2 * Copyright (C) 1995-2011 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 Structure Analysis
23 * @author Michael Beck
31 #include "firm_common.h"
33 #include "structure.h"
43 typedef union ir_reg_or_blk ir_reg_or_blk;
45 /* The structure tree. */
47 struct obstack obst; /**< The obstack where the data is allocated. */
48 ir_region *top; /**< The top region. */
49 ir_graph *irg; /**< Associated graph. */
54 firm_kind kind; /**< Must be k_ir_region. */
55 ir_region_kind type; /**< The type of this region. */
56 ir_region *parent; /**< points to the parent. */
57 ir_reg_or_blk *parts; /**< The list of all region parts. */
58 ir_region **pred; /**< The predecessor (control flow) regions of this region. */
59 ir_region **succ; /**< The successor (control flow) regions of this region. */
60 size_t prenum; /**< DFS pre-oder number */
61 size_t postnum; /**< DFS post-oder number */
62 void *link; /**< A link field. */
63 unsigned long nr; /**< for debugging */
64 unsigned visited:1; /**< The visited flag. */
65 unsigned exit:1; /**< If set, the parent region can be left by this node. */
66 unsigned enter:1; /**< If set, the parent region can be entered by this node. */
69 /* A helper type for unioning blocks and regions. */
71 firm_kind *kind; /**< For easier check. */
72 ir_node *blk; /**< A node */
73 ir_region *region; /**< A region. */
76 /* The debug handle. */
77 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
80 * Returns the link of a region.
82 void *get_region_link(const ir_region *reg)
88 * Sets the link of a region.
90 void set_region_link(ir_region *reg, void *data)
96 * Get the immediate region of a block.
98 ir_region *get_block_region(const ir_node *block)
100 assert(is_Block(block));
101 return block->attr.block.region;
105 * Sets the immediate region of a block.
107 void set_block_region(ir_node *block, ir_region *reg)
109 assert(is_Block(block));
110 block->attr.block.region = reg;
114 * Get the immediate region of a node.
116 ir_region *get_irn_region(ir_node *n)
119 n = get_nodes_block(n);
120 return get_block_region(n);
124 * Return non-zero if a given firm thing is a region.
126 int is_region(const void *thing)
128 const firm_kind *kind = (const firm_kind*) thing;
129 return *kind == k_ir_region;
133 * Return the number of predecessors of a region.
135 size_t get_region_n_preds(const ir_region *reg)
137 return ARR_LEN(reg->pred);
141 * Return the predecessor region at position pos.
143 ir_region *get_region_pred(const ir_region *reg, size_t pos)
145 assert(pos <= get_region_n_preds(reg));
146 return reg->pred[pos];
150 * Set the predecessor region at position pos.
152 void set_region_pred(ir_region *reg, size_t pos, ir_region *n)
154 assert(pos <= get_region_n_preds(reg));
159 * Return the number of successors in a region.
161 size_t get_region_n_succs(const ir_region *reg)
163 return ARR_LEN(reg->succ);
167 * Return the successor region at position pos.
169 ir_region *get_region_succ(const ir_region *reg, size_t pos)
171 assert(pos <= get_region_n_succs(reg));
172 return reg->succ[pos];
176 * Set the successor region at position pos.
178 void set_region_succ(ir_region *reg, size_t pos, ir_region *n)
180 assert(pos <= get_region_n_succs(reg));
184 /* ----------------------- construction -------------------------- */
186 /** Walker environment. */
187 typedef struct walk_env {
188 struct obstack *obst; /**< An obstack to allocate from. */
189 ir_region **post; /**< The list of all currently existent top regions. */
190 size_t l_post; /**< The length of the allocated regions array. */
191 size_t premax; /**< maximum pre counter */
192 size_t postmax; /**< maximum post counter */
193 ir_node *start_block; /**< The start block of the graph. */
194 ir_node *end_block; /**< The end block of the graph. */
198 * Do a DFS search on the initial regions, assign a prenum and a postnum to every
199 * node and store the region nodes into the post array.
201 static void dfs_walk2(ir_region *reg, walk_env *env)
205 if (reg->visited == 0) {
208 reg->prenum = env->premax++;
209 for (i = 0, n = get_region_n_succs(reg); i < n; ++i) {
211 ir_region *succ = get_region_succ(reg, i);
212 dfs_walk2(succ, env);
215 env->post[env->postmax] = reg;
216 reg->postnum = env->postmax++;
221 * Do a DFS search on the initial regions, assign a prenum and a postnum to every
222 * node and store the region nodes into the post array.
