Exemple #1
0
/* Gets basic blocks of a LOOP.  Header is the 0-th block, rest is in dfs
   order against direction of edges from latch.  Specially, if
   header != latch, latch is the 1-st block.  */
basic_block *
get_loop_body (const struct loop *loop)
{
  basic_block *tovisit, bb;
  unsigned tv = 0;

  if (!loop->num_nodes)
    abort ();

  tovisit = xcalloc (loop->num_nodes, sizeof (basic_block));
  tovisit[tv++] = loop->header;

  if (loop->latch == EXIT_BLOCK_PTR)
    {
      /* There may be blocks unreachable from EXIT_BLOCK.  */
      if (loop->num_nodes != (unsigned) n_basic_blocks + 2)
	abort ();
      FOR_EACH_BB (bb)
	tovisit[tv++] = bb;
      tovisit[tv++] = EXIT_BLOCK_PTR;
    }
  else if (loop->latch != loop->header)
    {
      tv = dfs_enumerate_from (loop->latch, 1, glb_enum_p,
			       tovisit + 1, loop->num_nodes - 1,
			       loop->header) + 1;
    }

  if (tv != loop->num_nodes)
    abort ();
  return tovisit;
}
Exemple #2
0
static void
combine_stack_adjustments (void)
{
    basic_block bb;

    FOR_EACH_BB (bb)
    combine_stack_adjustments_for_block (bb);
}
Exemple #3
0
void
gsi_commit_edge_inserts (void)
{
  basic_block bb;
  edge e;
  edge_iterator ei;

  gsi_commit_one_edge_insert (single_succ_edge (ENTRY_BLOCK_PTR), NULL);

  FOR_EACH_BB (bb)
    FOR_EACH_EDGE (e, ei, bb->succs)
      gsi_commit_one_edge_insert (e, NULL);
}
Exemple #4
0
static void
compute_rev_insert_delete (struct edge_list *edge_list, sbitmap *st_avloc,
			   sbitmap *nearer, sbitmap *nearerout,
			   sbitmap *insert, sbitmap *del)
{
  int x;
  basic_block bb;

  FOR_EACH_BB (bb)
    sbitmap_difference (del[bb->index], st_avloc[bb->index],
			nearerout[bb->index]);

  for (x = 0; x < NUM_EDGES (edge_list); x++)
    {
      basic_block b = INDEX_EDGE_PRED_BB (edge_list, x);
      if (b == ENTRY_BLOCK_PTR)
	sbitmap_difference (insert[x], nearer[x], nearerout[last_basic_block]);
      else
	sbitmap_difference (insert[x], nearer[x], nearerout[b->index]);
    }
}
Exemple #5
0
static void
compute_insert_delete (struct edge_list *edge_list, sbitmap *antloc,
		       sbitmap *later, sbitmap *laterin, sbitmap *insert,
		       sbitmap *del)
{
  int x;
  basic_block bb;

  FOR_EACH_BB (bb)
    sbitmap_difference (del[bb->index], antloc[bb->index],
			laterin[bb->index]);

  for (x = 0; x < NUM_EDGES (edge_list); x++)
    {
      basic_block b = INDEX_EDGE_SUCC_BB (edge_list, x);

      if (b == EXIT_BLOCK_PTR)
	sbitmap_difference (insert[x], later[x], laterin[last_basic_block]);
      else
	sbitmap_difference (insert[x], later[x], laterin[b->index]);
    }
}
Exemple #6
0
int
flow_loops_find (struct loops *loops, int flags)
{
  int i;
  int b;
  int num_loops;
  edge e;
  sbitmap headers;
  int *dfs_order;
  int *rc_order;
  basic_block header;
  basic_block bb;

  /* This function cannot be repeatedly called with different
     flags to build up the loop information.  The loop tree
     must always be built if this function is called.  */
  if (! (flags & LOOP_TREE))
    abort ();

  memset (loops, 0, sizeof *loops);

  /* Taking care of this degenerate case makes the rest of
     this code simpler.  */
  if (n_basic_blocks == 0)
    return 0;

  dfs_order = NULL;
  rc_order = NULL;

  /* Join loops with shared headers.  */
  canonicalize_loop_headers ();

  /* Compute the dominators.  */
  calculate_dominance_info (CDI_DOMINATORS);

