diff --git a/unittests/IR/InstructionsTest.cpp b/unittests/IR/InstructionsTest.cpp
index e04006508bd..5883e13c385 100644
--- a/unittests/IR/InstructionsTest.cpp
+++ b/unittests/IR/InstructionsTest.cpp
@@ -65,7 +65,7 @@ protected:
 
   LLVMContext Ctx;
   std::unique_ptr<Module> M;
-  std::vector<Type *> FArgTypes;
+  SmallVector<Type *, 3> FArgTypes;
   Function *F;
 };