Fix uint32-to-smi conversion in Lithium

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index 85895b39039d2eb460e4f9bd828c781c1cbd9830..7c70094fbf03cda94da80d04a01e604d2b42d75e 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4421,6 +4421,22 @@ void LCodeGen::DoUint32ToDouble(LUint32ToDouble* instr) {
 }
 
 
+void LCodeGen::DoUint32ToSmi(LUint32ToSmi* instr) {
+  LOperand* input = instr->value();
+  ASSERT(input->IsRegister());
+  LOperand* output = instr->result();
+  if (!instr->hydrogen()->value()->HasRange() ||
+      !instr->hydrogen()->value()->range()->IsInSmiRange() ||
+      instr->hydrogen()->value()->range()->upper() == kMaxInt) {
+    // The Range class can't express upper bounds in the (kMaxInt, kMaxUint32]
+    // interval, so we treat kMaxInt as a sentinel for this entire interval.
+    __ testl(ToRegister(input), Immediate(0x80000000));
+    DeoptimizeIf(not_zero, instr->environment());
+  }
+  __ Integer32ToSmi(ToRegister(output), ToRegister(input));
+}
+
+
 void LCodeGen::DoNumberTagI(LNumberTagI* instr) {
   LOperand* input = instr->value();
   ASSERT(input->IsRegister() && input->Equals(instr->result()));