2 * Copyright (C) 1995-2007 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
36 #include "iredges_t.h"
37 #include "irbackedge_t.h"
47 #include "irnodeset.h"
52 #include "besched_t.h"
56 #include "bechordal_t.h"
57 #include "bejavacoal.h"
58 #include "benodesets.h"
59 #include "bespilloptions.h"
60 #include "bestatevent.h"
61 #include "bessaconstr.h"
63 #include "beintlive_t.h"
66 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
68 #define REMAT_COST_INFINITE 1000
70 typedef struct reloader_t reloader_t;
73 ir_node *can_spill_after;
75 ir_node *rematted_node;
76 int remat_cost_delta; /** costs needed for rematerialization,
77 compared to placing a reload */
80 typedef struct spill_t spill_t;
83 ir_node *before; /**< spill has to be placed before this node (or earlier) */
87 typedef struct spill_info_t spill_info_t;
89 ir_node *to_spill; /**< the value that should get spilled */
90 reloader_t *reloaders; /**< list of places where the value should get
92 spill_t *spills; /**< list of latest places where spill must be
94 double spill_costs; /**< costs needed for spilling the value */
95 const arch_register_class_t *reload_cls; /** the register class in which the
96 reload should be placed */
100 const arch_env_t *arch_env;
104 int spill_cost; /**< the cost of a single spill node */
105 int reload_cost; /**< the cost of a reload node */
106 set *spills; /**< all spill_info_t's, which must be
108 ir_nodeset_t mem_phis; /**< set of all spilled phis. */
109 ir_exec_freq *exec_freq;
110 unsigned new_nodes_idx; /**< all old nodes idx is smaller than
113 #ifdef FIRM_STATISTICS
114 unsigned spill_count;
115 unsigned reload_count;
116 unsigned remat_count;
117 unsigned spilled_phi_count;
122 * Compare two spill infos.
124 static int cmp_spillinfo(const void *x, const void *y, size_t size)
126 const spill_info_t *xx = x;
127 const spill_info_t *yy = y;
130 return xx->to_spill != yy->to_spill;
134 * Returns spill info for a specific value (the value that is to be spilled)
136 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
138 spill_info_t info, *res;
139 int hash = nodeset_hash(value);
141 info.to_spill = value;
142 res = set_find(env->spills, &info, sizeof(info), hash);
145 info.reloaders = NULL;
147 info.spill_costs = -1;
148 info.reload_cls = NULL;
149 res = set_insert(env->spills, &info, sizeof(info), hash);
155 spill_env_t *be_new_spill_env(be_irg_t *birg)
157 const arch_env_t *arch_env = birg->main_env->arch_env;
159 spill_env_t *env = xmalloc(sizeof(env[0]));
160 env->spills = new_set(cmp_spillinfo, 1024);
161 env->irg = be_get_birg_irg(birg);
163 env->arch_env = arch_env;
164 ir_nodeset_init(&env->mem_phis);
165 env->spill_cost = arch_env->isa->spill_cost;
166 env->reload_cost = arch_env->isa->reload_cost;
167 env->exec_freq = be_get_birg_exec_freq(birg);
168 obstack_init(&env->obst);
170 #ifdef FIRM_STATISTICS
171 env->spill_count = 0;
172 env->reload_count = 0;
173 env->remat_count = 0;
174 env->spilled_phi_count = 0;
180 void be_delete_spill_env(spill_env_t *env)
182 del_set(env->spills);
183 ir_nodeset_destroy(&env->mem_phis);
184 obstack_free(&env->obst, NULL);
190 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
191 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
192 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
193 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
197 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *before)
199 spill_info_t *spill_info = get_spillinfo(env, to_spill);
204 DB((dbg, LEVEL_1, "Add spill of %+F before %+F\n", to_spill, before));
206 /* spills that are dominated by others are not needed */
208 s = spill_info->spills;
209 for( ; s != NULL; s = s->next) {
210 /* no need to add this spill if it is dominated by another */
211 if(value_dominates(s->before, before)) {
212 DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->before));
215 /* remove spills that we dominate */
216 if(value_dominates(before, s->before)) {
217 DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->before));
219 last->next = s->next;
221 spill_info->spills = s->next;
228 spill = obstack_alloc(&env->obst, sizeof(spill[0]));
229 spill->before = before;
230 spill->next = spill_info->spills;
233 spill_info->spills = spill;
236 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
237 ir_node *rematted_node)
239 spill_info_t *spill_info;
240 reloader_t *reloader;
242 spill_info = get_spillinfo(env, to_spill);
244 /* add the remat information */
245 reloader = obstack_alloc(&env->obst, sizeof(reloader[0]));
246 reloader->next = spill_info->reloaders;
247 reloader->reloader = before;
248 reloader->rematted_node = rematted_node;
249 reloader->remat_cost_delta = 0; /* We will never have a cost win over a
250 reload since we're not even allowed to
253 spill_info->reloaders = reloader;
255 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
259 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
260 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
