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 implementation of the spill/reload placement abstraction layer
23 * @author Daniel Grund, Sebastian Hack, Matthias Braun
35 #include "iredges_t.h"
36 #include "irbackedge_t.h"
46 #include "irnodeset.h"
53 #include "bespillutil.h"
56 #include "bechordal_t.h"
57 #include "bestatevent.h"
58 #include "bessaconstr.h"
61 #include "beintlive_t.h"
65 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
67 #define REMAT_COST_INFINITE 1000
69 typedef struct reloader_t reloader_t;
72 ir_node *can_spill_after;
74 ir_node *rematted_node;
75 int remat_cost_delta; /** costs needed for rematerialization,
76 compared to placing a reload */
79 typedef struct spill_t spill_t;
82 ir_node *after; /**< spill has to be placed after this node (or earlier) */
86 typedef struct spill_info_t spill_info_t;
88 ir_node *to_spill; /**< the value that should get spilled */
89 reloader_t *reloaders; /**< list of places where the value should get
91 spill_t *spills; /**< list of latest places where spill must be
93 double spill_costs; /**< costs needed for spilling the value */
94 const arch_register_class_t *reload_cls; /** the register class in which the
95 reload should be placed */
99 const arch_env_t *arch_env;
102 int spill_cost; /**< the cost of a single spill node */
103 int reload_cost; /**< the cost of a reload node */
104 set *spills; /**< all spill_info_t's, which must be
106 ir_nodeset_t mem_phis; /**< set of all spilled phis. */
107 ir_exec_freq *exec_freq;
109 #ifdef FIRM_STATISTICS
110 unsigned spill_count;
111 unsigned reload_count;
112 unsigned remat_count;
113 unsigned spilled_phi_count;
118 * Compare two spill infos.
120 static int cmp_spillinfo(const void *x, const void *y, size_t size)
122 const spill_info_t *xx = (const spill_info_t*)x;
123 const spill_info_t *yy = (const spill_info_t*)y;
126 return xx->to_spill != yy->to_spill;
130 * Returns spill info for a specific value (the value that is to be spilled)
132 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
134 spill_info_t info, *res;
135 int hash = hash_irn(value);
137 info.to_spill = value;
138 res = (spill_info_t*)set_find(env->spills, &info, sizeof(info), hash);
141 info.reloaders = NULL;
143 info.spill_costs = -1;
144 info.reload_cls = NULL;
145 res = (spill_info_t*)set_insert(env->spills, &info, sizeof(info), hash);
151 spill_env_t *be_new_spill_env(ir_graph *irg)
153 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
155 spill_env_t *env = XMALLOC(spill_env_t);
156 env->spills = new_set(cmp_spillinfo, 1024);
158 env->arch_env = arch_env;
159 ir_nodeset_init(&env->mem_phis);
160 env->spill_cost = arch_env->spill_cost;
161 env->reload_cost = arch_env->reload_cost;
162 env->exec_freq = be_get_irg_exec_freq(irg);
163 obstack_init(&env->obst);
165 #ifdef FIRM_STATISTICS
166 env->spill_count = 0;
167 env->reload_count = 0;
168 env->remat_count = 0;
169 env->spilled_phi_count = 0;
175 void be_delete_spill_env(spill_env_t *env)
177 del_set(env->spills);
178 ir_nodeset_destroy(&env->mem_phis);
179 obstack_free(&env->obst, NULL);
185 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
186 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
187 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
188 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
192 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
194 spill_info_t *spill_info = get_spillinfo(env, to_spill);
199 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
200 DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
202 /* Just for safety make sure that we do not insert the spill in front of a phi */
203 assert(!is_Phi(sched_next(after)));
205 /* spills that are dominated by others are not needed */
207 s = spill_info->spills;
208 for ( ; s != NULL; s = s->next) {
209 /* no need to add this spill if it is dominated by another */
210 if (value_dominates(s->after, after)) {
211 DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
214 /* remove spills that we dominate */
215 if (value_dominates(after, s->after)) {
216 DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
218 last->next = s->next;
220 spill_info->spills = s->next;
227 spill = OALLOC(&env->obst, spill_t);
228 spill->after = after;
229 spill->next = spill_info->spills;
232 spill_info->spills = spill;
235 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
236 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
242 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
244 info = get_spillinfo(env, to_spill);
246 if (is_Phi(to_spill)) {
249 /* create spillinfos for the phi arguments */
250 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
251 ir_node *arg = get_irn_n(to_spill, i);
252 get_spillinfo(env, arg);
256 assert(!is_Proj(before) && !be_is_Keep(before));
258 /* put reload into list */
259 rel = OALLOC(&env->obst, reloader_t);
260 rel->next = info->reloaders;
261 rel->reloader = before;
262 rel->rematted_node = NULL;
263 rel->can_spill_after = can_spill_after;
264 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
266 info->reloaders = rel;
267 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
268 info->reload_cls = reload_cls;
270 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
271 to_spill, before, allow_remat ? "" : " not"));
274 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
275 const arch_register_class_t *reload_cls, int allow_remat)
277 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
281 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
283 ir_node *last = sched_last(block);
285 /* we might have keeps behind the jump... */
286 while (be_is_Keep(last)) {
287 last = sched_prev(last);
288 assert(!sched_is_end(last));
291 assert(is_cfop(last));
293 /* add the reload before the (cond-)jump */
298 * determine final spill position: it should be after all phis, keep nodes
299 * and behind nodes marked as prolog
301 static ir_node *determine_spill_point(ir_node *node)
303 node = skip_Proj(node);
305 ir_node *next = sched_next(node);
306 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
314 * Returns the point at which you can insert a node that should be executed
315 * before block @p block when coming from pred @p pos.
