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;
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 = x;
123 const spill_info_t *yy = 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 = set_find(env->spills, &info, sizeof(info), hash);
141 info.reloaders = NULL;
143 info.spill_costs = -1;
144 info.reload_cls = NULL;
145 res = set_insert(env->spills, &info, sizeof(info), hash);
151 spill_env_t *be_new_spill_env(be_irg_t *birg)
153 const arch_env_t *arch_env = birg->main_env->arch_env;
155 spill_env_t *env = XMALLOC(spill_env_t);
156 env->spills = new_set(cmp_spillinfo, 1024);
157 env->irg = be_get_birg_irg(birg);
159 env->arch_env = arch_env;
160 ir_nodeset_init(&env->mem_phis);
161 env->spill_cost = arch_env->spill_cost;
162 env->reload_cost = arch_env->reload_cost;
163 env->exec_freq = be_get_birg_exec_freq(birg);
164 obstack_init(&env->obst);
166 #ifdef FIRM_STATISTICS
167 env->spill_count = 0;
168 env->reload_count = 0;
169 env->remat_count = 0;
170 env->spilled_phi_count = 0;
176 void be_delete_spill_env(spill_env_t *env)
178 del_set(env->spills);
179 ir_nodeset_destroy(&env->mem_phis);
180 obstack_free(&env->obst, NULL);
186 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
187 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
188 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
189 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
193 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
195 spill_info_t *spill_info = get_spillinfo(env, to_spill);
196 const ir_node *insn = skip_Proj_const(to_spill);
201 assert(!arch_irn_is(insn, dont_spill));
202 DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
204 /* Just for safety make sure that we do not insert the spill in front of a phi */
205 assert(!is_Phi(sched_next(after)));
207 /* spills that are dominated by others are not needed */
209 s = spill_info->spills;
210 for ( ; s != NULL; s = s->next) {
211 /* no need to add this spill if it is dominated by another */
212 if (value_dominates(s->after, after)) {
213 DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
216 /* remove spills that we dominate */
217 if (value_dominates(after, s->after)) {
218 DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
220 last->next = s->next;
222 spill_info->spills = s->next;
229 spill = OALLOC(&env->obst, spill_t);
230 spill->after = after;
231 spill->next = spill_info->spills;
234 spill_info->spills = spill;
237 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
238 ir_node *rematted_node)
240 spill_info_t *spill_info;
241 reloader_t *reloader;
243 spill_info = get_spillinfo(env, to_spill);
245 /* add the remat information */
246 reloader = OALLOC(&env->obst, reloader_t);
247 reloader->next = spill_info->reloaders;
248 reloader->reloader = before;
249 reloader->rematted_node = rematted_node;
250 reloader->remat_cost_delta = 0; /* We will never have a cost win over a
251 reload since we're not even allowed to
254 spill_info->reloaders = reloader;
256 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
260 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
261 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
266 const ir_node *insn = skip_Proj_const(to_spill);
268 assert(!arch_irn_is(insn, dont_spill));
270 info = get_spillinfo(env, to_spill);
272 if (is_Phi(to_spill)) {
275 /* create spillinfos for the phi arguments */
276 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
277 ir_node *arg = get_irn_n(to_spill, i);
278 get_spillinfo(env, arg);
282 assert(!is_Proj(before) && !be_is_Keep(before));
284 /* put reload into list */
285 rel = OALLOC(&env->obst, reloader_t);
286 rel->next = info->reloaders;
287 rel->reloader = before;
288 rel->rematted_node = NULL;
289 rel->can_spill_after = can_spill_after;
290 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
292 info->reloaders = rel;
293 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
294 info->reload_cls = reload_cls;
296 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
297 to_spill, before, allow_remat ? "" : " not"));
300 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
301 const arch_register_class_t *reload_cls, int allow_remat)
303 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
307 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
309 ir_node *last = sched_last(block);
311 /* we might have keeps behind the jump... */
312 while (be_is_Keep(last)) {
313 last = sched_prev(last);
314 assert(!sched_is_end(last));
317 assert(is_cfop(last));
319 /* add the reload before the (cond-)jump */
323 static ir_node *skip_keeps_phis(ir_node *node)
326 ir_node *next = sched_next(node);
327 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
335 * Returns the point at which you can insert a node that should be executed
336 * before block @p block when coming from pred @p pos.
