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 Control flow optimizations.
23 * @author Goetz Lindenmaier, Michael Beck, Sebastian Hack
28 #include "iroptimize.h"
35 #include "irgraph_t.h"
49 #include "irbackedge_t.h"
55 #include "iropt_dbg.h"
57 /*------------------------------------------------------------------*/
58 /* Control flow optimization. */
60 /* Removes Bad control flow predecessors and empty blocks. A block */
61 /* is empty if it contains only a Jmp node. */
62 /* Blocks can only be removed if they are not needed for the */
63 /* semantics of Phi nodes. */
64 /* Further, we NEVER remove labeled blocks (even if we could move */
66 /*------------------------------------------------------------------*/
68 #define set_Block_removable(block) set_Block_mark(block, 1)
69 #define set_Block_non_removable(block) set_Block_mark(block, 0)
70 #define is_Block_removable(block) (get_Block_mark(block) != 0)
73 * Replace binary Conds that jumps twice into the same block
79 * ProjX True ProjX False ==> | /
84 * Such pattern are the result of if-conversion.
86 * Note that the simple case that Block has only these two
87 * predecessors are already handled in equivalent_node_Block().
89 static int remove_senseless_conds(ir_node *bl)
92 int n = get_Block_n_cfgpreds(bl);
95 for (i = 0; i < n; ++i) {
96 ir_node *pred_i = get_Block_cfgpred(bl, i);
97 ir_node *cond_i = skip_Proj(pred_i);
100 if (is_Cond(cond_i) && get_irn_mode(get_Cond_selector(cond_i)) == mode_b) {
102 for (j = i + 1; j < n; ++j) {
103 ir_node *pred_j = get_Block_cfgpred(bl, j);
104 ir_node *cond_j = skip_Proj(pred_j);
106 if (cond_j == cond_i) {
107 ir_node *jmp = new_r_Jmp(get_nodes_block(cond_i));
108 set_irn_n(bl, i, jmp);
109 set_irn_n(bl, j, new_Bad());
111 DBG_OPT_IFSIM2(cond_i, jmp);
121 /** An environment for merge_blocks and collect nodes. */
122 typedef struct _merge_env {
123 int changed; /**< Set if the graph was changed. */
124 int phis_moved; /**< Set if Phi nodes were moved. */
125 plist_t *list; /**< Helper list for all found Switch Conds. */
129 * Removes Tuples from Block control flow predecessors.
130 * Optimizes blocks with equivalent_node(). This is tricky,
131 * as we want to avoid nodes that have as block predecessor Bads.
132 * Therefore we also optimize at control flow operations, depending
133 * how we first reach the Block.
135 static void merge_blocks(ir_node *node, void *ctx)
139 merge_env *env = ctx;
141 /* clear the link field for ALL nodes first */
142 set_irn_link(node, NULL);
144 if (is_Block(node)) {
146 for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
147 ir_node *pred = get_Block_cfgpred(node, i);
148 ir_node *skipped = skip_Tuple(pred);
149 if (pred != skipped) {
150 set_Block_cfgpred(node, i, skipped);
156 new_block = equivalent_node(node);
157 if (new_block != node && ! is_Block_dead(new_block)) {
158 exchange(node, new_block);
162 } else if (get_opt_optimize() && (get_irn_mode(node) == mode_X)) {
163 /* We will soon visit a block. Optimize it before visiting! */
164 ir_node *b = get_nodes_block(skip_Proj(node));
166 if (!is_Block_dead(b)) {
167 new_block = equivalent_node(b);
169 while (!irn_visited(b) && !is_Block_dead(new_block) && new_block != b) {
170 /* We would have to run gigo() if new is bad, so we
171 promote it directly below. Nevertheless, we sometimes reach a block
172 the first time through a dataflow node. In this case we optimized the
173 block as such and have to promote the Bad here. */
174 assert((get_opt_control_flow_straightening() ||
175 get_opt_control_flow_weak_simplification()) &&
176 ("strange flag setting"));
177 exchange(b, new_block);
180 new_block = equivalent_node(b);
183 /* normally, we would create a Bad block here, but this must be
184 * prevented, so just set it's cf to Bad.
