--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/strcmpopt_1.c	Thu Oct 25 07:37:49 2018 +0900
@@ -0,0 +1,28 @@
+/* { dg-do run } */
+/* { dg-options "-fdump-tree-gimple" } */
+
+#include <string.h>
+#include <stdlib.h>
+
+int cmp1 (char *p)
+{
+  return strncmp (p, "fis", 4);
+}
+int cmp2 (char *q)
+{
+  return strncmp ("fis", q, 4);
+}
+
+int main ()
+{
+
+  char *p = "fish";
+  char *q = "fis\0";
+
+  if (cmp1 (p) == 0 || cmp2 (q) != 0)
+    abort ();
+
+  return 0;
+}
+
+/* { dg-final { scan-tree-dump-times "strcmp \\(" 2 "gimple" } } */