224 static void dfs_walk(ir_graph *irg, walk_env *env)
226 ir_graph *rem = current_ir_graph;
229 current_ir_graph = irg;
230 reg = (ir_region*) get_irn_link(get_irg_start_block(irg));
235 current_ir_graph = rem;
239 * Post-walker: wrap all blocks with a BasicBlock region
242 static void wrap_BasicBlocks(ir_node *block, void *ctx)
244 walk_env *env = (walk_env*) ctx;
247 /* Allocate a Block wrapper */
248 reg = OALLOC(env->obst, ir_region);
249 reg->kind = k_ir_region;
250 reg->type = ir_rk_BasicBlock;
258 reg->nr = get_irn_node_nr(block);
259 reg->parts = NEW_ARR_D(ir_reg_or_blk, env->obst, 1);
261 reg->parts[0].blk = block;
262 set_irn_link(block, reg);
265 } /* wrap_BasicBlocks */
268 * Post-walker: Create the pred and succ edges for Block wrapper.
269 * Kill edges to the Start and End blocks.
271 static void update_BasicBlock_regions(ir_node *blk, void *ctx)
273 walk_env *env = (walk_env*) ctx;
274 ir_region *reg = (ir_region*) get_irn_link(blk);
278 if (blk == env->start_block) {
279 /* handle Firm's self loop: Start block has no predecessors */
280 reg->pred = NEW_ARR_D(ir_region *, env->obst, 0);
282 len = get_Block_n_cfgpreds(blk);
283 reg->pred = NEW_ARR_D(ir_region *, env->obst, len);
284 for (j = i = 0; i < len; ++i) {
285 ir_node *pred = get_Block_cfgpred_block(blk, i);
286 reg->pred[j++] = (ir_region*) get_irn_link(pred);
288 ARR_SHRINKLEN(reg->pred, j);
291 len = get_Block_n_cfg_outs(blk);
292 reg->succ = NEW_ARR_D(ir_region *, env->obst, len);
293 for (j = i = 0; i < len; ++i) {
294 ir_node *succ = get_Block_cfg_out(blk, i);
295 reg->succ[j++] = (ir_region*) get_irn_link(succ);
297 ARR_SHRINKLEN(reg->succ, j);
298 } /* update_BasicBlock_regions */
300 /** Allocate a new region on an obstack */
301 static ir_region *alloc_region(struct obstack *obst, ir_region_kind type)
303 ir_region *reg = OALLOC(obst, ir_region);
304 reg->kind = k_ir_region;
318 * Creates a new Sequence region.
320 static ir_region *new_Sequence(struct obstack *obst, ir_region *nset, size_t nset_len)
322 ir_region *reg = alloc_region(obst, ir_rk_Sequence);
326 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, nset_len);
328 /* beware: list is in reverse order, reverse */
330 for (i = nset_len; i > 0;) {
333 reg->parts[i].region = nset;
335 next = (ir_region*) nset->link;
339 reg->nr = reg->parts[0].region->nr;
340 reg->pred = DUP_ARR_D(ir_region *, obst, reg->parts[0].region->pred);
341 reg->succ = DUP_ARR_D(ir_region *, obst, reg->parts[nset_len - 1].region->succ);
344 DB((dbg, LEVEL_2, " Created Sequence "));
345 for (i = 0; i < nset_len; ++i) {
346 DB((dbg, LEVEL_2, "(%lu)", reg->parts[i].region->nr));
348 DB((dbg, LEVEL_2, "\n"));
354 * Create a new IfThenElse region.
356 static ir_region *new_IfThenElse(struct obstack *obst, ir_region *if_b, ir_region *then_b, ir_region *else_b)
358 ir_region *reg = alloc_region(obst, ir_rk_IfThenElse);
361 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 3);
363 reg->parts[0].region = if_b; if_b->parent = reg;
364 reg->parts[1].region = then_b; then_b->parent = reg;
365 reg->parts[2].region = else_b; else_b->parent = reg;
367 reg->pred = DUP_ARR_D(ir_region *, obst, if_b->pred);
368 reg->succ = DUP_ARR_D(ir_region *, obst, then_b->succ);
370 DB((dbg, LEVEL_2, " Created If(%lu)Then(%lu)Else(%lu)\n", reg->nr, then_b->nr, else_b->nr));
373 } /* new_IfThenElse */
376 * Create a new IfThen region.
