diff --git a/lib/Target/PTX/PTXMachineFunctionInfo.h b/lib/Target/PTX/PTXMachineFunctionInfo.h
index d3a259b624b..b5b3c3be17b 100644
--- a/lib/Target/PTX/PTXMachineFunctionInfo.h
+++ b/lib/Target/PTX/PTXMachineFunctionInfo.h
@@ -42,6 +42,7 @@ public:
   void setRetReg(unsigned reg) { reg_ret = reg; }
 
   void doneAddArg(void) {
+    std::sort(reg_arg.begin(), reg_arg.end());
     _isDoneAddArg = true;
   }
   void doneAddLocalVar(void) {