3 * File name: ir/opt/gvn_pre.c
4 * Purpose: Global Value Numbering Partial Redundancy Elimination
5 * (VanDrunen Hosking 2004)
6 * Author: Michael Beck, Rubino Geiss
9 * Copyright: (c) 1998-2006 Universität Karlsruhe
10 * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
26 #include "irgraph_t.h"
41 /** The debug module handle. */
42 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
46 typedef struct set value_set;
49 typedef struct pset node_set;
51 /** An entry in the value set. */
52 typedef struct value_entry {
53 ir_node *node; /**< the node */
54 ir_node *value; /**< the value of the node */
57 /** Additional info we need for every block. */
58 typedef struct block_info {
59 node_set *nodes; /**< The set of nodes per block. */
60 value_set *avail_out; /**< The Avail_out set for a block. */
61 node_set *antic_in; /**< The Antic_in set for a block. */
62 value_set *new_set; /**< The set of all new values for a block. */
63 ir_node *avail; /**< The get_map(avail, block) result. */
64 int not_found; /**< Non-zero, if avail was not found in this block. */
65 struct block_info *next; /**< Links all entries, so we can recover the sets easily. */
69 * A pair of nodes that must be exchanged.
70 * We must defer the exchange because our hash-sets cannot
71 * find an already replace node else.
73 typedef struct elim_pair {
74 ir_node *old_node; /**< The old node that will be replaced. */
75 ir_node *new_node; /**< The new node. */
76 struct elim_pair *next; /**< Links all entries in a list. */
79 /** The environment for the GVN-PRE algorithm */
80 typedef struct pre_env {
81 struct obstack *obst; /**< The obstack to allocate on. */
82 node_set *trans_set; /**< The set of all translated values. */
83 ir_node *start_block; /**< The start block of the current graph. */
84 ir_node *end_block; /**< The end block of the current graph */
85 block_info *list; /**< Links all block info entires for easier recovery. */
86 elim_pair *pairs; /**< A list of node pairs that must be eliminated. */
87 char changes; /**< Non-zero, if calculation of Antic_in has changed. */
88 char first_iter; /**< non-zero for first iteration */
91 /* ---------- Functions for Node sets ---------- */
93 #define node_set_first(s) pset_first(s)
94 #define node_set_next(s) pset_next(s)
95 #define node_set_break(s) pset_break(s)
96 #define node_set_foreach(v, s) for ((v) = node_set_first(s); (v); (v) = node_set_next(s))
99 * Creates a new node set.
101 static node_set *new_node_set(void) {
102 return new_pset(identities_cmp, 8);
106 * Deletes a node set.
108 static void del_node_set(node_set *set) {
113 * Add a node to the set.
115 static ir_node *node_add(node_set *set, ir_node *node) {
116 return identify_remember(set, node);
120 * Remove a node from a node set.
122 static void node_set_remove(node_set *set, ir_node *node) {
123 pset_remove(set, node, ir_node_hash(node));
127 * Return the number of entries in a node set.
129 static int node_set_count(node_set *set) {
130 return pset_count(set);
133 /** computes dst = dst \/ src for node sets */
134 static void node_union(node_set *dst, node_set *src)
137 node_set_foreach(entry, src)
138 node_add(dst, entry);
142 * Lookup a node in a node set.
144 static ir_node *node_lookup(node_set *set, ir_node *n)
146 return pset_find(set, n, ir_node_hash(n));
150 /* ---------- Functions for Value sets ---------- */
152 #define value_set_foreach(v, s) for ((v) = set_first(s); (v); (v) = set_next(s))
155 * calculate a hash value for a value represented by a node
157 static unsigned value_hash(ir_node *value) {
158 return ir_node_hash(value);
162 * Compare two value entries.
164 static int value_cmp(const void *elt, const void *key, size_t size)
166 const value_entry *e1 = elt;
167 const value_entry *e2 = key;
169 return identities_cmp(e1->value, e2->value);
172 /** Create a new value set. */
173 static value_set *new_value_set(void) {
174 return new_set(value_cmp, 8);
177 /** Deletes a value set. */
178 static void del_value_set(value_set *set) {
183 * Add a node node representing the value value to the set.