378 static ir_region *new_IfThen(struct obstack *obst, ir_region *if_b, ir_region *then_b)
380 ir_region *reg = alloc_region(obst, ir_rk_IfThen);
383 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
385 reg->parts[0].region = if_b; if_b->parent = reg;
386 reg->parts[1].region = then_b; then_b->parent = reg;
388 reg->pred = DUP_ARR_D(ir_region *, obst, if_b->pred);
389 reg->succ = DUP_ARR_D(ir_region *, obst, then_b->succ);
391 DB((dbg, LEVEL_2, " Created If(%lu)Then(%lu)\n", reg->nr, then_b->nr));
394 } /* new_IfThenElse */
397 * Create a new Switch/case region.
399 static ir_region *new_SwitchCase(struct obstack *obst, ir_region_kind type, ir_region *head, ir_region *exit,
400 ir_region *cases, size_t cases_len)
402 ir_region *reg = alloc_region(obst, type);
407 /* check, if the exit block is in the list */
408 for (c = cases; c != NULL; c = (ir_region*) c->link) {
416 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, cases_len + add);
418 reg->parts[0].region = head; head->parent = reg;
420 for (c = cases; c != NULL; c = n) {
421 n = (ir_region*) c->link;
423 reg->parts[i++].region = c;
429 reg->pred = DUP_ARR_D(ir_region *, obst, head->pred);
430 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
435 DB((dbg, LEVEL_2, " Created %s(%u)\n", reg->type == ir_rk_Switch ? "Switch" : "Case", reg->nr));
436 for (i = 1; i < ARR_LEN(reg->parts); ++i) {
437 DB((dbg, LEVEL_2, " Case(%lu)\n", reg->parts[i].region->nr));
439 DB((dbg, LEVEL_2, " Exit(%lu)\n", exit->nr));
442 } /* new_SwitchCase */
445 * Create a new SelfLoop region.
447 static ir_region *new_SelfLoop(struct obstack *obst, ir_region *head)
449 ir_region *reg = alloc_region(obst, ir_rk_SelfLoop);
454 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 1);
456 reg->parts[0].region = head; head->parent = reg;
458 len = ARR_LEN(head->pred);
459 reg->pred = NEW_ARR_D(ir_region *, obst, len - 1);
460 for (i = j = 0; i < len; ++i) {
461 ir_region *pred = get_region_pred(head, i);
463 reg->pred[j++] = pred;
465 assert(j == len - 1);
467 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
468 assert(ARR_LEN(head->succ) == 2);
470 succ = get_region_succ(head, 0);
474 reg->succ[0] = get_region_succ(head, 1);
476 DB((dbg, LEVEL_2, " Created SelfLoop(%lu)\n", reg->nr));
482 * Create a new RepeatLoop region.
484 static ir_region *new_RepeatLoop(struct obstack *obst, ir_region *head, ir_region *body)
486 ir_region *reg = alloc_region(obst, ir_rk_RepeatLoop);
490 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
492 reg->parts[0].region = head; head->parent = reg;
493 reg->parts[1].region = body; body->parent = reg;
495 reg->pred = DUP_ARR_D(ir_region *, obst, head->pred);
496 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
497 assert(ARR_LEN(body->succ) == 2);
499 succ = get_region_succ(body, 0);
503 reg->succ[0] = get_region_succ(body, 1);
505 DB((dbg, LEVEL_2, " Created RepeatLoop(%lu)Body(%lu)\n", reg->nr, body->nr));
508 } /* new_RepeatLoop */
511 * Create a new WhileLoop region.
513 static ir_region *new_WhileLoop(struct obstack *obst, ir_region *head)
515 ir_region *reg = alloc_region(obst, ir_rk_WhileLoop);
516 ir_region *body = (ir_region*) head->link;
523 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, 2);
525 reg->parts[0].region = head; head->parent = reg;
526 reg->parts[1].region = body; body->parent = reg;
528 len = ARR_LEN(head->pred);
529 reg->pred = NEW_ARR_D(ir_region *, obst, len - 1);
530 for (i = j = 0; i < len; ++i) {
531 ir_region *pred = get_region_pred(head, i);
533 reg->pred[j++] = pred;
535 assert(j == len - 1);
537 reg->succ = NEW_ARR_D(ir_region *, obst, 1);
538 assert(ARR_LEN(head->succ) == 2);
540 succ = get_region_succ(head, 0);
544 reg->succ[0] = get_region_succ(head, 1);
546 DB((dbg, LEVEL_2, " Created WhileLoop(%lu)Body(%lu)\n", reg->nr, body->nr));
549 } /* new_WhileLoop */
552 * Create a new new_NaturalLoop region.
