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 MIN-algorithm with some twists (aka belady spiller v3)
23 * @author Matthias Braun
28 * - handle phis correctly, decide whether we should spill them ~ok
29 * - merge multiple start worksets of blocks ~ok
30 * - how to and when to do the tentative phase...
42 #include "iredges_t.h"
50 #include "bespilloptions.h"
51 #include "besched_t.h"
55 #define EXPENSIVE_CHECKS
58 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
60 typedef struct loop_edge_t loop_edge_t;
67 typedef struct loop_info_t loop_info_t;
70 loop_edge_t *entry_edges;
71 loop_edge_t *exit_edges;
72 size_t max_register_pressure;
75 typedef struct worklist_entry_t worklist_entry_t;
76 struct worklist_entry_t {
77 struct list_head head;
79 ir_node *reload_point;
80 ir_loop *unused_livethrough_loop;
83 #define foreach_worklist(entry, wl) list_for_each_entry(worklist_entry_t, entry, &(wl)->live_values, head)
85 typedef struct worklist_t worklist_t;
87 struct list_head live_values;
92 typedef struct block_info_t block_info_t;
94 worklist_t *start_worklist;
95 worklist_t *end_worklist;
98 /** The register class we currently run on. */
99 static const arch_register_class_t *cls;
100 static struct obstack obst;
101 static spill_env_t *senv;
102 static size_t n_regs;
103 static size_t max_register_pressure;
104 static bool tentative_mode;
105 static bool should_have_reached_fixpoint;
106 static bool do_push_unused_livethroughs;
107 /** Execution frequency for the current graph. */
108 static ir_exec_freq *exec_freq;
109 static ir_visited_t worklist_visited;
111 static worklist_t *new_worklist(void)
113 worklist_t *worklist = obstack_alloc(&obst, sizeof(worklist[0]));
114 memset(worklist, 0, sizeof(worklist[0]));
116 INIT_LIST_HEAD(&worklist->live_values);
117 worklist->n_live_values = 0;
122 static void mark_irn_not_visited(ir_node *node)
124 set_irn_visited(node, get_irg_visited(current_ir_graph) - 1);
127 static bool worklist_contains(const ir_node *node)
129 return irn_visited(node);
132 static block_info_t *get_block_info(ir_node *block)
134 block_info_t *info = get_irn_link(block);
138 info = obstack_alloc(&obst, sizeof(info[0]));
139 memset(info, 0, sizeof(info[0]));
140 set_irn_link(block, info);
144 static void deactivate_worklist(const worklist_t *worklist)
146 worklist_entry_t *entry;
148 foreach_worklist(entry, worklist) {
149 assert(worklist_contains(entry->value));
150 mark_irn_not_visited(entry->value);
151 set_irn_link(entry->value, NULL);
155 static void activate_worklist(const worklist_t *worklist)
157 worklist_entry_t *entry;
159 foreach_worklist(entry, worklist) {
160 assert(!worklist_contains(entry->value));
161 mark_irn_visited(entry->value);
162 set_irn_link(entry->value, entry);
167 * duplicate a worklist and directly activates it
169 static void fill_and_activate_worklist(worklist_t *new_worklist,
170 const worklist_t *worklist, ir_node *block, ir_node *succ_block,
173 ir_node *reload_point = NULL;
174 size_t n_live_values = 0;
175 worklist_entry_t *entry;
177 if (succ_block != NULL &&
178 (get_Block_n_cfgpreds(succ_block) > 1
179 || get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) > 1)) {
180 reload_point = be_get_end_of_block_insertion_point(block);
183 foreach_worklist(entry, worklist) {
184 ir_node *value = entry->value;
185 worklist_entry_t *new_entry;
187 if (new_worklist->n_live_values >= n_regs)
190 if (is_Phi(value) && get_nodes_block(value) == succ_block) {
191 value = get_Phi_pred(value, succ_pos);
193 /* can happen for unknown phi preds */
194 if (!arch_irn_consider_in_reg_alloc(cls, value))
198 if (irn_visited_else_mark(value))
201 new_entry = obstack_alloc(&obst, sizeof(new_entry[0]));
202 memset(new_entry, 0, sizeof(new_entry[0]));
204 new_entry->value = value;
205 if (reload_point != NULL) {
206 new_entry->reload_point = reload_point;
208 new_entry->reload_point = entry->reload_point;
