2 * Copyright (C) 1995-2008 University of Karlsruhe. All right reserved.
4 * This file is part of libFirm.
6 * This file may be distributed and/or modified under the terms of the
7 * GNU General Public License version 2 as published by the Free Software
8 * Foundation and appearing in the file LICENSE.GPL included in the
9 * packaging of this file.
11 * Licensees holding valid libFirm Professional Edition licenses may use
12 * this file in accordance with the libFirm Commercial License.
13 * Agreement provided with the Software.
15 * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
16 * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * @brief Construct and access dominator / post dominator tree.
23 * @author Goetz Lindenmaier, Michael Beck, Rubino Geiss
36 #include "irgraph_t.h" /* To access state field. */
43 #define get_dom_info(bl) (&(bl)->attr.block.dom)
44 #define get_pdom_info(bl) (&(bl)->attr.block.pdom)
46 /*--------------------------------------------------------------------*/
47 /** Accessing the dominator and post dominator data structures **/
48 /*--------------------------------------------------------------------*/
50 ir_node *get_Block_idom(const ir_node *bl) {
52 if (get_Block_dom_depth(bl) == -1) {
53 /* This block is not reachable from Start */
56 return get_dom_info(bl)->idom;
59 void set_Block_idom(ir_node *bl, ir_node *n) {
60 ir_dom_info *bli = get_dom_info(bl);
64 /* Set the immediate dominator of bl to n */
68 * If we don't set the root of the dominator tree
69 * Append bl to the dominates queue of n.
72 ir_dom_info *ni = get_dom_info(n);
74 bli->next = ni->first;
79 ir_node *get_Block_ipostdom(const ir_node *bl) {
81 if (get_Block_postdom_depth(bl) == -1) {
82 /* This block is not reachable from Start */
85 return get_pdom_info(bl)->idom;
88 void set_Block_ipostdom(ir_node *bl, ir_node *n) {
89 ir_dom_info *bli = get_pdom_info(bl);
93 /* Set the immediate post dominator of bl to n */
97 * If we don't set the root of the post dominator tree
98 * Append bl to the post dominates queue of n.
101 ir_dom_info *ni = get_pdom_info(n);
103 bli->next = ni->first;
108 int get_Block_dom_pre_num(const ir_node *bl) {
109 assert(is_Block(bl));
110 return get_dom_info(bl)->pre_num;
113 void set_Block_dom_pre_num(ir_node *bl, int num) {
114 assert(is_Block(bl));
115 get_dom_info(bl)->pre_num = num;
118 int get_Block_dom_depth(const ir_node *bl) {
119 assert(is_Block(bl));
120 return get_dom_info(bl)->dom_depth;
123 void set_Block_dom_depth(ir_node *bl, int depth) {
124 assert(is_Block(bl));
125 get_dom_info(bl)->dom_depth = depth;
129 int get_Block_postdom_pre_num(const ir_node *bl) {
130 assert(is_Block(bl));
131 return get_pdom_info(bl)->pre_num;
134 void set_Block_postdom_pre_num(ir_node *bl, int num) {
135 assert(is_Block(bl));
136 get_pdom_info(bl)->pre_num = num;
139 int get_Block_postdom_depth(const ir_node *bl) {
140 assert(is_Block(bl));
141 return get_pdom_info(bl)->dom_depth;
144 void set_Block_postdom_depth(ir_node *bl, int depth) {
145 assert(is_Block(bl));
146 get_pdom_info(bl)->dom_depth = depth;
149 unsigned get_Block_dom_tree_pre_num(const ir_node *bl) {
150 assert(is_Block(bl));
151 return get_dom_info(bl)->tree_pre_num;
154 unsigned get_Block_dom_max_subtree_pre_num(const ir_node *bl) {
155 assert(is_Block(bl));
156 return get_dom_info(bl)->max_subtree_pre_num;
159 unsigned get_Block_pdom_tree_pre_num(const ir_node *bl) {
160 assert(is_Block(bl));
161 return get_pdom_info(bl)->tree_pre_num;
164 unsigned get_Block_pdom_max_subtree_pre_num(const ir_node *bl) {
165 assert(is_Block(bl));
166 return get_pdom_info(bl)->max_subtree_pre_num;
169 /* Check, if a block dominates another block. */
170 int block_dominates(const ir_node *a, const ir_node *b) {
171 const ir_dom_info *ai, *bi;
173 if (is_Block(a) && is_Block(b)) {
174 ai = get_dom_info(a);
175 bi = get_dom_info(b);
176 return bi->tree_pre_num - ai->tree_pre_num
177 <= ai->max_subtree_pre_num - ai->tree_pre_num;
183 /* Check, if a block strictly dominates another block. */