554 static ir_region *new_NaturalLoop(struct obstack *obst, ir_region *head)
556 ir_region *reg = alloc_region(obst, ir_rk_WhileLoop);
558 size_t i, j, k, len, n_pred, n_succ;
560 /* count number of parts */
561 for (len = 0, c = head; c != NULL; c = (ir_region*) c->link)
565 reg->parts = NEW_ARR_D(ir_reg_or_blk, obst, len);
567 /* enter all parts */
568 for (i = 0, c = head; c != NULL; c = n) {
569 reg->parts[i++].region = c;
571 n = (ir_region*) c->link;
575 /* count number of preds */
577 for (i = get_region_n_preds(head); i > 0;) {
578 ir_region *pred = get_region_pred(head, --i);
579 if (pred->parent != reg)
582 reg->pred = NEW_ARR_D(ir_region *, obst, n_pred);
583 for (j = 0, i = get_region_n_preds(head); i > 0;) {
584 ir_region *pred = get_region_pred(head, --i);
585 if (pred->parent != reg)
586 reg->pred[j++] = pred;
589 /* count number of succs */
591 for (j = 0; j < len; ++j) {
592 ir_region *pc = reg->parts[j].region;
593 for (i = get_region_n_succs(pc); i > 0;) {
594 ir_region *succ = get_region_succ(pc, --i);
595 if (succ->parent != reg)
599 reg->succ = NEW_ARR_D(ir_region *, obst, n_succ);
601 for (j = 0; j < len; ++j) {
602 ir_region *pc = reg->parts[j].region;
603 for (i = get_region_n_succs(pc); i > 0;) {
604 ir_region *succ = get_region_succ(pc, --i);
605 if (succ->parent != reg)
606 reg->succ[k++] = succ;
611 DB((dbg, LEVEL_2, " Created NaturalLoop(%u)Head(%u)\n", reg->nr, head->nr));
612 for (i = 1; i < len; ++i) {
613 ir_region *p = reg->parts[i].region;
614 DB((dbg, LEVEL_2, " Body(%u)\n", p->nr));
618 } /* new_NaturalLoop */
621 * Return true if region a is an ancestor of region b in DFS search.
623 static int is_ancestor(const ir_region *a, const ir_region *b)
625 return (a->prenum <= b->prenum && a->postnum > b->postnum);
629 * Return true if region pred is a predecessor of region n.
631 static bool pred_of(const ir_region *pred, const ir_region *n)
634 for (i = 0, n_preds = get_region_n_preds(n); i < n_preds; ++i) {
635 if (get_region_pred(n, i) == pred)
642 * Return true if region succ is a successor of region n.
644 static bool succ_of(const ir_region *succ, const ir_region *n)
647 for (i = 0, n_succs = get_region_n_succs(n); i < n_succs; ++i) {
648 if (get_region_succ(n, i) == succ)
655 * Reverse a linked list of regions.
657 static struct ir_region *reverse_list(ir_region *n)
659 ir_region *prev = NULL, *next;
661 for (; n; n = next) {
662 next = (ir_region*) n->link;
670 * Find the cyclic region in the subgraph entered by node.
672 static ir_region *find_cyclic_region(ir_region *node)
675 ir_region *last = node;
678 for (i = get_region_n_preds(node); i > 0;) {
679 ir_region *pred = get_region_pred(node, --i);
681 /* search backedges */
682 if (!pred->link && pred != last && is_ancestor(node, pred)) {
683 ir_region *rem = last;
688 for (j = get_region_n_preds(pred); j > 0;) {
689 ir_region *p = get_region_pred(pred, --j);
691 /* Search regions we didn't visited yet and
692 link them into the list. */
693 if (!p->link && p != last) {
694 if (is_ancestor(node, p)) {
702 /* reverse the list. */
703 last = (ir_region*) rem->link;
704 rem->link = reverse_list(last);
708 if (node->link && improper) {
709 /* found an improper region, do minimization */
716 * Detect a cyclic region.