338 static ir_node *get_block_insertion_point(ir_node *block, int pos)
342 /* simply add the reload to the beginning of the block if we only have 1
343 * predecessor. We don't need to check for phis as there can't be any in a
344 * block with only 1 pred. */
345 if (get_Block_n_cfgpreds(block) == 1) {
346 assert(!is_Phi(sched_first(block)));
347 return sched_first(block);
350 /* We have to reload the value in pred-block */
351 predblock = get_Block_cfgpred_block(block, pos);
352 return be_get_end_of_block_insertion_point(predblock);
355 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
356 const ir_node *block,
357 const arch_register_class_t *reload_cls,
360 ir_node *before = be_get_end_of_block_insertion_point(block);
361 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
364 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
365 int pos, const arch_register_class_t *reload_cls,
368 ir_node *before = get_block_insertion_point(block, pos);
369 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
372 void be_spill_phi(spill_env_t *env, ir_node *node)
377 assert(is_Phi(node));
379 ir_nodeset_insert(&env->mem_phis, node);
381 /* create spills for the phi arguments */
382 block = get_nodes_block(node);
383 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
384 ir_node *arg = get_irn_n(node, i);
387 /* some backends have virtual noreg/unknown nodes that are not scheduled
388 * and simply always available. */
389 if (!sched_is_scheduled(arg)) {
390 ir_node *pred_block = get_Block_cfgpred_block(block, i);
391 insert = be_get_end_of_block_insertion_point(pred_block);
392 insert = sched_prev(insert);
394 insert = skip_keeps_phis(arg);
397 be_add_spill(env, arg, insert);
403 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
404 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
405 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
406 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
410 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
415 * @param senv the spill environment
416 * @param irn the node that should be spilled
417 * @param ctx_irn an user of the spilled node
419 * @return a be_Spill node
421 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
423 ir_node *to_spill = spillinfo->to_spill;
424 const ir_node *insn = skip_Proj_const(to_spill);
427 /* determine_spill_costs must have been run before */
428 assert(spillinfo->spill_costs >= 0);
430 /* some backends have virtual noreg/unknown nodes that are not scheduled
431 * and simply always available. */
432 if (!sched_is_scheduled(insn)) {
433 /* override spillinfos or create a new one */
434 spillinfo->spills->spill = new_NoMem();
435 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
439 DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
440 spill = spillinfo->spills;
441 for ( ; spill != NULL; spill = spill->next) {
442 ir_node *after = spill->after;
443 ir_node *block = get_block(after);
445 after = skip_keeps_phis(after);
447 spill->spill = be_spill(block, to_spill);
448 sched_add_after(skip_Proj(after), spill->spill);
449 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
450 #ifdef FIRM_STATISTICS
454 DBG((dbg, LEVEL_1, "\n"));
457 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
460 * If the first usage of a Phi result would be out of memory
461 * there is no sense in allocating a register for it.
462 * Thus we spill it and all its operands to the same spill slot.
