Beispiel #1
0
struct loops *
loop_optimizer_init (FILE *dumpfile)
{
  struct loops *loops = xcalloc (1, sizeof (struct loops));
  edge e;
  edge_iterator ei;
  static bool first_time = true;

  if (first_time)
    {
      first_time = false;
      init_set_costs ();
    }

  /* Avoid annoying special cases of edges going to exit
     block.  */

  for (ei = ei_start (EXIT_BLOCK_PTR->preds); (e = ei_safe_edge (ei)); )
    if ((e->flags & EDGE_FALLTHRU) && !single_succ_p (e->src))
      split_edge (e);
    else
      ei_next (&ei);

  /* Find the loops.  */

  if (flow_loops_find (loops) <= 1)
    {
      /* No loops.  */
      flow_loops_free (loops);
      free (loops);

      return NULL;
    }

  /* Not going to update these.  */
  free (loops->cfg.rc_order);
  loops->cfg.rc_order = NULL;
  free (loops->cfg.dfs_order);
  loops->cfg.dfs_order = NULL;

  /* Create pre-headers.  */
  create_preheaders (loops, CP_SIMPLE_PREHEADERS);

  /* Force all latches to have only single successor.  */
  force_single_succ_latches (loops);

  /* Mark irreducible loops.  */
  mark_irreducible_loops (loops);

  /* Dump loops.  */
  flow_loops_dump (loops, dumpfile, NULL, 1);

#ifdef ENABLE_CHECKING
  verify_dominators (CDI_DOMINATORS);
  verify_loop_structure (loops);
#endif

  return loops;
}
Beispiel #2
0
void
loop_optimizer_init (unsigned flags)
{
  timevar_push (TV_LOOP_INIT);

  if (!current_loops)
    {
      gcc_assert (!(cfun->curr_properties & PROP_loops));

      /* Find the loops.  */
      current_loops = flow_loops_find (NULL);
    }
  else
    {
      bool recorded_exits = loops_state_satisfies_p (LOOPS_HAVE_RECORDED_EXITS);
      bool needs_fixup = loops_state_satisfies_p (LOOPS_NEED_FIXUP);

      gcc_assert (cfun->curr_properties & PROP_loops);

      /* Ensure that the dominators are computed, like flow_loops_find does.  */
      calculate_dominance_info (CDI_DOMINATORS);

#ifdef ENABLE_CHECKING
      if (!needs_fixup)
	verify_loop_structure ();
#endif

      /* Clear all flags.  */
      if (recorded_exits)
	release_recorded_exits ();
      loops_state_clear (~0U);

      if (needs_fixup)
	{
	  /* Apply LOOPS_MAY_HAVE_MULTIPLE_LATCHES early as fix_loop_structure
	     re-applies flags.  */
	  loops_state_set (flags & LOOPS_MAY_HAVE_MULTIPLE_LATCHES);
	  fix_loop_structure (NULL);
	}
    }

  /* Apply flags to loops.  */
  apply_loop_flags (flags);

  /* Dump loops.  */
  flow_loops_dump (dump_file, NULL, 1);

#ifdef ENABLE_CHECKING
  verify_loop_structure ();
#endif

  timevar_pop (TV_LOOP_INIT);
}
Beispiel #3
0
/* Finalize loop optimizer.  */
void
loop_optimizer_finalize (struct loops *loops, FILE *dumpfile)
{
  unsigned i;

  if (!loops)
    return;

  for (i = 1; i < loops->num; i++)
    if (loops->parray[i])
      free_simple_loop_desc (loops->parray[i]);

  /* Another dump.  */
  flow_loops_dump (loops, dumpfile, NULL, 1);

  /* Clean up.  */
  flow_loops_free (loops);
  free (loops);

  /* Checking.  */
#ifdef ENABLE_CHECKING
  verify_flow_info ();
#endif
}
Beispiel #4
0
static funct_state
analyze_function (struct cgraph_node *fn, bool ipa)
{
  tree decl = fn->symbol.decl;
  funct_state l;
  basic_block this_block;

  l = XCNEW (struct funct_state_d);
  l->pure_const_state = IPA_CONST;
  l->state_previously_known = IPA_NEITHER;
  l->looping_previously_known = true;
  l->looping = false;
  l->can_throw = false;
  state_from_flags (&l->state_previously_known, &l->looping_previously_known,
		    flags_from_decl_or_type (fn->symbol.decl),
		    cgraph_node_cannot_return (fn));

  if (fn->thunk.thunk_p || fn->symbol.alias)
    {
      /* Thunk gets propagated through, so nothing interesting happens.  */
      gcc_assert (ipa);
      return l;
    }

  if (dump_file)
    {
      fprintf (dump_file, "\n\n local analysis of %s\n ",
	       cgraph_node_name (fn));
    }

  push_cfun (DECL_STRUCT_FUNCTION (decl));

  FOR_EACH_BB (this_block)
    {
      gimple_stmt_iterator gsi;
      struct walk_stmt_info wi;

      memset (&wi, 0, sizeof(wi));
      for (gsi = gsi_start_bb (this_block);
	   !gsi_end_p (gsi);
	   gsi_next (&gsi))
	{
	  check_stmt (&gsi, l, ipa);
	  if (l->pure_const_state == IPA_NEITHER && l->looping && l->can_throw)
	    goto end;
	}
    }

end:
  if (l->pure_const_state != IPA_NEITHER)
    {
      /* Const functions cannot have back edges (an
	 indication of possible infinite loop side
	 effect.  */
      if (mark_dfs_back_edges ())
        {
	  /* Preheaders are needed for SCEV to work.
	     Simple latches and recorded exits improve chances that loop will
	     proved to be finite in testcases such as in loop-15.c
	     and loop-24.c  */
	  loop_optimizer_init (LOOPS_HAVE_PREHEADERS
			       | LOOPS_HAVE_SIMPLE_LATCHES
			       | LOOPS_HAVE_RECORDED_EXITS);
	  if (dump_file && (dump_flags & TDF_DETAILS))
	    flow_loops_dump (dump_file, NULL, 0);
	  if (mark_irreducible_loops ())
	    {
	      if (dump_file)
	        fprintf (dump_file, "    has irreducible loops\n");
	      l->looping = true;
	    }
	  else
	    {
	      loop_iterator li;
	      struct loop *loop;
	      scev_initialize ();
	      FOR_EACH_LOOP (li, loop, 0)
		if (!finite_loop_p (loop))
		  {
		    if (dump_file)
		      fprintf (dump_file, "    can not prove finiteness of "
			       "loop %i\n", loop->num);
		    l->looping =true;
		    FOR_EACH_LOOP_BREAK (li);
		  }
	      scev_finalize ();
	    }
          loop_optimizer_finalize ();
	}
    }

  if (dump_file && (dump_flags & TDF_DETAILS))
    fprintf (dump_file, "    checking previously known:");

  better_state (&l->pure_const_state, &l->looping,
		l->state_previously_known,
		l->looping_previously_known);
  if (TREE_NOTHROW (decl))
    l->can_throw = false;

  pop_cfun ();
  if (dump_file)
    {
      if (l->looping)
        fprintf (dump_file, "Function is locally looping.\n");
      if (l->can_throw)
        fprintf (dump_file, "Function is locally throwing.\n");
      if (l->pure_const_state == IPA_CONST)
        fprintf (dump_file, "Function is locally const.\n");
      if (l->pure_const_state == IPA_PURE)
        fprintf (dump_file, "Function is locally pure.\n");
    }
  return l;
}