211 list_add_tail(&new_entry->head, &new_worklist->live_values);
214 set_irn_link(value, new_entry);
215 new_worklist->n_live_values++;
219 static worklist_t *duplicate_worklist(const worklist_t *worklist)
221 worklist_t *new_worklist;
222 struct list_head *entry;
224 new_worklist = obstack_alloc(&obst, sizeof(new_worklist[0]));
225 memset(new_worklist, 0, sizeof(new_worklist[0]));
226 INIT_LIST_HEAD(&new_worklist->live_values);
227 new_worklist->n_live_values = worklist->n_live_values;
229 list_for_each(entry, &worklist->live_values) {
230 worklist_entry_t *wl_entry = list_entry(entry, worklist_entry_t, head);
231 worklist_entry_t *new_entry
232 = obstack_alloc(&obst, sizeof(new_entry[0]));
234 memcpy(new_entry, wl_entry, sizeof(new_entry[0]));
235 list_add_tail(&new_entry->head, &new_worklist->live_values);
242 static void print_worklist(const worklist_t *worklist, int level)
244 struct list_head *entry;
246 DB((dbg, level, "%d values: ", worklist->n_live_values));
247 list_for_each(entry, &worklist->live_values) {
248 worklist_entry_t *wl_entry
249 = list_entry(entry, worklist_entry_t, head);
251 DB((dbg, level, "%+F ", wl_entry->value));
258 * Clear the link fields of a loop and all
261 * @param loop the root loop
263 static void clear_loop_info(ir_loop *loop)
265 int n_elements = get_loop_n_elements(loop);
269 for (i = 0; i < n_elements; ++i) {
270 loop_element element = get_loop_element(loop, i);
271 if (*element.kind != k_ir_loop)
274 clear_loop_info(element.son);
278 static loop_info_t *get_loop_info(ir_loop *loop)
280 loop_info_t *info = loop->link;
284 info = obstack_alloc(&obst, sizeof(info[0]));
285 memset(info, 0, sizeof(info[0]));
292 * constructs loop in+out edges when called in a block walker
294 static void construct_loop_edges(ir_node *block, void *data)
296 int n_cfgpreds = get_Block_n_cfgpreds(block);
297 ir_loop *loop = get_irn_loop(block);
302 for (i = 0; i < n_cfgpreds; ++i) {
303 ir_node *cfgpred_block = get_Block_cfgpred_block(block, i);
304 ir_loop *cfgpred_loop = get_irn_loop(cfgpred_block);
309 if (cfgpred_loop == loop)
312 /* critical edges are splitted, so we can't jump from 1 loop
313 * directly into another without going out of it */
314 assert(get_loop_depth(cfgpred_loop) != get_loop_depth(loop));
316 /* edge out of loop */
317 if (get_loop_depth(cfgpred_loop) > get_loop_depth(loop)) {
322 is_exit_edge = false;
327 /* this might be a jump out/in multiple loops */
329 loop_info_t *l_info = get_loop_info(l);
331 edge = obstack_alloc(&obst, sizeof(edge[0]));
332 memset(edge, 0, sizeof(edge[0]));
337 edge->next = l_info->exit_edges;
338 l_info->exit_edges = edge;
339 assert(get_loop_depth(loop) < get_loop_depth(l));
341 edge->next = l_info->entry_edges;
342 l_info->entry_edges = edge;
343 assert(get_loop_depth(cfgpred_loop) < get_loop_depth(l));
345 l = get_loop_outer_loop(l);
353 static void place_reload(worklist_entry_t *entry)
358 DB((dbg, LEVEL_1, "reload of %+F before %+F\n", entry->value,
359 entry->reload_point));
360 assert(entry->reload_point != NULL);
361 be_add_reload(senv, entry->value, entry->reload_point, cls, 1);
362 entry->reload_point = NULL;
366 * makes sure the worklist contains not more than n_regs - room_needed entries
368 static void make_room(worklist_t *worklist, size_t room_needed)
372 struct list_head *entry;
374 spills_needed = worklist->n_live_values + room_needed - n_regs;
375 if (spills_needed <= 0)
378 entry = worklist->live_values.next;
379 for(i = spills_needed; i > 0; --i) {
380 struct list_head *next = entry->next;
381 worklist_entry_t *wl_entry
382 = list_entry(entry, worklist_entry_t, head);
384 assert(worklist_contains(wl_entry->value));
385 mark_irn_not_visited(wl_entry->value);
386 place_reload(wl_entry);
391 worklist->n_live_values -= spills_needed;
395 * a value was used, so bring it to the back of the worklist (which might
396 * result in a spill of another value).