185 static value_entry *value_add(value_set *set, ir_node *node, ir_node *value)
190 return set_insert(set, &key, sizeof(key), value_hash(value));
193 /** computes dst = dst \/ src for value sets */
194 static void value_union(value_set *dst, value_set *src)
197 value_set_foreach(entry, src)
198 value_add(dst, entry->node, entry->value);
201 /** computes dst = dst \/ (value_set)src for value sets */
202 static void value_union_nodes(value_set *dst, node_set *src)
205 node_set_foreach(n, src)
206 value_add(dst, n, n);
210 * Lookup a value in a value set.
212 static ir_node *value_lookup(value_set *value_set, ir_node *n)
217 e = set_find(value_set, &key, sizeof(key), value_hash(n));
218 return e ? e->node : NULL;
222 * Add or replace a value in a set by an node computing the same
223 * value in a dominator block.
225 * @return non-zero if a replacement took place
227 static int value_add_or_replace(value_set *set, ir_node *node, ir_node *value)
229 value_entry *e = value_add(set, node, value);
231 if (e->node != node) {
232 /* node must dominate old one here */
233 assert(block_dominates(get_nodes_block(node), get_nodes_block(e->node)));
242 * Returns non-zero if a node is movable.
244 static int is_nice_value(ir_node *n) {
248 n = get_Proj_pred(n);
249 mode = get_irn_mode(n);
251 * FIXME: For now, we cannot handle Div/even if it's movable.
252 * That should be fixed.
254 if (!mode_is_data(mode))
256 if (is_irn_constlike(n))
258 return (get_irn_pinned(n) != op_pin_state_pinned);
265 static void dump_node_set(node_set *set, char *txt, ir_node *block)
270 DB((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block));
272 node_set_foreach(n, set) {
274 DB((dbg, LEVEL_2, "\n"));
275 DB((dbg, LEVEL_2, " %+F,", n));
278 DB((dbg, LEVEL_2, "\n}\n"));
284 static void dump_value_set(value_set *set, char *txt, ir_node *block)
289 DB((dbg, LEVEL_2, "%s(%+F) = {\n", txt, block));
291 value_set_foreach(e, set) {
293 DB((dbg, LEVEL_2, "\n"));
294 if (e->node != e->value)
295 DB((dbg, LEVEL_2, " %+F(%+F),", e->node, e->value));
297 DB((dbg, LEVEL_2, " %+F,", e->node));
300 DB((dbg, LEVEL_2, "\n}\n"));
304 #define dump_node_set(set, txt, block)
305 #define dump_value_set(set, txt, block)
306 #endif /* DEBUG_libfirm */
310 * Return the block info of a block
312 static block_info *get_block_info(ir_node *block) {
313 return get_irn_link(block);
317 * Computes Avail_out(block):
319 * Avail_in(block) = Avail_out(dom(block))
320 * Avail_out(block) = Avail_in(block) \/ Nodes(block)
323 * This function must be called in the top-down dominance order:
324 * Then, it computes Leader(Nodes(block)) instead of Nodes(block) !
326 static void compute_avail_top_down(ir_node *block, void *ctx)
329 block_info *dom_info;
330 block_info *info = get_block_info(block);
333 /* we don't need the end block Avail */
334 if (block == env->end_block)
338 * First add all nodes from the dominator.
339 * This must be done to ensure that Antic_out contains the leader
340 * for every node. The root has no dominator.
342 if (block != env->start_block) {
343 dom_blk = get_Block_idom(block);
344 assert(is_Block(dom_blk));
346 dom_info = get_block_info(dom_blk);
349 value_union(info->avail_out, dom_info->avail_out);
351 value_union_nodes(info->avail_out, info->nodes);
353 dump_value_set(info->avail_out, "Avail_out", block);
357 * returns non-zero if a tree node must be copied because of
360 static int need_copy(ir_node *node, ir_node *block)
364 /* Phi always stop the recursion */
366 return get_irn_intra_n(node, -1) == block;
368 if (! is_nice_value(node))
371 /* check predecessor */
372 arity = get_irn_intra_arity(node);
373 for (i = 0; i < arity; ++i) {
374 ir_node *pred = get_irn_intra_n(node, i);
375 ir_node *local_bl = get_irn_intra_n(pred, -1);
376 ir_node *leader = value_lookup(get_block_info(local_bl)->avail_out, pred);
378 pred = leader != NULL ? leader : pred;
379 if (need_copy(pred, block))
388 static ir_node *translate(ir_node *node, ir_node *block, int pos, pre_env *env)
390 int i, arity, need_new;
391 ir_node *res, *nn, **in;
393 /* Phi always stop the recursion */
395 if (get_irn_intra_n(node, -1) == block)
396 return get_Phi_pred(node, pos);
400 if (! is_nice_value(node))
403 arity = get_irn_intra_arity(node);
405 NEW_ARR_A(ir_node *, in, arity);
409 ir_node *pred = get_irn_intra_n(node, i);
410 ir_node *pred_blk = get_irn_intra_n(pred, -1);
411 ir_node *leader = value_lookup(get_block_info(pred_blk)->avail_out, pred);
412 in[i] = translate(leader ? leader : pred, block, pos, env);
413 need_new |= (in[i] != pred);
421 get_irn_dbg_info(node),
423 get_Block_cfgpred_block(block, pos),
428 /* We need the attribute copy here, because the Hash value of a
429 node might depend on that. */
430 copy_node_attr(node, nn);
431 res = node_add(env->trans_set, nn);
433 obstack_free(env->obst, nn);
435 DB((dbg, LEVEL_2, "--> Translate %+F in <%+F,%d> into %+F\n", node, block, pos, res));
442 * Implements phi_translate.