266 info = get_spillinfo(env, to_spill);
268 if (is_Phi(to_spill)) {
271 /* create spillinfos for the phi arguments */
272 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
273 ir_node *arg = get_irn_n(to_spill, i);
274 get_spillinfo(env, arg);
278 assert(!is_Proj(before) && !be_is_Keep(before));
280 /* put reload into list */
281 rel = obstack_alloc(&env->obst, sizeof(rel[0]));
282 rel->next = info->reloaders;
283 rel->reloader = before;
284 rel->rematted_node = NULL;
285 rel->can_spill_after = can_spill_after;
286 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
288 info->reloaders = rel;
289 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
290 info->reload_cls = reload_cls;
292 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
293 to_spill, before, allow_remat ? "" : " not"));
296 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
297 const arch_register_class_t *reload_cls, int allow_remat)
299 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
303 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
305 ir_node *last = sched_last(block);
307 /* we might have keeps behind the jump... */
308 while(be_is_Keep(last)) {
309 last = sched_prev(last);
310 assert(!sched_is_end(last));
313 assert(is_cfop(last));
315 /* add the reload before the (cond-)jump */
320 * Returns the point at which you can insert a node that should be executed
321 * before block @p block when coming from pred @p pos.
323 static ir_node *get_block_insertion_point(ir_node *block, int pos)
327 /* simply add the reload to the beginning of the block if we only have 1
328 * predecessor. We don't need to check for phis as there can't be any in a
329 * block with only 1 pred. */
330 if(get_Block_n_cfgpreds(block) == 1) {
331 assert(!is_Phi(sched_first(block)));
332 return sched_first(block);
335 /* We have to reload the value in pred-block */
336 predblock = get_Block_cfgpred_block(block, pos);
337 return be_get_end_of_block_insertion_point(predblock);
340 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
341 const ir_node *block,
342 const arch_register_class_t *reload_cls,
345 ir_node *before = be_get_end_of_block_insertion_point(block);
346 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
349 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
350 int pos, const arch_register_class_t *reload_cls,
353 ir_node *before = get_block_insertion_point(block, pos);
354 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
357 void be_spill_phi(spill_env_t *env, ir_node *node)
363 assert(is_Phi(node));
365 ir_nodeset_insert(&env->mem_phis, node);
367 /* create spills for the phi arguments */
368 block = get_nodes_block(node);
369 spill = get_spillinfo(env, node);
370 for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
371 ir_node *arg = get_irn_n(node, i);
372 ir_node *pred_block = get_Block_cfgpred_block(block, i);
373 ir_node *insert = be_get_end_of_block_insertion_point(pred_block);
374 //get_spillinfo(env, arg);
375 be_add_spill(env, arg, insert);
381 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
382 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
383 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
384 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
388 static ir_node *skip_keeps_phis(ir_node *node)
390 node = sched_next(node);
391 while(is_Phi(node) || be_is_Keep(node)) {
392 node = sched_next(node);
397 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
402 * @param senv the spill environment
403 * @param irn the node that should be spilled
404 * @param ctx_irn an user of the spilled node
406 * @return a be_Spill node
408 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
410 ir_node *to_spill = spillinfo->to_spill;
413 /* determine_spill_costs must have been run before */
414 assert(spillinfo->spill_costs >= 0);
416 /* some backends have virtual noreg/unknown nodes that are not scheduled
417 * and simply always available. */
418 if(!sched_is_scheduled(to_spill)) {
419 /* override spillinfos or create a new one */
420 spillinfo->spills->spill = new_NoMem();
421 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
425 DBG((dbg, LEVEL_1, "spilling %+F ... ", to_spill));
426 spill = spillinfo->spills;
427 for( ; spill != NULL; spill = spill->next) {
428 ir_node *block = get_block(spill->before);
429 ir_node *before = spill->before;
431 /* place all spills before the reloads (as we can't guarantee the
432 * same order as the be_add_spill and be_add_reload calls */
433 while(get_irn_idx(sched_prev(before)) > env->new_nodes_idx) {
434 before = sched_prev(before);
437 spill->spill = be_spill(env->arch_env, block, to_spill);
438 sched_add_before(before, spill->spill);
439 DB((dbg, LEVEL_1, "\t%+F before %+F,", spill->spill, before));
440 #ifdef FIRM_STATISTICS
444 DBG((dbg, LEVEL_1, "\n"));
447 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
450 * If the first usage of a Phi result would be out of memory
451 * there is no sense in allocating a register for it.
