Fix representation requirement in HReturn.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index f7cbbee51a2b1caeeaa3161edef631d2c27e245a..fe701aeca6a11471ccdc35c48a4e89ba0ccd73f5 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1581,6 +1581,8 @@ class HReturn V8_FINAL : public HTemplateControlInstruction<0, 3> {
   DECLARE_INSTRUCTION_WITH_CONTEXT_FACTORY_P1(HReturn, HValue*);
 
   virtual Representation RequiredInputRepresentation(int index) V8_OVERRIDE {
+    // TODO(titzer): require an Int32 input for faster returns.
+    if (index == 2) return Representation::Smi();
     return Representation::Tagged();
   }