184 int block_strictly_dominates(const ir_node *a, const ir_node *b) {
185 return (a != b) && block_dominates(a, b);
188 /* Returns the smallest common dominator block of two nodes. */
189 ir_node *node_smallest_common_dominator(ir_node *a, ir_node *b) {
190 ir_node *bl_a = is_Block(a) ? a : get_nodes_block(a);
191 ir_node *bl_b = is_Block(b) ? b : get_nodes_block(b);
192 ir_node *dom_bl = NULL;
194 /* Check if block of a dominates block of b */
195 if (block_dominates(bl_a, bl_b))
197 /* Check if block of b dominates block of a */
198 else if (block_dominates(bl_b, bl_a))
201 /* walk up dominator tree and search for first block dominating a and b */
203 bl_a = get_Block_idom(bl_a);
205 assert(! is_Bad(bl_a) && "block is dead?");
207 if (block_dominates(bl_a, bl_b))
215 /* Returns the smallest common dominator block of all users of a node. */
216 ir_node *node_users_smallest_common_dominator(ir_node *irn, int handle_phi) {
217 int n, j, i = 0, success;
218 ir_node **user_blocks, *dom_bl;
219 const ir_edge_t *edge;
221 assert(! is_Block(irn) && "WRONG USAGE of node_users_smallest_common_dominator");
222 assert(edges_activated(get_irn_irg(irn)) && "need edges activated");
224 n = get_irn_n_edges(irn);
226 /* get array to hold all block of the node users */
227 NEW_ARR_A(ir_node *, user_blocks, n);
228 foreach_out_edge(irn, edge) {
229 ir_node *src = get_edge_src_irn(edge);
231 if (is_Phi(src) && handle_phi) {
232 /* get the corresponding cfg predecessor block if phi handling requested */
233 j = get_edge_src_pos(edge);
234 assert(j >= 0 && "kaputt");
235 user_blocks[i++] = get_Block_cfgpred_block(get_nodes_block(src), j);
238 user_blocks[i++] = is_Block(src) ? src : get_nodes_block(src);
241 assert(i == n && "get_irn_n_edges probably broken");
243 /* in case of only one user: return the block of the user */
245 return user_blocks[0];
248 /* search the smallest block dominating all user blocks */
250 dom_bl = node_smallest_common_dominator(user_blocks[i], user_blocks[i + 1]);
253 /* check if this block dominates all remaining blocks as well */
254 for (j = i + 2; j < n; j++) {
255 if (! block_dominates(dom_bl, user_blocks[j]))
262 /* inherit the dominator block of the first (i + 1) users */
263 user_blocks[++i] = dom_bl;
266 assert(success && "no block found dominating all users");
272 /* Get the first node in the list of nodes dominated by a given block. */
273 ir_node *get_Block_dominated_first(const ir_node *bl) {
274 assert(is_Block(bl));
275 return get_dom_info(bl)->first;
278 /* Get the next node in a list of nodes which are dominated by some
280 ir_node *get_Block_dominated_next(const ir_node *bl) {
281 assert(is_Block(bl));
282 return get_dom_info(bl)->next;
285 /* Check, if a block post dominates another block. */
286 int block_postdominates(const ir_node *a, const ir_node *b) {
287 const ir_dom_info *ai, *bi;
289 if (is_Block(a) && is_Block(b)) {
290 ai = get_pdom_info(a);
291 bi = get_pdom_info(b);
292 return bi->tree_pre_num - ai->tree_pre_num
293 <= ai->max_subtree_pre_num - ai->tree_pre_num;
299 /* Check, if a block strictly dominates another block. */
300 int block_strictly_postdominates(const ir_node *a, const ir_node *b) {
301 return (a != b) && block_postdominates(a, b);
305 /* Get the first node in the list of nodes post dominated by a given block. */
306 ir_node *get_Block_postdominated_first(const ir_node *bl) {
307 assert(is_Block(bl));
308 return get_pdom_info(bl)->first;
311 /* Get the next node in a list of nodes which are post dominated by some
313 ir_node *get_Block_postdominated_next(const ir_node *bl) {
314 assert(is_Block(bl));
315 return get_pdom_info(bl)->next;
318 /* Visit all nodes in the dominator subtree of a given node. */
319 void dom_tree_walk(ir_node *bl, irg_walk_func *pre,
320 irg_walk_func *post, void *env)
327 dominates_for_each(bl, p) {
328 dom_tree_walk(p, pre, post, env);
335 /* Visit all nodes in the post dominator subtree of a given node. */
336 void postdom_tree_walk(ir_node *bl, irg_walk_func *pre,
