+static INLINE void remove_edge(set *edges, ir_node *n1, ir_node *n2, int *counter) {
+ edge_t new_edge, *e;
+
+ if (PTR_TO_INT(n1) < PTR_TO_INT(n2)) {
+ new_edge.n1 = n1;
+ new_edge.n2 = n2;
+ } else {
+ new_edge.n1 = n2;
+ new_edge.n2 = n1;
+ }
+ e = set_find(edges, &new_edge, sizeof(new_edge), HASH_EDGE(&new_edge));
+ if (e) {
+ e->n1 = NULL;
+ e->n2 = NULL;
+ (*counter)--;
+ }
+}
+
+#define pset_foreach(pset, irn) for(irn=pset_first(pset); irn; irn=pset_next(pset))
+
+/**
+ * Search for an interference clique and an external node
+ * with affinity edges to all nodes of the clique.
+ * At most 1 node of the clique can be colored equally with the external node.
+ */
+static void build_clique_star_cstr(ilp_env_t *ienv) {
+ affinity_node_t *aff;
+
+ /* for each node with affinity edges */
+ co_gs_foreach_aff_node(ienv->co, aff) {
+ struct obstack ob;
+ neighb_t *nbr;
+ ir_node *center = aff->irn;
+ ir_node **nodes;
+ set *edges;
+ int i, o, n_nodes, n_edges;
+
+ obstack_init(&ob);
+ edges = new_set(compare_edge_t, 8);
+
+ /* get all affinity neighbours */
+ n_nodes = 0;
+ co_gs_foreach_neighb(aff, nbr) {
+ obstack_ptr_grow(&ob, nbr->irn);
+ ++n_nodes;
+ }
+ nodes = obstack_finish(&ob);
+
+ /* get all interference edges between these */
+ n_edges = 0;
+ for (i=0; i<n_nodes; ++i)
+ for (o=0; o<i; ++o)
+ if (be_ifg_connected(ienv->co->cenv->ifg, nodes[i], nodes[o]))
+ add_edge(edges, nodes[i], nodes[o], &n_edges);
+
+ /* cover all these interference edges with maximal cliques */
+ while (n_edges) {
+ edge_t *e;
+ pset *clique = pset_new_ptr(8);
+ int growed;
+
+ /* get 2 starting nodes to form a clique */
+ for (e=set_first(edges); !e->n1; e=set_next(edges))
+ /*nothing*/ ;
+
+ pset_insert_ptr(clique, e->n1);
+ pset_insert_ptr(clique, e->n2);
+ remove_edge(edges, e->n1, e->n2, &n_edges);
+
+ /* while the clique is growing */
+ do {
+ growed = 0;
+
+ /* search for a candidate to extend the clique */
+ for (i=0; i<n_nodes; ++i) {
+ ir_node *member, *cand = nodes[i];
+ int is_cand;
+
+ /* if its already in the clique try the next */
+ if (pset_find_ptr(clique, cand))
+ continue;
+
+ /* are there all necessary interferences? */
+ is_cand = 1;
+ pset_foreach(clique, member) {
+ if (!find_edge(edges, cand, member)) {
+ is_cand = 0;
+ pset_break(clique);
+ break;
+ }
+ }
+
+ /* now we know if we have a clique extender */
+ if (is_cand) {
+ /* first remove all covered edges */
+ pset_foreach(clique, member)
+ remove_edge(edges, cand, member, &n_edges);
+
+ /* insert into clique */
+ pset_insert_ptr(clique, cand);
+ growed = 1;
+ break;
+ }
+ }
+ } while (growed);
+
+ /* now the clique is maximal. Finally add the constraint */
+ {
+ ir_node *member;
+ int var_idx, cst_idx, center_nr, member_nr;
+ char buf[16];
+
+ cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater, pset_count(clique)-1);
+ center_nr = get_irn_node_nr(center);
+
+ pset_foreach(clique, member) {
+ member_nr = get_irn_node_nr(member);
+ var_idx = lpp_get_var_idx(ienv->lp, name_cdd_sorted(buf, 'y', center_nr, member_nr));
+ lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
+ }
+ }
+
+ del_pset(clique);
+ }
+
+ del_set(edges);
+ obstack_free(&ob, NULL);
+ }
+}
+
+
+static void extend_path(ilp_env_t *ienv, pdeq *path, ir_node *irn) {
+ be_ifg_t *ifg = ienv->co->cenv->ifg;
+ int i, len;
+ ir_node **curr_path;
+ affinity_node_t *aff;
+ neighb_t *nbr;
+
+ /* do not walk backwards or in circles */
+ if (pdeq_contains(path, irn))
+ return;
+
+ /* insert the new irn */
+ pdeq_putr(path, irn);
+
+
+
+ /* check for forbidden interferences */
+ len = pdeq_len(path);
+ curr_path = alloca(len * sizeof(*curr_path));
+ pdeq_copyl(path, (const void **)curr_path);
+
+ for (i=1; i<len; ++i)
+ if (be_ifg_connected(ifg, irn, curr_path[i]))
+ goto end;
+
+
+
+ /* check for terminating interference */
+ if (be_ifg_connected(ifg, irn, curr_path[0])) {
+
+ /* One node is not a path. */
+ /* And a path of length 2 is covered by a clique star constraint. */
+ if (len > 2) {
+ /* finally build the constraint */
+ int cst_idx = lpp_add_cst(ienv->lp, NULL, lpp_greater, 1.0);
+ for (i=1; i<len; ++i) {
+ char buf[16];
+ int nr_1 = get_irn_node_nr(curr_path[i-1]);
+ int nr_2 = get_irn_node_nr(curr_path[i]);
+ int var_idx = lpp_get_var_idx(ienv->lp, name_cdd_sorted(buf, 'y', nr_1, nr_2));
+ lpp_set_factor_fast(ienv->lp, cst_idx, var_idx, 1.0);
+ }
+ }
+
+ /* this path cannot be extended anymore */
+ goto end;
+ }
+
+
+
+ /* recursively extend the path */
+ aff = get_affinity_info(ienv->co, irn);
+ co_gs_foreach_neighb(aff, nbr)
+ extend_path(ienv, path, nbr->irn);
+
+
+end:
+ /* remove the irn */
+ pdeq_getr(path);
+
+}
+
+/**
+ * Search a path of affinity edges, whose ends are connected
+ * by an interference edge and there are no other interference
+ * edges in between.
+ * Then at least one of these affinity edges must break.
+ */
+static void build_path_cstr(ilp_env_t *ienv) {
+ affinity_node_t *aff_info;
+
+ /* for each node with affinity edges */
+ co_gs_foreach_aff_node(ienv->co, aff_info) {
+ pdeq *path = new_pdeq();
+
+ extend_path(ienv, path, aff_info->irn);
+
+ del_pdeq(path);
+ }