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) {
91 int n = get_Block_n_cfgpreds(bl);
94 for (i = 0; i < n; ++i) {
95 ir_node *pred_i = get_Block_cfgpred(bl, i);
96 ir_node *cond_i = skip_Proj(pred_i);
99 if (is_Cond(cond_i) && get_irn_mode(get_Cond_selector(cond_i)) == mode_b) {
101 for (j = i + 1; j < n; ++j) {
102 ir_node *pred_j = get_Block_cfgpred(bl, j);
103 ir_node *cond_j = skip_Proj(pred_j);
105 if (cond_j == cond_i) {
106 ir_node *jmp = new_r_Jmp(get_nodes_block(cond_i));
107 set_irn_n(bl, i, jmp);
108 set_irn_n(bl, j, new_Bad());
110 DBG_OPT_IFSIM2(cond_i, jmp);
120 /** An environment for merge_blocks and collect nodes. */
121 typedef struct _merge_env {
122 int changed; /**< Set if the graph was changed. */
123 int phis_moved; /**< Set if Phi nodes were moved. */
124 plist_t *list; /**< Helper list for all found Switch Conds. */
128 * Removes Tuples from Block control flow predecessors.
129 * Optimizes blocks with equivalent_node(). This is tricky,
130 * as we want to avoid nodes that have as block predecessor Bads.
131 * Therefore we also optimize at control flow operations, depending
132 * how we first reach the Block.
134 static void merge_blocks(ir_node *node, void *ctx) {
137 merge_env *env = ctx;
139 /* clear the link field for ALL nodes first */
140 set_irn_link(node, NULL);
142 if (is_Block(node)) {
144 for (i = get_Block_n_cfgpreds(node) - 1; i >= 0; --i) {
145 ir_node *pred = get_Block_cfgpred(node, i);
146 ir_node *skipped = skip_Tuple(pred);
147 if (pred != skipped) {
148 set_Block_cfgpred(node, i, skipped);
154 new_block = equivalent_node(node);
155 if (new_block != node && ! is_Block_dead(new_block)) {
156 exchange(node, new_block);
160 } else if (get_opt_optimize() && (get_irn_mode(node) == mode_X)) {
161 /* We will soon visit a block. Optimize it before visiting! */
162 ir_node *b = get_nodes_block(skip_Proj(node));
164 if (!is_Block_dead(b)) {
165 new_block = equivalent_node(b);
167 while (!irn_visited(b) && !is_Block_dead(new_block) && new_block != b) {
168 /* We would have to run gigo() if new is bad, so we
169 promote it directly below. Nevertheless, we sometimes reach a block
170 the first time through a dataflow node. In this case we optimized the
171 block as such and have to promote the Bad here. */
172 assert((get_opt_control_flow_straightening() ||
173 get_opt_control_flow_weak_simplification()) &&
174 ("strange flag setting"));
175 exchange(b, new_block);
178 new_block = equivalent_node(b);
181 /* normally, we would create a Bad block here, but this must be
182 * prevented, so just set it's cf to Bad.
184 if (is_Block_dead(new_block)) {
185 exchange(node, new_Bad());
193 * Block walker removing control flow from dead block by
194 * inspecting dominance info.
195 * Do not replace blocks by Bad. This optimization shall
196 * ensure, that all Bad control flow predecessors are
197 * removed, and no new other Bads are introduced.
198 * Further removed useless Conds and clear the mark of all blocks.
200 * Must be run in the post walker.
202 static void remove_unreachable_blocks_and_conds(ir_node *block, void *env) {
206 /* Check block predecessors and turn control flow into bad.
