gcc/testsuite/gcc.dg/tree-ssa/vrp03.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -fdump-tree-vrp1" } */
   3
   4 struct A
   5 {
   6   int a;
   7   int b;
   8 };
   9
  10 foo (struct A *p, struct A *q)
  11 {
  12   int *r = 0;
  13
  14   if (p)
  15     {
  16       if (p == q)
  17         {
  18           /* This should be folded to 'if (1)' because q is [p, p]
  19              and p is ~[0, 0].  */
  20           if (q)
  21             r = &q->a;
  22
  23           /* This should be folded to 'if (1)' because q should be
  24              ~[0, 0] and thus &q->a should be ~[0, 0].  */
  25           if (r)
  26             return 5;
  27         }
  28     }
  29
  30   return q->a;
  31 }
  32
  33 /* { dg-final { scan-tree-dump-times "Folding predicate q_.*to 1" 1 "vrp1" } } */
  34 /* { dg-final { scan-tree-dump-times "Folding predicate r_.*to 1" 1 "vrp1" } } */
  35 /* { dg-final { cleanup-tree-dump "vrp1" } } */