--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/c-c++-common/memset-array.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,36 @@
+/* { dg-do compile } */
+/* { dg-options "-Wmemset-elt-size" } */
+enum a {
+  a_1,
+  a_2,
+  a_n
+};
+int t1[20];
+int t2[a_n];
+
+struct s
+{
+  int t[20];
+};
+
+void foo (struct s *s)
+{
+  __builtin_memset (t1, 0, 20); /* { dg-warning "element size" } */
+  __builtin_memset (t2, 0, a_n); /* { dg-warning "element size" } */
+  __builtin_memset (s->t, 0, 20); /* { dg-warning "element size" } */
+}
+
+char u1[20];
+char u2[a_n];
+
+struct s2
+{
+  char u[20];
+};
+
+void bar (struct s2 *s)
+{
+  __builtin_memset (u1, 0, 20);
+  __builtin_memset (u2, 0, a_n);
+  __builtin_memset (s->u, 0, 20);
+}