if (l.stack_addr == 0 || r.stack_addr == 0)
if (!l.stack_addr_p || !r.stack_addr_p)
frame_id_inner (struct frame_id l, struct frame_id r){  int inner;  if (l.stack_addr == 0 || r.stack_addr == 0)    /* Like NaN, any operation involving an invalid ID always fails.  */    inner = 0;  else    /* Only return non-zero when strictly inner than.  Note that, per       comment in "frame.h", there is some fuzz here.  Frameless       functions are not strictly inner than (same .stack but       different .code and/or .special address).  */    inner = INNER_THAN (l.stack_addr, r.stack_addr);  if (frame_debug)    {      fprintf_unfiltered (gdb_stdlog, "{ frame_id_inner (l=");      fprint_frame_id (gdb_stdlog, l);      fprintf_unfiltered (gdb_stdlog, ",r=");      fprint_frame_id (gdb_stdlog, r);      fprintf_unfiltered (gdb_stdlog, ") -> %d }\n", inner);    }  return inner;}