+typedef struct _cliques_iter_t {
+ struct obstack ob;
+ const be_chordal_env_t *cenv;
+ ir_node **buf;
+ ir_node **blocks;
+ int n_blocks, blk;
+ struct list_head *bor;
+ pset *living;
+} cliques_iter_t;
+
+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 = env;
+ obstack_ptr_grow(&it->ob, blk);
+}
+
+#define pset_foreach(pset, irn) for(irn=pset_first(pset); irn; irn=pset_next(pset))
+
+
+/**
+ * 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 */
+ pset_foreach(it->living, irn)
+ 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;
+}
+
+static int ifg_std_cliques_begin(const void *self, void *iter, ir_node **buf)
+{
+ const ifg_std_t *ifg = self;
+ cliques_iter_t *it = iter;
+ ir_node *start_bl = get_irg_start_block(it->cenv->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 = 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);
+}
+
+static int ifg_std_cliques_next(const void *self, void *iter)
+{
+ return get_next_clique(iter);
+}
+
+static void ifg_std_cliques_break(const void *self, void *iter)
+{
+ free_clique_iter(iter);
+}
+
+