gcc/testsuite/c-c++-common/pr58346-1.c

   1 /* PR c/58346 */
   2 /* { dg-do compile } */
   3
   4 struct U {
   5 #ifdef __cplusplus
   6   char a[0];
   7 #endif
   8 };
   9 static struct U b[6];
  10 static struct U *u1, *u2;
  11
  12 int
  13 foo (struct U *p, struct U *q)
  14 {
  15   return q - p; /* { dg-error "arithmetic on pointer to an empty aggregate" } */
  16 }
  17
  18 void
  19 bar (void)
  20 {
  21   __PTRDIFF_TYPE__ d = u1 - u2; /* { dg-error "arithmetic on pointer to an empty aggregate" } */
  22   __asm volatile ("" : "+g" (d));
  23   foo (&b[0], &b[4]);
  24 }