317 static ir_node *get_block_insertion_point(ir_node *block, int pos)
321 /* simply add the reload to the beginning of the block if we only have 1
322 * predecessor. We don't need to check for phis as there can't be any in a
323 * block with only 1 pred. */
324 if (get_Block_n_cfgpreds(block) == 1) {
325 assert(!is_Phi(sched_first(block)));
326 return sched_first(block);
329 /* We have to reload the value in pred-block */
330 predblock = get_Block_cfgpred_block(block, pos);
331 return be_get_end_of_block_insertion_point(predblock);
334 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
335 const ir_node *block,
336 const arch_register_class_t *reload_cls,
339 ir_node *before = be_get_end_of_block_insertion_point(block);
340 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
343 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
344 int pos, const arch_register_class_t *reload_cls,
347 ir_node *before = get_block_insertion_point(block, pos);
348 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
351 void be_spill_phi(spill_env_t *env, ir_node *node)
356 assert(is_Phi(node));
358 ir_nodeset_insert(&env->mem_phis, node);
360 /* create spills for the phi arguments */
361 block = get_nodes_block(node);
362 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
363 ir_node *arg = get_irn_n(node, i);
366 /* some backends have virtual noreg/unknown nodes that are not scheduled
367 * and simply always available. */
368 if (!sched_is_scheduled(arg)) {
369 ir_node *pred_block = get_Block_cfgpred_block(block, i);
370 insert = be_get_end_of_block_insertion_point(pred_block);
371 insert = sched_prev(insert);
373 insert = determine_spill_point(arg);
376 be_add_spill(env, arg, insert);
382 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
383 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
384 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
385 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
389 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
394 * @param senv the spill environment
395 * @param irn the node that should be spilled
396 * @param ctx_irn an user of the spilled node
398 * @return a be_Spill node
400 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
402 ir_node *to_spill = spillinfo->to_spill;
403 const ir_node *insn = skip_Proj_const(to_spill);
406 /* determine_spill_costs must have been run before */
407 assert(spillinfo->spill_costs >= 0);
409 /* some backends have virtual noreg/unknown nodes that are not scheduled
410 * and simply always available. */
411 if (!sched_is_scheduled(insn)) {
412 /* override spillinfos or create a new one */
413 ir_graph *irg = get_irn_irg(to_spill);
414 spillinfo->spills->spill = new_r_NoMem(irg);
415 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
419 DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
420 spill = spillinfo->spills;
421 for ( ; spill != NULL; spill = spill->next) {
422 ir_node *after = spill->after;
423 ir_node *block = get_block(after);
425 after = determine_spill_point(after);
427 spill->spill = be_spill(block, to_spill);
428 sched_add_after(skip_Proj(after), spill->spill);
429 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
430 #ifdef FIRM_STATISTICS
434 DBG((dbg, LEVEL_1, "\n"));
437 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
440 * If the first usage of a Phi result would be out of memory
441 * there is no sense in allocating a register for it.
442 * Thus we spill it and all its operands to the same spill slot.