207 Beware of Tuple, kill them. */
208 for (i = get_Block_n_cfgpreds(block) - 1; i >= 0; --i) {
209 ir_node *pred_X = get_Block_cfgpred(block, i);
210 ir_node *skipped = skip_Tuple(pred_X);
212 if (! is_Bad(skipped)) {
213 ir_node *pred_bl = get_nodes_block(skip_Proj(skipped));
215 if (is_Block_dead(pred_bl) || (get_Block_dom_depth(pred_bl) < 0)) {
216 set_Block_dead(pred_bl);
217 exchange(pred_X, new_Bad());
219 } else if (skipped != pred_X) {
220 set_Block_cfgpred(block, i, skipped);
226 *changed |= remove_senseless_conds(block);
228 /* clear the block mark of all non labeled blocks */
229 if (has_Block_entity(block))
230 set_Block_non_removable(block);
232 set_Block_removable(block);
236 * Collects all Phi nodes in link list of Block.
237 * Marks all blocks "non_removable" if they contain a node other
238 * than Jmp (and Proj).
239 * Links all Proj nodes to their predecessors.
240 * Collects all switch-Conds in a list.
242 static void collect_nodes(ir_node *n, void *ctx) {
243 ir_opcode code = get_irn_opcode(n);
244 merge_env *env = ctx;
246 if (code == iro_Block) {
247 /* mark the block as non-removable if it is labeled */
248 if (has_Block_entity(n))
249 set_Block_non_removable(n);
251 ir_node *b = get_nodes_block(n);
253 if (code == iro_Phi && get_irn_arity(n) > 0) {
254 /* Collect Phi nodes to compact ins along with block's ins. */
255 set_irn_link(n, get_irn_link(b));
257 } else if (code != iro_Jmp && !is_Bad(b)) { /* Check for non-empty block. */
258 set_Block_non_removable(b);
260 if (code == iro_Proj) { /* link Proj nodes */
261 ir_node *pred = get_Proj_pred(n);
263 set_irn_link(n, get_irn_link(pred));
264 set_irn_link(pred, n);
265 } else if (code == iro_Cond) {
266 ir_node *sel = get_Cond_selector(n);
267 if (mode_is_int(get_irn_mode(sel))) {
268 /* found a switch-Cond, collect */
269 plist_insert_back(env->list, n);
276 /** Returns true if pred is predecessor of block. */
277 static int is_pred_of(ir_node *pred, ir_node *b) {
280 for (i = get_Block_n_cfgpreds(b) - 1; i >= 0; --i) {
281 ir_node *b_pred = get_Block_cfgpred_block(b, i);
288 /** Test whether we can optimize away pred block pos of b.
290 * @param b A block node.
291 * @param pos The position of the predecessor block to judge about.
293 * @returns The number of predecessors
295 * The test is rather tricky.
297 * The situation is something like the following:
306 * b merges the control flow of an if-then-else. We may not remove
307 * the 'then' _and_ the 'else' block of an 'if' if there is a Phi
308 * node in b, even if both are empty. The destruction of this Phi
309 * requires that a copy is added before the merge. We have to
310 * keep one of the case blocks to place the copies in.
312 * To perform the test for pos, we must regard predecessors before pos
313 * as already removed.
315 static int test_whether_dispensable(ir_node *b, int pos) {
316 int i, j, n_preds = 1;
317 ir_node *pred = get_Block_cfgpred_block(b, pos);
319 /* Bad blocks will be optimized away, so we don't need space for them */
320 if (is_Block_dead(pred))
323 if (is_Block_removable(pred)) {
324 if (!get_opt_optimize() || !get_opt_control_flow_strong_simplification()) {
325 /* Mark block so that is will not be removed: optimization is turned off. */
326 set_Block_non_removable(pred);
330 /* Seems to be empty. At least we detected this in collect_nodes. */
331 if (get_irn_link(b) == NULL) {
332 /* There are no Phi nodes ==> all predecessors are dispensable. */
333 n_preds = get_Block_n_cfgpreds(pred);
335 /* b's pred blocks and pred's pred blocks must be pairwise disjunct.