186 if (is_Block_dead(new_block)) {
187 exchange(node, new_Bad());
195 * Block walker removing control flow from dead block by
196 * inspecting dominance info.
197 * Do not replace blocks by Bad. This optimization shall
198 * ensure, that all Bad control flow predecessors are
199 * removed, and no new other Bads are introduced.
200 * Further removed useless Conds and clear the mark of all blocks.
202 * Must be run in the post walker.
204 static void remove_unreachable_blocks_and_conds(ir_node *block, void *env)
209 /* Check block predecessors and turn control flow into bad.
210 Beware of Tuple, kill them. */
211 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
212 ir_node *pred_X = get_Block_cfgpred(block, i);
213 ir_node *skipped = skip_Tuple(pred_X);
215 if (! is_Bad(skipped)) {
216 ir_node *pred_bl = get_nodes_block(skip_Proj(skipped));
218 if (is_Block_dead(pred_bl) || (get_Block_dom_depth(pred_bl) < 0)) {
219 set_Block_dead(pred_bl);
220 exchange(pred_X, new_Bad());
222 } else if (skipped != pred_X) {
223 set_Block_cfgpred(block, i, skipped);
229 *changed |= remove_senseless_conds(block);
231 /* clear the block mark of all non labeled blocks */
232 if (has_Block_entity(block))
233 set_Block_non_removable(block);
235 set_Block_removable(block);
239 * Collects all Phi nodes in link list of Block.
240 * Marks all blocks "non_removable" if they contain a node other
241 * than Jmp (and Proj).
242 * Links all Proj nodes to their predecessors.
243 * Collects all switch-Conds in a list.
245 static void collect_nodes(ir_node *n, void *ctx)
247 ir_opcode code = get_irn_opcode(n);
248 merge_env *env = ctx;
250 if (code == iro_Block) {
251 /* mark the block as non-removable if it is labeled */
252 if (has_Block_entity(n))
253 set_Block_non_removable(n);
255 ir_node *b = get_nodes_block(n);
257 if (code == iro_Phi && get_irn_arity(n) > 0) {
258 /* Collect Phi nodes to compact ins along with block's ins. */
259 set_irn_link(n, get_irn_link(b));
261 } else if (code != iro_Jmp && !is_Bad(b)) { /* Check for non-empty block. */
262 set_Block_non_removable(b);
264 if (code == iro_Proj) { /* link Proj nodes */
265 ir_node *pred = get_Proj_pred(n);
267 set_irn_link(n, get_irn_link(pred));
268 set_irn_link(pred, n);
269 } else if (code == iro_Cond) {
270 ir_node *sel = get_Cond_selector(n);
271 if (mode_is_int(get_irn_mode(sel))) {
272 /* found a switch-Cond, collect */
273 plist_insert_back(env->list, n);
280 /** Returns true if pred is predecessor of block. */
281 static int is_pred_of(ir_node *pred, ir_node *b)
285 for (i = get_Block_n_cfgpreds(b) - 1; i >= 0; --i) {
286 ir_node *b_pred = get_Block_cfgpred_block(b, i);
293 /** Test whether we can optimize away pred block pos of b.
295 * @param b A block node.
296 * @param pos The position of the predecessor block to judge about.
298 * @returns The number of predecessors
300 * The test is rather tricky.
302 * The situation is something like the following:
311 * b merges the control flow of an if-then-else. We may not remove
312 * the 'then' _and_ the 'else' block of an 'if' if there is a Phi
313 * node in b, even if both are empty. The destruction of this Phi
314 * requires that a copy is added before the merge. We have to
315 * keep one of the case blocks to place the copies in.
317 * To perform the test for pos, we must regard predecessors before pos
318 * as already removed.
