diff --git a/lib/IR/Constants.cpp b/lib/IR/Constants.cpp
index 8093a09749f..dafca987fe7 100644
--- a/lib/IR/Constants.cpp
+++ b/lib/IR/Constants.cpp
@@ -1416,9 +1416,9 @@ static inline Constant *getFoldedCast(
 
   LLVMContextImpl *pImpl = Ty->getContext().pImpl;
 
-  // Look up the constant in the table first to ensure uniqueness
-  std::vector<Constant*> argVec(1, C);
-  ExprMapKeyType Key(opc, argVec);
+  // Look up the constant in the table first to ensure uniqueness.
+  ArrayRef<Constant*> Ops(&C, 1);
+  ExprMapKeyType Key(opc, Ops);
 
   return pImpl->ExprConstants.getOrCreate(Ty, Key);
 }