443 * Therefore the phi/dataB becomes a phi/Memory
445 * @param senv the spill environment
446 * @param phi the Phi node that should be spilled
447 * @param ctx_irn an user of the spilled node
449 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
451 ir_graph *irg = env->irg;
452 ir_node *phi = spillinfo->to_spill;
453 ir_node *block = get_nodes_block(phi);
461 assert(!get_opt_cse());
462 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
464 /* build a new PhiM */
465 arity = get_irn_arity(phi);
466 ins = ALLOCAN(ir_node*, arity);
467 unknown = new_r_Unknown(irg, mode_M);
468 for (i = 0; i < arity; ++i) {
472 /* override or replace spills list... */
473 spill = OALLOC(&env->obst, spill_t);
474 spill->after = determine_spill_point(phi);
475 spill->spill = be_new_Phi(block, arity, ins, mode_M, NULL);
477 sched_add_after(block, spill->spill);
479 spillinfo->spills = spill;
480 #ifdef FIRM_STATISTICS
481 env->spilled_phi_count++;
484 for (i = 0; i < arity; ++i) {
485 ir_node *arg = get_irn_n(phi, i);
486 spill_info_t *arg_info = get_spillinfo(env, arg);
488 determine_spill_costs(env, arg_info);
489 spill_node(env, arg_info);
491 set_irn_n(spill->spill, i, arg_info->spills->spill);
493 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
500 * @param senv the spill environment
501 * @param to_spill the node that should be spilled
503 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
507 /* node is already spilled */
508 if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
511 to_spill = spillinfo->to_spill;
513 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
514 spill_phi(env, spillinfo);
516 spill_irn(env, spillinfo);
523 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
524 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
525 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
526 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
531 * Tests whether value @p arg is available before node @p reloader
532 * @returns 1 if value is available, 0 otherwise
534 static int is_value_available(spill_env_t *env, const ir_node *arg,
535 const ir_node *reloader)
537 if (is_Unknown(arg) || is_NoMem(arg))
540 if (be_is_Spill(skip_Proj_const(arg)))
543 if (arg == get_irg_frame(env->irg))
548 if (get_irn_mode(arg) == mode_T)
552 * Ignore registers are always available
554 if (arch_irn_is_ignore(arg))
561 * Check if a node is rematerializable. This tests for the following conditions:
563 * - The node itself is rematerializable
564 * - All arguments of the node are available or also rematerialisable
565 * - The costs for the rematerialisation operation is less or equal a limit
567 * Returns the costs needed for rematerialisation or something
568 * >= REMAT_COST_INFINITE if remat is not possible.
570 static int check_remat_conditions_costs(spill_env_t *env,
571 const ir_node *spilled, const ir_node *reloader, int parentcosts)
576 const ir_node *insn = skip_Proj_const(spilled);
578 assert(!be_is_Spill(insn));
579 if (!arch_irn_is(insn, rematerializable))
580 return REMAT_COST_INFINITE;
582 if (be_is_Reload(insn)) {
585 costs += arch_get_op_estimated_cost(insn);
587 if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
588 return REMAT_COST_INFINITE;
590 /* never rematerialize a node which modifies the flags.
591 * (would be better to test whether the flags are actually live at point
594 if (arch_irn_is(insn, modify_flags)) {
595 return REMAT_COST_INFINITE;
599 for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
600 ir_node *arg = get_irn_n(insn, i);
602 if (is_value_available(env, arg, reloader))
605 /* we have to rematerialize the argument as well */
608 /* we only support rematerializing 1 argument at the moment,
609 * as multiple arguments could increase register pressure */
610 return REMAT_COST_INFINITE;
613 costs += check_remat_conditions_costs(env, arg, reloader,
614 parentcosts + costs);
615 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
616 return REMAT_COST_INFINITE;
623 * Re-materialize a node.
