gcc/testsuite/c-c++-common/attr-may-alias-1.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -Wall" } */
   3
   4 typedef int T __attribute__((may_alias));
   5
   6 extern T *p;
   7 extern int *p;
   8
   9 extern int *p2;
  10 extern T *p2;
  11
  12 void fn1 (T);
  13 void fn1 (int);
  14
  15 void fn2 (int);
  16 void fn2 (T);
  17
  18 /* Ensure that the composite types have may_alias.  */
  19 void
  20 f (long *i)
  21 {
  22   *i = *(__typeof (*p) *) &p;
  23   asm ("" : : "r" (*p));
  24   *i = *(__typeof (*p2) *) &p2;
  25   asm ("" : : "r" (*p2));
  26 }