320 static int test_whether_dispensable(ir_node *b, int pos)
322 int i, j, n_preds = 1;
323 ir_node *pred = get_Block_cfgpred_block(b, pos);
325 /* Bad blocks will be optimized away, so we don't need space for them */
326 if (is_Block_dead(pred))
329 if (is_Block_removable(pred)) {
330 if (!get_opt_optimize() || !get_opt_control_flow_strong_simplification()) {
331 /* Mark block so that is will not be removed: optimization is turned off. */
332 set_Block_non_removable(pred);
336 /* Seems to be empty. At least we detected this in collect_nodes. */
337 if (get_irn_link(b) == NULL) {
338 /* There are no Phi nodes ==> all predecessors are dispensable. */
339 n_preds = get_Block_n_cfgpreds(pred);
341 /* b's pred blocks and pred's pred blocks must be pairwise disjunct.
342 Handle all pred blocks with preds < pos as if they were already removed. */
343 for (i = 0; i < pos; i++) {
344 ir_node *b_pred = get_Block_cfgpred_block(b, i);
345 if (! is_Block_dead(b_pred) && is_Block_removable(b_pred)) {
346 for (j = get_Block_n_cfgpreds(b_pred) - 1; j >= 0; --j) {
347 ir_node *b_pred_pred = get_Block_cfgpred_block(b_pred, j);
348 if (is_pred_of(b_pred_pred, pred))
349 goto non_dispensable;
352 if (is_pred_of(b_pred, pred))
353 goto non_dispensable;
356 for (i = pos +1; i < get_Block_n_cfgpreds(b); i++) {
357 ir_node *b_pred = get_Block_cfgpred_block(b, i);
358 if (is_pred_of(b_pred, pred))
359 goto non_dispensable;
361 /* if we get here, the block is dispensable */
362 n_preds = get_Block_n_cfgpreds(pred);
369 set_Block_non_removable(pred);
374 * This method removed Bad cf predecessors from Blocks and Phis, and removes
375 * empty blocks. A block is empty if it only contains Phi and Jmp nodes.
377 * We first adapt Phi nodes, then Block nodes, as we need the old ins
378 * of the Block to adapt the Phi nodes. We do this by computing new
379 * in arrays, and then replacing the old ones. So far we compute new in arrays
380 * for all nodes, not regarding whether there is a possibility for optimization.
382 * For each predecessor p of a Block b there are three cases:
383 * -1. The predecessor p is a Bad node: just skip it. The in array of b shrinks by one.
384 * -2. The predecessor p is empty. Remove p. All predecessors of p are now
386 * -3. The predecessor p is a block containing useful code. Just keep p as is.
388 * For Phi nodes f we have to check the conditions at the Block of f.
389 * For cases 1 and 3 we proceed as for Blocks. For case 2 we can have two
391 * -2a: The old predecessor of the Phi f is a Phi pred_f IN THE BLOCK REMOVED. In this
392 * case we proceed as for blocks. We remove pred_f. All
393 * predecessors of pred_f now are predecessors of f.
394 * -2b: The old predecessor of f is NOT in the block removed. It might be a Phi, too.
395 * We have to replicate f for each predecessor of the removed block. Or, with
396 * other words, the removed predecessor block has exactly one predecessor.
398 * Further there is a special case for self referencing blocks:
401 * then_b else_b then_b else_b
407 * | | | === optimized to ===> \ | | |
414 * If there is a Phi in pred_b, but we remove pred_b, we have to generate a
415 * Phi in loop_b, that has the ins of the Phi in pred_b and a self referencing
417 * @@@ It is negotiable whether we should do this ... there might end up a copy
418 * from the Phi in the loop when removing the Phis.
