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"
60 #include "beintlive_t.h"
64 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
66 #define REMAT_COST_INFINITE 1000
68 typedef struct reloader_t reloader_t;
71 ir_node *can_spill_after;
73 ir_node *rematted_node;
74 int remat_cost_delta; /** costs needed for rematerialization,
75 compared to placing a reload */
78 typedef struct spill_t spill_t;
81 ir_node *after; /**< spill has to be placed after this node (or earlier) */
85 typedef struct spill_info_t spill_info_t;
87 ir_node *to_spill; /**< the value that should get spilled */
88 reloader_t *reloaders; /**< list of places where the value should get
90 spill_t *spills; /**< list of latest places where spill must be
92 double spill_costs; /**< costs needed for spilling the value */
93 const arch_register_class_t *reload_cls; /** the register class in which the
94 reload should be placed */
98 const arch_env_t *arch_env;
101 int spill_cost; /**< the cost of a single spill node */
102 int reload_cost; /**< the cost of a reload node */
103 set *spills; /**< all spill_info_t's, which must be
105 ir_nodeset_t mem_phis; /**< set of all spilled phis. */
106 ir_exec_freq *exec_freq;
108 #ifdef FIRM_STATISTICS
109 unsigned spill_count;
110 unsigned reload_count;
111 unsigned remat_count;
112 unsigned spilled_phi_count;
117 * Compare two spill infos.
119 static int cmp_spillinfo(const void *x, const void *y, size_t size)
121 const spill_info_t *xx = x;
122 const spill_info_t *yy = y;
125 return xx->to_spill != yy->to_spill;
129 * Returns spill info for a specific value (the value that is to be spilled)
131 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
133 spill_info_t info, *res;
134 int hash = hash_irn(value);
136 info.to_spill = value;
137 res = set_find(env->spills, &info, sizeof(info), hash);
140 info.reloaders = NULL;
142 info.spill_costs = -1;
143 info.reload_cls = NULL;
144 res = set_insert(env->spills, &info, sizeof(info), hash);
150 spill_env_t *be_new_spill_env(ir_graph *irg)
152 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
154 spill_env_t *env = XMALLOC(spill_env_t);
155 env->spills = new_set(cmp_spillinfo, 1024);
157 env->arch_env = arch_env;
158 ir_nodeset_init(&env->mem_phis);
159 env->spill_cost = arch_env->spill_cost;
160 env->reload_cost = arch_env->reload_cost;
161 env->exec_freq = be_get_irg_exec_freq(irg);
162 obstack_init(&env->obst);
164 #ifdef FIRM_STATISTICS
165 env->spill_count = 0;
166 env->reload_count = 0;
167 env->remat_count = 0;
168 env->spilled_phi_count = 0;
174 void be_delete_spill_env(spill_env_t *env)
176 del_set(env->spills);
177 ir_nodeset_destroy(&env->mem_phis);
178 obstack_free(&env->obst, NULL);
184 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
185 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
186 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
187 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
191 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
193 spill_info_t *spill_info = get_spillinfo(env, to_spill);
194 const ir_node *insn = skip_Proj_const(to_spill);
199 assert(!arch_irn_is(insn, 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_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
236 ir_node *rematted_node)
238 spill_info_t *spill_info;
239 reloader_t *reloader;
241 spill_info = get_spillinfo(env, to_spill);
243 /* add the remat information */
244 reloader = OALLOC(&env->obst, reloader_t);
245 reloader->next = spill_info->reloaders;
246 reloader->reloader = before;
247 reloader->rematted_node = rematted_node;
248 reloader->remat_cost_delta = 0; /* We will never have a cost win over a
249 reload since we're not even allowed to
252 spill_info->reloaders = reloader;
254 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
258 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
259 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
264 const ir_node *insn = skip_Proj_const(to_spill);
266 assert(!arch_irn_is(insn, dont_spill));
268 info = get_spillinfo(env, to_spill);
270 if (is_Phi(to_spill)) {
273 /* create spillinfos for the phi arguments */
274 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
275 ir_node *arg = get_irn_n(to_spill, i);
276 get_spillinfo(env, arg);
280 assert(!is_Proj(before) && !be_is_Keep(before));
282 /* put reload into list */
283 rel = OALLOC(&env->obst, reloader_t);
284 rel->next = info->reloaders;
285 rel->reloader = before;
286 rel->rematted_node = NULL;
287 rel->can_spill_after = can_spill_after;
288 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
290 info->reloaders = rel;
291 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
292 info->reload_cls = reload_cls;
294 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
295 to_spill, before, allow_remat ? "" : " not"));
298 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
299 const arch_register_class_t *reload_cls, int allow_remat)
301 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
305 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
307 ir_node *last = sched_last(block);
309 /* we might have keeps behind the jump... */
310 while (be_is_Keep(last)) {
311 last = sched_prev(last);
312 assert(!sched_is_end(last));
315 assert(is_cfop(last));
317 /* add the reload before the (cond-)jump */
321 static ir_node *skip_keeps_phis(ir_node *node)
324 ir_node *next = sched_next(node);
325 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
333 * Returns the point at which you can insert a node that should be executed
334 * before block @p block when coming from pred @p pos.