336 Handle all pred blocks with preds < pos as if they were already removed. */
337 for (i = 0; i < pos; i++) {
338 ir_node *b_pred = get_Block_cfgpred_block(b, i);
339 if (! is_Block_dead(b_pred) && is_Block_removable(b_pred)) {
340 for (j = get_Block_n_cfgpreds(b_pred) - 1; j >= 0; --j) {
341 ir_node *b_pred_pred = get_Block_cfgpred_block(b_pred, j);
342 if (is_pred_of(b_pred_pred, pred))
343 goto non_dispensable;
346 if (is_pred_of(b_pred, pred))
347 goto non_dispensable;
350 for (i = pos +1; i < get_Block_n_cfgpreds(b); i++) {
351 ir_node *b_pred = get_Block_cfgpred_block(b, i);
352 if (is_pred_of(b_pred, pred))
353 goto non_dispensable;
355 /* if we get here, the block is dispensable */
356 n_preds = get_Block_n_cfgpreds(pred);
363 set_Block_non_removable(pred);
368 * This method removed Bad cf predecessors from Blocks and Phis, and removes
369 * empty blocks. A block is empty if it only contains Phi and Jmp nodes.
371 * We first adapt Phi nodes, then Block nodes, as we need the old ins
372 * of the Block to adapt the Phi nodes. We do this by computing new
373 * in arrays, and then replacing the old ones. So far we compute new in arrays
374 * for all nodes, not regarding whether there is a possibility for optimization.
376 * For each predecessor p of a Block b there are three cases:
377 * -1. The predecessor p is a Bad node: just skip it. The in array of b shrinks by one.
378 * -2. The predecessor p is empty. Remove p. All predecessors of p are now
380 * -3. The predecessor p is a block containing useful code. Just keep p as is.
382 * For Phi nodes f we have to check the conditions at the Block of f.
383 * For cases 1 and 3 we proceed as for Blocks. For case 2 we can have two
385 * -2a: The old predecessor of the Phi f is a Phi pred_f IN THE BLOCK REMOVED. In this
386 * case we proceed as for blocks. We remove pred_f. All
387 * predecessors of pred_f now are predecessors of f.
388 * -2b: The old predecessor of f is NOT in the block removed. It might be a Phi, too.
389 * We have to replicate f for each predecessor of the removed block. Or, with
390 * other words, the removed predecessor block has exactly one predecessor.
392 * Further there is a special case for self referencing blocks:
395 * then_b else_b then_b else_b
401 * | | | === optimized to ===> \ | | |
408 * If there is a Phi in pred_b, but we remove pred_b, we have to generate a
409 * Phi in loop_b, that has the ins of the Phi in pred_b and a self referencing
411 * @@@ It is negotiable whether we should do this ... there might end up a copy
412 * from the Phi in the loop when removing the Phis.
414 static void optimize_blocks(ir_node *b, void *ctx) {
415 int i, j, k, n, max_preds, n_preds, p_preds = -1;
416 ir_node *pred, *phi, *next;
418 merge_env *env = ctx;
420 /* Count the number of predecessor if this block is merged with pred blocks
423 for (i = 0, k = get_Block_n_cfgpreds(b); i < k; ++i) {
424 max_preds += test_whether_dispensable(b, i);
426 in = XMALLOCN(ir_node*, max_preds);
428 /*- Fix the Phi nodes of the current block -*/
429 for (phi = get_irn_link(b); phi != NULL; phi = next) {
431 next = get_irn_link(phi);
433 /* Find the new predecessors for the Phi */
435 for (i = 0, n = get_Block_n_cfgpreds(b); i < n; ++i) {
436 pred = get_Block_cfgpred_block(b, i);
438 if (is_Block_dead(pred)) {
439 /* case Phi 1: Do nothing */
440 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
441 /* case Phi 2: It's an empty block and not yet visited. */
442 ir_node *phi_pred = get_Phi_pred(phi, i);
444 for (j = 0, k = get_Block_n_cfgpreds(pred); j < k; j++) {
445 /* because of breaking loops, not all predecessors are Bad-clean,
446 * so we must check this here again */
447 if (! is_Bad(get_Block_cfgpred(pred, j))) {
448 if (get_nodes_block(phi_pred) == pred) {
450 assert(is_Phi(phi_pred)); /* Block is empty!! */
452 in[p_preds++] = get_Phi_pred(phi_pred, j);
455 in[p_preds++] = phi_pred;
461 in[p_preds++] = get_Phi_pred(phi, i);
464 assert(p_preds <= max_preds);
468 /* By removal of Bad ins the Phi might be degenerated. */
469 exchange(phi, in[0]);
471 set_irn_in(phi, p_preds, in);
475 /*- This happens only if merge between loop backedge and single loop entry.
