--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.c-torture/execute/fprintf-2.c	Thu Feb 13 11:34:05 2020 +0900
@@ -0,0 +1,55 @@
+/* Verify that calls to fprintf don't get eliminated even if their
+   result on success can be computed at compile time (they can fail).
+   The calls can still be transformed into those of other functions.
+   { dg-prune-output "warning: warning: \[^\n\r\]* possibly used unsafely" }
+   { dg-skip-if "requires io" { avr-*-* } }
+   { dg-skip-if "requires io" { freestanding } } */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+int main (void)
+{
+  char *tmpfname = tmpnam (0);
+  FILE *f = fopen (tmpfname, "w");
+  if (!f)
+    {
+      perror ("fopen for writing");
+      return 1;
+    }
+
+  fprintf (f, "1");
+  fprintf (f, "%c", '2');
+  fprintf (f, "%c%c", '3', '4');
+  fprintf (f, "%s", "5");
+  fprintf (f, "%s%s", "6", "7");
+  fprintf (f, "%i", 8);
+  fprintf (f, "%.1s\n", "9x");
+  fclose (f);
+
+  f = fopen (tmpfname, "r");
+  if (!f)
+    {
+      perror ("fopen for reading");
+      remove (tmpfname);
+      return 1;
+    }
+
+  char buf[12] = "";
+  if (1 != fscanf (f, "%s", buf))
+    {
+      perror ("fscanf");
+      fclose (f);
+      remove (tmpfname);
+      return 1;
+    }
+
+  fclose (f);
+  remove (tmpfname);
+
+  if (strcmp (buf, "123456789"))
+    abort ();
+
+  return 0;
+}