diff --git a/lib/VMCore/Verifier.cpp b/lib/VMCore/Verifier.cpp
index f6fd236bd16..d672901cc17 100644
--- a/lib/VMCore/Verifier.cpp
+++ b/lib/VMCore/Verifier.cpp
@@ -60,6 +60,7 @@
 #include <algorithm>
 #include <iostream>
 #include <sstream>
+#include <cstdarg>
 using namespace llvm;
 
 namespace {  // Anonymous namespace for class