463 * Therefore the phi/dataB becomes a phi/Memory
465 * @param senv the spill environment
466 * @param phi the Phi node that should be spilled
467 * @param ctx_irn an user of the spilled node
469 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
471 ir_graph *irg = env->irg;
472 ir_node *phi = spillinfo->to_spill;
473 ir_node *block = get_nodes_block(phi);
481 assert(!get_opt_cse());
482 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
484 /* build a new PhiM */
485 arity = get_irn_arity(phi);
486 ins = ALLOCAN(ir_node*, arity);
487 unknown = new_r_Unknown(irg, mode_M);
488 for (i = 0; i < arity; ++i) {
492 /* override or replace spills list... */
493 spill = OALLOC(&env->obst, spill_t);
494 spill->after = skip_keeps_phis(phi);
495 spill->spill = new_r_Phi(block, arity, ins, mode_M);
498 spillinfo->spills = spill;
499 #ifdef FIRM_STATISTICS
500 env->spilled_phi_count++;
503 for (i = 0; i < arity; ++i) {
504 ir_node *arg = get_irn_n(phi, i);
505 spill_info_t *arg_info = get_spillinfo(env, arg);
507 determine_spill_costs(env, arg_info);
508 spill_node(env, arg_info);
510 set_irn_n(spill->spill, i, arg_info->spills->spill);
512 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
519 * @param senv the spill environment
520 * @param to_spill the node that should be spilled
522 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
526 /* node is already spilled */
527 if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
530 to_spill = spillinfo->to_spill;
532 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
533 spill_phi(env, spillinfo);
535 spill_irn(env, spillinfo);
542 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
543 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
544 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
545 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
550 * Tests whether value @p arg is available before node @p reloader
551 * @returns 1 if value is available, 0 otherwise
553 static int is_value_available(spill_env_t *env, const ir_node *arg,
554 const ir_node *reloader)
556 if (is_Unknown(arg) || arg == new_NoMem())
559 if (be_is_Spill(skip_Proj_const(arg)))
562 if (arg == get_irg_frame(env->irg))
568 * Ignore registers are always available
570 if (arch_irn_is_ignore(arg))
577 * Check if a node is rematerializable. This tests for the following conditions:
579 * - The node itself is rematerializable
580 * - All arguments of the node are available or also rematerialisable
581 * - The costs for the rematerialisation operation is less or equal a limit
583 * Returns the costs needed for rematerialisation or something
584 * >= REMAT_COST_INFINITE if remat is not possible.
586 static int check_remat_conditions_costs(spill_env_t *env,
587 const ir_node *spilled, const ir_node *reloader, int parentcosts)
592 const ir_node *insn = skip_Proj_const(spilled);
594 assert(!be_is_Spill(insn));
595 if (!arch_irn_is(insn, rematerializable))
596 return REMAT_COST_INFINITE;
598 if (be_is_Reload(insn)) {
601 costs += arch_get_op_estimated_cost(insn);
603 if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
604 return REMAT_COST_INFINITE;
606 /* never rematerialize a node which modifies the flags.
607 * (would be better to test wether the flags are actually live at point
610 if (arch_irn_is(insn, modify_flags)) {
611 return REMAT_COST_INFINITE;
615 for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
616 ir_node *arg = get_irn_n(insn, i);
618 if (is_value_available(env, arg, reloader))
621 /* we have to rematerialize the argument as well */
624 /* we only support rematerializing 1 argument at the moment,
625 * as multiple arguments could increase register pressure */
626 return REMAT_COST_INFINITE;
629 costs += check_remat_conditions_costs(env, arg, reloader,
630 parentcosts + costs);
631 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
632 return REMAT_COST_INFINITE;
639 * Re-materialize a node.
641 * @param senv the spill environment
642 * @param spilled the node that was spilled
643 * @param reloader a irn that requires a reload
645 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
652 if (is_Block(reloader)) {
655 bl = get_nodes_block(reloader);
658 ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
659 for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
660 ir_node *arg = get_irn_n(spilled, i);
662 if (is_value_available(env, arg, reloader)) {
665 ins[i] = do_remat(env, arg, reloader);
666 #ifdef FIRM_STATISTICS
667 /* don't count the recursive call as remat */
673 /* create a copy of the node */
674 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
675 get_irn_op(spilled), get_irn_mode(spilled),
676 get_irn_arity(spilled), ins);
677 copy_node_attr(env->irg, spilled, res);
678 arch_env_mark_remat(env->arch_env, res);
680 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
682 if (! is_Proj(res)) {
683 /* insert in schedule */
685 sched_add_before(reloader, res);
686 #ifdef FIRM_STATISTICS
694 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
696 ir_node *block = get_nodes_block(before);
697 double freq = get_block_execfreq(env->exec_freq, block);
700 return env->spill_cost * freq;
703 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
704 const ir_node *before)
707 /* is the node rematerializable? */
708 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
709 if (costs < (unsigned) env->reload_cost)
713 return env->reload_cost;
716 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
718 ir_node *block = get_nodes_block(before);
719 double freq = get_block_execfreq(env->exec_freq, block);
722 /* is the node rematerializable? */
723 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
724 if (costs < env->reload_cost)
728 return env->reload_cost * freq;
731 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
732 const ir_node *before)
734 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
737 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
738 ir_node *block, int pos)
740 ir_node *before = get_block_insertion_point(block, pos);
741 return be_get_reload_costs(env, to_spill, before);
746 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
747 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
748 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
749 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
754 * analyzes how to best spill a node and determine costs for that
756 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
758 ir_node *to_spill = spillinfo->to_spill;
759 const ir_node *insn = skip_Proj_const(to_spill);
760 ir_node *spill_block;
762 double spill_execfreq;
764 /* already calculated? */
765 if (spillinfo->spill_costs >= 0)
768 assert(!arch_irn_is(insn, dont_spill));
769 assert(!be_is_Reload(insn));
771 /* some backends have virtual noreg/unknown nodes that are not scheduled
772 * and simply always available.
