gcc/testsuite/gcc.dg/tree-ssa/20040324-1.c

   1 /* { dg-do run } */
   2 /* { dg-options "-O2" } */
   3
   4 /* Ensure that BIT_FIELD_REFs gets the appropriate VUSE.
   5    Contributed by Paolo Bonzini  <bonzini@gnu.org>.
   6
   7    This testcase actually never triggered in the CVS repo, but it did
   8    in my local tree and it seems worth testing.  In this test, the if's
   9    are folded to BIT_FIELD_REFs but the VUSEs were erroneously left out.
  10    Therefore, DOM did not see that i was modified between the two ifs
  11    and optimized away the second if.  */
  12
  13 extern void abort (void);
  14 extern void exit (int);
  15
  16 struct x
  17 {
  18   unsigned b:1;
  19   unsigned c:1;
  20 };
  21
  22 struct x i = { 1, 1 };
  23
  24 int
  25 main ()
  26 {
  27   i.b = 1;
  28   if (i.b == 1 && i.c == 0)
  29     exit (0);
  30   i.c = 0;
  31   if (i.b == 1 && i.c == 0)
  32     exit (0);
  33   abort ();
  34 }