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
34 #include "iredges_t.h"
35 #include "irbackedge_t.h"
45 #include "irnodeset.h"
52 #include "bespillutil.h"
55 #include "bechordal_t.h"
56 #include "bestatevent.h"
57 #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 */
95 bool spilled_phi; /* true when the whole Phi has been spilled and
96 will be replaced with a PhiM. false if only the
97 value of the Phi gets spilled */
101 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 spill_info_t **mem_phis; /**< set of all spilled phis. */
109 ir_exec_freq *exec_freq;
111 unsigned spill_count;
112 unsigned reload_count;
113 unsigned remat_count;
114 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 info.spilled_phi = false;
146 res = (spill_info_t*)set_insert(env->spills, &info, sizeof(info), hash);
152 spill_env_t *be_new_spill_env(ir_graph *irg)
154 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
156 spill_env_t *env = XMALLOC(spill_env_t);
157 env->spills = new_set(cmp_spillinfo, 1024);
159 env->arch_env = arch_env;
160 env->mem_phis = NEW_ARR_F(spill_info_t*, 0);
161 env->spill_cost = arch_env->spill_cost;
162 env->reload_cost = arch_env->reload_cost;
163 env->exec_freq = be_get_irg_exec_freq(irg);
164 obstack_init(&env->obst);
166 env->spill_count = 0;
167 env->reload_count = 0;
168 env->remat_count = 0;
169 env->spilled_phi_count = 0;
174 void be_delete_spill_env(spill_env_t *env)
176 del_set(env->spills);
177 DEL_ARR_F(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);
198 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
199 DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
201 /* Just for safety make sure that we do not insert the spill in front of a phi */
202 assert(!is_Phi(sched_next(after)));
204 /* spills that are dominated by others are not needed */
206 s = spill_info->spills;
207 for ( ; s != NULL; s = s->next) {
208 /* no need to add this spill if it is dominated by another */
209 if (value_dominates(s->after, after)) {
210 DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
213 /* remove spills that we dominate */
214 if (value_dominates(after, s->after)) {
215 DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
217 last->next = s->next;
219 spill_info->spills = s->next;
226 spill = OALLOC(&env->obst, spill_t);
227 spill->after = after;
228 spill->next = spill_info->spills;
231 spill_info->spills = spill;
234 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
235 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
241 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
243 info = get_spillinfo(env, to_spill);
245 if (is_Phi(to_spill)) {
248 /* create spillinfos for the phi arguments */
249 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
250 ir_node *arg = get_irn_n(to_spill, i);
251 get_spillinfo(env, arg);
255 assert(!is_Proj(before) && !be_is_Keep(before));
257 /* put reload into list */
258 rel = OALLOC(&env->obst, reloader_t);
259 rel->next = info->reloaders;
260 rel->reloader = before;
261 rel->rematted_node = NULL;
262 rel->can_spill_after = can_spill_after;
263 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
265 info->reloaders = rel;
266 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
267 info->reload_cls = reload_cls;
269 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
270 to_spill, before, allow_remat ? "" : " not"));
273 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
274 const arch_register_class_t *reload_cls, int allow_remat)
276 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
280 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
282 ir_node *last = sched_last(block);
284 /* we might have keeps behind the jump... */
285 while (be_is_Keep(last)) {
286 last = sched_prev(last);
287 assert(!sched_is_end(last));
290 assert(is_cfop(last));
292 /* add the reload before the (cond-)jump */
297 * determine final spill position: it should be after all phis, keep nodes
298 * and behind nodes marked as prolog
300 static ir_node *determine_spill_point(ir_node *node)
302 node = skip_Proj(node);
304 ir_node *next = sched_next(node);
305 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
313 * Returns the point at which you can insert a node that should be executed
314 * before block @p block when coming from pred @p pos.