337 irg_walk_func *post, void *env)
344 postdominates_for_each(bl, p) {
345 postdom_tree_walk(p, pre, post, env);
352 /* Walk over the dominator tree of an irg starting at the root. */
353 void dom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
354 irg_walk_func *post, void *env)
356 /* The root of the dominator tree should be the Start block. */
357 ir_node *root = get_irg_start_block(irg);
359 assert(irg->dom_state == dom_consistent
360 && "The dominators of the irg must be consistent");
361 assert(root && "The start block of the graph is NULL?");
362 assert(get_dom_info(root)->idom == NULL
363 && "The start node in the graph must be the root of the dominator tree");
364 dom_tree_walk(root, pre, post, env);
367 /* Walk over the post dominator tree of an irg starting at the root. */
368 void postdom_tree_walk_irg(ir_graph *irg, irg_walk_func *pre,
369 irg_walk_func *post, void *env)
371 /* The root of the dominator tree should be the End block. */
372 ir_node *root = get_irg_end_block(irg);
374 assert(irg->pdom_state == dom_consistent
375 && "The dominators of the irg must be consistent");
376 assert(root && "The end block of the graph is NULL?");
377 assert(get_pdom_info(root)->idom == NULL
378 && "The End block node in the graph must be the root of the post dominator tree");
379 postdom_tree_walk(root, pre, post, env);
383 static void assign_tree_dom_pre_order(ir_node *bl, void *data)
385 unsigned *num = data;
386 ir_dom_info *bi = get_dom_info(bl);
388 bi->tree_pre_num = (*num)++;
391 static void assign_tree_dom_pre_order_max(ir_node *bl, void *data)
393 ir_dom_info *bi = get_dom_info(bl);
396 unsigned children = 0;
399 for(p = bi->first; p; p = get_dom_info(p)->next) {
400 unsigned max_p = get_dom_info(p)->max_subtree_pre_num;
401 max = max > max_p ? max : max_p;
405 bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
406 assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
409 static void assign_tree_postdom_pre_order(ir_node *bl, void *data)
411 unsigned *num = data;
412 ir_dom_info *bi = get_pdom_info(bl);
414 bi->tree_pre_num = (*num)++;
417 static void assign_tree_postdom_pre_order_max(ir_node *bl, void *data)
419 ir_dom_info *bi = get_pdom_info(bl);
422 unsigned children = 0;
425 for(p = bi->first; p; p = get_pdom_info(p)->next) {
426 unsigned max_p = get_pdom_info(p)->max_subtree_pre_num;
427 max = max > max_p ? max : max_p;
431 bi->max_subtree_pre_num = children > 0 ? max : bi->tree_pre_num;
432 assert(bi->max_subtree_pre_num >= bi->tree_pre_num);
435 /*--------------------------------------------------------------------*/
436 /* Building and Removing the dominator data structure */
437 /*--------------------------------------------------------------------*/
440 * count the number of blocks and clears the post dominance info
442 static void count_and_init_blocks_pdom(ir_node *bl, void *env) {
443 int *n_blocks = (int *) env;
446 memset(get_pdom_info(bl), 0, sizeof(ir_dom_info));
447 set_Block_ipostdom(bl, NULL);
448 set_Block_postdom_pre_num(bl, -1);
449 set_Block_postdom_depth(bl, -1);
452 /** temporary type used while constructing the dominator / post dominator tree. */
453 typedef struct tmp_dom_info {
454 ir_node *block; /**< backlink */
456 struct tmp_dom_info *semi; /**< semidominator */
457 struct tmp_dom_info *parent;
458 struct tmp_dom_info *label; /**< used for LINK and EVAL */
459 struct tmp_dom_info *ancestor;/**< used for LINK and EVAL */
460 struct tmp_dom_info *dom; /**< After step 3, if the semidominator of w is
461 its immediate dominator, then w->dom is the
462 immediate dominator of w. Otherwise w->dom
463 is a vertex v whose number is smaller than
464 w and whose immediate dominator is also w's
465 immediate dominator. After step 4, w->dom
466 is the immediate dominator of w. */
467 struct tmp_dom_info *bucket; /**< set of vertices with same semidominator */
470 /** Struct to pass info through walker. */
478 * Walks Blocks along the out data structure. If recursion started with
479 * Start block misses control dead blocks.