452 * Thus we spill it and all its operands to the same spill slot.
453 * Therefore the phi/dataB becomes a phi/Memory
455 * @param senv the spill environment
456 * @param phi the Phi node that should be spilled
457 * @param ctx_irn an user of the spilled node
459 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
461 ir_graph *irg = env->irg;
462 ir_node *phi = spillinfo->to_spill;
463 ir_node *block = get_nodes_block(phi);
471 assert(!get_opt_cse());
472 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
474 /* build a new PhiM */
475 arity = get_irn_arity(phi);
476 ins = alloca(sizeof(ir_node*) * arity);
477 unknown = new_r_Unknown(irg, mode_M);
478 for(i = 0; i < arity; ++i) {
482 /* override or replace spills list... */
483 spill = obstack_alloc(&env->obst, sizeof(spill[0]));
484 spill->before = skip_keeps_phis(phi);
485 spill->spill = new_r_Phi(irg, block, arity, ins, mode_M);
488 spillinfo->spills = spill;
489 #ifdef FIRM_STATISTICS
490 env->spilled_phi_count++;
493 for(i = 0; i < arity; ++i) {
494 ir_node *arg = get_irn_n(phi, i);
495 spill_info_t *arg_info = get_spillinfo(env, arg);
497 determine_spill_costs(env, arg_info);
498 spill_node(env, arg_info);
500 set_irn_n(spill->spill, i, arg_info->spills->spill);
502 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
509 * @param senv the spill environment
510 * @param to_spill the node that should be spilled
512 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
516 /* node is already spilled */
517 if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
520 to_spill = spillinfo->to_spill;
522 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
523 spill_phi(env, spillinfo);
525 spill_irn(env, spillinfo);
532 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
533 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
534 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
535 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
540 * Tests whether value @p arg is available before node @p reloader
541 * @returns 1 if value is available, 0 otherwise
543 static int is_value_available(spill_env_t *env, const ir_node *arg,
544 const ir_node *reloader)
546 if(is_Unknown(arg) || arg == new_NoMem())
552 if(arg == get_irg_frame(env->irg))
555 /* hack for now (happens when command should be inserted at end of block) */
556 if(is_Block(reloader)) {
561 * Ignore registers are always available
563 if(arch_irn_is(env->arch_env, arg, ignore)) {
567 /* the following test does not work while spilling,
568 * because the liveness info is not adapted yet to the effects of the
569 * additional spills/reloads.
572 /* we want to remat before the insn reloader
573 * thus an arguments is alive if
574 * - it interferes with the reloaders result
575 * - or it is (last-) used by reloader itself
577 if (values_interfere(env->birg->lv, reloader, arg)) {
581 arity = get_irn_arity(reloader);
582 for (i = 0; i < arity; ++i) {
583 ir_node *rel_arg = get_irn_n(reloader, i);
593 * Checks whether the node can principally be rematerialized
595 static int is_remat_node(spill_env_t *env, const ir_node *node)
597 const arch_env_t *arch_env = env->arch_env;
599 assert(!be_is_Spill(node));
601 if(arch_irn_is(arch_env, node, rematerializable))
608 * Check if a node is rematerializable. This tests for the following conditions:
610 * - The node itself is rematerializable
611 * - All arguments of the node are available or also rematerialisable
612 * - The costs for the rematerialisation operation is less or equal a limit
614 * Returns the costs needed for rematerialisation or something
615 * >= REMAT_COST_INFINITE if remat is not possible.
617 static int check_remat_conditions_costs(spill_env_t *env,
618 const ir_node *spilled, const ir_node *reloader, int parentcosts)
624 if(!is_remat_node(env, spilled))
625 return REMAT_COST_INFINITE;
627 if(be_is_Reload(spilled)) {
630 costs += arch_get_op_estimated_cost(env->arch_env, spilled);
632 if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
633 return REMAT_COST_INFINITE;
635 if(arch_irn_is(env->arch_env, spilled, modify_flags)) {
636 return REMAT_COST_INFINITE;
640 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
641 ir_node *arg = get_irn_n(spilled, i);
643 if(is_value_available(env, arg, reloader))
646 /* we have to rematerialize the argument as well */
648 /* we only support rematerializing 1 argument at the moment,
649 * so that we don't have to care about register pressure
651 return REMAT_COST_INFINITE;
655 costs += check_remat_conditions_costs(env, arg, reloader,
656 parentcosts + costs);
657 if(parentcosts + costs >= env->reload_cost + env->spill_cost)
658 return REMAT_COST_INFINITE;
665 * Re-materialize a node.
