--- /dev/null
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-undef %s
+// rdar://2362963
+
+#if FOO // ok.
+#endif
+
+#pragma GCC diagnostic warning "-Wundef"
+
+#if FOO // expected-warning {{'FOO' is not defined}}
+#endif
+
+#pragma GCC diagnostic ignored "-Wun" "def"
+
+#if FOO // ok.
+#endif
+
+#pragma GCC diagnostic error "-Wundef"
+
+#if FOO // expected-error {{'FOO' is not defined}}
+#endif
+
+
+
+#define foo error
+#pragma GCC diagnostic foo "-Wundef" // expected-warning {{pragma diagnostic expected 'error', 'warning', 'ignored', or 'fatal'}}
+
+#pragma GCC diagnostic error 42 // expected-warning {{unexpected token in pragma diagnostic}}
+
+#pragma GCC diagnostic error "-Wundef" 42 // expected-warning {{unexpected token in pragma diagnostic}}
+#pragma GCC diagnostic error "invalid-name" // expected-warning {{pragma diagnostic expected option name (e.g. "-Wundef")}}
+
+#pragma GCC diagnostic error "-Winvalid-name" // expected-warning {{unknown warning group '-Winvalid-name', ignored}}
+