444 static ir_node *deep_phi_translate(ir_node *node, ir_node *block, int pos, pre_env *env)
449 if (! need_copy(node, block))
452 /* Create a copy of the node in the pos'th predecessor block.
453 Use our environmental obstack, as these nodes are always
455 old = current_ir_graph->obst;
456 current_ir_graph->obst = env->obst;
457 res = translate(node, block, pos, env);
458 current_ir_graph->obst = old;
461 } /* phi_translate */
464 * Implements phi_translate.
466 static ir_node *phi_translate(ir_node *node, ir_node *block, int pos, pre_env *env)
471 ir_node *pred_block = get_Block_cfgpred_block(block, pos);
474 if (get_irn_intra_n(node, -1) == block)
475 return get_Phi_pred(node, pos);
479 arity = get_irn_intra_arity(node);
481 /* check if the node has at least one Phi predecessor */
482 for (i = 0; i < arity; ++i) {
483 ir_node *pred = get_irn_intra_n(node, i);
484 ir_node *pred_bl = get_irn_intra_n(pred, -1);
485 ir_node *leader = value_lookup(get_block_info(pred_bl)->avail_out, pred);
487 leader = leader != NULL ? leader : pred;
488 if (is_Phi(leader) && get_irn_intra_n(pred, -1) == block)
492 /* no Phi in the predecessors */
496 /* Create a copy of the node in the pos'th predecessor block.
497 Use our environmental obstack, as these nodes are always
499 old = current_ir_graph->obst;
500 current_ir_graph->obst = env->obst;
502 get_irn_dbg_info(node),
509 /* We need the attribute copy here, because the Hash value of a
510 node might depend on that. */
511 copy_node_attr(node, nn);
513 set_irn_n(nn, -1, get_irn_intra_n(node, -1));
514 for (i = 0; i < arity; ++i) {
515 ir_node *pred = get_irn_intra_n(node, i);
516 ir_node *pred_bl = get_irn_intra_n(pred, -1);
517 ir_node *leader = value_lookup(get_block_info(pred_bl)->avail_out, pred);
519 leader = leader != NULL ? leader : pred;
520 if (is_Phi(leader) && get_irn_intra_n(pred, -1) == block)
521 set_irn_n(nn, i, get_Phi_pred(leader, pos));
523 set_irn_n(nn, i, leader);
525 res = node_add(env->trans_set, nn);
526 current_ir_graph->obst = old;
529 obstack_free(env->obst, nn);
531 DB((dbg, LEVEL_2, "--> Translate %+F in <%+F,%d> into %+F\n", node, block, pos, res));
534 } /* phi_translate */
537 * check if a node n is clean in block block.
539 static int _is_clean(ir_node *n, ir_node *block)
543 if (get_nodes_block(n) != block)
551 if (! is_nice_value(n))
553 for (i = get_irn_arity(n) - 1; i >= 0; --i) {
554 ir_node *pred = get_irn_n(n, i);
555 if (! _is_clean(pred, block))
565 * check if a node n is clean.
