Shorten live ranges for arguments to runtime calls.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index 9f5170ca2bcc9e5f9d7dcdd9d5fccdbf1f2eb910..1f72d649f2ff10d43661b536c7970c114af8a65f 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -1048,7 +1048,9 @@ class HLeaveInlined: public HInstruction {
 
 class HPushArgument: public HUnaryOperation {
  public:
-  explicit HPushArgument(HValue* value) : HUnaryOperation(value) { }
+  explicit HPushArgument(HValue* value) : HUnaryOperation(value) {
+    set_representation(Representation::Tagged());
+  }
 
   virtual Representation RequiredInputRepresentation(int index) const {
     return Representation::Tagged();