Index: llvm/lib/Support/ARMTargetParser.cpp
===================================================================
--- llvm/lib/Support/ARMTargetParser.cpp
+++ llvm/lib/Support/ARMTargetParser.cpp
@@ -15,6 +15,8 @@
 #include "llvm/Support/ARMTargetParser.h"
 #include "llvm/ADT/StringSwitch.h"
 
+#include <cctype>
+
 using namespace llvm;
 
 static StringRef getHWDivSynonym(StringRef HWDiv) {