--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/llvm/test/TableGen/nul-char.td	Tue Jun 08 06:07:14 2021 +0900
@@ -0,0 +1,28 @@
+// RUN: cat %s | tr '@' '\0' > %t
+// RUN: not llvm-tblgen -DERROR1 %t 2>&1 | FileCheck --check-prefix=ERROR1 %s
+
+// This test file checks that NUL is treated as an invalid character.
+// Each at sign is replaced with a NUL before running the test.
+
+#ifdef ERROR1
+
+// ERROR1: error: NUL character is invalid in source; treated as space
+// ERROR1: error: NUL character is invalid in source; treated as space
+// ERROR1: error: NUL character is invalid in source; treated as space
+// ERROR1: error: NUL character is invalid in source; treated as space
+// ERROR1: error: expected ';' after declaration
+
+def Foo@ {
+  int @ ID = 42;
+}
+
+@
+
+// Comment with a NUL @ there. They are ignored in comments.
+
+def Bar {
+  int Biggie = 12345@789;
+}
+
+#endif
+