, HValue* b) {
+    // The same SSA value always references the same object.
+    if (a == b) return kMustAlias;
+
+    if (a->IsAllocate() || a->IsInnerAllocatedObject()) {
+      // Two non-identical allocations can never be aliases.
+      if (b->IsAllocate()) return kNoAlias;
+      if (b->IsInnerAllocatedObject()) return kNoAlias;
+      // An allocation can never alias a parameter or a constant.
+      if (b->IsParameter()) return kNoAlias;
+      if (b->IsConstant()) return kNoAlias;
+    }
+    if (b->IsAllocate() || b->IsInnerAllocatedObject()) {
+      // An allocation can never alias a parameter or a constant.
+      if (a->IsParameter()) return kNoAlias;
+      if (a->IsConstant()) return kNoAlias;
+    }
+
+    // Constant objects can be distinguished statically.
+    if (a->IsConstant()) {
+      // TODO(titzer): DataEquals() is more efficient, but that's protected.
+      return a->Equals(b) ? kMustAlias : kNoAlias;
+    }
+    return kMayAlias;
+  }
+
+  // Checks whether the objects referred to by the given instructions may
+  // ever be aliases. Note that this is more conservative than checking
+  // {Query(a, b) == kMayAlias}, since this method considers kMustAlias
+  // objects to also be may-aliasing.
+  inline bool MayAlias(HValue* a, HValue* b) {
+    return Query(a, b) != kNoAlias;
+  }
+
+  inline bool MustAlias(HValue* a, HValue* b) {
+    return Query(a, b) == kMustAlias;
+  }
+
+  inline bool NoAlias(HValue* a, HValue* b) {
+    return Query(a, b) == kNoAlias;
+  }
+};
+
+
+}  // namespace internal
+}  // namespace v8
+
+#endif  // V8_CRANKSHAFT_HYDROGEN_ALIAS_ANALYSIS_H_