The macros defined by the language standard are still available even when the
-undef flag is passed in. Also __ASSEMBLER__ with -x assembler-with-cpp. (Don't
ask.)
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@132708 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Frontend/undef.c b/test/Frontend/undef.c
new file mode 100644
index 0000000..f539cdc
--- /dev/null
+++ b/test/Frontend/undef.c
@@ -0,0 +1,4 @@
+// RUN: %clang -undef -x assembler-with-cpp -E %s
+#ifndef __ASSEMBLER__
+#error "Must be preprocessed as assembler."
+#endif