Fix uint32-to-smi conversion in Lithium

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index 590f47af4a7d7d237d658a07dcf4891e54646cf9..06cb1719233acd551fe5c7cd0af115a6f0877451 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -181,6 +181,7 @@ class LCodeGen;
   V(Typeof)                                     \
   V(TypeofIsAndBranch)                          \
   V(Uint32ToDouble)                             \
+  V(Uint32ToSmi)                                \
   V(UnknownOSRValue)                            \
   V(ValueOf)                                    \
   V(WrapReceiver)
@@ -1943,6 +1944,19 @@ class LUint32ToDouble V8_FINAL : public LTemplateInstruction<1, 1, 1> {
 };
 
 
+class LUint32ToSmi V8_FINAL : public LTemplateInstruction<1, 1, 0> {
+ public:
+  explicit LUint32ToSmi(LOperand* value) {
+    inputs_[0] = value;
+  }
+
+  LOperand* value() { return inputs_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(Uint32ToSmi, "uint32-to-smi")
+  DECLARE_HYDROGEN_ACCESSOR(Change)
+};
+
+
 class LNumberTagI V8_FINAL : public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LNumberTagI(LOperand* value) {