398 static void val_used(worklist_t *worklist, ir_node *value, ir_node *sched_point)
400 /* already in the worklist? move around, otherwise add at back */
401 worklist_entry_t *entry = get_irn_link(value);
403 assert(arch_irn_consider_in_reg_alloc(cls, value));
405 if (worklist_contains(value)) {
406 assert(entry != NULL);
408 list_del(&entry->head);
411 entry = obstack_alloc(&obst, sizeof(entry[0]));
412 memset(entry, 0, sizeof(entry[0]));
414 entry->value = value;
415 set_irn_link(value, entry);
418 ++worklist->n_live_values;
419 mark_irn_visited(value);
422 entry->reload_point = sched_point;
423 list_add_tail(&entry->head, &worklist->live_values);
426 static void worklist_remove(worklist_t *worklist, ir_node *value)
428 worklist_entry_t *entry = get_irn_link(value);
429 assert(entry != NULL);
430 list_del(&entry->head);
431 --worklist->n_live_values;
433 assert(worklist_contains(value));
434 mark_irn_not_visited(value);
437 static void update_max_pressure(worklist_t *worklist)
439 if (worklist->n_live_values > max_register_pressure)
440 max_register_pressure = worklist->n_live_values;
443 static void do_spilling(ir_node *block, worklist_t *worklist)
447 assert(worklist != NULL);
449 sched_foreach_reverse(block, node) {
453 DB((dbg, LEVEL_2, "\t%+F... ", node));
454 update_max_pressure(worklist);
458 /* TODO: if we have some free registers, then we could decide to
459 * not spill some phis (but not for phis where at least 1 input is
462 /* we have to spill all phis that are not live */
463 sched_foreach_reverse_from(node, node2) {
464 assert(is_Phi(node2));
466 if (worklist_contains(node2))
468 if (!arch_irn_consider_in_reg_alloc(cls, node2))
472 be_spill_phi(senv, node2);
474 DB((dbg, LEVEL_2, "\n"));
478 /* remove values defined by this instruction from the workset. Values
479 * defined but not in the workset need free registers */
480 if (get_irn_mode(node) == mode_T) {
481 const ir_edge_t *edge;
483 foreach_out_edge(node, edge) {
484 ir_node *proj = get_edge_src_irn(edge);
485 if (!arch_irn_consider_in_reg_alloc(cls, proj))
487 if (worklist_contains(proj)) {
488 worklist_remove(worklist, proj);
493 } else if (arch_irn_consider_in_reg_alloc(cls, node)) {
494 if (worklist_contains(node)) {
495 worklist_remove(worklist, node);
501 /* make sure we have enough free registers for the spills */
502 make_room(worklist, n_defs);
504 /* put all values used by the instruction into the workset */
505 arity = get_irn_arity(node);
506 for(i = 0; i < arity; ++i) {
507 ir_node *use = get_irn_n(node, i);
509 if (!arch_irn_consider_in_reg_alloc(cls, use))
512 val_used(worklist, use, node);
515 /* we might have too many values in the worklist now and need to spill
517 make_room(worklist, 0);
520 print_worklist(worklist, LEVEL_2);
521 DB((dbg, LEVEL_2, "\n"));
525 update_max_pressure(worklist);
528 DB((dbg, LEVEL_1, "worklist at begin of %+F:", block));
529 print_worklist(worklist, LEVEL_1);
530 DB((dbg, LEVEL_1, "\n"));
534 static bool worklists_equal(const worklist_t *wl1, const worklist_t *wl2)
536 const struct list_head *i1 = &wl1->live_values;
537 const struct list_head *i2 = &wl2->live_values;
539 for ( ; i1 != &wl1->live_values && i2 != &wl2->live_values;
540 i1 = i1->next, i2 = i2->next) {
541 worklist_entry_t *entry1 = list_entry(i1, worklist_entry_t, head);