336 static ir_node *get_block_insertion_point(ir_node *block, int pos)
340 /* simply add the reload to the beginning of the block if we only have 1
341 * predecessor. We don't need to check for phis as there can't be any in a
342 * block with only 1 pred. */
343 if (get_Block_n_cfgpreds(block) == 1) {
344 assert(!is_Phi(sched_first(block)));
345 return sched_first(block);
348 /* We have to reload the value in pred-block */
349 predblock = get_Block_cfgpred_block(block, pos);
350 return be_get_end_of_block_insertion_point(predblock);
353 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
354 const ir_node *block,
355 const arch_register_class_t *reload_cls,
358 ir_node *before = be_get_end_of_block_insertion_point(block);
359 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
362 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
363 int pos, const arch_register_class_t *reload_cls,
366 ir_node *before = get_block_insertion_point(block, pos);
367 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
370 void be_spill_phi(spill_env_t *env, ir_node *node)
375 assert(is_Phi(node));
377 ir_nodeset_insert(&env->mem_phis, node);
379 /* create spills for the phi arguments */
380 block = get_nodes_block(node);
381 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
382 ir_node *arg = get_irn_n(node, i);
385 /* some backends have virtual noreg/unknown nodes that are not scheduled
386 * and simply always available. */
387 if (!sched_is_scheduled(arg)) {
388 ir_node *pred_block = get_Block_cfgpred_block(block, i);
389 insert = be_get_end_of_block_insertion_point(pred_block);
390 insert = sched_prev(insert);
392 insert = skip_keeps_phis(arg);
395 be_add_spill(env, arg, insert);
401 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
402 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
403 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
404 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
408 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
413 * @param senv the spill environment
414 * @param irn the node that should be spilled
415 * @param ctx_irn an user of the spilled node
417 * @return a be_Spill node
419 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
421 ir_node *to_spill = spillinfo->to_spill;
422 const ir_node *insn = skip_Proj_const(to_spill);
425 /* determine_spill_costs must have been run before */
426 assert(spillinfo->spill_costs >= 0);
428 /* some backends have virtual noreg/unknown nodes that are not scheduled
429 * and simply always available. */
430 if (!sched_is_scheduled(insn)) {
431 /* override spillinfos or create a new one */
432 spillinfo->spills->spill = new_NoMem();
433 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
437 DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
438 spill = spillinfo->spills;
439 for ( ; spill != NULL; spill = spill->next) {
440 ir_node *after = spill->after;
441 ir_node *block = get_block(after);
443 after = skip_keeps_phis(after);
445 spill->spill = be_spill(block, to_spill);
446 sched_add_after(skip_Proj(after), spill->spill);
447 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
448 #ifdef FIRM_STATISTICS
452 DBG((dbg, LEVEL_1, "\n"));
455 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
458 * If the first usage of a Phi result would be out of memory
459 * there is no sense in allocating a register for it.
460 * Thus we spill it and all its operands to the same spill slot.