773 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
774 * predecessor (of a PhiM) but this test might match other things too...
776 if (!sched_is_scheduled(insn)) {
777 /* override spillinfos or create a new one */
778 spill_t *spill = OALLOC(&env->obst, spill_t);
781 spill->spill = new_NoMem();
783 spillinfo->spills = spill;
784 spillinfo->spill_costs = 0;
786 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
790 spill_block = get_nodes_block(insn);
791 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
793 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
794 /* TODO calculate correct costs...
795 * (though we can't remat this node anyway so no big problem) */
796 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
800 if (spillinfo->spills != NULL) {
802 double spills_execfreq;
804 /* calculate sum of execution frequencies of individual spills */
806 s = spillinfo->spills;
807 for ( ; s != NULL; s = s->next) {
808 ir_node *spill_block = get_block(s->after);
809 double freq = get_block_execfreq(env->exec_freq, spill_block);
811 spills_execfreq += freq;
814 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
815 spills_execfreq * env->spill_cost,
816 spill_execfreq * env->spill_cost));
818 /* multi-/latespill is advantageous -> return*/
819 if (spills_execfreq < spill_execfreq) {
820 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
821 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
826 /* override spillinfos or create a new one */
827 spill = OALLOC(&env->obst, spill_t);
828 spill->after = skip_keeps_phis(to_spill);
832 spillinfo->spills = spill;
833 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
834 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
837 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
839 const spill_info_t *si = get_spillinfo(env, irn);
840 ir_node *start_block = get_irg_start_block(get_irn_irg(irn));
841 int n_blocks = get_Block_dom_max_subtree_pre_num(start_block);
842 bitset_t *reloads = bitset_alloca(n_blocks);
849 /* Fill the bitset with the dominance pre-order numbers
850 * of the blocks the reloads are located in. */
851 for (r = si->reloaders; r != NULL; r = r->next) {
852 ir_node *bl = get_nodes_block(r->reloader);
853 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
856 /* Now, cancel out all the blocks that are dominated by each spill.
857 * If the bitset is not empty after that, we have reloads that are
858 * not dominated by any spill. */
859 for (s = si->spills; s != NULL; s = s->next) {
860 ir_node *bl = get_nodes_block(s->after);
861 int start = get_Block_dom_tree_pre_num(bl);
862 int end = get_Block_dom_max_subtree_pre_num(bl);
864 bitset_clear_range(reloads, start, end);
867 if (!bitset_is_empty(reloads))
868 be_add_spill(env, si->to_spill, si->to_spill);
871 void be_insert_spills_reloads(spill_env_t *env)
873 const ir_exec_freq *exec_freq = env->exec_freq;
875 ir_nodeset_iterator_t iter;
878 be_timer_push(T_RA_SPILL_APPLY);
880 /* create all phi-ms first, this is needed so, that phis, hanging on
881 spilled phis work correctly */
882 foreach_ir_nodeset(&env->mem_phis, node, iter) {
883 spill_info_t *info = get_spillinfo(env, node);
884 spill_node(env, info);
887 /* process each spilled node */
888 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
890 ir_node *to_spill = si->to_spill;
891 ir_mode *mode = get_irn_mode(to_spill);
892 ir_node **copies = NEW_ARR_F(ir_node*, 0);
893 double all_remat_costs = 0; /** costs when we would remat all nodes */
896 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
898 determine_spill_costs(env, si);
900 /* determine possibility of rematerialisations */
902 /* calculate cost savings for each indivial value when it would
903 be rematted instead of reloaded */
904 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
907 int remat_cost_delta;
909 ir_node *reloader = rld->reloader;
911 if (rld->rematted_node != NULL) {
912 DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
913 rld->rematted_node, reloader));
