diff --git a/clang/lib/Driver/ToolChains/AIX.cpp b/clang/lib/Driver/ToolChains/AIX.cpp
index 7a62b0f9aec41..3f10888596a29 100644
--- a/clang/lib/Driver/ToolChains/AIX.cpp
+++ b/clang/lib/Driver/ToolChains/AIX.cpp
@@ -17,6 +17,8 @@
 #include "llvm/ProfileData/InstrProf.h"
 #include "llvm/Support/Path.h"
 
+#include <set>
+
 using AIX = clang::driver::toolchains::AIX;
 using namespace clang::driver;
 using namespace clang::driver::tools;