476 Moreover, it is only needed if predb is the direct dominator of b, else there can be no uses
477 of the Phi's in predb ... -*/
478 for (k = 0, n = get_Block_n_cfgpreds(b); k < n; ++k) {
479 ir_node *predb = get_nodes_block(get_Block_cfgpred(b, k));
481 if (is_Block_removable(predb) && !Block_block_visited(predb)) {
484 /* we found a predecessor block at position k that will be removed */
485 for (phi = get_irn_link(predb); phi; phi = next_phi) {
487 next_phi = get_irn_link(phi);
491 if (get_Block_idom(b) != predb) {
492 /* predb is not the dominator. There can't be uses of pred's Phi nodes, kill them .*/
493 exchange(phi, new_Bad());
495 /* predb is the direct dominator of b. There might be uses of the Phi nodes from
496 predb in further block, so move this phi from the predecessor into the block b */
497 set_nodes_block(phi, b);
498 set_irn_link(phi, get_irn_link(b));
499 set_irn_link(b, phi);
502 /* first, copy all 0..k-1 predecessors */
503 for (i = 0; i < k; i++) {
504 pred = get_Block_cfgpred_block(b, i);
506 if (is_Block_dead(pred)) {
508 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
509 /* It's an empty block and not yet visited. */
510 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
511 if (! is_Bad(get_Block_cfgpred(pred, j)))
519 /* now we are at k, copy the phi predecessors */
520 pred = get_nodes_block(get_Block_cfgpred(b, k));
521 for (i = 0; i < get_Phi_n_preds(phi); i++) {
522 if (! is_Bad(get_Block_cfgpred(pred, i)))
523 in[q_preds++] = get_Phi_pred(phi, i);
526 /* and now all the rest */
527 for (i = k+1; i < get_Block_n_cfgpreds(b); i++) {
528 pred = get_Block_cfgpred_block(b, i);
530 if (is_Block_dead(pred)) {
532 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
533 /* It's an empty block and not yet visited. */
534 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
535 if (! is_Bad(get_Block_cfgpred(pred, j)))
545 exchange(phi, in[0]);
547 set_irn_in(phi, q_preds, in);
550 assert(q_preds <= max_preds);
551 // assert(p_preds == q_preds && "Wrong Phi Fix");
557 /*- Fix the block -*/
559 for (i = 0; i < get_Block_n_cfgpreds(b); i++) {
560 pred = get_Block_cfgpred_block(b, i);
562 if (is_Block_dead(pred)) {
563 /* case 1: Do nothing */
564 } else if (is_Block_removable(pred) && !Block_block_visited(pred)) {
565 /* case 2: It's an empty block and not yet visited. */
566 assert(get_Block_n_cfgpreds(b) > 1 || has_Block_entity(b));
567 /* Else it should be optimized by equivalent_node. */
568 for (j = 0; j < get_Block_n_cfgpreds(pred); j++) {
569 ir_node *pred_X = get_Block_cfgpred(pred, j);
571 /* because of breaking loops, not all predecessors are Bad-clean,
572 * so we must check this here again */
573 if (! is_Bad(pred_X))
574 in[n_preds++] = pred_X;
576 /* Remove block as it might be kept alive. */
577 exchange(pred, b/*new_Bad()*/);
580 in[n_preds++] = get_Block_cfgpred(b, i);
583 assert(n_preds <= max_preds);
585 set_irn_in(b, n_preds, in);
588 assert(get_irn_link(b) == NULL || p_preds == -1 || (n_preds == p_preds && "Wrong Phi Fix"));
593 * Block walker: optimize all blocks using the default optimizations.
594 * This removes Blocks that with only a Jmp predecessor.