567 static int is_clean(ir_node *n)
569 int res = _is_clean(n, get_nodes_block(n));
575 * This function is called for node sets with is_clean
576 * nodes only, so we must just remove nodes that don't
577 * have available inputs
579 static void clean_node_set(node_set *set, ir_node *blk)
581 ir_node *n, *pred, *pred_blk;
585 for (n = node_set_first(set); n; n = node_set_next(set)) {
586 for (i = get_irn_intra_arity(n) - 1; i >= 0; --i) {
587 pred = get_irn_intra_n(n, i);
589 pred_blk = get_irn_intra_n(pred, -1);
590 if (block_dominates(pred_blk, blk))
592 /* pred do not dominate it, but may be in the set */
593 if (node_lookup(set, pred) != NULL)
595 /* we found a node that must be removed */
597 node_set_remove(set, n);
598 DB((dbg, LEVEL_2, "<-- Cleaning %+F\n", n));
605 * computes Antic_in(block):
607 static void compute_antic(ir_node *block, void *ctx)
610 block_info *succ_info;
611 block_info *info = get_block_info(block);
615 /* no need for computations in start block */
616 if (block == env->start_block)
619 size = node_set_count(info->antic_in);
621 /* the end block has no successor */
622 if (block != env->end_block) {
623 int n_succ = get_Block_n_cfg_outs(block);
626 ir_node *node, *list;
629 /* find blocks position in succ's block predecessors */
630 succ = get_Block_cfg_out(block, 0);
631 for (i = get_Block_n_cfgpreds(succ) - 1; i >= 0; --i) {
632 if (get_Block_cfgpred_block(succ, i) == block) {
639 succ_info = get_block_info(succ);
640 /* translate into list: we cannot insert into a set we iterate
641 * and succ might be equal to block for endless loops */
643 node_set_foreach(node, succ_info->antic_in) {
644 set_irn_link(node, list);
647 for (node = list; node; node = get_irn_link(node)) {
648 ir_node *trans = phi_translate(node, succ, pos, env);
651 node_add(info->antic_in, trans);
656 block_info *succ0_info;
661 /* Select a successor to compute the disjoint of all Nodes
662 sets, it might be useful to select the block with the
663 smallest number of nodes. For simplicity we choose the
665 succ0 = get_Block_cfg_out(block, 0);
666 succ0_info = get_block_info(succ0);
667 node_set_foreach(n, succ0_info->antic_in) {
668 /* we need the disjoint */
669 for (i = 1; i < n_succ; ++i) {
670 ir_node *succ = get_Block_cfg_out(block, i);
671 block_info *succ_info = get_block_info(succ);
672 if (node_lookup(succ_info->antic_in, n) == NULL)
676 /* we found a node that is common in all Antic_in(succ(b)),
677 put it in Antic_in(b) */
678 node_add(info->antic_in, n);
684 * This step calculates Antic_in(b) = Antic_out(b) \/ Nodes(b).
685 * It is enough to do this in the first iteration, because
686 * the set info->nodes is not changed anymore.
688 if (env->first_iter) {
690 node_set_foreach(n, info->nodes) {
692 node_add(info->antic_in, n);
697 // clean_node_set(info->antic_in, block);
699 dump_node_set(info->antic_in, "Antic_in", block);
700 if (size != node_set_count(info->antic_in)) {
701 /* the Antic_in set has changed */
704 } /* compute_antic */
707 * allocate a block info
709 static void alloc_blk_info(ir_node *block, void *ctx)
713 block_info *info = obstack_alloc(env->obst, sizeof(*info));
715 set_irn_link(block, info);
716 info->nodes = new_node_set();
717 info->antic_in = new_node_set();
718 info->avail_out = new_value_set();
721 info->new_set = NULL;
722 info->next = env->list;
725 /* fill the nodes set, we will need it later */
726 for (i = get_irn_n_outs(block) - 1; i >= 0; --i) {
727 ir_node *n = get_irn_out(block, i);
729 set_irn_link(n, NULL);
731 /* we cannot optimize pinned nodes, so do not remember them */
732 if (is_nice_value(n))
733 node_add(info->nodes, n);
738 * Perform insertion of partially redundant values.
739 * For every Block node, do the following:
740 * 1. Propagate the NEW_SETS of the dominator into the current block.
741 * If the block has multiple predecessors,
742 * 2a. Iterate over the ANTIC expressions for the block to see if
743 * any of them are partially redundant.
744 * 2b. If so, insert them into the necessary predecessors to make
745 * the expression fully redundant.
746 * 2c. Insert a new Phi merging the values of the predecessors.