481 static void init_tmp_dom_info(ir_node *bl, tmp_dom_info *parent,
482 tmp_dom_info *tdi_list, int *used, int n_blocks) {
486 assert(is_Block(bl));
487 if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
489 mark_Block_block_visited(bl);
490 set_Block_dom_pre_num(bl, *used);
492 assert(*used < n_blocks);
493 tdi = &tdi_list[*used];
498 tdi->ancestor = NULL;
500 tdi->parent = parent;
504 for (i = get_Block_n_cfg_outs_ka(bl) - 1; i >= 0; --i) {
505 ir_node *pred = get_Block_cfg_out_ka(bl, i);
506 /* can happen for half-optimized dead code (I've seen this in student
511 init_tmp_dom_info(pred, tdi, tdi_list, used, n_blocks);
516 * Walks Blocks along the control flow. If recursion started with
517 * End block misses blocks in endless loops.
519 static void init_tmp_pdom_info(ir_node *bl, tmp_dom_info *parent,
520 tmp_dom_info *tdi_list, int* used, int n_blocks) {
524 assert(is_Block(bl));
525 if (get_irg_block_visited(current_ir_graph) == get_Block_block_visited(bl))
527 mark_Block_block_visited(bl);
528 set_Block_postdom_pre_num(bl, *used);
530 assert(*used < n_blocks);
531 tdi = &tdi_list[*used];
536 tdi->ancestor = NULL;
538 tdi->parent = parent;
542 for (i = get_Block_n_cfgpreds(bl) - 1; i >= 0; --i) {
543 ir_node *pred = get_Block_cfgpred_block(bl, i);
546 assert(is_Block(pred));
547 init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
550 /* Handle keep-alives. Note that the preprocessing
551 in init_construction() had already killed all
552 phantom keep-alive edges. All remaining block keep-alives
553 are really edges to endless loops.
555 if (bl == get_irg_end_block(current_ir_graph)) {
556 ir_node *end = get_irg_end(current_ir_graph);
558 for (i = get_irn_arity(end) - 1; i >= 0; --i) {
559 ir_node *pred = get_irn_n(end, i);
562 init_tmp_pdom_info(pred, tdi, tdi_list, used, n_blocks);
567 static void dom_compress(tmp_dom_info *v) {
568 assert (v->ancestor);
569 if (v->ancestor->ancestor) {
570 dom_compress (v->ancestor);
571 if (v->ancestor->label->semi < v->label->semi) {
572 v->label = v->ancestor->label;
574 v->ancestor = v->ancestor->ancestor;
579 * if V is a root, return v, else return the vertex u, not being the
580 * root, with minimum u->semi on the path from v to its root.