667 * @param senv the spill environment
668 * @param spilled the node that was spilled
669 * @param reloader a irn that requires a reload
671 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
678 if(is_Block(reloader)) {
681 bl = get_nodes_block(reloader);
684 ins = alloca(get_irn_arity(spilled) * sizeof(ins[0]));
685 for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
686 ir_node *arg = get_irn_n(spilled, i);
688 if(is_value_available(env, arg, reloader)) {
691 ins[i] = do_remat(env, arg, reloader);
692 #ifdef FIRM_STATISTICS
693 /* don't count the recursive call as remat */
699 /* create a copy of the node */
700 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
701 get_irn_op(spilled), get_irn_mode(spilled),
702 get_irn_arity(spilled), ins);
703 copy_node_attr(spilled, res);
704 new_backedge_info(res);
706 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
708 if (! is_Proj(res)) {
709 /* insert in schedule */
711 sched_add_before(reloader, res);
712 #ifdef FIRM_STATISTICS
720 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
722 ir_node *block = get_nodes_block(before);
723 double freq = get_block_execfreq(env->exec_freq, block);
726 return env->spill_cost * freq;
729 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
731 ir_node *block = get_nodes_block(before);
732 double freq = get_block_execfreq(env->exec_freq, block);
735 /* is the node rematerializable? */
736 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
737 if(costs < env->reload_cost)
741 return env->reload_cost * freq;
744 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
745 const ir_node *before)
747 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
750 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
751 ir_node *block, int pos)
753 ir_node *before = get_block_insertion_point(block, pos);
754 return be_get_reload_costs(env, to_spill, before);
759 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
760 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
761 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
762 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
767 * analyzes how to best spill a node and determine costs for that
769 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
771 ir_node *to_spill = spillinfo->to_spill;
772 ir_node *spill_block;
774 double spill_execfreq;
776 /* already calculated? */
777 if(spillinfo->spill_costs >= 0)
780 assert(! arch_irn_is(env->arch_env, to_spill, dont_spill));
781 assert(!be_is_Reload(to_spill));
783 /* some backends have virtual noreg/unknown nodes that are not scheduled
784 * and simply always available.
785 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
786 * predecessor (of a PhiM) but this test might match other things too...
788 if(!sched_is_scheduled(to_spill)) {
789 /* override spillinfos or create a new one */
790 spill_t *spill = obstack_alloc(&env->obst, sizeof(spill[0]));
791 spill->before = NULL;
793 spill->spill = new_NoMem();
795 spillinfo->spills = spill;
796 spillinfo->spill_costs = 0;
798 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
802 spill_block = get_nodes_block(to_spill);
803 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
805 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
806 /* TODO calculate correct costs...
807 * (though we can't remat this node anyway so no big problem) */
808 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
812 if(spillinfo->spills != NULL) {
814 double spills_execfreq;
816 /* calculate sum of executaion frequencies of individual spills */
818 s = spillinfo->spills;
819 for( ; s != NULL; s = s->next) {
820 ir_node *spill_block = s->before;
823 if(!is_Block(spill_block)) {
824 spill_block = get_nodes_block(spill_block);
826 freq = get_block_execfreq(env->exec_freq, spill_block);
828 spills_execfreq += freq;
831 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
832 spills_execfreq * env->spill_cost,
833 spill_execfreq * env->spill_cost));
835 /* multi-/latespill is advantageous -> return*/
836 if(spills_execfreq < spill_execfreq) {
837 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
838 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
843 /* override spillinfos or create a new one */
844 spill = obstack_alloc(&env->obst, sizeof(spill[0]));
845 spill->before = skip_keeps_phis(to_spill);
849 spillinfo->spills = spill;
850 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
851 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
854 void be_insert_spills_reloads(spill_env_t *env)
856 ir_graph *irg = env->irg;
857 const arch_env_t *arch_env = env->arch_env;
858 const ir_exec_freq *exec_freq = env->exec_freq;
860 ir_nodeset_iterator_t iter;
863 env->new_nodes_idx = get_irg_last_idx(irg);
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 for (si = set_first(env->spills); si; si = set_next(env->spills)) {
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(arch_env, 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_birg_liveness(env->birg); */
978 be_ssa_construction_init(&senv, env->birg);
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->birg);
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(env->birg->lv);
1032 be_remove_dead_nodes_from_schedule(env->birg);
1035 void be_init_spill(void)
1037 FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1040 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);