596 static void remove_simple_blocks(ir_node *block, void *ctx) {
597 ir_node *new_blk = equivalent_node(block);
598 merge_env *env = ctx;
600 if (new_blk != block) {
601 exchange(block, new_blk);
607 * Handle pre-optimized table switch Cond's.
608 * During iropt, all Projs from a switch-Cond are already removed except
609 * the defProj and maybe the taken one.
610 * The defProj cannot be removed WITHOUT looking backwards, so we do this here.
612 * @param cond the switch-Cond
614 * @return non-zero if a switch-Cond was optimized
616 * Expects all Proj's linked to the cond node
618 static int handle_switch_cond(ir_node *cond) {
619 ir_node *sel = get_Cond_selector(cond);
621 ir_node *proj1 = get_irn_link(cond);
622 ir_node *proj2 = get_irn_link(proj1);
625 blk = get_nodes_block(cond);
628 /* this Cond has only one Proj: must be the defProj */
629 assert(get_Cond_default_proj(cond) == get_Proj_proj(proj1));
630 /* convert it into a Jmp */
631 jmp = new_r_Jmp(blk);
632 exchange(proj1, jmp);
634 } else if (get_irn_link(proj2) == NULL) {
635 /* We have two Proj's here. Check if the Cond has
636 a constant argument */
637 tarval *tv = value_of(sel);
639 if (tv != tarval_bad) {
640 /* we have a constant switch */
641 long num = get_tarval_long(tv);
642 long def_num = get_Cond_default_proj(cond);
644 if (def_num == get_Proj_proj(proj1)) {
645 /* first one is the defProj */
646 if (num == get_Proj_proj(proj2)) {
647 jmp = new_r_Jmp(blk);
648 exchange(proj2, jmp);
649 exchange(proj1, new_Bad());
652 } else if (def_num == get_Proj_proj(proj2)) {
653 /* second one is the defProj */
654 if (num == get_Proj_proj(proj1)) {
655 jmp = new_r_Jmp(blk);
656 exchange(proj1, jmp);
657 exchange(proj2, new_Bad());
661 /* neither: strange, Cond was not optimized so far */
662 if (num == get_Proj_proj(proj1)) {
663 jmp = new_r_Jmp(blk);
664 exchange(proj1, jmp);
665 exchange(proj2, new_Bad());
667 } else if (num == get_Proj_proj(proj2)) {
668 jmp = new_r_Jmp(blk);
669 exchange(proj2, jmp);
670 exchange(proj1, new_Bad());
679 /* Optimizations of the control flow that also require changes of Phi nodes.
681 * This optimization performs two passes over the graph.
683 * The first pass collects all Phi nodes in a link list in the block
684 * nodes. Further it performs simple control flow optimizations.
685 * Finally it marks all blocks that do not contain useful
686 * computations, i.e., these blocks might be removed.
688 * The second pass performs the optimizations intended by this algorithm.
689 * It walks only over block nodes and adapts these and the Phi nodes in these blocks,
690 * which it finds in a linked list computed by the first pass.
692 * We use the mark flag to mark removable blocks in the first
695 void optimize_cf(ir_graph *irg) {
696 int i, j, n, changed;
698 ir_node *cond, *end = get_irg_end(irg);
699 ir_graph *rem = current_ir_graph;
703 assert(get_irg_phase_state(irg) != phase_building);
705 /* if the graph is not pinned, we cannot determine empty blocks */
706 assert(get_irg_pinned(irg) != op_pin_state_floats &&
707 "Control flow optimization need a pinned graph");
709 current_ir_graph = irg;
711 /* FIXME: control flow opt destroys block edges. So edges are deactivated here. Fix the edges! */
712 edges_deactivate(irg);
714 /* we use the mark flag to mark removable blocks */
715 ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK);
720 /* ALWAYS kill unreachable control flow. Backend cannot handle it anyway.
