diff --git a/llvm/include/llvm/Support/ItaniumManglingCanonicalizer.h b/llvm/include/llvm/Support/ItaniumManglingCanonicalizer.h
index 8774b9e4dbb0e..8e1b3d631983d 100644
--- a/llvm/include/llvm/Support/ItaniumManglingCanonicalizer.h
+++ b/llvm/include/llvm/Support/ItaniumManglingCanonicalizer.h
@@ -15,6 +15,7 @@
 #define LLVM_SUPPORT_ITANIUMMANGLINGCANONICALIZER_H
 
 #include <cstddef>
+#include <cstdint>
 
 namespace llvm {