461 * Therefore the phi/dataB becomes a phi/Memory
463 * @param senv the spill environment
464 * @param phi the Phi node that should be spilled
465 * @param ctx_irn an user of the spilled node
467 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
469 ir_graph *irg = env->irg;
470 ir_node *phi = spillinfo->to_spill;
471 ir_node *block = get_nodes_block(phi);
479 assert(!get_opt_cse());
480 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
482 /* build a new PhiM */
483 arity = get_irn_arity(phi);
484 ins = ALLOCAN(ir_node*, arity);
485 unknown = new_r_Unknown(irg, mode_M);
486 for (i = 0; i < arity; ++i) {
490 /* override or replace spills list... */
491 spill = OALLOC(&env->obst, spill_t);
492 spill->after = skip_keeps_phis(phi);
493 spill->spill = new_r_Phi(block, arity, ins, mode_M);
496 spillinfo->spills = spill;
497 #ifdef FIRM_STATISTICS
498 env->spilled_phi_count++;
501 for (i = 0; i < arity; ++i) {
502 ir_node *arg = get_irn_n(phi, i);
503 spill_info_t *arg_info = get_spillinfo(env, arg);
505 determine_spill_costs(env, arg_info);
506 spill_node(env, arg_info);
508 set_irn_n(spill->spill, i, arg_info->spills->spill);
510 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
517 * @param senv the spill environment
518 * @param to_spill the node that should be spilled
520 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
524 /* node is already spilled */
525 if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
528 to_spill = spillinfo->to_spill;
530 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
531 spill_phi(env, spillinfo);
533 spill_irn(env, spillinfo);
540 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
541 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
542 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
543 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
548 * Tests whether value @p arg is available before node @p reloader
549 * @returns 1 if value is available, 0 otherwise
551 static int is_value_available(spill_env_t *env, const ir_node *arg,
552 const ir_node *reloader)
554 if (is_Unknown(arg) || arg == new_NoMem())
557 if (be_is_Spill(skip_Proj_const(arg)))
560 if (arg == get_irg_frame(env->irg))
565 if (get_irn_mode(arg) == mode_T)
569 * Ignore registers are always available
571 if (arch_irn_is_ignore(arg))
578 * Check if a node is rematerializable. This tests for the following conditions:
580 * - The node itself is rematerializable
581 * - All arguments of the node are available or also rematerialisable
582 * - The costs for the rematerialisation operation is less or equal a limit
584 * Returns the costs needed for rematerialisation or something
585 * >= REMAT_COST_INFINITE if remat is not possible.
587 static int check_remat_conditions_costs(spill_env_t *env,
588 const ir_node *spilled, const ir_node *reloader, int parentcosts)
593 const ir_node *insn = skip_Proj_const(spilled);
595 assert(!be_is_Spill(insn));
596 if (!arch_irn_is(insn, rematerializable))
597 return REMAT_COST_INFINITE;
599 if (be_is_Reload(insn)) {
602 costs += arch_get_op_estimated_cost(insn);
604 if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
605 return REMAT_COST_INFINITE;
607 /* never rematerialize a node which modifies the flags.
608 * (would be better to test wether the flags are actually live at point
611 if (arch_irn_is(insn, modify_flags)) {
612 return REMAT_COST_INFINITE;
616 for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
617 ir_node *arg = get_irn_n(insn, i);
619 if (is_value_available(env, arg, reloader))
622 /* we have to rematerialize the argument as well */
625 /* we only support rematerializing 1 argument at the moment,
626 * as multiple arguments could increase register pressure */
627 return REMAT_COST_INFINITE;
630 costs += check_remat_conditions_costs(env, arg, reloader,
631 parentcosts + costs);
632 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
633 return REMAT_COST_INFINITE;
640 * Re-materialize a node.
642 * @param senv the spill environment
643 * @param spilled the node that was spilled
644 * @param reloader a irn that requires a reload
646 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
653 if (is_Block(reloader)) {
656 bl = get_nodes_block(reloader);
659 ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
660 for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
661 ir_node *arg = get_irn_n(spilled, i);
663 if (is_value_available(env, arg, reloader)) {
666 ins[i] = do_remat(env, arg, reloader);
667 #ifdef FIRM_STATISTICS
668 /* don't count the recursive call as remat */
674 /* create a copy of the node */
675 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
676 get_irn_op(spilled), get_irn_mode(spilled),
677 get_irn_arity(spilled), ins);
678 copy_node_attr(env->irg, spilled, res);
679 arch_env_mark_remat(env->arch_env, res);
681 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
683 if (! is_Proj(res)) {
684 /* insert in schedule */
686 sched_add_before(reloader, res);
687 #ifdef FIRM_STATISTICS
695 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
697 ir_node *block = get_nodes_block(before);
698 double freq = get_block_execfreq(env->exec_freq, block);
701 return env->spill_cost * freq;
704 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
705 const ir_node *before)
708 /* is the node rematerializable? */
709 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
710 if (costs < (unsigned) env->reload_cost)
714 return env->reload_cost;
717 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
719 ir_node *block = get_nodes_block(before);
720 double freq = get_block_execfreq(env->exec_freq, block);
723 /* is the node rematerializable? */
724 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
725 if (costs < env->reload_cost)
729 return env->reload_cost * freq;
732 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
733 const ir_node *before)
735 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
738 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
739 ir_node *block, int pos)
741 ir_node *before = get_block_insertion_point(block, pos);
742 return be_get_reload_costs(env, to_spill, before);
747 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
748 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
749 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
750 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
755 * analyzes how to best spill a node and determine costs for that
757 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
759 ir_node *to_spill = spillinfo->to_spill;
760 const ir_node *insn = skip_Proj_const(to_spill);
761 ir_node *spill_block;
763 double spill_execfreq;
765 /* already calculated? */
766 if (spillinfo->spill_costs >= 0)
769 assert(!arch_irn_is(insn, dont_spill));
770 assert(!be_is_Reload(insn));
772 /* some backends have virtual noreg/unknown nodes that are not scheduled
773 * and simply always available.
