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

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