316 static ir_node *get_block_insertion_point(ir_node *block, int pos)
320 /* simply add the reload to the beginning of the block if we only have 1
321 * predecessor. We don't need to check for phis as there can't be any in a
322 * block with only 1 pred. */
323 if (get_Block_n_cfgpreds(block) == 1) {
324 assert(!is_Phi(sched_first(block)));
325 return sched_first(block);
328 /* We have to reload the value in pred-block */
329 predblock = get_Block_cfgpred_block(block, pos);
330 return be_get_end_of_block_insertion_point(predblock);
333 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
334 const ir_node *block,
335 const arch_register_class_t *reload_cls,
338 ir_node *before = be_get_end_of_block_insertion_point(block);
339 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
342 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
343 int pos, const arch_register_class_t *reload_cls,
346 ir_node *before = get_block_insertion_point(block, pos);
347 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
350 void be_spill_phi(spill_env_t *env, ir_node *node)
356 assert(is_Phi(node));
358 info = get_spillinfo(env, node);
359 info->spilled_phi = true;
360 ARR_APP1(spill_info_t*, env->mem_phis, info);
362 /* create spills for the phi arguments */
363 block = get_nodes_block(node);
364 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
365 ir_node *arg = get_irn_n(node, i);
368 /* some backends have virtual noreg/unknown nodes that are not scheduled
369 * and simply always available. */
370 if (!sched_is_scheduled(arg)) {
371 ir_node *pred_block = get_Block_cfgpred_block(block, i);
372 insert = be_get_end_of_block_insertion_point(pred_block);
373 insert = sched_prev(insert);
375 insert = determine_spill_point(arg);
378 be_add_spill(env, arg, insert);
384 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
385 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
386 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
387 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
391 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
396 * @param senv the spill environment
397 * @param irn the node that should be spilled
398 * @param ctx_irn an user of the spilled node
400 * @return a be_Spill node
402 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
404 ir_node *to_spill = spillinfo->to_spill;
405 const ir_node *insn = skip_Proj_const(to_spill);
408 /* determine_spill_costs must have been run before */
409 assert(spillinfo->spill_costs >= 0);
411 /* some backends have virtual noreg/unknown nodes that are not scheduled
412 * and simply always available. */
413 if (!sched_is_scheduled(insn)) {
414 /* override spillinfos or create a new one */
415 ir_graph *irg = get_irn_irg(to_spill);
416 spillinfo->spills->spill = get_irg_no_mem(irg);
417 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
421 DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
422 spill = spillinfo->spills;
423 for ( ; spill != NULL; spill = spill->next) {
424 ir_node *after = spill->after;
425 after = determine_spill_point(after);
427 spill->spill = arch_env_new_spill(env->arch_env, to_spill, after);
428 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
431 DBG((dbg, LEVEL_1, "\n"));
434 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
437 * If the first usage of a Phi result would be out of memory
438 * there is no sense in allocating a register for it.
439 * Thus we spill it and all its operands to the same spill slot.
440 * Therefore the phi/dataB becomes a phi/Memory
442 * @param senv the spill environment
443 * @param phi the Phi node that should be spilled
444 * @param ctx_irn an user of the spilled node
446 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
448 ir_graph *irg = env->irg;
449 ir_node *phi = spillinfo->to_spill;
450 ir_node *block = get_nodes_block(phi);
458 assert(!get_opt_cse());
459 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
461 /* build a new PhiM */
462 arity = get_irn_arity(phi);
463 ins = ALLOCAN(ir_node*, arity);
464 unknown = new_r_Unknown(irg, mode_M);
465 for (i = 0; i < arity; ++i) {
469 /* override or replace spills list... */
470 spill = OALLOC(&env->obst, spill_t);
471 spill->after = determine_spill_point(phi);
472 spill->spill = be_new_Phi(block, arity, ins, mode_M, arch_no_register_req);
474 sched_add_after(block, spill->spill);
476 spillinfo->spills = spill;
477 env->spilled_phi_count++;
479 for (i = 0; i < arity; ++i) {
480 ir_node *arg = get_irn_n(phi, i);
481 spill_info_t *arg_info = get_spillinfo(env, arg);
483 determine_spill_costs(env, arg_info);
484 spill_node(env, arg_info);
486 set_irn_n(spill->spill, i, arg_info->spills->spill);
488 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
495 * @param senv the spill environment
496 * @param to_spill the node that should be spilled
498 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
500 /* node is already spilled */
501 if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
504 if (spillinfo->spilled_phi) {
505 spill_phi(env, spillinfo);
507 spill_irn(env, spillinfo);
514 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
515 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
516 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
517 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
522 * Tests whether value @p arg is available before node @p reloader
523 * @returns 1 if value is available, 0 otherwise
525 static int is_value_available(spill_env_t *env, const ir_node *arg,
526 const ir_node *reloader)
528 if (is_Unknown(arg) || is_NoMem(arg))
531 if (be_is_Spill(skip_Proj_const(arg)))
534 if (arg == get_irg_frame(env->irg))
539 if (get_irn_mode(arg) == mode_T)
543 * Ignore registers are always available
545 if (arch_irn_is_ignore(arg))
552 * Check if a node is rematerializable. This tests for the following conditions:
554 * - The node itself is rematerializable
555 * - All arguments of the node are available or also rematerialisable
556 * - The costs for the rematerialisation operation is less or equal a limit
558 * Returns the costs needed for rematerialisation or something
559 * >= REMAT_COST_INFINITE if remat is not possible.