774 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
775 * predecessor (of a PhiM) but this test might match other things too...
777 if (!sched_is_scheduled(insn)) {
778 /* override spillinfos or create a new one */
779 spill_t *spill = OALLOC(&env->obst, spill_t);
782 spill->spill = new_NoMem();
784 spillinfo->spills = spill;
785 spillinfo->spill_costs = 0;
787 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
791 spill_block = get_nodes_block(insn);
792 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
794 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
795 /* TODO calculate correct costs...
796 * (though we can't remat this node anyway so no big problem) */
797 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
801 if (spillinfo->spills != NULL) {
803 double spills_execfreq;
805 /* calculate sum of execution frequencies of individual spills */
807 s = spillinfo->spills;
808 for ( ; s != NULL; s = s->next) {
809 ir_node *spill_block = get_block(s->after);
810 double freq = get_block_execfreq(env->exec_freq, spill_block);
812 spills_execfreq += freq;
815 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
816 spills_execfreq * env->spill_cost,
817 spill_execfreq * env->spill_cost));
819 /* multi-/latespill is advantageous -> return*/
820 if (spills_execfreq < spill_execfreq) {
821 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
822 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
827 /* override spillinfos or create a new one */
828 spill = OALLOC(&env->obst, spill_t);
829 spill->after = skip_keeps_phis(to_spill);
833 spillinfo->spills = spill;
834 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
835 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
838 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
840 const spill_info_t *si = get_spillinfo(env, irn);
841 ir_node *start_block = get_irg_start_block(get_irn_irg(irn));
842 int n_blocks = get_Block_dom_max_subtree_pre_num(start_block);
843 bitset_t *reloads = bitset_alloca(n_blocks);
850 /* Fill the bitset with the dominance pre-order numbers
851 * of the blocks the reloads are located in. */
852 for (r = si->reloaders; r != NULL; r = r->next) {
853 ir_node *bl = get_nodes_block(r->reloader);
854 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
857 /* Now, cancel out all the blocks that are dominated by each spill.
858 * If the bitset is not empty after that, we have reloads that are
859 * not dominated by any spill. */
860 for (s = si->spills; s != NULL; s = s->next) {
861 ir_node *bl = get_nodes_block(s->after);
862 int start = get_Block_dom_tree_pre_num(bl);
863 int end = get_Block_dom_max_subtree_pre_num(bl);
865 bitset_clear_range(reloads, start, end);
868 if (!bitset_is_empty(reloads))
869 be_add_spill(env, si->to_spill, si->to_spill);
872 void be_insert_spills_reloads(spill_env_t *env)
874 const ir_exec_freq *exec_freq = env->exec_freq;
876 ir_nodeset_iterator_t iter;
879 be_timer_push(T_RA_SPILL_APPLY);
881 /* create all phi-ms first, this is needed so, that phis, hanging on
882 spilled phis work correctly */
883 foreach_ir_nodeset(&env->mem_phis, node, iter) {
884 spill_info_t *info = get_spillinfo(env, node);
885 spill_node(env, info);
888 /* process each spilled node */
889 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
891 ir_node *to_spill = si->to_spill;
892 ir_mode *mode = get_irn_mode(to_spill);
893 ir_node **copies = NEW_ARR_F(ir_node*, 0);
894 double all_remat_costs = 0; /** costs when we would remat all nodes */
897 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
899 determine_spill_costs(env, si);
901 /* determine possibility of rematerialisations */
903 /* calculate cost savings for each indivial value when it would
904 be rematted instead of reloaded */
905 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
908 int remat_cost_delta;
910 ir_node *reloader = rld->reloader;
912 if (rld->rematted_node != NULL) {
913 DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
914 rld->rematted_node, reloader));
