diff --git a/include/llvm/ADT/UniqueVector.h b/include/llvm/ADT/UniqueVector.h
index 8f0e686bf85..f3fd7b1d26f 100644
--- a/include/llvm/ADT/UniqueVector.h
+++ b/include/llvm/ADT/UniqueVector.h
@@ -10,6 +10,7 @@
 #ifndef LLVM_ADT_UNIQUEVECTOR_H
 #define LLVM_ADT_UNIQUEVECTOR_H
 
+#include <cassert>
 #include <map>
 #include <vector>