gcc/testsuite/gcc.dg/sibcall-1.c

   1 /* Simple check that sibling calls are performed from a
   2    void non-leaf-function taking one int argument calling itself.
   3
   4    Copyright (C) 2002 Free Software Foundation Inc.
   5    Contributed by Hans-Peter Nilsson  <hp@bitrange.com>  */
   6
   7 /* { dg-do run } */
   8 /* { dg-options "-O2 -foptimize-sibling-calls" } */
   9
  10 /* See note in recurser_void() as to why we disable threading.  */
  11 /* { dg-additional-options "-fdisable-tree-thread1" } */
  12
  13 /* The option -foptimize-sibling-calls is the default, but serves as
  14    marker.  Self-recursion tail calls are optimized for all targets,
  15    regardless of presence of sibcall patterns.  */
  16
  17 extern void abort (void);
  18 extern void exit (int);
  19
  20 extern void recurser_void (int);
  21 extern void track (int);
  22
  23 int main ()
  24 {
  25   recurser_void (0);
  26   exit (0);
  27 }
  28
  29 void
  30 recurser_void (int n)
  31 {
  32   /* In some architectures like ppc64*, jump threading may thread
  33      paths such that there are two calls into track(), one for
  34      track(0) and one for track(7).  The track(7) call can be
  35      transformed into a jump instead of a call, which means that
  36      different calls into track() may end up with a different
  37      &stackpos.  This is the reason we disable jump threading for this
  38      test.  */
  39   if (n == 0 || n == 7)
  40     track (n);
  41
  42   if (n == 10)
  43     return;
  44
  45   recurser_void (n + 1);
  46 }
  47
  48 void *trackpoint;
  49
  50 void __attribute__ ((noipa))
  51 track (int n)
  52 {
  53   char stackpos[1];
  54
  55   if (n == 0)
  56     trackpoint = stackpos;
  57   else if (n != 7 || trackpoint != stackpos)
  58     abort ();
  59 }