747 * 2d. Insert the new Phi, and the new expressions, into the
750 static void insert_nodes(ir_node *block, void *ctx)
754 ir_node *e, *idom, *first_s, *worklist;
755 block_info *curr_info, *idom_info;
756 int pos, arity = get_irn_intra_arity(block);
757 int all_same, by_some, updated;
759 /* ensure that even the start block has a new_set */
760 curr_info = get_block_info(block);
761 if (curr_info->new_set)
762 del_value_set(curr_info->new_set);
763 curr_info->new_set = new_value_set();
765 if (block == env->start_block)
768 idom = get_Block_idom(block);
769 idom_info = get_block_info(idom);
771 /* update the new_sets */
773 dump_value_set(idom_info->new_set, "[New Set]", idom);
774 value_set_foreach(entry, idom_info->new_set) {
775 updated |= value_add_or_replace(curr_info->avail_out, entry->node, entry->value);
778 dump_value_set(curr_info->avail_out, "Updated [Avail_out]", block);
783 /* convert the set into a list. This allows the removal of
784 * elements from the set */
786 node_set_foreach(e, curr_info->antic_in) {
787 set_irn_link(e, worklist);
791 for (e = worklist; e != NULL; e = get_irn_link(e)) {
794 /* If the value was already computed in the dominator, then
795 it is totally redundant. Hence we have nothing to insert. */
796 if (value_lookup(idom_info->avail_out, e)) {
797 // DB((dbg, LEVEL_2, "Found %+F from block %+F avail in dom %+F\n", v, block, idom));
806 /* for all predecessor blocks */
807 for (pos = 0; pos < arity; ++pos) {
808 block_info *pred_info;
809 ir_node *pred_blk = get_Block_cfgpred_block(block, pos);
810 ir_node *e_prime, *v_prime, *e_dprime;
812 /* ignore bad blocks. */
813 if (is_Bad(pred_blk))
816 e_prime = phi_translate(e, block, pos, env);
819 pred_info = get_block_info(pred_blk);
820 e_dprime = value_lookup(pred_info->avail_out, v_prime);
822 if (e_dprime == NULL) {
824 pred_info->avail = e_prime;
825 pred_info->not_found = 1;
828 mode = get_irn_mode(e_dprime);
830 pred_info->avail = e_dprime;
831 pred_info->not_found = 0;
835 else if (first_s != e_dprime)
838 DB((dbg, LEVEL_2, "Found %+F from block %+F as %+F in pred %+F\n", e, block, e_dprime, pred_blk));
842 /* If it's not the same value already existing along every predecessor, and
843 it's defined by some predecessor, it is partially redundant. */
844 if (! all_same && by_some) {
847 DB((dbg, LEVEL_1, "Partial redundant %+F from block %+F found\n", e, block));
849 in = xmalloc(arity * sizeof(*in));
850 /* for all predecessor blocks */
851 for (pos = 0; pos < arity; ++pos) {
852 ir_node *pred_blk = get_Block_cfgpred_block(block, pos);
853 block_info *pred_info = get_block_info(pred_blk);
855 /* ignore bad blocks. */
856 if (is_Bad(pred_blk)) {
861 /* ignore blocks that already have the expression */
862 if (pred_info->not_found) {
863 ir_node *e_prime = pred_info->avail;
865 if (!is_Phi(e_prime)) {
866 mode = get_irn_mode(e_prime);
868 get_irn_dbg_info(e_prime),
869 current_ir_graph, pred_blk,
872 get_irn_arity(e_prime),
873 get_irn_in(e_prime) + 1);
874 copy_node_attr(e_prime, nn);
876 DB((dbg, LEVEL_2, "New node %+F in block %+F created\n", nn, pred_blk));
877 pred_info->avail = value_add(pred_info->avail_out, nn, e_prime)->node;
880 in[pos] = pred_info->avail;
882 phi = new_r_Phi(current_ir_graph, block, arity, in, mode);
884 value_add_or_replace(curr_info->avail_out, phi, e);
885 value_add(curr_info->new_set, phi, e);
886 DB((dbg, LEVEL_2, "New %+F for redundant %+F created\n", phi, e));
888 /* the good case: we really replace an instruction */
889 node_set_remove(curr_info->antic_in, e);
893 } /* node_set_foreach */
897 * Do the elimination step: collect all changes
898 * We cannot do the changes right here, as this would change
899 * the hash values of the nodes in the avail_out set!
901 static void collect_elim_pairs(ir_node *block, void *ctx)
904 block_info *curr_info = get_block_info(block);
907 dump_node_set(curr_info->nodes, "Updating nodes", block);
908 node_set_foreach(v, curr_info->nodes) {
909 ir_node *l = value_lookup(curr_info->avail_out, v);
913 elim_pair *p = obstack_alloc(env->obst, sizeof(*p));
917 p->next = env->pairs;
924 * Do all the recorded changes and optimize
925 * newly created Phi's.
