diff --git a/clang/lib/Basic/Targets/AVR.h b/clang/lib/Basic/Targets/AVR.h
--- a/clang/lib/Basic/Targets/AVR.h
+++ b/clang/lib/Basic/Targets/AVR.h
@@ -53,6 +53,7 @@
     Char16Type = UnsignedInt;
     WIntType = SignedInt;
     Int16Type = SignedInt;
+    IntMaxType = SignedInt;
     Char32Type = UnsignedLong;
     SigAtomicType = SignedChar;
     resetDataLayout("e-P1-p:16:8-i8:8-i16:8-i32:8-i64:8-f32:8-f64:8-n8-a:8");