718 static ir_region *cyclic_region_type(struct obstack *obst, ir_region *node)
720 ir_region *list, *next;
722 /* simple cases first */
723 if (succ_of(node, node)) {
724 return new_SelfLoop(obst, node);
726 if (get_region_n_succs(node) == 1) {
727 ir_region *succ = get_region_succ(node, 0);
728 if (get_region_n_preds(succ) == 1 && succ_of(node, succ)) {
729 return new_RepeatLoop(obst, node, succ);
732 list = find_cyclic_region(node);
734 next = (ir_region*) list->link;
736 if (!next->link && get_region_n_succs(next) == 1) {
737 /* only one body block with only one successor (the head) */
738 return new_WhileLoop(obst, list);
740 /* A Loop with one head */
741 return new_NaturalLoop(obst, list);
748 * Clear all links on a list. Needed, because we expect cleared links.
750 static void clear_list(ir_region *list)
754 for (next = list; next; list = next) {
755 next = (ir_region*) list->link;
760 #define ADD_LIST(list, n) do { n->link = list; list = n; ++list##_len; } while (0)
763 * Detect an acyclic region.
765 static ir_region *acyclic_region_type(struct obstack *obst, ir_region *node)
770 ir_region *nset = NULL;
774 /* check for a block containing node */
776 p = get_region_n_preds(n) == 1;
779 n = get_region_pred(n, 0);
780 p = get_region_n_preds(n) == 1;
781 s = get_region_n_succs(n) == 1;
784 s = get_region_n_succs(n) == 1;
787 n = get_region_succ(n, 0);
788 p = get_region_n_preds(n) == 1;
789 s = get_region_n_succs(n) == 1;
795 /* node --> .. --> .. */
796 res = new_Sequence(obst, nset, nset_len);
801 /* check for IfThenElse */
802 k = get_region_n_succs(node);
804 size_t n_succs, m_succs, n_preds, m_preds;
806 n = get_region_succ(node, 0);
807 m = get_region_succ(node, 1);
809 n_succs = get_region_n_succs(n);
810 m_succs = get_region_n_succs(m);
811 n_preds = get_region_n_preds(n);
812 m_preds = get_region_n_preds(m);
813 if (n_succs == 1 && n_succs == m_succs && n_preds == m_preds &&
814 get_region_succ(n, 0) == get_region_succ(m, 0)) {
820 return new_IfThenElse(obst, node, n, m);
823 get_region_succ(n, 0) == m &&
829 return new_IfThen(obst, node, n);
832 get_region_succ(m, 0) == m &&
838 return new_IfThen(obst, node, m);
841 /* check for Switch, case */
843 ir_region *rexit = NULL;
845 nset = NULL; nset_len = 0;
846 for (i = k; i > 0;) {
847 n = get_region_succ(node, i--);
849 if (get_region_n_succs(n) != 1) {
850 /* must be the exit */
858 ir_region_kind kind = ir_rk_Case;
859 ir_region *pos_exit_1 = NULL;
860 ir_region *pos_exit_2 = NULL;
863 for (m = nset; m != NULL; m = (ir_region*) m->link) {
864 if (get_region_n_succs(m) != 1) {
865 /* must be the exit block */
868 } else if (rexit != m) {
874 ir_region *succ = get_region_succ(m, 0);
876 if (succ->link == NULL) {
878 if (succ == pos_exit_1)
880 else if (succ == pos_exit_2)
882 else if (pos_exit_1 == NULL)
884 else if (pos_exit_2 == NULL)
887 /* more than two possible exits */
890 } else if (rexit != succ) {
900 for (n = nset; n != NULL; n = (ir_region*) n->link) {
903 /* good, default fall through */
906 succ = get_region_succ(n, 0);
908 /* good, switch to exit */
911 if (succ->link == NULL) {
922 return new_SwitchCase(obst, kind, node, rexit, nset, nset_len);
932 * replace all pred edges from region pred that points to any of the set set
933 * to ONE edge to reg.
935 static void replace_pred(ir_region *succ, ir_region *reg)
938 size_t len = get_region_n_preds(succ);
941 for (i = 0; i < len; ++i) {
942 ir_region *pred = get_region_pred(succ, i);
944 if (pred->parent == reg) {
949 r = get_region_pred(succ, --len);
955 set_region_pred(succ, i, r);
957 /* the current region can be entered by this node */
961 ARR_SHRINKLEN(succ->pred, len);
965 * replace all succ edges from region pred that points to any of the set set
966 * to ONE edge to reg.
