--- a/llvm/include/llvm/ADT/STLExtras.h
+++ b/llvm/include/llvm/ADT/STLExtras.h
@@ -21,6 +21,7 @@
 #include <algorithm> // for std::all_of
 #include <cassert>
 #include <cstddef> // for std::size_t
+#include <cstdint>
 #include <cstdlib> // for qsort
 #include <functional>
 #include <iterator>