/* 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;
}
static void
combine_stack_adjustments (void)
{
basic_block bb;
FOR_EACH_BB (bb)
combine_stack_adjustments_for_block (bb);
}
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);
}
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]);
}
}
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]);
}
}
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;
}