  /* Count the number of loop headers.  This should be the
     same as the number of natural loops.  */
  headers = sbitmap_alloc (last_basic_block);
  sbitmap_zero (headers);

  num_loops = 0;
  FOR_EACH_BB (header)
    {
      int more_latches = 0;

      header->loop_depth = 0;

      /* If we have an abnormal predecessor, do not consider the
	 loop (not worth the problems).  */
      for (e = header->pred; e; e = e->pred_next)
	if (e->flags & EDGE_ABNORMAL)
	  break;
      if (e)
	continue;

      for (e = header->pred; e; e = e->pred_next)
	{
	  basic_block latch = e->src;

	  if (e->flags & EDGE_ABNORMAL)
	    abort ();

	  /* Look for back edges where a predecessor is dominated
	     by this block.  A natural loop has a single entry
	     node (header) that dominates all the nodes in the
	     loop.  It also has single back edge to the header
	     from a latch node.  */
	  if (latch != ENTRY_BLOCK_PTR
	      && dominated_by_p (CDI_DOMINATORS, latch, header))
	    {
	      /* Shared headers should be eliminated by now.  */
	      if (more_latches)
		abort ();
	      more_latches = 1;
	      SET_BIT (headers, header->index);
	      num_loops++;
	    }
	}
    }

  /* Allocate loop structures.  */
  loops->parray = xcalloc (num_loops + 1, sizeof (struct loop *));

  /* Dummy loop containing whole function.  */
  loops->parray[0] = xcalloc (1, sizeof (struct loop));
  loops->parray[0]->next = NULL;
  loops->parray[0]->inner = NULL;
  loops->parray[0]->outer = NULL;
  loops->parray[0]->depth = 0;
  loops->parray[0]->pred = NULL;
  loops->parray[0]->num_nodes = n_basic_blocks + 2;
  loops->parray[0]->latch = EXIT_BLOCK_PTR;
  loops->parray[0]->header = ENTRY_BLOCK_PTR;
  ENTRY_BLOCK_PTR->loop_father = loops->parray[0];
  EXIT_BLOCK_PTR->loop_father = loops->parray[0];

  loops->tree_root = loops->parray[0];

  /* Find and record information about all the natural loops
     in the CFG.  */
  loops->num = 1;
  FOR_EACH_BB (bb)
    bb->loop_father = loops->tree_root;

  if (num_loops)
    {
      /* Compute depth first search order of the CFG so that outer
	 natural loops will be found before inner natural loops.  */
      dfs_order = xmalloc (n_basic_blocks * sizeof (int));
      rc_order = xmalloc (n_basic_blocks * sizeof (int));
      flow_depth_first_order_compute (dfs_order, rc_order);

      /* Save CFG derived information to avoid recomputing it.  */
      loops->cfg.dfs_order = dfs_order;
      loops->cfg.rc_order = rc_order;

      num_loops = 1;

      for (b = 0; b < n_basic_blocks; b++)
	{
	  struct loop *loop;

	  /* Search the nodes of the CFG in reverse completion order
	     so that we can find outer loops first.  */
	  if (!TEST_BIT (headers, rc_order[b]))
	    continue;

	  header = BASIC_BLOCK (rc_order[b]);

	  loop = loops->parray[num_loops] = xcalloc (1, sizeof (struct loop));

	  loop->header = header;
	  loop->num = num_loops;
	  num_loops++;

	  /* Look for the latch for this header block.  */
	  for (e = header->pred; e; e = e->pred_next)
	    {
	      basic_block latch = e->src;

	      if (latch != ENTRY_BLOCK_PTR
		  && dominated_by_p (CDI_DOMINATORS, latch, header))
		{
		  loop->latch = latch;
		  break;
		}
	    }

	  flow_loop_tree_node_add (header->loop_father, loop);
	  loop->num_nodes = flow_loop_nodes_find (loop->header, loop);
	}

      /* Assign the loop nesting depth and enclosed loop level for each
	 loop.  */
      loops->levels = flow_loops_level_compute (loops);

      /* Scan the loops.  */
      for (i = 1; i < num_loops; i++)
	flow_loop_scan (loops->parray[i], flags);

      loops->num = num_loops;
    }
  else
    {
      free_dominance_info (CDI_DOMINATORS);
    }

  sbitmap_free (headers);

  loops->state = 0;
#ifdef ENABLE_CHECKING
  verify_flow_info ();
  verify_loop_structure (loops);
#endif

  return loops->num;
}