968 static void replace_succ(ir_region *pred, ir_region *reg)
971 size_t len = get_region_n_succs(pred);
974 for (i = 0; i < len; ++i) {
975 ir_region *succ = get_region_succ(pred, i);
977 if (succ->parent == reg) {
982 r = get_region_succ(pred, --len);
988 set_region_succ(pred, i, r);
990 /* current region can be left by this node */
994 ARR_SHRINKLEN(pred->succ, len);
998 * Reduce the graph by the node reg.
1000 static void reduce(walk_env *env, ir_region *reg)
1003 ir_region *head = reg->parts[0].region;
1004 size_t maxorder = head->postnum;
1005 size_t minorder = head->prenum;
1007 /* second step: replace all preds in successors */
1008 for (i = get_region_n_succs(reg); i > 0;) {
1009 ir_region *succ = get_region_succ(reg, --i);
1011 replace_pred(succ, reg);
1014 /* third step: replace all succs in predessors */
1015 for (i = get_region_n_preds(reg); i > 0;) {
1016 ir_region *pred = get_region_pred(reg, --i);
1018 replace_succ(pred, reg);
1021 reg->prenum = minorder;
1022 reg->postnum = maxorder;
1023 env->post[maxorder] = reg;
1027 * Construct the region tree of a graph by doing
1028 * structural analysis.
1030 * Uses link fields of nodes.
1032 * @param irg the graph
1034 ir_reg_tree *construct_region_tree(ir_graph *irg)
1037 ir_graph *rem = current_ir_graph;
1038 ir_reg_tree *res = XMALLOC(ir_reg_tree);
1040 obstack_init(&res->obst);
1042 current_ir_graph = irg;
1044 FIRM_DBG_REGISTER(dbg, "firm.ana.structure");
1045 firm_dbg_set_mask(dbg, SET_LEVEL_5);
1047 DB((dbg, LEVEL_1, "Structural analysis on %+F started ...\n", irg));
1049 /* we need dominance info */
1052 assure_irg_outs(irg);
1054 env.start_block = get_irg_start_block(irg);
1055 env.end_block = get_irg_end_block(irg);
1057 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
1059 /* create the Block wrapper and count them */
1061 env.obst = &res->obst;
1062 irg_block_walk_graph(irg, NULL, wrap_BasicBlocks, &env);
1063 irg_block_walk_graph(irg, NULL, update_BasicBlock_regions, &env);
1065 env.post = NEW_ARR_F(ir_region *, env.l_post);
1067 /* do the DFS walk */
1068 dfs_walk(irg, &env);
1070 DB((dbg, LEVEL_1, "%zu regions left\n", env.postmax));
1071 if (env.postmax > 1) {
1074 ir_region *reg, *n = env.post[postctr];
1076 if (n->parent != NULL) {
1077 /* already folded */
1080 /* locate an acyclic region if present */
1081 reg = acyclic_region_type(env.obst, n);
1083 /* locate a cyclic region */
1084 reg = cyclic_region_type(env.obst, n);
1087 /* found a new region */
1091 } while (reg != NULL);
1093 } while (postctr < env.postmax);
1095 DB((dbg, LEVEL_1, "Structural analysis finished.\n"));
1097 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
1099 DEL_ARR_F(env.post);
1100 current_ir_graph = rem;
1102 res->top = env.post[0];
1108 * Walk over the region tree.
1110 * @param reg a region node
1111 * @param pre walker function, executed before the children of a tree node are visited
1112 * @param post walker function, executed after the children of a tree node are visited
1113 * @param env environment, passed to pre and post
1115 static void region_tree_walk2(ir_region *reg, irg_reg_walk_func *pre, irg_reg_walk_func *post, void *env)
1121 if (reg->type != ir_rk_BasicBlock) {
1122 for (i = 0, n = ARR_LEN(reg->parts); i < n; ++i)
1123 region_tree_walk2(reg->parts[i].region, pre, post, env);
1130 * Walk over the region tree.
1132 * @param tree the tree
1133 * @param pre walker function, executed before the children of a tree node are visited
1134 * @param post walker function, executed after the children of a tree node are visited
1135 * @param env environment, passed to pre and post
1137 void region_tree_walk(ir_reg_tree *tree, irg_reg_walk_func *pre, irg_reg_walk_func *post, void *env)
1139 region_tree_walk2(tree->top, pre, post, env);