gcc/testsuite/gcc.dg/tree-ssa/pr21559.c

   1 /* { dg-do compile } */
   2 /* { dg-options "-O2 -fdump-tree-vrp1-details" } */
   3
   4 static int blocksize = 4096;
   5
   6 int bar (int);
   7
   8 void foo (void)
   9 {
  10   int toread;
  11   int bytes;
  12   static char eof_reached = 0;
  13
  14   toread = blocksize;
  15   bytes = 1;
  16
  17   while (toread != 0)
  18     {
  19       bytes = bar (toread);
  20       if (bytes <= 0)
  21         {
  22           if (bytes < 0)
  23             continue;
  24           break;
  25         }
  26       toread -= bytes;
  27     }
  28
  29   if (bytes == 0)
  30     eof_reached = 1;
  31 }
  32
  33
  34 /* First, we should simplify the bits < 0 test within the loop.  */
  35 /* { dg-final { scan-tree-dump-times "Simplified relational" 1 "vrp1" } } */
  36
  37 /* Second, we should thread the edge out of the loop via the break
  38    statement.  */
  39 /* { dg-final { scan-tree-dump-times "Threaded jump" 1 "vrp1" } } */
  40
  41 /* Now if we were really good, we'd realize that the final bytes == 0
  42    test is totally useless.  That's not likely to happen anytime soon.  */
  43
  44 /* { dg-final { cleanup-tree-dump "vrp1" } } */
  45