diff --git a/include/llvm/ADT/SmallVector.h b/include/llvm/ADT/SmallVector.h
index dd3a6d006038..ec6a2c4800c4 100644
--- a/include/llvm/ADT/SmallVector.h
+++ b/include/llvm/ADT/SmallVector.h
@@ -20,6 +20,7 @@
 #include <cassert>
 #include <cstring>
 #include <memory>
+#include <cstddef>
 
 #ifdef _MSC_VER
 namespace std {
diff --git a/include/llvm/ADT/ilist.h b/include/llvm/ADT/ilist.h
index 1db648b0ff25..4017b74664ec 100644
--- a/include/llvm/ADT/ilist.h
+++ b/include/llvm/ADT/ilist.h
@@ -40,6 +40,7 @@
 
 #include "llvm/ADT/iterator.h"
 #include <cassert>
+#include <cstddef>
 
 namespace llvm {
 
diff --git a/include/llvm/Use.h b/include/llvm/Use.h
index 489dbc50a041..fb25a659f1f2 100644
--- a/include/llvm/Use.h
+++ b/include/llvm/Use.h
@@ -28,6 +28,7 @@
 #include "llvm/Support/Casting.h"
 #include "llvm/ADT/iterator.h"
 #include "llvm/ADT/PointerIntPair.h"
+#include <cstddef>
 
 namespace llvm {