625 * @param senv the spill environment
626 * @param spilled the node that was spilled
627 * @param reloader a irn that requires a reload
629 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
636 if (is_Block(reloader)) {
639 bl = get_nodes_block(reloader);
642 ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
643 for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
644 ir_node *arg = get_irn_n(spilled, i);
646 if (is_value_available(env, arg, reloader)) {
649 ins[i] = do_remat(env, arg, reloader);
650 #ifdef FIRM_STATISTICS
651 /* don't count the recursive call as remat */
657 /* create a copy of the node */
658 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
659 get_irn_op(spilled), get_irn_mode(spilled),
660 get_irn_arity(spilled), ins);
661 copy_node_attr(env->irg, spilled, res);
662 arch_env_mark_remat(env->arch_env, res);
664 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
666 if (! is_Proj(res)) {
667 /* insert in schedule */
669 sched_add_before(reloader, res);
670 #ifdef FIRM_STATISTICS
678 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
680 ir_node *block = get_nodes_block(before);
681 double freq = get_block_execfreq(env->exec_freq, block);
684 return env->spill_cost * freq;
687 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
688 const ir_node *before)
691 /* is the node rematerializable? */
692 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
693 if (costs < (unsigned) env->reload_cost)
697 return env->reload_cost;
700 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
702 ir_node *block = get_nodes_block(before);
703 double freq = get_block_execfreq(env->exec_freq, block);
706 /* is the node rematerializable? */
707 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
708 if (costs < env->reload_cost)
712 return env->reload_cost * freq;
715 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
716 const ir_node *before)
718 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
721 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
722 ir_node *block, int pos)
724 ir_node *before = get_block_insertion_point(block, pos);
725 return be_get_reload_costs(env, to_spill, before);
730 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
731 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
732 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
733 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
738 * analyzes how to best spill a node and determine costs for that
740 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
742 ir_node *to_spill = spillinfo->to_spill;
743 const ir_node *insn = skip_Proj_const(to_spill);
744 ir_node *spill_block;
746 double spill_execfreq;
748 /* already calculated? */
749 if (spillinfo->spill_costs >= 0)
752 assert(!arch_irn_is(insn, dont_spill));
753 assert(!be_is_Reload(insn));
755 /* some backends have virtual noreg/unknown nodes that are not scheduled
756 * and simply always available.
757 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
758 * predecessor (of a PhiM) but this test might match other things too...
760 if (!sched_is_scheduled(insn)) {
761 ir_graph *irg = get_irn_irg(to_spill);
762 /* override spillinfos or create a new one */
763 spill_t *spill = OALLOC(&env->obst, spill_t);
766 spill->spill = new_r_NoMem(irg);
768 spillinfo->spills = spill;
769 spillinfo->spill_costs = 0;
771 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
775 spill_block = get_nodes_block(insn);
776 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
778 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
779 /* TODO calculate correct costs...
780 * (though we can't remat this node anyway so no big problem) */
781 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
785 if (spillinfo->spills != NULL) {
787 double spills_execfreq;
789 /* calculate sum of execution frequencies of individual spills */
791 s = spillinfo->spills;
792 for ( ; s != NULL; s = s->next) {
793 ir_node *spill_block = get_block(s->after);
794 double freq = get_block_execfreq(env->exec_freq, spill_block);
796 spills_execfreq += freq;
799 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
800 spills_execfreq * env->spill_cost,
801 spill_execfreq * env->spill_cost));
803 /* multi-/latespill is advantageous -> return*/
804 if (spills_execfreq < spill_execfreq) {
805 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
806 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
811 /* override spillinfos or create a new one */
812 spill = OALLOC(&env->obst, spill_t);
813 spill->after = determine_spill_point(to_spill);
817 spillinfo->spills = spill;
818 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
819 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
822 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
824 const spill_info_t *si = get_spillinfo(env, irn);
825 ir_node *start_block = get_irg_start_block(get_irn_irg(irn));
826 int n_blocks = get_Block_dom_max_subtree_pre_num(start_block);
827 bitset_t *reloads = bitset_alloca(n_blocks);
834 /* Fill the bitset with the dominance pre-order numbers
835 * of the blocks the reloads are located in. */
836 for (r = si->reloaders; r != NULL; r = r->next) {
837 ir_node *bl = get_nodes_block(r->reloader);
838 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
841 /* Now, cancel out all the blocks that are dominated by each spill.
