diff --git a/llvm-project/llvm/include/llvm/Support/Threading.h b/llvm-project/llvm/include/llvm/Support/Threading.h
index ba6c531ab4..78aa5e7be5 100644
--- a/llvm-project/llvm/include/llvm/Support/Threading.h
+++ b/llvm-project/llvm/include/llvm/Support/Threading.h
@@ -18,7 +18,7 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Config/llvm-config.h" // for LLVM_ON_UNIX
 #include "llvm/Support/Compiler.h"
-#include <ciso646> // So we can check the C++ standard lib macros.
+#include <version> // So we can check the C++ standard lib macros.
 #include <optional>
 
 #if defined(_MSC_VER)