420 static void optimize_blocks(ir_node *b, void *ctx)
422 int i, j, k, n, max_preds, n_preds, p_preds = -1;
423 ir_node *pred, *phi, *next;
425 merge_env *env = ctx;
427 /* Count the number of predecessor if this block is merged with pred blocks
430 for (i = 0, k = get_Block_n_cfgpreds(b); i < k; ++i) {
431 max_preds += test_whether_dispensable(b, i);
433 in = XMALLOCN(ir_node*, max_preds);
435 /*- Fix the Phi nodes of the current block -*/
436 for (phi = get_irn_link(b); phi != NULL; phi = next) {
438 next = get_irn_link(phi);
440 /* Find the new predecessors for the Phi */
442 for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) {
443 pred = get_Block_cfgpred_block(b, i);
445 if (is_Block_dead(pred)) {
446 /* case Phi 1: Do nothing */
447 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
448 /* case Phi 2: It's an empty block and not yet visited. */
449 ir_node *phi_pred = get_Phi_pred(phi, i);
451 for (j = 0, k = get_Block_n_cfgpreds(pred); j < k; j++) {
452 /* because of breaking loops, not all predecessors are Bad-clean,
453 * so we must check this here again */
454 if (! is_Bad(get_Block_cfgpred(pred, j))) {
455 if (get_nodes_block(phi_pred) == pred) {
457 assert(is_Phi(phi_pred)); /* Block is empty!! */
459 in[p_preds++] = get_Phi_pred(phi_pred, j);
462 in[p_preds++] = phi_pred;
468 in[p_preds++] = get_Phi_pred(phi, i);
471 assert(p_preds <= max_preds);
475 /* By removal of Bad ins the Phi might be degenerated. */
476 exchange(phi, in[0]);
478 set_irn_in(phi, p_preds, in);
482 /*- This happens only if merge between loop backedge and single loop entry.
483 Moreover, it is only needed if predb is the direct dominator of b, else there can be no uses
484 of the Phi's in predb ... -*/
485 for (k = 0, n = get_Block_n_cfgpreds(b); k < n; ++k) {
486 ir_node *predb = get_nodes_block(get_Block_cfgpred(b, k));
488 if (is_Block_removable(predb) && !Block_block_visited(predb)) {
491 /* we found a predecessor block at position k that will be removed */
492 for (phi = get_irn_link(predb); phi; phi = next_phi) {
494 next_phi = get_irn_link(phi);
498 if (get_Block_idom(b) != predb) {
499 /* predb is not the dominator. There can't be uses of pred's Phi nodes, kill them .*/
500 exchange(phi, new_Bad());
502 /* predb is the direct dominator of b. There might be uses of the Phi nodes from
503 predb in further block, so move this phi from the predecessor into the block b */
504 set_nodes_block(phi, b);
505 set_irn_link(phi, get_irn_link(b));
506 set_irn_link(b, phi);
509 /* first, copy all 0..k-1 predecessors */
510 for (i = 0; i < k; i++) {
511 pred = get_Block_cfgpred_block(b, i);
513 if (is_Block_dead(pred)) {
515 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
516 /* It's an empty block and not yet visited. */
517 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
518 if (! is_Bad(get_Block_cfgpred(pred, j)))
526 /* now we are at k, copy the phi predecessors */
527 pred = get_nodes_block(get_Block_cfgpred(b, k));
528 for (i = 0; i < get_Phi_n_preds(phi); i++) {
529 if (! is_Bad(get_Block_cfgpred(pred, i)))
530 in[q_preds++] = get_Phi_pred(phi, i);
533 /* and now all the rest */
534 for (i = k+1; i < get_Block_n_cfgpreds(b); i++) {
535 pred = get_Block_cfgpred_block(b, i);
537 if (is_Block_dead(pred)) {
539 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
540 /* It's an empty block and not yet visited. */
541 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
542 if (! is_Bad(get_Block_cfgpred(pred, j)))
552 exchange(phi, in[0]);
554 set_irn_in(phi, q_preds, in);
557 assert(q_preds <= max_preds);
558 // assert(p_preds == q_preds && "Wrong Phi Fix");
564 /*- Fix the block -*/
566 for (i = 0; i < get_Block_n_cfgpreds(b); i++) {
567 pred = get_Block_cfgpred_block(b, i);
569 if (is_Block_dead(pred)) {
570 /* case 1: Do nothing */
571 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
572 /* case 2: It's an empty block and not yet visited. */
573 assert(get_Block_n_cfgpreds(b) > 1 || has_Block_entity(b));
574 /* Else it should be optimized by equivalent_node. */
575 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
576 ir_node *pred_X = get_Block_cfgpred(pred, j);
578 /* because of breaking loops, not all predecessors are Bad-clean,
579 * so we must check this here again */
580 if (! is_Bad(pred_X))
581 in[n_preds++] = pred_X;
583 /* Remove block as it might be kept alive. */
584 exchange(pred, b/*new_Bad()*/);
587 in[n_preds++] = get_Block_cfgpred(b, i);
590 assert(n_preds <= max_preds);
592 set_irn_in(b, n_preds, in);
595 assert(get_irn_link(b) == NULL || p_preds == -1 || (n_preds == p_preds && "Wrong Phi Fix"));
600 * Block walker: optimize all blocks using the default optimizations.