582 inline static tmp_dom_info *dom_eval(tmp_dom_info *v) {
583 if (!v->ancestor) return v;
588 /** make V W's ancestor */
589 inline static void dom_link(tmp_dom_info *v, tmp_dom_info *w) {
594 * Walker: count the number of blocks and clears the dominance info
596 static void count_and_init_blocks_dom(ir_node *bl, void *env) {
597 int *n_blocks = (int *) env;
600 memset(get_dom_info(bl), 0, sizeof(ir_dom_info));
601 set_Block_idom(bl, NULL);
602 set_Block_dom_pre_num(bl, -1);
603 set_Block_dom_depth(bl, -1);
607 * Initialize the dominance/postdominance construction:
609 * - count the number of blocks
610 * - clear the dominance info
611 * - remove Block-keepalives of live blocks to reduce
612 * the number of "phantom" block edges
614 * @param irg the graph
615 * @param pre a walker function that will be called for every block in the graph
617 static int init_construction(ir_graph *irg, irg_walk_func *pre) {
618 ir_graph *rem = current_ir_graph;
623 current_ir_graph = irg;
625 /* this visits only the reachable blocks */
626 irg_block_walk(get_irg_end_block(irg), pre, NULL, &n_blocks);
628 /* now visit the unreachable (from End) Blocks and remove unnecessary keep-alives */
629 end = get_irg_end(irg);
630 arity = get_End_n_keepalives(end);
631 if (arity) { /* we have keep-alives */
635 NEW_ARR_A(ir_node *, in, arity);
636 for (i = j = 0; i < arity; i++) {
637 ir_node *pred = get_End_keepalive(end, i);
639 if (!is_Block(pred)) {
640 pred = get_nodes_block(pred);
641 if (!is_Block(pred)) {
642 /* a node which has a bad block input: kill it */
646 dec_irg_block_visited(irg);
647 irg_block_walk(pred, pre, NULL, &n_blocks);
651 /* we kill some keep-alives */
652 set_End_keepalives(end, j, in);
653 set_irg_outs_inconsistent(irg);
657 current_ir_graph = rem;
662 /* Computes the dominator trees. Sets a flag in irg to "dom_consistent".
663 If the control flow of the graph is changed this flag must be set to
664 "dom_inconsistent". */
665 void compute_doms(ir_graph *irg) {
666 ir_graph *rem = current_ir_graph;
667 int n_blocks, used, i, j;
668 tmp_dom_info *tdi_list; /* Ein Golf? */
670 current_ir_graph = irg;
672 /* Update graph state */
673 assert(get_irg_phase_state(irg) != phase_building);
674 irg->dom_state = dom_consistent;
676 /* Count the number of blocks in the graph. */
677 n_blocks = init_construction(irg, count_and_init_blocks_dom);
679 /* Memory for temporary information. */
680 tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
682 /* We need the out data structure. */
683 assure_irg_outs(irg);
685 /* this with a standard walker as passing the parent to the sons isn't
688 inc_irg_block_visited(irg);
689 init_tmp_dom_info(get_irg_start_block(irg), NULL, tdi_list, &used, n_blocks);
690 /* If not all blocks are reachable from Start by out edges this assertion
692 assert(used == n_blocks && "Precondition for dom construction violated"); */
693 assert(used <= n_blocks && "Precondition for dom construction violated");
697 for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
699 tmp_dom_info *w = &tdi_list[i];
703 irn_arity = get_irn_arity(w->block);
704 for (j = 0; j < irn_arity; j++) {
705 ir_node *pred = get_Block_cfgpred_block(w->block, j);
708 if (is_Bad(pred) || (get_Block_dom_pre_num (pred) == -1))
709 continue; /* control-dead */
711 u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
712 if (u->semi < w->semi) w->semi = u->semi;
715 /* handle keep-alives if we are at the end block */
716 if (w->block == get_irg_end_block(irg)) {
717 ir_node *end = get_irg_end(irg);
719 irn_arity = get_irn_arity(end);
720 for (j = 0; j < irn_arity; j++) {
721 ir_node *pred = get_irn_n(end, j);
724 if (is_no_Block(pred) || get_Block_dom_pre_num(pred) == -1)
725 continue; /* control-dead */
727 u = dom_eval (&tdi_list[get_Block_dom_pre_num(pred)]);
728 if (u->semi < w->semi) w->semi = u->semi;
732 /* Add w to w->semi's bucket. w is in exactly one bucket, so
733 buckets can been implemented as linked lists. */
734 w->bucket = w->semi->bucket;
737 dom_link (w->parent, w);
740 while (w->parent->bucket) {
742 v = w->parent->bucket;
743 /* remove v from w->parent->bucket */
744 w->parent->bucket = v->bucket;
748 if (u->semi < v->semi)
755 tdi_list[0].dom = NULL;
756 set_Block_idom(tdi_list[0].block, NULL);
757 set_Block_dom_depth(tdi_list[0].block, 1);
758 for (i = 1; i < n_blocks; i++) {
759 tmp_dom_info *w = &tdi_list[i];
763 continue; /* control dead */
765 if (w->dom != w->semi) w->dom = w->dom->dom;
766 set_Block_idom(w->block, w->dom->block);
768 /* blocks dominated by dead one's are still dead */
769 depth = get_Block_dom_depth(w->dom->block);
772 set_Block_dom_depth(w->block, depth);
778 /* Do a walk over the tree and assign the tree pre orders. */
780 unsigned tree_pre_order = 0;
781 dom_tree_walk_irg(irg, assign_tree_dom_pre_order,
782 assign_tree_dom_pre_order_max, &tree_pre_order);
784 current_ir_graph = rem;
787 void assure_doms(ir_graph *irg) {
788 if (get_irg_dom_state(irg) != dom_consistent)
792 void free_dom(ir_graph *irg) {
793 /* Update graph state */
794 assert(get_irg_phase_state(irg) != phase_building);
795 irg->dom_state = dom_none;
797 /* With the implementation right now there is nothing to free,
798 but better call it anyways... */
801 /* Computes the post dominator trees. Sets a flag in irg to "dom_consistent".