542 worklist_entry_t *entry2 = list_entry(i2, worklist_entry_t, head);
544 if (entry1->value != entry2->value)
547 /* both lists at the end */
548 if (i1 != &wl1->live_values || i2 != &wl2->live_values)
554 static bool fill_start_worklist(worklist_t *new_worklist, ir_node *block)
556 double best_execfreq = -1;
557 worklist_t *best_worklist = NULL;
558 ir_node *best_succ_block = NULL;
560 const ir_edge_t *edge;
562 /* construct worklist */
563 foreach_block_succ(block, edge) {
564 ir_node *succ_block = get_edge_src_irn(edge);
565 double execfreq = get_block_execfreq(exec_freq, succ_block);
566 block_info_t *block_info;
567 worklist_t *succ_worklist;
569 if (execfreq < best_execfreq)
572 block_info = get_block_info(succ_block);
573 succ_worklist = block_info->start_worklist;
575 if (succ_worklist == NULL || succ_worklist->visited >= worklist_visited)
578 best_execfreq = execfreq;
579 best_worklist = succ_worklist;
580 best_succ_block = succ_block;
581 best_pos = get_edge_src_pos(edge);
584 if (best_worklist == NULL)
586 best_worklist->visited = worklist_visited;
588 fill_and_activate_worklist(new_worklist, best_worklist, block,
589 best_succ_block, best_pos);
593 static worklist_t *construct_start_worklist(ir_node *block)
595 worklist_t *worklist = new_worklist();
599 while(fill_start_worklist(worklist, block)) {
600 if (worklist->n_live_values >= n_regs)
607 static void process_block(ir_node *block, void *env)
609 block_info_t *block_info;
610 worklist_t *worklist;
614 DB((dbg, LEVEL_1, "Processing %+F\n", block));
616 worklist = construct_start_worklist(block);
617 block_info = get_block_info(block);
620 DB((dbg, LEVEL_1, "worklist at end of %+F:", block));
621 print_worklist(worklist, LEVEL_1);
622 DB((dbg, LEVEL_1, "\n"));
624 if (should_have_reached_fixpoint) {
625 assert(worklists_equal(block_info->end_worklist, worklist));
628 block_info->end_worklist = duplicate_worklist(worklist);
630 do_spilling(block, worklist);
631 deactivate_worklist(worklist);
634 if (should_have_reached_fixpoint) {
635 assert(worklists_equal(block_info->start_worklist, worklist));
638 block_info->start_worklist = worklist;
640 /* we shouldn't have any live values left at the start block */
641 n_preds = get_Block_n_cfgpreds(block);
642 //assert(n_preds != 0 || worklist->n_live_values == 0);
645 typedef union block_or_loop_t block_or_loop_t;
646 union block_or_loop_t {
651 static block_or_loop_t *loop_blocks;
652 static ir_loop *current_loop;
654 static void find_blocks(ir_node *block);
656 static void find_in_loop(ir_loop *loop, ir_node *entry)
658 loop_info_t *loop_info = get_loop_info(loop);
659 block_or_loop_t block_or_loop;
662 /* simply mark 1 block in the loop to indicate that the loop was already
664 ir_node *some_block = loop_info->entry_edges->block;
665 if (Block_block_visited(some_block))
668 block_or_loop.loop = loop;
669 ARR_APP1(block_or_loop_t, loop_blocks, block_or_loop);
673 /* we should be 1 of the entry blocks */
674 loop_edge_t *edge = loop_info->entry_edges;
676 for ( ; edge != NULL; edge = edge->next) {
677 if (edge->block == entry) {
688 /* check all loop successors */
689 for (edge = loop_info->exit_edges; edge != NULL; edge = edge->next) {
690 ir_node *succ = edge->block;
