gcc/testsuite/gcc.dg/20020310-1.c

   1 /* PR optimization/5844
   2    This testcase was miscompiled because of an rtx sharing bug.  */
   3 /* { dg-do run } */
   4 /* { dg-options "-O2" } */
   5 /* { dg-options "-O2 -mtune=i586" { target i?86-*-* } } */
   6
   7 struct A
   8 {
   9   struct A *a;
  10   int b;
  11 };
  12
  13 struct B
  14 {
  15   struct A *c;
  16   unsigned int d;
  17 };
  18
  19 struct A p = { &p, -1 };
  20 struct B q = { &p, 0 };
  21
  22 extern void abort (void);
  23 extern void exit (int);
  24
  25 struct B *
  26 foo (void)
  27 {
  28   return &q;
  29 }
  30
  31 void
  32 bar (void)
  33 {
  34   struct B *e = foo ();
  35   struct A *f = e->c;
  36   int g = f->b;
  37
  38   if (++g == 0)
  39     {
  40       e->d++;
  41       e->c = f->a;
  42     }
  43
  44   f->b = g;
  45 }
  46
  47 int
  48 main ()
  49 {
  50   bar ();
  51   if (p.b != 0 || q.d != 1 || q.c != &p)
  52     abort ();
  53   exit (0);
  54 }