721 Use dominator info to kill blocks. Also optimize useless Conds. */
723 irg_block_walk_graph(irg, NULL, remove_unreachable_blocks_and_conds, &env.changed);
725 /* fix the keep-alives */
727 for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) {
728 ir_node *ka = get_End_keepalive(end, i);
731 /* do NOT keep dead blocks */
732 if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) {
733 set_End_keepalive(end, i, new_Bad());
737 ir_node *block = get_nodes_block(ka);
739 if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) {
740 /* do NOT keep nodes in dead blocks */
741 set_End_keepalive(end, i, new_Bad());
746 env.changed |= changed;
748 ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
750 env.list = plist_new();
751 irg_walk(end, merge_blocks, collect_nodes, &env);
753 ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
756 /* Handle graph state if was changed. */
757 set_irg_outs_inconsistent(irg);
758 set_irg_doms_inconsistent(irg);
759 set_irg_extblk_inconsistent(irg);
760 set_irg_loopinfo_inconsistent(irg);
761 set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
765 /* handle all collected switch-Conds */
766 foreach_plist(env.list, el) {
767 cond = plist_element_get_value(el);
768 env.changed |= handle_switch_cond(cond);
770 plist_free(env.list);
773 /* The Cond optimization might generate unreachable code, so restart if
778 /* Optimize the standard code. */
781 irg_block_walk_graph(irg, optimize_blocks, remove_simple_blocks, &env);
783 /* in rare cases a node may be kept alive more than once, use the visited flag to detect this */
784 ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED);
785 inc_irg_visited(irg);
787 /* fix the keep-alives again */
789 for (i = 0, n = get_End_n_keepalives(end); i < n; ++i) {
790 ir_node *ka = get_End_keepalive(end, i);
793 /* do NOT keep dead blocks */
794 if (is_Block_dead(ka) || get_Block_dom_depth(ka) < 0) {
795 set_End_keepalive(end, i, new_Bad());
799 ir_node *block = get_nodes_block(ka);
801 if (is_Bad(block) || is_Block_dead(block) || get_Block_dom_depth(block) < 0) {
802 /* do NOT keep nodes in dead blocks */
803 set_End_keepalive(end, i, new_Bad());
808 env.changed |= changed;
810 remove_End_Bads_and_doublets(end);
813 ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_IRN_VISITED);
815 if (env.phis_moved) {
816 /* Bad: when we moved Phi's, we might produce dead Phi nodes
818 Some other phases cannot copy with this, so will them.
820 n = get_End_n_keepalives(end);
822 NEW_ARR_A(ir_node *, in, n);
824 /* Handle graph state if was changed. */
825 set_irg_outs_inconsistent(irg);
827 assure_irg_outs(irg);
829 for (i = j = 0; i < n; ++i) {
830 ir_node *ka = get_End_keepalive(end, i);
835 for (k = get_irn_n_outs(ka) - 1; k >= 0; --k) {
836 ir_node *user = get_irn_out(ka, k);
838 if (user != ka && user != end) {
839 /* Is it a real user or just a self loop ? */
849 set_End_keepalives(end, j, in);
856 /* Handle graph state if was changed. */
857 set_irg_outs_inconsistent(irg);
858 set_irg_doms_inconsistent(irg);
859 set_irg_extblk_inconsistent(irg);
860 set_irg_loopinfo_inconsistent(irg);
861 set_irg_entity_usage_state(irg, ir_entity_usage_not_computed);
865 /* the verifier doesn't work yet with floating nodes */
866 if (get_irg_pinned(irg) == op_pin_state_pinned) {
867 /* after optimize_cf(), only Bad data flow may remain. */
868 if (irg_vrfy_bads(irg, BAD_DF | BAD_BLOCK | TUPLE)) {
869 dump_ir_block_graph(irg, "-vrfy-cf");
870 dump_ir_graph(irg, "-vrfy-cf");
871 fprintf(stderr, "VRFY_BAD in optimize_cf()\n");
875 current_ir_graph = rem;
878 /* Creates an ir_graph pass for optimize_cf. */
879 ir_graph_pass_t *optimize_cf_pass(const char *name)
881 return def_graph_pass(name ? name : "optimize_cf", optimize_cf);
882 } /* optimize_cf_pass */