917 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
918 DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
920 all_remat_costs = REMAT_COST_INFINITE;
924 remat_cost = check_remat_conditions_costs(env, to_spill,
926 if (remat_cost >= REMAT_COST_INFINITE) {
927 DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
929 rld->remat_cost_delta = REMAT_COST_INFINITE;
930 all_remat_costs = REMAT_COST_INFINITE;
934 remat_cost_delta = remat_cost - env->reload_cost;
935 rld->remat_cost_delta = remat_cost_delta;
936 block = is_Block(reloader) ? reloader : get_nodes_block(reloader);
937 freq = get_block_execfreq(exec_freq, block);
938 all_remat_costs += remat_cost_delta * freq;
939 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
940 "%d (rel %f)\n", reloader, remat_cost_delta,
941 remat_cost_delta * freq));
943 if (all_remat_costs < REMAT_COST_INFINITE) {
944 /* we don't need the costs for the spill if we can remat
946 all_remat_costs -= si->spill_costs;
948 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
949 env->spill_cost, si->spill_costs));
952 if (all_remat_costs < 0) {
953 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
959 /* go through all reloads for this spill */
960 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
961 ir_node *copy; /* a reload is a "copy" of the original value */
963 if (rld->rematted_node != NULL) {
964 copy = rld->rematted_node;
965 sched_add_before(rld->reloader, copy);
966 } else if (be_do_remats &&
967 (force_remat || rld->remat_cost_delta < 0)) {
968 copy = do_remat(env, to_spill, rld->reloader);
970 /* make sure we have a spill */
973 /* create a reload, use the first spill for now SSA
974 * reconstruction for memory comes below */
975 assert(si->spills != NULL);
976 copy = be_reload(si->reload_cls, rld->reloader, mode,
978 #ifdef FIRM_STATISTICS
983 DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
984 copy, to_spill, rld->reloader));
985 ARR_APP1(ir_node*, copies, copy);
988 /* if we had any reloads or remats, then we need to reconstruct the
989 * SSA form for the spilled value */
990 if (ARR_LEN(copies) > 0) {
991 be_ssa_construction_env_t senv;
992 /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
994 be_ssa_construction_init(&senv, env->irg);
995 be_ssa_construction_add_copy(&senv, to_spill);
996 be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
997 be_ssa_construction_fix_users(&senv, to_spill);
1000 /* no need to enable this as long as we invalidate liveness
1001 after this function... */
1002 be_ssa_construction_update_liveness_phis(&senv);
1003 be_liveness_update(to_spill);
1004 len = ARR_LEN(copies);
1005 for (i = 0; i < len; ++i) {
1006 be_liveness_update(lv, copies[i]);
1009 be_ssa_construction_destroy(&senv);
1011 /* need to reconstruct SSA form if we had multiple spills */
1012 if (si->spills != NULL && si->spills->next != NULL) {
1014 int spill_count = 0;
1016 be_ssa_construction_env_t senv;
1018 be_ssa_construction_init(&senv, env->irg);
1020 for ( ; spill != NULL; spill = spill->next) {
1021 /* maybe we rematerialized the value and need no spill */
1022 if (spill->spill == NULL)
1024 be_ssa_construction_add_copy(&senv, spill->spill);
1027 if (spill_count > 1) {
1028 /* all reloads are attached to the first spill, fix them now */
1029 be_ssa_construction_fix_users(&senv, si->spills->spill);
1032 be_ssa_construction_destroy(&senv);
1036 si->reloaders = NULL;
1039 stat_ev_dbl("spill_spills", env->spill_count);
1040 stat_ev_dbl("spill_reloads", env->reload_count);
1041 stat_ev_dbl("spill_remats", env->remat_count);
1042 stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1044 /* Matze: In theory be_ssa_construction should take care of the liveness...
1045 * try to disable this again in the future */
1046 be_liveness_invalidate(be_get_irg_liveness(env->irg));
1048 be_remove_dead_nodes_from_schedule(env->irg);
1050 be_timer_pop(T_RA_SPILL_APPLY);
1053 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1054 void be_init_spill(void)
1056 FIRM_DBG_REGISTER(dbg, "firm.be.spill");