561 static int check_remat_conditions_costs(spill_env_t *env,
562 const ir_node *spilled, const ir_node *reloader, int parentcosts)
567 const ir_node *insn = skip_Proj_const(spilled);
569 assert(!be_is_Spill(insn));
570 if (!arch_irn_is(insn, rematerializable))
571 return REMAT_COST_INFINITE;
573 if (be_is_Reload(insn)) {
576 costs += arch_get_op_estimated_cost(insn);
578 if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
579 return REMAT_COST_INFINITE;
581 /* never rematerialize a node which modifies the flags.
582 * (would be better to test whether the flags are actually live at point
585 if (arch_irn_is(insn, modify_flags)) {
586 return REMAT_COST_INFINITE;
590 for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
591 ir_node *arg = get_irn_n(insn, i);
593 if (is_value_available(env, arg, reloader))
596 /* we have to rematerialize the argument as well */
599 /* we only support rematerializing 1 argument at the moment,
600 * as multiple arguments could increase register pressure */
601 return REMAT_COST_INFINITE;
604 costs += check_remat_conditions_costs(env, arg, reloader,
605 parentcosts + costs);
606 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
607 return REMAT_COST_INFINITE;
614 * Re-materialize a node.
616 * @param env the spill environment
617 * @param spilled the node that was spilled
618 * @param reloader a irn that requires a reload
620 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
627 if (is_Block(reloader)) {
630 bl = get_nodes_block(reloader);
633 ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
634 for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
635 ir_node *arg = get_irn_n(spilled, i);
637 if (is_value_available(env, arg, reloader)) {
640 ins[i] = do_remat(env, arg, reloader);
641 /* don't count the argument rematerialization as an extra remat */
646 /* create a copy of the node */
647 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
648 get_irn_op(spilled), get_irn_mode(spilled),
649 get_irn_arity(spilled), ins);
650 copy_node_attr(env->irg, spilled, res);
651 arch_env_mark_remat(env->arch_env, res);
653 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
655 if (! is_Proj(res)) {
656 /* insert in schedule */
658 sched_add_before(reloader, res);
665 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
667 ir_node *block = get_nodes_block(before);
668 double freq = get_block_execfreq(env->exec_freq, block);
671 return env->spill_cost * freq;
674 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
675 const ir_node *before)
678 /* is the node rematerializable? */
679 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
680 if (costs < (unsigned) env->reload_cost)
684 return env->reload_cost;
687 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
689 ir_node *block = get_nodes_block(before);
690 double freq = get_block_execfreq(env->exec_freq, block);
693 /* is the node rematerializable? */
694 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
695 if (costs < env->reload_cost)
699 return env->reload_cost * freq;
702 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
703 const ir_node *before)
705 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
708 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
709 ir_node *block, int pos)
711 ir_node *before = get_block_insertion_point(block, pos);
712 return be_get_reload_costs(env, to_spill, before);
715 ir_node *be_new_spill(ir_node *value, ir_node *after)
717 ir_graph *irg = get_irn_irg(value);
718 ir_node *frame = get_irg_frame(irg);
719 const arch_register_class_t *cls = arch_get_irn_reg_class(value);
720 const arch_register_class_t *cls_frame = arch_get_irn_reg_class(frame);
721 ir_node *block = get_block(after);
723 = be_new_Spill(cls, cls_frame, block, frame, value);
725 sched_add_after(after, spill);
729 ir_node *be_new_reload(ir_node *value, ir_node *spill, ir_node *before)
731 ir_graph *irg = get_irn_irg(value);
732 ir_node *frame = get_irg_frame(irg);
733 ir_node *block = get_block(before);
734 const arch_register_class_t *cls = arch_get_irn_reg_class(value);
735 const arch_register_class_t *cls_frame = arch_get_irn_reg_class(frame);
736 ir_mode *mode = get_irn_mode(value);
739 assert(be_is_Spill(spill) || is_Phi(spill));
740 assert(get_irn_mode(spill) == mode_M);
742 reload = be_new_Reload(cls, cls_frame, block, frame, spill, mode);
743 sched_add_before(before, reload);
750 * |_ _|_ __ ___ ___ _ __| |_ | _ \ ___| | ___ __ _ __| |___
751 * | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
752 * | || | | \__ \ __/ | | |_ | _ < __/ | (_) | (_| | (_| \__ \
753 * |___|_| |_|___/\___|_| \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
758 * analyzes how to best spill a node and determine costs for that
760 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
762 ir_node *to_spill = spillinfo->to_spill;
763 const ir_node *insn = skip_Proj_const(to_spill);
764 ir_node *spill_block;
766 double spill_execfreq;
768 /* already calculated? */
769 if (spillinfo->spill_costs >= 0)
772 assert(!arch_irn_is(insn, dont_spill));
773 assert(!be_is_Reload(insn));
775 /* some backends have virtual noreg/unknown nodes that are not scheduled
776 * and simply always available.
