diff --git a/compiler-rt/lib/builtins/clear_cache.c b/compiler-rt/lib/builtins/clear_cache.c
index 80115531d82f6ef7405377860abfc35a65e14386..d1826391d5904210105e2921e4a078cc03308157 100644
--- a/compiler-rt/lib/builtins/clear_cache.c
+++ b/compiler-rt/lib/builtins/clear_cache.c
@@ -9,6 +9,7 @@
  */
 
 #include "int_lib.h"
+#include <stddef.h>
 
 #if __APPLE__
   #include <libkern/OSCacheControl.h>