diff --git a/lib/Transforms/Utils/InstructionNamer.cpp b/lib/Transforms/Utils/InstructionNamer.cpp
index 5e5ec15f622..e6a94e3007d 100644
--- a/lib/Transforms/Utils/InstructionNamer.cpp
+++ b/lib/Transforms/Utils/InstructionNamer.cpp
@@ -30,7 +30,12 @@ namespace {
     }
 
     bool runOnFunction(Function &F) {
-      for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
+      for (Function::arg_iterator AI = F.arg_begin(), AE = F.arg_end();
+           AI != AE; ++AI)
+        if (!AI->hasName() && AI->getType() != Type::VoidTy)
+          AI->setName("tmp");
+
+       for (Function::iterator BB = F.begin(), E = F.end(); BB != E; ++BB)
         for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
           if (!I->hasName() && I->getType() != Type::VoidTy)
             I->setName("tmp");