691 ir_loop *succ_loop = get_irn_loop(succ);
693 if (succ_loop == current_loop) {
696 assert(get_loop_depth(succ_loop) < get_loop_depth(current_loop));
701 static void find_blocks(ir_node *block)
703 const ir_edge_t *edge;
704 block_or_loop_t block_or_loop;
706 if (Block_block_visited(block))
709 block_or_loop.block = block;
711 ARR_APP1(block_or_loop_t, loop_blocks, block_or_loop);
712 mark_Block_block_visited(block);
714 foreach_block_succ(block, edge) {
715 ir_node *succ = get_edge_src_irn(edge);
717 /* is it part of the current loop? */
718 ir_loop *loop = get_irn_loop(succ);
719 if (loop != current_loop) {
721 if (get_loop_depth(loop) > get_loop_depth(current_loop)) {
722 find_in_loop(loop, succ);
724 /* parent loop: we're not interested in the block */
733 * append an entry to a worklist. WARNING: The entry must not already be in the
736 static void worklist_append(worklist_t *worklist, ir_node *value,
737 ir_node *reload_point,
738 ir_loop *unused_livethrough_loop)
740 worklist_entry_t *entry;
742 #ifdef EXPENSIVE_CHECKS
743 foreach_worklist(entry, worklist) {
744 assert(entry->value != value);
748 entry = obstack_alloc(&obst, sizeof(*entry));
749 memset(entry, 0, sizeof(entry[0]));
751 entry->value = value;
752 entry->reload_point = reload_point;
753 entry->unused_livethrough_loop = unused_livethrough_loop;
754 list_add_tail(&entry->head, &worklist->live_values);
755 ++worklist->n_live_values;
756 assert(worklist->n_live_values <= n_regs);
759 static void push_unused_livethrough(loop_info_t *loop_info, ir_node *value)
764 /* add the value to all loop exit and entry blocks */
765 for (edge = loop_info->exit_edges; edge != NULL; edge = edge->next) {
767 = get_Block_cfgpred_block(edge->block, edge->pos);
768 const block_info_t *info = get_block_info(block);
769 worklist_t *worklist = info->end_worklist;
770 ir_node *reload_point = NULL;
772 if (worklist->visited >= worklist_visited)
774 worklist->visited = worklist_visited;
776 /* TODO: we need a smarter mechanism here, that makes the reloader place
777 * reload nodes on all loop exits... */
779 worklist_append(worklist, value, reload_point, loop_info->loop);
781 edge = loop_info->entry_edges;
782 for ( ; edge != NULL; edge = edge->next) {
783 ir_node *entry_block = edge->block;
784 const block_info_t *info = get_block_info(entry_block);
785 worklist_t *worklist = info->start_worklist;
787 ir_node *reload_point;
789 if (worklist->visited >= worklist_visited)
791 worklist->visited = worklist_visited;
793 pred_block = get_Block_cfgpred_block(entry_block, edge->pos);
794 reload_point = be_get_end_of_block_insertion_point(pred_block);
796 worklist_append(worklist, value, reload_point, loop_info->loop);
799 set_irn_link(value, NULL);
800 ++loop_info->max_register_pressure;
803 static void push_unused_livethroughs(loop_info_t *loop_info)
807 /* we can only push unused livethroughs if register pressure inside the loop
809 if (loop_info->max_register_pressure >= n_regs)
812 /* find unused livethroughs: register pressure in the loop was low enough
813 * which means that we had no spills which implies that at every point in
815 for (edge = loop_info->exit_edges; edge != NULL; edge = edge->next) {
816 ir_node *block = edge->block;
817 const block_info_t *info = get_block_info(block);