842 * If the bitset is not empty after that, we have reloads that are
843 * not dominated by any spill. */
844 for (s = si->spills; s != NULL; s = s->next) {
845 ir_node *bl = get_nodes_block(s->after);
846 int start = get_Block_dom_tree_pre_num(bl);
847 int end = get_Block_dom_max_subtree_pre_num(bl);
849 bitset_clear_range(reloads, start, end);
852 if (!bitset_is_empty(reloads))
853 be_add_spill(env, si->to_spill, si->to_spill);
856 void be_insert_spills_reloads(spill_env_t *env)
858 const ir_exec_freq *exec_freq = env->exec_freq;
860 ir_nodeset_iterator_t iter;
863 be_timer_push(T_RA_SPILL_APPLY);
865 /* create all phi-ms first, this is needed so, that phis, hanging on
866 spilled phis work correctly */
867 foreach_ir_nodeset(&env->mem_phis, node, iter) {
868 spill_info_t *info = get_spillinfo(env, node);
869 spill_node(env, info);
872 /* process each spilled node */
873 foreach_set(env->spills, spill_info_t*, si) {
875 ir_node *to_spill = si->to_spill;
876 ir_mode *mode = get_irn_mode(to_spill);
877 ir_node **copies = NEW_ARR_F(ir_node*, 0);
878 double all_remat_costs = 0; /** costs when we would remat all nodes */
881 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
883 determine_spill_costs(env, si);
885 /* determine possibility of rematerialisations */
887 /* calculate cost savings for each indivial value when it would
888 be rematted instead of reloaded */
889 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
892 int remat_cost_delta;
894 ir_node *reloader = rld->reloader;
896 if (rld->rematted_node != NULL) {
897 DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
898 rld->rematted_node, reloader));
901 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
902 DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
904 all_remat_costs = REMAT_COST_INFINITE;
908 remat_cost = check_remat_conditions_costs(env, to_spill,
910 if (remat_cost >= REMAT_COST_INFINITE) {
911 DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
913 rld->remat_cost_delta = REMAT_COST_INFINITE;
914 all_remat_costs = REMAT_COST_INFINITE;
918 remat_cost_delta = remat_cost - env->reload_cost;
919 rld->remat_cost_delta = remat_cost_delta;
920 block = is_Block(reloader) ? reloader : get_nodes_block(reloader);
921 freq = get_block_execfreq(exec_freq, block);
922 all_remat_costs += remat_cost_delta * freq;
923 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
924 "%d (rel %f)\n", reloader, remat_cost_delta,
925 remat_cost_delta * freq));
927 if (all_remat_costs < REMAT_COST_INFINITE) {
928 /* we don't need the costs for the spill if we can remat
930 all_remat_costs -= si->spill_costs;
932 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
933 env->spill_cost, si->spill_costs));
936 if (all_remat_costs < 0) {
937 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
943 /* go through all reloads for this spill */
944 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
945 ir_node *copy; /* a reload is a "copy" of the original value */
947 if (rld->rematted_node != NULL) {
948 copy = rld->rematted_node;
949 sched_add_before(rld->reloader, copy);
950 } else if (be_do_remats &&
951 (force_remat || rld->remat_cost_delta < 0)) {
952 copy = do_remat(env, to_spill, rld->reloader);
954 /* make sure we have a spill */
957 /* create a reload, use the first spill for now SSA
958 * reconstruction for memory comes below */
959 assert(si->spills != NULL);
960 copy = be_reload(si->reload_cls, rld->reloader, mode,
962 #ifdef FIRM_STATISTICS
967 DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
968 copy, to_spill, rld->reloader));
969 ARR_APP1(ir_node*, copies, copy);
972 /* if we had any reloads or remats, then we need to reconstruct the
973 * SSA form for the spilled value */
974 if (ARR_LEN(copies) > 0) {
975 be_ssa_construction_env_t senv;
976 /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
978 be_ssa_construction_init(&senv, env->irg);
979 be_ssa_construction_add_copy(&senv, to_spill);
980 be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
981 be_ssa_construction_fix_users(&senv, to_spill);
984 /* no need to enable this as long as we invalidate liveness
985 after this function... */
986 be_ssa_construction_update_liveness_phis(&senv);
987 be_liveness_update(to_spill);
988 len = ARR_LEN(copies);
989 for (i = 0; i < len; ++i) {
990 be_liveness_update(lv, copies[i]);
993 be_ssa_construction_destroy(&senv);
995 /* need to reconstruct SSA form if we had multiple spills */
996 if (si->spills != NULL && si->spills->next != NULL) {
1000 be_ssa_construction_env_t senv;
1002 be_ssa_construction_init(&senv, env->irg);
1004 for ( ; spill != NULL; spill = spill->next) {
1005 /* maybe we rematerialized the value and need no spill */
1006 if (spill->spill == NULL)
1008 be_ssa_construction_add_copy(&senv, spill->spill);
1011 if (spill_count > 1) {
1012 /* all reloads are attached to the first spill, fix them now */
1013 be_ssa_construction_fix_users(&senv, si->spills->spill);
1016 be_ssa_construction_destroy(&senv);
1020 si->reloaders = NULL;
1023 stat_ev_dbl("spill_spills", env->spill_count);
1024 stat_ev_dbl("spill_reloads", env->reload_count);
1025 stat_ev_dbl("spill_remats", env->remat_count);
1026 stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1028 /* Matze: In theory be_ssa_construction should take care of the liveness...
1029 * try to disable this again in the future */
1030 be_liveness_invalidate(be_get_irg_liveness(env->irg));
1032 be_remove_dead_nodes_from_schedule(env->irg);
1034 be_timer_pop(T_RA_SPILL_APPLY);
1037 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1038 void be_init_spill(void)
1040 FIRM_DBG_REGISTER(dbg, "firm.be.spill");