diff --git a/include/llvm/MC/MCImm.h b/include/llvm/MC/MCImm.h
index 5b1efd88206..1d836c7534b 100644
--- a/include/llvm/MC/MCImm.h
+++ b/include/llvm/MC/MCImm.h
@@ -16,6 +16,8 @@
 #ifndef LLVM_MC_MCIMM_H
 #define LLVM_MC_MCIMM_H
 
+#include "llvm/Support/DataTypes.h"
+
 namespace llvm {
 class MCSymbol;