diff --git a/lib/AsmParser/LLLexer.cpp b/lib/AsmParser/LLLexer.cpp
index 5b1f0740dce..72e19f1d4d3 100644
--- a/lib/AsmParser/LLLexer.cpp
+++ b/lib/AsmParser/LLLexer.cpp
@@ -14,6 +14,7 @@
 #include "LLLexer.h"
 #include "ParserInternals.h"
 #include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/MathExtras.h"
 
 #include <list>
 #include "llvmAsmParser.h"