--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/c-c++-common/Wformat-pr84258.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,19 @@
+/* { dg-options "-Wformat" } */
+
+int main (int argc, char **argv)
+{
+  char buf[10];
+
+  char c[] = "%i";
+  unsigned char uc[] = "%i";
+  const char cc[] = "%i";
+  const unsigned char cuc[] = "%i";
+
+  __builtin_sprintf(buf, (char *)c, 1);
+  __builtin_sprintf(buf, (char *)uc, 1);
+  __builtin_sprintf(buf, (char *)cc, 1);
+  __builtin_sprintf(buf, (char *)cuc, 1); /* { dg-warning "format string is not an array of type 'char'" } */
+  __builtin_sprintf(buf, (const char *)L"foo"); /* { dg-warning "format is a wide character string" } */
+
+  return 0;
+}