1 /* Duff's device is legal C; test to make sure the compiler
2 doesn't complain about it.
3
4 Jason Thorpe <thorpej@wasabisystems.com>
5 Derived from PR 3846. */
6
7 /* { dg-do run } */
8 /* { dg-options "-O2" } */
9
10 extern void abort (void);
11 extern void exit (int);
12
13 typedef __SIZE_TYPE__ size_t;
14 extern int memcmp (const void *, const void *, size_t);
15
16 void
duffcpy(char * dst,const char * src,unsigned long size)17 duffcpy (char *dst, const char *src, unsigned long size)
18 {
19 switch (size & 3)
20 {
21 for (;;)
22 {
23 *dst++ = *src++;
24 case 3:
25 *dst++ = *src++;
26 case 2:
27 *dst++ = *src++;
28 case 1:
29 *dst++ = *src++;
30 case 0:
31 if (size <= 3)
32 break;
33 size -= 4;
34 }
35 }
36 }
37
38 const char testpat[] = "The quick brown fox jumped over the lazy dog.";
39
40 int
main()41 main()
42 {
43 char buf[64];
44
45 duffcpy (buf, testpat, sizeof (testpat));
46 if (memcmp (buf, testpat, sizeof (testpat)) != 0)
47 abort ();
48
49 exit (0);
50 }
51