818 worklist_t *start_worklist = info->start_worklist;
820 const block_info_t *exit_info;
821 worklist_t *end_worklist;
822 struct list_head *entry;
824 if (start_worklist == NULL)
827 exit_block = get_Block_cfgpred_block(edge->block, edge->pos);
828 exit_info = get_block_info(exit_block);
829 end_worklist = exit_info->end_worklist;
831 activate_worklist(end_worklist);
832 /* all values contained in the start_worklist, which are not available
833 * in the end_worklist, must be unused livethroughs */
835 list_for_each(entry, &start_worklist->live_values) {
836 worklist_entry_t *wl_entry
837 = list_entry(entry, worklist_entry_t, head);
838 ir_node *value = wl_entry->value;
840 if (loop_info->max_register_pressure >= n_regs)
844 if (!worklist_contains(value)) {
845 /* add it to all loop exits */
846 DB((dbg, LEVEL_2, "Found unused livethrough: %+F (regpressure in loop %d)\n", value, loop_info->max_register_pressure));
847 push_unused_livethrough(loop_info, value);
848 /* the value should now be part of end_worklist, so mark it */
849 mark_irn_visited(value);
853 deactivate_worklist(end_worklist);
857 static void process_block_or_loop(const block_or_loop_t block_or_loop)
859 if (block_or_loop.loop->kind == k_ir_loop) {
860 loop_info_t *loop_info = get_loop_info(block_or_loop.loop);
862 if (do_push_unused_livethroughs)
863 push_unused_livethroughs(loop_info);
865 if (loop_info->max_register_pressure > max_register_pressure)
866 max_register_pressure = loop_info->max_register_pressure;
870 process_block(block_or_loop.block, NULL);
873 static void process_loop(ir_loop *loop)
875 int n_elements = get_loop_n_elements(loop);
877 loop_info_t *loop_info;
881 /* first handle all sub-loops */
882 for (i = 0; i < n_elements; ++i) {
883 loop_element element = get_loop_element(loop, i);
884 if (*element.kind != k_ir_loop)
887 process_loop(element.son);
890 /* create a postorder of the blocks */
891 loop_info = get_loop_info(loop);
892 edge = loop_info->entry_edges;
894 some_block = edge->block;
896 assert(loop == get_irg_loop(current_ir_graph));
897 some_block = get_irg_start_block(current_ir_graph);
900 loop_blocks = NEW_ARR_F(block_or_loop_t, 0);
903 ir_reserve_resources(current_ir_graph, IR_RESOURCE_BLOCK_VISITED);
904 inc_irg_block_visited(current_ir_graph);
905 find_blocks(some_block);
906 /* for endless loops the end-block might be unreachable */
907 if (loop == get_irg_loop(current_ir_graph)) {
908 find_blocks(get_irg_end_block(current_ir_graph));
910 ir_free_resources(current_ir_graph, IR_RESOURCE_BLOCK_VISITED);
912 DB((dbg, LEVEL_3, "Block List for loop %p\n", loop));
913 len = ARR_LEN(loop_blocks);
914 for (i = 0; i < len; ++i) {
915 block_or_loop_t block_or_loop = loop_blocks[i];
916 if (block_or_loop.loop->kind == k_ir_loop) {
917 DB((dbg, LEVEL_3, " L-%p", block_or_loop.loop));
919 DB((dbg, LEVEL_3, " B-%+F", block_or_loop.block));
922 DB((dbg, LEVEL_3, "\n"));
924 max_register_pressure = 0;
926 /* run1: tentative phase */
927 tentative_mode = true;
928 for (i = len-1; i >= 0; --i) {
929 process_block_or_loop(loop_blocks[i]);
932 /* run2: tentative phase - should reach fixpoint */
933 tentative_mode = true;
934 for (i = len-1; i >= 0; --i) {
935 process_block_or_loop(loop_blocks[i]);
939 /* run3: tentative phase - check fixpoint */
