+
+/* Computes the post dominator trees. Sets a flag in irg to "dom_consistent".
+ If the control flow of the graph is changed this flag must be set to
+ "dom_inconsistent". */
+void compute_postdoms(ir_graph *irg) {
+ ir_graph *rem = current_ir_graph;
+ int n_blocks, used, i, j;
+ tmp_dom_info *tdi_list;
+
+ current_ir_graph = irg;
+
+ /* Update graph state */
+ assert(get_irg_phase_state(current_ir_graph) != phase_building);
+ current_ir_graph->pdom_state = dom_consistent;
+
+ /* Count the number of blocks in the graph. */
+ n_blocks = 0;
+ irg_block_walk(get_irg_end(current_ir_graph), count_and_init_blocks_pdom, NULL, &n_blocks);
+
+ /* Memory for temporary information. */
+ tdi_list = xcalloc(n_blocks, sizeof(tdi_list[0]));
+
+ /* We need the out datastructure. */
+ if (current_ir_graph->outs_state != outs_consistent)
+ compute_irg_outs(current_ir_graph);
+
+ /* this with a standard walker as passing the parent to the sons isn't
+ simple. */
+ used = 0;
+ inc_irg_block_visited(current_ir_graph);
+ init_tmp_pdom_info(get_irg_end_block(current_ir_graph), NULL, tdi_list, &used);
+ /* If not all blocks are reachable from End by cfg edges this assertion
+ fails.
+ assert(used == n_blocks && "Precondition for dom construction violated"); */
+ n_blocks = used;
+
+
+ for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
+ int irn_arity;
+ tmp_dom_info *w = &tdi_list[i];
+ tmp_dom_info *v;
+
+ /* Step 2 */
+ irn_arity = get_Block_n_cfg_outs(w->block);
+ for (j = 0; j < irn_arity; j++) {
+ ir_node *succ = get_Block_cfg_out(w->block, j);
+ tmp_dom_info *u;
+
+ if (get_Block_postdom_pre_num (succ) == -1)
+ continue; /* endless-loop */
+
+ u = dom_eval (&tdi_list[get_Block_postdom_pre_num(succ)]);
+ if (u->semi < w->semi) w->semi = u->semi;
+ }
+ /* Add w to w->semi's bucket. w is in exactly one bucket, so
+ buckets can be implemented as linked lists. */
+ w->bucket = w->semi->bucket;
+ w->semi->bucket = w;
+
+ dom_link (w->parent, w);
+
+ /* Step 3 */
+ while (w->parent->bucket) {
+ tmp_dom_info *u;
+ v = w->parent->bucket;
+ /* remove v from w->parent->bucket */
+ w->parent->bucket = v->bucket;
+ v->bucket = NULL;
+
+ u = dom_eval(v);
+ if (u->semi < v->semi)
+ v->dom = u;
+ else
+ v->dom = w->parent;
+ }
+ }
+ /* Step 4 */
+ tdi_list[0].dom = NULL;
+ set_Block_ipostdom(tdi_list[0].block, NULL);
+ set_Block_postdom_depth(tdi_list[0].block, 1);
+ for (i = 1; i < n_blocks; i++) {
+ tmp_dom_info *w = &tdi_list[i];
+
+ if (w->dom != w->semi) w->dom = w->dom->dom;
+ set_Block_ipostdom(w->block, w->dom->block);
+ set_Block_postdom_depth(w->block, get_Block_postdom_depth(w->dom->block) + 1);
+ }
+
+ /* clean up */
+ free(tdi_list);
+ current_ir_graph = rem;
+
+ /* Do a walk over the tree and assign the tree pre orders. */
+ {
+ unsigned tree_pre_order = 0;
+ postdom_tree_walk_irg(irg, assign_tree_postdom_pre_order,
+ assign_tree_postdom_pre_order_max, &tree_pre_order);
+ }
+}
+
+void free_postdom(ir_graph *irg) {
+ /* Update graph state */
+ assert(get_irg_phase_state(current_ir_graph) != phase_building);
+ current_ir_graph->pdom_state = dom_none;
+
+ /* With the implementation right now there is nothing to free,
+ but better call it anyways... */
+}