1 files changed, 47 insertions, 0 deletions
diff --git a/gcc/testsuite/gcc.dg/duff-3.c b/gcc/testsuite/gcc.dg/duff-3.c
new file mode 100644
index 000000000..23cddeff9
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/duff-3.c
@@ -0,0 +1,47 @@
+/* Duff's device is legal C; test to make sure the compiler
+   doesn't complain about it.
+
+   Jason Thorpe <thorpej@wasabisystems.com>
+   Derived from Tom Duff's original usenet message about the device.  */
+
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+extern void abort (void);
+extern void exit (int);
+
+typedef __SIZE_TYPE__ size_t;
+extern int memcmp (const void *, const void *, size_t);
+
+void
+duffcpy (char *dst, const char *src, unsigned long size)
+{
+  unsigned long n = (size + 7) / 8;
+
+  switch (size % 8)
+    {
+    case 0:	do {	*dst++ = *src++;
+    case 7:		*dst++ = *src++;
+    case 6:		*dst++ = *src++;
+    case 5:		*dst++ = *src++;
+    case 4:		*dst++ = *src++;
+    case 3:		*dst++ = *src++;
+    case 2:		*dst++ = *src++;
+    case 1:		*dst++ = *src++;
+		} while (--n > 0);
+    }
+}
+
+const char testpat[] = "The quick brown fox jumped over the lazy dog.";
+
+int
+main()
+{
+  char buf[64];
+
+  duffcpy (buf, testpat, sizeof (testpat));
+  if (memcmp (buf, testpat, sizeof (testpat)) != 0)
+    abort ();
+
+  exit (0);
+}