--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/testsuite/gcc.dg/Wunused-parm-1.c	Fri Oct 27 22:46:09 2017 +0900
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options "-Wunused -W" } */
+
+long
+f1 (unsigned long long x)
+{
+  unsigned long long a = 1;
+  const union { unsigned long long l; unsigned int p[2]; } b = { .l = x };
+  const union { unsigned long long l; unsigned int p[2]; } c = { .l = a };
+  return b.p[0] + c.p[0];
+}
+
+int
+f2 (int x, int y)
+{
+  int a = 1;
+  int b[] = { 1, 2, x, a, 3, 4 };
+  return b[y];
+}
+
+int
+f3 (int a,	/* { dg-warning "unused parameter" } */
+    int b,	/* { dg-warning "set but not used" } */
+    int c)
+{
+  b = 1;
+  c = 1;
+  return c;
+}