+typedef int(*confl_f)(const ir_node *a, const ir_node *b, void *data);
+
+/**
+ * @param result Gets filled with the computed maximum independent set.
+ * @param count The size of input arrays / the number of nodes
+ * @param nodes A set of nodes to copmute the max. ind. set for
+ * @param weights Weights associated to the nodes in @p nodes
+ * @param confl Callback function to decide if two values interfere
+ * @param data Passed into all callbacks
+ * @return The size of the computed set
+ */
+//int max_ind_set(ir_node **result, int count, ir_node **nodes, int *weights, confl_f confl, void *data) {
+//
+//}
+
+/**
+ * Determines a maximum weighted independent set with respect to
+ * the interference and conflict edges of all nodes in a qnode.
+ */
+static INLINE void qnode_max_ind_set(qnode_t *qn, const unit_t *ou) {
+ ir_node **safe, **unsafe;
+ int i, o, safe_count, safe_costs, unsafe_count, *unsafe_costs;
+ bitset_t *curr, *best;
+ int max, next, pos, curr_weight, best_weight = 0;
+
+ /* assign the nodes into two groups.
+ * safe: node has no interference, hence it is in every max stable set.
+ * unsafe: node has an interference
+ */
+ safe = alloca((ou->node_count-1) * sizeof(*safe));
+ safe_costs = 0;
+ safe_count = 0;
+ unsafe = alloca((ou->node_count-1) * sizeof(*unsafe));
+ unsafe_costs = alloca((ou->node_count-1) * sizeof(*unsafe_costs));
+ unsafe_count = 0;
+ for(i=1; i<ou->node_count; ++i) {
+ int is_safe = 1;
+ for(o=1; o<ou->node_count; ++o) {
+ if (qnode_are_conflicting(qn, ou->nodes[i], ou->nodes[o])) {
+ if (i!=o) {
+ unsafe_costs[unsafe_count] = ou->costs[i];
+ unsafe[unsafe_count] = ou->nodes[i];
+ ++unsafe_count;
+ }
+ is_safe = 0;
+ break;
+ }
+ }
+ if (is_safe) {
+ safe_costs += ou->costs[i];
+ safe[safe_count++] = ou->nodes[i];
+ }
+ }
+
+
+
+ /* now compute the best set out of the unsafe nodes*/
+ best = bitset_alloca(unsafe_count);
+
+ if (unsafe_count > MIS_HEUR_TRIGGER) {
+ /* Heuristik: Greedy trial and error form index 0 to unsafe_count-1 */
+ for (i=0; i<unsafe_count; ++i) {
+ bitset_set(best, i);
+ /* check if it is a stable set */
+ for (o=bitset_next_set(best, 0); o!=-1 && o<=i; o=bitset_next_set(best, o+1))
+ if (qnode_are_conflicting(qn, unsafe[i], unsafe[o])) {
+ bitset_clear(best, i); /* clear the bit and try next one */
+ break;
+ }
+ }
+ /* compute the weight */
+ bitset_foreach(best, pos)
+ best_weight += unsafe_costs[pos];
+ } else {
+ /* Exact Algorithm: Brute force */
+ curr = bitset_alloca(unsafe_count);
+ bitset_set_all(curr);
+ while ((max = bitset_popcnt(curr)) != 0) {
+ /* check if curr is a stable set */
+ for (i=bitset_next_set(curr, 0); i!=-1; i=bitset_next_set(curr, i+1))
+ for (o=bitset_next_set(curr, i); o!=-1; o=bitset_next_set(curr, o+1)) /* !!!!! difference to ou_max_ind_set_costs(): NOT (curr, i+1) */
+ if (qnode_are_conflicting(qn, unsafe[i], unsafe[o]))
+ goto no_stable_set;
+
+ /* if we arrive here, we have a stable set */
+ /* compute the weigth of the stable set*/
+ curr_weight = 0;
+ bitset_foreach(curr, pos)
+ curr_weight += unsafe_costs[pos];
+
+ /* any better ? */
+ if (curr_weight > best_weight) {
+ best_weight = curr_weight;
+ bitset_copy(best, curr);
+ }
+
+no_stable_set:
+ bitset_minus1(curr);
+ }
+ }
+
+ /* transfer the best set into the qn */
+ qn->mis_size = 1+safe_count+bitset_popcnt(best);
+ qn->mis_costs = safe_costs+best_weight;
+ qn->mis[0] = ou->nodes[0]; /* the root is always in a max stable set */
+ next = 1;
+ for (i=0; i<safe_count; ++i)
+ qn->mis[next++] = safe[i];
+ bitset_foreach(best, pos)
+ qn->mis[next++] = unsafe[pos];
+}
+