1 /* PR c/25682 */
2 /* { dg-do compile } */
3 /* { dg-options "-ansi" } */
4 /* { dg-require-effective-target alloca } */
5 /* Test whether we don't ICE on questionable constructs where offsetof
6    should have been used instead.  */
7 
8 struct S
9 {
10   char a[4];
11   int b;
12 };
13 
14 char c[(char *) &((struct S *) 0)->b - (char *) 0]; /* { dg-warning "variably modified" } */
15 char d[(__UINTPTR_TYPE__) &((struct S *) 8)->b]; /* { dg-warning "variably modified" } */
16 char e[sizeof (c) == __builtin_offsetof (struct S, b) ? 1 : -1];
17 char f[sizeof (d) == __builtin_offsetof (struct S, b) + 8 ? 1 : -1];
18 
19 extern void bar (char *, char *);
20 
21 void
foo(void)22 foo (void)
23 {
24   char g[(char *) &((struct S *) 0)->b - (char *) 0];
25   char h[(__UINTPTR_TYPE__) &((struct S *) 8)->b];
26   char i[sizeof (g) == __builtin_offsetof (struct S, b) ? 1 : -1];
27   char j[sizeof (h) == __builtin_offsetof (struct S, b) + 8 ? 1 : -1];
28   bar (g, h);
29 }
30