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

   1 /* PR c/58346 */
   2 /* { dg-do compile } */
   3 /* { dg-options "-Wno-c++-compat" { target c } } */
   4
   5 struct U {
   6 #ifdef __cplusplus
   7   char a[0];
   8 #endif
   9 };
  10 static struct U b[6];
  11 static struct U *u1, *u2;
  12
  13 int
  14 foo (struct U *p, struct U *q)
  15 {
  16   return q - p; /* { dg-error "arithmetic on pointer to an empty aggregate" } */
  17 }
  18
  19 void
  20 bar (void)
  21 {
  22   __PTRDIFF_TYPE__ d = u1 - u2; /* { dg-error "arithmetic on pointer to an empty aggregate" } */
  23   __asm volatile ("" : "+g" (d));
  24   foo (&b[0], &b[4]);
  25 }