diff --git a/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h b/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
--- a/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
+++ b/llvm/include/llvm/Demangle/MicrosoftDemangleNodes.h
@@ -16,6 +16,7 @@
 #include "llvm/Demangle/DemangleConfig.h"
 #include "llvm/Demangle/StringView.h"
 #include <array>
+#include <cstdint>
 
 namespace llvm {
 namespace itanium_demangle {