gcc/testsuite/gcc.dg/tree-ssa/ssa-thread-backedge.c

   1 // { dg-do compile }
   2 // { dg-options "-O2 -fdisable-tree-ethread -fdisable-tree-thread1 -fdisable-tree-thread2 -fno-tree-dominator-opts -fdump-tree-threadfull2-details" }
   3
   4 // Test that we can thread jumps across the backedge of a loop through
   5 // the switch statement to a particular case.
   6 //
   7 // Just in case, we disable all the jump threaders before loop
   8 // optimizations to make sure we get a clean stab at this.
   9
  10 int foo (unsigned int x, int s)
  11 {
  12   while (s != 999)
  13     {
  14       switch (s)
  15         {
  16         case 0:
  17           if (x)
  18             s = 1;
  19           break;
  20         case 1:
  21           if (x)
  22             s = 999;
  23           break;
  24         default:
  25           break;
  26         }
  27       x++;
  28     }
  29   return s;
  30 }
  31
  32 // { dg-final { scan-tree-dump "Registering jump thread:.*normal \\(back\\)" "threadfull2" } }