601 * This removes Blocks that with only a Jmp predecessor.
603 static void remove_simple_blocks(ir_node *block, void *ctx)
605 ir_node *new_blk = equivalent_node(block);
606 merge_env *env = ctx;
608 if (new_blk != block) {
609 exchange(block, new_blk);
615 * Handle pre-optimized table switch Cond's.
616 * During iropt, all Projs from a switch-Cond are already removed except
617 * the defProj and maybe the taken one.
618 * The defProj cannot be removed WITHOUT looking backwards, so we do this here.
620 * @param cond the switch-Cond
622 * @return non-zero if a switch-Cond was optimized
624 * Expects all Proj's linked to the cond node
626 static int handle_switch_cond(ir_node *cond)
628 ir_node *sel = get_Cond_selector(cond);
630 ir_node *proj1 = get_irn_link(cond);
631 ir_node *proj2 = get_irn_link(proj1);
634 blk = get_nodes_block(cond);
637 /* this Cond has only one Proj: must be the defProj */
638 assert(get_Cond_default_proj(cond) == get_Proj_proj(proj1));
639 /* convert it into a Jmp */
640 jmp = new_r_Jmp(blk);
641 exchange(proj1, jmp);
643 } else if (get_irn_link(proj2) == NULL) {
644 /* We have two Proj's here. Check if the Cond has
645 a constant argument */
646 tarval *tv = value_of(sel);
648 if (tv != tarval_bad) {
649 /* we have a constant switch */
650 long num = get_tarval_long(tv);
651 long def_num = get_Cond_default_proj(cond);
653 if (def_num == get_Proj_proj(proj1)) {
654 /* first one is the defProj */
655 if (num == get_Proj_proj(proj2)) {
656 jmp = new_r_Jmp(blk);
657 exchange(proj2, jmp);
658 exchange(proj1, new_Bad());
661 } else if (def_num == get_Proj_proj(proj2)) {
662 /* second one is the defProj */
663 if (num == get_Proj_proj(proj1)) {
664 jmp = new_r_Jmp(blk);
665 exchange(proj1, jmp);
666 exchange(proj2, new_Bad());
670 /* neither: strange, Cond was not optimized so far */
671 if (num == get_Proj_proj(proj1)) {
672 jmp = new_r_Jmp(blk);
673 exchange(proj1, jmp);
674 exchange(proj2, new_Bad());
676 } else if (num == get_Proj_proj(proj2)) {
677 jmp = new_r_Jmp(blk);
678 exchange(proj2, jmp);
679 exchange(proj1, new_Bad());
688 /* Optimizations of the control flow that also require changes of Phi nodes.
690 * This optimization performs two passes over the graph.
692 * The first pass collects all Phi nodes in a link list in the block
693 * nodes. Further it performs simple control flow optimizations.
694 * Finally it marks all blocks that do not contain useful
695 * computations, i.e., these blocks might be removed.
697 * The second pass performs the optimizations intended by this algorithm.
698 * It walks only over block nodes and adapts these and the Phi nodes in these blocks,
699 * which it finds in a linked list computed by the first pass.
701 * We use the mark flag to mark removable blocks in the first
704 void optimize_cf(ir_graph *irg)
706 int i, j, n, changed;
708 ir_node *cond, *end = get_irg_end(irg);
709 ir_graph *rem = current_ir_graph;
713 assert(get_irg_phase_state(irg) != phase_building);
715 /* if the graph is not pinned, we cannot determine empty blocks */
716 assert(get_irg_pinned(irg) != op_pin_state_floats &&
717 "Control flow optimization need a pinned graph");
719 current_ir_graph = irg;
721 /* FIXME: control flow opt destroys block edges. So edges are deactivated here. Fix the edges! */
722 edges_deactivate(irg);
724 /* we use the mark flag to mark removable blocks */
725 ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK);
730 /* ALWAYS kill unreachable control flow. Backend cannot handle it anyway.