927 static void eliminate_nodes(elim_pair *pairs)
931 for (p = pairs; p != NULL; p = p->next) {
932 DB((dbg, LEVEL_2, "Replacing %+F by %+F\n", p->old_node, p->new_node));
934 * PRE tends to create Phi(self, self, ... , x, self, self, ...)
935 * which we can optimize here
937 if (is_Phi(p->new_node)) {
941 for (i = get_irn_intra_arity(p->new_node) - 1; i >= 0; --i) {
942 ir_node *pred = get_irn_n(p->new_node, i);
944 if (pred != p->old_node) {
955 exchange(p->old_node, p->new_node);
960 * Argh: Endless loops cause problems, because the
961 * insert algorithm did not terminate. We get tranalated nodes that
962 * references the origin. These nodes are translated again and again...
964 * The current fix is to use post-dominance. This simple ignores
965 * endless loops, ie we cannot optimize them.
967 void do_gvn_pre(ir_graph *irg)
971 optimization_state_t state;
973 unsigned antic_iter, insert_iter;
975 /* register a debug mask */
976 FIRM_DBG_REGISTER(dbg, "firm.opt.gvn_pre");
977 firm_dbg_set_mask(dbg, SET_LEVEL_2);
981 a_env.trans_set = new_node_set();
983 a_env.start_block = get_irg_start_block(irg);
984 a_env.end_block = get_irg_end_block(irg);
987 /* Move Proj's into the same block as their args,
988 else we would assign the result to wrong blocks */
989 normalize_proj_nodes(irg);
991 /* critical edges MUST be removed */
992 remove_critical_cf_edges(irg);
994 /* we need dominator for Antic_out calculation */
995 if (get_irg_dom_state(irg) != dom_consistent)
997 if (get_irg_postdom_state(irg) != dom_consistent)
998 compute_postdoms(irg);
999 /* we get all nodes of a block by following outs */
1000 if (get_irg_outs_state(irg) != outs_consistent)
1001 compute_irg_outs(irg);
1004 * Switch on GCSE. We need it to correctly compute
1005 * the leader of a node by hashing.
1007 save_optimization_state(&state);
1008 set_opt_global_cse(1);
1010 DB((dbg, LEVEL_1, "Doing GVN-PRE for %e\n", get_irg_entity(irg)));
1011 printf("Doing GVN-PRE for %s\n", get_entity_name(get_irg_entity(irg)));
1013 /* allocate block info for all blocks */
1014 irg_block_walk_graph(irg, NULL, alloc_blk_info, &a_env);
1016 /* compute the available value sets for all blocks */
1017 dom_tree_walk_irg(irg, compute_avail_top_down, NULL, &a_env);
1019 /* compute the anticipated value sets for all blocks */
1020 inc_irg_visited(irg);
1022 a_env.first_iter = 1;
1024 DB((dbg, LEVEL_1, "Antic_in Iteration %d starts ...\n", ++antic_iter));
1026 irg_block_walk_graph(irg, compute_antic, NULL, &a_env);
1027 // postdom_tree_walk_irg(irg, compute_antic, NULL, &a_env);
1028 a_env.first_iter = 0;
1029 DB((dbg, LEVEL_1, "------------------------\n"));
1030 } while (a_env.changes != 0);
1032 /* compute redundant expressions */
1035 DB((dbg, LEVEL_1, "Insert Iteration %d starts ...\n", ++insert_iter));
1037 dom_tree_walk_irg(irg, insert_nodes, NULL, &a_env);
1038 DB((dbg, LEVEL_1, "------------------------\n"));
1039 } while (a_env.changes != 0);
1041 /* last step: eliminate nodes */
1042 dom_tree_walk_irg(irg, collect_elim_pairs, NULL, &a_env);
1043 eliminate_nodes(a_env.pairs);
1045 restore_optimization_state(&state);
1047 /* clean up: delete all sets */
1048 for (p = a_env.list; p != NULL; p = p->next) {
1050 del_node_set(p->antic_in);
1052 del_value_set(p->avail_out);
1054 del_node_set(p->nodes);
1056 del_value_set(p->new_set);
1058 del_node_set(a_env.trans_set);
1059 obstack_free(&obst, NULL);
1060 set_irg_pinned(irg, op_pin_state_pinned);
1063 set_irg_outs_inconsistent(irg);
1064 set_irg_loopinfo_inconsistent(irg);