diff --git a/llvm/include/llvm/ADT/CoalescingBitVector.h b/llvm/include/llvm/ADT/CoalescingBitVector.h
--- a/llvm/include/llvm/ADT/CoalescingBitVector.h
+++ b/llvm/include/llvm/ADT/CoalescingBitVector.h
@@ -15,6 +15,7 @@
 #define LLVM_ADT_COALESCINGBITVECTOR_H
 
 #include "llvm/ADT/IntervalMap.h"
+#include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/iterator_range.h"
 #include "llvm/Support/Debug.h"