802 If the control flow of the graph is changed this flag must be set to
803 "dom_inconsistent". */
804 void compute_postdoms(ir_graph *irg) {
805 ir_graph *rem = current_ir_graph;
806 int n_blocks, used, i, j;
807 tmp_dom_info *tdi_list;
809 current_ir_graph = irg;
811 /* Update graph state */
812 assert(get_irg_phase_state(irg) != phase_building);
813 irg->pdom_state = dom_consistent;
815 /* Count the number of blocks in the graph. */
816 n_blocks = init_construction(irg, count_and_init_blocks_pdom);
818 /* Memory for temporary information. */
819 tdi_list = XMALLOCNZ(tmp_dom_info, n_blocks);
821 /* We need the out data structure. */
822 assure_irg_outs(irg);
824 /* this with a standard walker as passing the parent to the sons isn't
827 inc_irg_block_visited(irg);
828 init_tmp_pdom_info(get_irg_end_block(irg), NULL, tdi_list, &used, n_blocks);
829 /* If not all blocks are reachable from End by cfg edges this assertion
831 assert(used == n_blocks && "Precondition for dom construction violated"); */
835 for (i = n_blocks-1; i > 0; i--) { /* Don't iterate the root, it's done. */
837 tmp_dom_info *w = &tdi_list[i];
841 irn_arity = get_Block_n_cfg_outs_ka(w->block);
842 for (j = 0; j < irn_arity; j++) {
843 ir_node *succ = get_Block_cfg_out_ka(w->block, j);
846 if (get_Block_postdom_pre_num (succ) == -1)
847 continue; /* endless-loop */
849 u = dom_eval (&tdi_list[get_Block_postdom_pre_num(succ)]);
850 if (u->semi < w->semi) w->semi = u->semi;
852 /* Add w to w->semi's bucket. w is in exactly one bucket, so
853 buckets can be implemented as linked lists. */
854 w->bucket = w->semi->bucket;
857 dom_link (w->parent, w);
860 while (w->parent->bucket) {
862 v = w->parent->bucket;
863 /* remove v from w->parent->bucket */
864 w->parent->bucket = v->bucket;
868 if (u->semi < v->semi)
875 tdi_list[0].dom = NULL;
876 set_Block_ipostdom(tdi_list[0].block, NULL);
877 set_Block_postdom_depth(tdi_list[0].block, 1);
878 for (i = 1; i < n_blocks; i++) {
879 tmp_dom_info *w = &tdi_list[i];
881 if (w->dom != w->semi) w->dom = w->dom->dom;
882 set_Block_ipostdom(w->block, w->dom->block);
883 set_Block_postdom_depth(w->block, get_Block_postdom_depth(w->dom->block) + 1);
889 /* Do a walk over the tree and assign the tree pre orders. */
891 unsigned tree_pre_order = 0;
892 postdom_tree_walk_irg(irg, assign_tree_postdom_pre_order,
893 assign_tree_postdom_pre_order_max, &tree_pre_order);
895 current_ir_graph = rem;
898 void assure_postdoms(ir_graph *irg) {
899 if (get_irg_postdom_state(irg) != dom_consistent)
900 compute_postdoms(irg);
903 void free_postdom(ir_graph *irg) {
904 /* Update graph state */
905 assert(get_irg_phase_state(irg) != phase_building);
906 irg->pdom_state = dom_none;
908 /* With the implementation right now there is nothing to free,
909 but better call it anyways... */