916 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
917 DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
919 all_remat_costs = REMAT_COST_INFINITE;
923 remat_cost = check_remat_conditions_costs(env, to_spill,
925 if (remat_cost >= REMAT_COST_INFINITE) {
926 DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
928 rld->remat_cost_delta = REMAT_COST_INFINITE;
929 all_remat_costs = REMAT_COST_INFINITE;
933 remat_cost_delta = remat_cost - env->reload_cost;
934 rld->remat_cost_delta = remat_cost_delta;
935 block = is_Block(reloader) ? reloader : get_nodes_block(reloader);
936 freq = get_block_execfreq(exec_freq, block);
937 all_remat_costs += remat_cost_delta * freq;
938 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
939 "%d (rel %f)\n", reloader, remat_cost_delta,
940 remat_cost_delta * freq));
942 if (all_remat_costs < REMAT_COST_INFINITE) {
943 /* we don't need the costs for the spill if we can remat
945 all_remat_costs -= si->spill_costs;
947 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
948 env->spill_cost, si->spill_costs));
951 if (all_remat_costs < 0) {
952 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
958 /* go through all reloads for this spill */
959 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
960 ir_node *copy; /* a reload is a "copy" of the original value */
962 if (rld->rematted_node != NULL) {
963 copy = rld->rematted_node;
964 sched_add_before(rld->reloader, copy);
965 } else if (be_do_remats &&
966 (force_remat || rld->remat_cost_delta < 0)) {
967 copy = do_remat(env, to_spill, rld->reloader);
969 /* make sure we have a spill */
972 /* create a reload, use the first spill for now SSA
973 * reconstruction for memory comes below */
974 assert(si->spills != NULL);
975 copy = be_reload(si->reload_cls, rld->reloader, mode,
977 #ifdef FIRM_STATISTICS
982 DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
983 copy, to_spill, rld->reloader));
984 ARR_APP1(ir_node*, copies, copy);
987 /* if we had any reloads or remats, then we need to reconstruct the
988 * SSA form for the spilled value */
989 if (ARR_LEN(copies) > 0) {
990 be_ssa_construction_env_t senv;
991 /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
993 be_ssa_construction_init(&senv, env->birg);
994 be_ssa_construction_add_copy(&senv, to_spill);
995 be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
996 be_ssa_construction_fix_users(&senv, to_spill);
999 /* no need to enable this as long as we invalidate liveness
1000 after this function... */
1001 be_ssa_construction_update_liveness_phis(&senv);
1002 be_liveness_update(to_spill);
1003 len = ARR_LEN(copies);
1004 for (i = 0; i < len; ++i) {
1005 be_liveness_update(lv, copies[i]);
1008 be_ssa_construction_destroy(&senv);
1010 /* need to reconstruct SSA form if we had multiple spills */
1011 if (si->spills != NULL && si->spills->next != NULL) {
1013 int spill_count = 0;
1015 be_ssa_construction_env_t senv;
1017 be_ssa_construction_init(&senv, env->birg);
1019 for ( ; spill != NULL; spill = spill->next) {
1020 /* maybe we rematerialized the value and need no spill */
1021 if (spill->spill == NULL)
1023 be_ssa_construction_add_copy(&senv, spill->spill);
1026 if (spill_count > 1) {
1027 /* all reloads are attached to the first spill, fix them now */
1028 be_ssa_construction_fix_users(&senv, si->spills->spill);
1031 be_ssa_construction_destroy(&senv);
1035 si->reloaders = NULL;
1038 stat_ev_dbl("spill_spills", env->spill_count);
1039 stat_ev_dbl("spill_reloads", env->reload_count);
1040 stat_ev_dbl("spill_remats", env->remat_count);
1041 stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1043 /* Matze: In theory be_ssa_construction should take care of the liveness...
1044 * try to disable this again in the future */
1045 be_liveness_invalidate(env->birg->lv);
1047 be_remove_dead_nodes_from_schedule(env->birg);
1049 be_timer_pop(T_RA_SPILL_APPLY);
1052 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1053 void be_init_spill(void)
1055 FIRM_DBG_REGISTER(dbg, "firm.be.spill");