+static ir_node *get_next_neighbour(neighbours_iter_t *it)
+{
+ ir_node *res = ir_nodeset_iterator_next(&it->iter);
+
+ if (res == NULL) {
+ ir_nodeset_destroy(&it->neighbours);
+ }
+ return res;
+}
+
+ir_node *be_ifg_neighbours_begin(const be_ifg_t *ifg, neighbours_iter_t *iter,
+ const ir_node *irn)
+{
+ find_neighbours(ifg, iter, irn);
+ return get_next_neighbour(iter);
+}
+
+ir_node *be_ifg_neighbours_next(neighbours_iter_t *iter)
+{
+ return get_next_neighbour(iter);
+}
+
+void be_ifg_neighbours_break(neighbours_iter_t *iter)
+{
+ neighbours_break(iter, 1);
+}
+
+static inline void free_clique_iter(cliques_iter_t *it)
+{
+ it->n_blocks = -1;
+ obstack_free(&it->ob, NULL);
+ del_pset(it->living);
+}
+
+static void get_blocks_dom_order(ir_node *blk, void *env)
+{
+ cliques_iter_t *it = (cliques_iter_t*)env;
+ obstack_ptr_grow(&it->ob, blk);
+}
+
+/**
+ * NOTE: Be careful when changing this function!
+ * First understand the control flow of consecutive calls.
+ */
+static inline int get_next_clique(cliques_iter_t *it)
+{
+
+ /* continue in the block we left the last time */
+ for (; it->blk < it->n_blocks; it->blk++) {
+ int output_on_shrink = 0;
+ struct list_head *head = get_block_border_head(it->cenv, it->blocks[it->blk]);
+
+ /* on entry to a new block set the first border ... */
+ if (!it->bor)
+ it->bor = head->prev;
+
+ /* ... otherwise continue with the border we left the last time */
+ for (; it->bor != head; it->bor = it->bor->prev) {
+ border_t *b = list_entry(it->bor, border_t, list);
+
+ /* if its a definition irn starts living */
+ if (b->is_def) {
+ pset_insert_ptr(it->living, b->irn);
+ if (b->is_real)
+ output_on_shrink = 1;
+ } else
+
+ /* if its the last usage the irn dies */
+ {
+ /* before shrinking the set, return the current maximal clique */
+ if (output_on_shrink) {
+ int count = 0;
+ ir_node *irn;
+
+ /* fill the output buffer */
+ for (irn = (ir_node*)pset_first(it->living); irn != NULL;
+ irn = (ir_node*)pset_next(it->living)) {
+ it->buf[count++] = irn;
+ }
+
+ assert(count > 0 && "We have a 'last usage', so there must be sth. in it->living");
+
+ return count;
+ }
+
+ pset_remove_ptr(it->living, b->irn);
+ }
+ }
+
+ it->bor = NULL;
+ assert(0 == pset_count(it->living) && "Something has survived! (At the end of the block it->living must be empty)");
+ }
+
+ if (it->n_blocks != -1)
+ free_clique_iter(it);
+
+ return -1;
+}
+
+int be_ifg_cliques_begin(const be_ifg_t *ifg, cliques_iter_t *it,
+ ir_node **buf)
+{
+ ir_node *start_bl = get_irg_start_block(ifg->env->irg);
+
+ obstack_init(&it->ob);
+ dom_tree_walk(start_bl, get_blocks_dom_order, NULL, it);
+
+ it->cenv = ifg->env;
+ it->buf = buf;
+ it->n_blocks = obstack_object_size(&it->ob) / sizeof(void *);
+ it->blocks = (ir_node**)obstack_finish(&it->ob);
+ it->blk = 0;
+ it->bor = NULL;
+ it->living = pset_new_ptr(2 * arch_register_class_n_regs(it->cenv->cls));
+
+ return get_next_clique(it);
+}
+
+int be_ifg_cliques_next(cliques_iter_t *iter)
+{
+ return get_next_clique(iter);
+}
+
+void be_ifg_cliques_break(cliques_iter_t *iter)
+{
+ free_clique_iter(iter);
+}
+
+int be_ifg_degree(const be_ifg_t *ifg, const ir_node *irn)
+{
+ neighbours_iter_t it;
+ int degree;
+ find_neighbours(ifg, &it, irn);
+ degree = ir_nodeset_size(&it.neighbours);
+ neighbours_break(&it, 1);
+ return degree;
+}
+
+be_ifg_t *be_create_ifg(const be_chordal_env_t *env)
+{
+ be_ifg_t *ifg = XMALLOC(be_ifg_t);
+ ifg->env = env;
+
+ return ifg;
+}
+
+static void int_comp_rec(be_ifg_t *ifg, ir_node *n, bitset_t *seen)
+{
+ neighbours_iter_t neigh_it;
+ ir_node *m;
+
+ be_ifg_foreach_neighbour(ifg, &neigh_it, n, m) {
+ if (bitset_is_set(seen, get_irn_idx(m)))
+ continue;
+
+ if (arch_get_irn_register_req(m)->type & arch_register_req_type_ignore)
+ continue;
+
+ bitset_set(seen, get_irn_idx(m));
+ int_comp_rec(ifg, m, seen);
+ }
+
+}
+
+static int int_component_stat(ir_graph *irg, be_ifg_t *ifg)
+{
+ int n_comp = 0;
+ nodes_iter_t nodes_it;
+ bitset_t *seen = bitset_malloc(get_irg_last_idx(irg));
+
+ ir_node *n;
+
+ be_ifg_foreach_node(ifg, &nodes_it, n) {
+ if (bitset_is_set(seen, get_irn_idx(n)))
+ continue;
+
+ if (arch_get_irn_register_req(n)->type & arch_register_req_type_ignore)
+ continue;
+
+ ++n_comp;
+ bitset_set(seen, get_irn_idx(n));
+ int_comp_rec(ifg, n, seen);
+ }
+
+ free(seen);
+ return n_comp;
+}
+
+void be_ifg_stat(ir_graph *irg, be_ifg_t *ifg, be_ifg_stat_t *stat)
+{
+ nodes_iter_t nodes_it;
+ neighbours_iter_t neigh_it;
+ bitset_t *nodes = bitset_malloc(get_irg_last_idx(irg));
+ ir_node *n, *m;
+
+ memset(stat, 0, sizeof(stat[0]));
+
+ be_ifg_foreach_node(ifg, &nodes_it, n) {
+ stat->n_nodes += 1;
+ be_ifg_foreach_neighbour(ifg, &neigh_it, n, m) {
+ bitset_set(nodes, get_irn_idx(n));
+ stat->n_edges += !bitset_is_set(nodes, get_irn_idx(m));
+ }
+ }
+
+ stat->n_comps = int_component_stat(irg, ifg);
+ bitset_free(nodes);