--- a/llvm/include/llvm/ADT/SmallVector.h
+++ b/llvm/include/llvm/ADT/SmallVector.h
@@ -735,6 +735,10 @@
     return(N);
   }
 
+#ifdef CS
+#undef CS
+#endif
+
   iterator erase(const_iterator CS, const_iterator CE) {
     // Just cast away constness because this is a non-const member function.
     iterator S = const_cast<iterator>(CS);