gcc/testsuite/gcc.c-torture/execute/20010124-1.c

   1 /* Verify that structure return doesn't invoke memcpy on
   2    overlapping objects.  */
   3
   4 extern void abort (void);
   5 typedef __SIZE_TYPE__ size_t;
   6
   7 struct S {
   8   char stuff[1024];
   9 };
  10
  11 union U {
  12   struct {
  13     int space;
  14     struct S s;
  15   } a;
  16   struct {
  17     struct S s;
  18     int space;
  19   } b;
  20 };
  21
  22 static struct S f(struct S *);
  23 static void g(union U *);
  24
  25 int main()
  26 {
  27   union U u;
  28   u.b.s = f(&u.a.s);
  29   u.a.s = f(&u.b.s);
  30   g(&u);
  31   return 0;
  32 }
  33
  34 static struct S f(struct S *p)
  35 {
  36   return *p;
  37 }
  38
  39 static void g(union U *p)
  40 {
  41 }
  42
  43 static void *memcpy(void *a, const void *b, size_t len)
  44 {
  45   if (a < b && a+len > b)
  46     abort ();
  47   if (b < a && b+len > a)
  48     abort ();
  49   return a;
  50 }