940 tentative_mode = true;
941 should_have_reached_fixpoint = true;
942 for (i = len-1; i >= 0; --i) {
943 process_block_or_loop(loop_blocks[i]);
945 should_have_reached_fixpoint = false;
948 /* run4: add spills/reloads */
949 tentative_mode = false;
950 do_push_unused_livethroughs = true;
951 for (i = len-1; i >= 0; --i) {
952 process_block_or_loop(loop_blocks[i]);
954 do_push_unused_livethroughs = false;
956 loop_info->max_register_pressure = max_register_pressure;
957 DB((dbg, LEVEL_2, "Regpressure in loop %p: %u\n", loop,
958 (unsigned) max_register_pressure));
960 DEL_ARR_F(loop_blocks);
963 static void fix_block_borders(ir_node *block, void *data)
965 block_info_t *block_info = get_block_info(block);
966 worklist_t *start_worklist = block_info->start_worklist;
967 int n_cfgpreds = get_Block_n_cfgpreds(block);
968 ir_loop *loop = get_irn_loop(block);
972 assert(start_worklist != NULL);
974 for (i = 0; i < n_cfgpreds; ++i) {
975 ir_node *pred_block = get_Block_cfgpred_block(block, i);
976 block_info_t *pred_block_info = get_block_info(pred_block);
977 worklist_t *end_worklist = pred_block_info->end_worklist;
978 ir_loop *pred_loop = get_irn_loop(pred_block);
979 bool is_loop_entry = false;
980 worklist_entry_t *entry;
982 assert(end_worklist != NULL);
984 if (get_loop_depth(pred_loop) < get_loop_depth(loop)) {
985 is_loop_entry = true;
988 /* reload missing values */
989 activate_worklist(end_worklist);
991 foreach_worklist(entry, start_worklist) {
992 ir_node *value = entry->value;
994 if (!is_loop_entry && entry->unused_livethrough_loop != NULL)
997 if (is_Phi(value) && get_nodes_block(value) == block) {
998 value = get_irn_n(value, i);
1000 /* we might have unknowns as argument for the phi */
1001 if (!arch_irn_consider_in_reg_alloc(cls, value))
1004 if (worklist_contains(value))
1006 be_add_reload_on_edge(senv, value, block, i, cls, 1);
1009 deactivate_worklist(end_worklist);
1014 * Run the spill algorithm.
1016 * @param birg the graph to run on
1017 * @param ncls the register class to run on
1019 static void be_spill_belady3(be_irg_t *birg, const arch_register_class_t *ncls)
1021 ir_graph *irg = be_get_birg_irg(birg);
1024 n_regs = cls->n_regs - be_put_ignore_regs(birg, cls, NULL);
1026 /* shortcut for register classes with ignore regs only */
1030 worklist_visited = 0;
1031 exec_freq = be_get_birg_exec_freq(birg);
1033 be_clear_links(irg);
1034 ir_reserve_resources(irg, IR_RESOURCE_IRN_VISITED | IR_RESOURCE_IRN_LINK
1035 | IR_RESOURCE_LOOP_LINK);
1036 inc_irg_visited(irg);
1038 obstack_init(&obst);
1039 senv = be_new_spill_env(birg);
1041 assure_cf_loop(irg);
1042 clear_loop_info(get_irg_loop(irg));
1043 irg_block_walk_graph(irg, construct_loop_edges, NULL, NULL);
1045 process_loop(get_irg_loop(irg));
1047 irg_block_walk_graph(irg, fix_block_borders, NULL, NULL);
1049 ir_free_resources(irg, IR_RESOURCE_IRN_VISITED | IR_RESOURCE_IRN_LINK
1050 | IR_RESOURCE_LOOP_LINK);
1052 be_insert_spills_reloads(senv);
1054 obstack_free(&obst, NULL);
1057 be_delete_spill_env(senv);
1060 void be_init_spillbelady3(void)
1062 static be_spiller_t belady3_spiller = {
1066 be_register_spiller("belady3", &belady3_spiller);
1067 FIRM_DBG_REGISTER(dbg, "firm.be.spill.belady3");
1070 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spillbelady3);