--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/cpp/warn-traditional.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,23 @@
+// { dg-do compile }
+// { dg-options "-std=gnu99 -fdiagnostics-show-option -Wtraditional -Wno-deprecated -Wno-long-long" }
+
+#assert x(x)         // { dg-warning "suggest hiding #assert from traditional C with an indented # .-Wtraditional." }
+
+ #define X X         // { dg-warning "traditional C ignores #define with the # indented .-Wtraditional." }
+
+#if 0
+#elif 1              // { dg-warning "suggest not using #elif in traditional C .-Wtraditional." }
+#endif
+
+#define f(X) X
+int f;               // { dg-warning "function-like macro \"f\" must be used with arguments in traditional C .-Wtraditional." }
+
+#if 0U               // { dg-warning "traditional C rejects the \"U\" suffix .-Wtraditional." }
+#endif
+
+#if +1               // { dg-warning " traditional C rejects the unary plus operator .-Wtraditional." }
+#endif
+
+char *x = "\x0";     // { dg-warning "the meaning of '.x' is different in traditional C .-Wtraditional." }
+char *y = "\a";      // { dg-warning "the meaning of '.a' is different in traditional C .-Wtraditional." }
+char *z = "\u0F43";  // { dg-warning "the meaning of '.u' is different in traditional C .-Wtraditional." }