731 Use dominator info to kill blocks. Also optimize useless Conds. */
733 irg_block_walk_graph(irg, NULL, remove_unreachable_blocks_and_conds, &env.changed);
735 /* fix the keep-alives */
737 for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) {
738 ir_node *ka = get_End_keepalive(end, i);
741 /* do NOT keep dead blocks */
742 if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) {
743 set_End_keepalive(end, i, new_Bad());
747 ir_node *block = get_nodes_block(ka);
749 if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) {
750 /* do NOT keep nodes in dead blocks */
751 set_End_keepalive(end, i, new_Bad());
756 env.changed |= changed;
758 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
760 env.list = plist_new();
761 irg_walk(end, merge_blocks, collect_nodes, &env);
763 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
766 /* Handle graph state if was changed. */
767 set_irg_outs_inconsistent(irg);
768 set_irg_doms_inconsistent(irg);
769 set_irg_extblk_inconsistent(irg);
770 set_irg_loopinfo_inconsistent(irg);
771 set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
775 /* handle all collected switch-Conds */
776 foreach_plist(env.list, el) {
777 cond = plist_element_get_value(el);
778 env.changed |= handle_switch_cond(cond);
780 plist_free(env.list);
783 /* The Cond optimization might generate unreachable code, so restart if
788 /* Optimize the standard code. */
791 irg_block_walk_graph(irg, optimize_blocks, remove_simple_blocks, &env);
793 /* in rare cases a node may be kept alive more than once, use the visited flag to detect this */
794 ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
795 inc_irg_visited(irg);
797 /* fix the keep-alives again */
799 for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) {
800 ir_node *ka = get_End_keepalive(end, i);
803 /* do NOT keep dead blocks */
804 if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) {
805 set_End_keepalive(end, i, new_Bad());
809 ir_node *block = get_nodes_block(ka);
811 if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) {
812 /* do NOT keep nodes in dead blocks */
813 set_End_keepalive(end, i, new_Bad());
818 env.changed |= changed;
820 remove_End_Bads_and_doublets(end);
823 ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_VISITED);
825 if (env.phis_moved) {
826 /* Bad: when we moved Phi's, we might produce dead Phi nodes
828 Some other phases cannot copy with this, so will them.
830 n = get_End_n_keepalives(end);
832 NEW_ARR_A(ir_node *, in, n);
834 /* Handle graph state if was changed. */
835 set_irg_outs_inconsistent(irg);
837 assure_irg_outs(irg);
839 for (i = j = 0; i < n; ++i) {
840 ir_node *ka = get_End_keepalive(end, i);
845 for (k = get_irn_n_outs(ka) - 1; k >= 0; --k) {
846 ir_node *user = get_irn_out(ka, k);
848 if (user != ka && user != end) {
849 /* Is it a real user or just a self loop ? */
859 set_End_keepalives(end, j, in);
866 /* Handle graph state if was changed. */
867 set_irg_outs_inconsistent(irg);
868 set_irg_doms_inconsistent(irg);
869 set_irg_extblk_inconsistent(irg);
870 set_irg_loopinfo_inconsistent(irg);
871 set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
875 /* the verifier doesn't work yet with floating nodes */
876 if (get_irg_pinned(irg) == op_pin_state_pinned) {
877 /* after optimize_cf(), only Bad data flow may remain. */
878 if (irg_verify_bads(irg, BAD_DF | BAD_BLOCK | TUPLE)) {
879 dump_ir_graph(irg, "-verify-cf");
880 fprintf(stderr, "VERIFY_BAD in optimize_cf()\n");
884 current_ir_graph = rem;
887 /* Creates an ir_graph pass for optimize_cf. */
888 ir_graph_pass_t *optimize_cf_pass(const char *name)
890 return def_graph_pass(name ? name : "optimize_cf", optimize_cf);
891 } /* optimize_cf_pass */