gcc/testsuite/gcc.dg/tree-ssa/20050719-1.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2" } */
   3
   4 extern void abort (void) __attribute__ ((__nothrow__)) __attribute__
   5 ((__noreturn__));
   6 extern void exit (int __status) __attribute__ ((__nothrow__))
   7 __attribute__ ((__noreturn__));
   8 int useboot (void *);
   9
  10 struct bootLoader {
  11   int x;
  12 };
  13
  14 void
  15 zap(struct bootLoader *bootLoader)
  16 {
  17   /* The expression on the RHS of the assignment is *not* a
  18      dereference of pointer 'bootLoader'.  It is merely used as an
  19      offset calculation.  VRP was erroneously removing the if()
  20      because it thought that 'bootLoader' was always dereferenced.  */
  21   int *boot = &bootLoader->x;
  22
  23   if (bootLoader)
  24     {
  25       useboot (boot);
  26     }
  27 }
  28
  29 int
  30 useboot (void *boot)
  31 {
  32   abort ();
  33 }
  34
  35 int
  36 main()
  37 {
  38   zap (0);
  39   return 0;
  40 }