[Bug target/42240] wrong Epilog on nacked function

["j at uriah dot heep dot sax dot de" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #5 from j at uriah dot heep dot sax dot de  2009-12-01 16:58 -------
My first analysis shows that this is likely to be related to the
introduction of RTL prologues/epilogues in GCC 4.3.  GCC 4.2.2
has:

  if (avr_naked_function_p (current_function_decl))
    {
      fputs ("/* epilogue: naked */\n", file);
      goto out;
    }
...
 out:
  fprintf (file, "/* epilogue end (size=%d) */\n", epilogue_size);
  fprintf (file, "/* function %s size %d (%d) */\n", current_function_name (),
           prologue_size + function_size + epilogue_size, function_size);
  commands_in_file += prologue_size + function_size + epilogue_size;
  commands_in_prologues += prologue_size;
  commands_in_epilogues += epilogue_size;
}

GCC 4.3.4 has:

  /* epilogue: naked  */
  if (cfun->machine->is_naked)
    {
      emit_jump_insn (gen_return ());
      return;
    }

So apparently, emit_jump_insn (gen_return ()); is responsible for creating
the infinite loop.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42240