777 * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
778 * predecessor (of a PhiM) but this test might match other things too...
780 if (!sched_is_scheduled(insn)) {
781 ir_graph *irg = get_irn_irg(to_spill);
782 /* override spillinfos or create a new one */
783 spill_t *spill = OALLOC(&env->obst, spill_t);
786 spill->spill = get_irg_no_mem(irg);
788 spillinfo->spills = spill;
789 spillinfo->spill_costs = 0;
791 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
795 spill_block = get_nodes_block(insn);
796 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
798 if (spillinfo->spilled_phi) {
799 /* TODO calculate correct costs...
800 * (though we can't remat this node anyway so no big problem) */
801 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
805 if (spillinfo->spills != NULL) {
807 double spills_execfreq;
809 /* calculate sum of execution frequencies of individual spills */
811 s = spillinfo->spills;
812 for ( ; s != NULL; s = s->next) {
813 ir_node *spill_block = get_block(s->after);
814 double freq = get_block_execfreq(env->exec_freq, spill_block);
816 spills_execfreq += freq;
819 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
820 spills_execfreq * env->spill_cost,
821 spill_execfreq * env->spill_cost));
823 /* multi-/latespill is advantageous -> return*/
824 if (spills_execfreq < spill_execfreq) {
825 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
826 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
831 /* override spillinfos or create a new one */
832 spill = OALLOC(&env->obst, spill_t);
833 spill->after = determine_spill_point(to_spill);
837 spillinfo->spills = spill;
838 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
839 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
842 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
844 const spill_info_t *si = get_spillinfo(env, irn);
845 ir_node *start_block = get_irg_start_block(get_irn_irg(irn));
846 int n_blocks = get_Block_dom_max_subtree_pre_num(start_block);
847 bitset_t *reloads = bitset_alloca(n_blocks);
854 /* Fill the bitset with the dominance pre-order numbers
855 * of the blocks the reloads are located in. */
856 for (r = si->reloaders; r != NULL; r = r->next) {
857 ir_node *bl = get_nodes_block(r->reloader);
858 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
861 /* Now, cancel out all the blocks that are dominated by each spill.
862 * If the bitset is not empty after that, we have reloads that are
863 * not dominated by any spill. */
864 for (s = si->spills; s != NULL; s = s->next) {
865 ir_node *bl = get_nodes_block(s->after);
866 int start = get_Block_dom_tree_pre_num(bl);
867 int end = get_Block_dom_max_subtree_pre_num(bl);
869 bitset_clear_range(reloads, start, end);
872 if (!bitset_is_empty(reloads))
873 be_add_spill(env, si->to_spill, si->to_spill);
876 void be_insert_spills_reloads(spill_env_t *env)
878 const ir_exec_freq *exec_freq = env->exec_freq;
879 size_t n_mem_phis = ARR_LEN(env->mem_phis);
883 be_timer_push(T_RA_SPILL_APPLY);
885 /* create all phi-ms first, this is needed so, that phis, hanging on
886 spilled phis work correctly */
887 for (i = 0; i < n_mem_phis; ++i) {
888 spill_info_t *info = env->mem_phis[i];
889 spill_node(env, info);
892 /* process each spilled node */
893 foreach_set(env->spills, spill_info_t*, si) {
894 ir_node *to_spill = si->to_spill;
895 ir_node **copies = NEW_ARR_F(ir_node*, 0);
896 double all_remat_costs = 0; /** costs when we would remat all nodes */
897 bool force_remat = false;
900 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
902 determine_spill_costs(env, si);
904 /* determine possibility of rematerialisations */
906 /* calculate cost savings for each indivial value when it would
907 be rematted instead of reloaded */
908 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
911 int remat_cost_delta;
913 ir_node *reloader = rld->reloader;
915 if (rld->rematted_node != NULL) {
916 DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
917 rld->rematted_node, reloader));
920 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
921 DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
923 all_remat_costs = REMAT_COST_INFINITE;
927 remat_cost = check_remat_conditions_costs(env, to_spill,
929 if (remat_cost >= REMAT_COST_INFINITE) {
930 DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
932 rld->remat_cost_delta = REMAT_COST_INFINITE;
933 all_remat_costs = REMAT_COST_INFINITE;
937 remat_cost_delta = remat_cost - env->reload_cost;
938 rld->remat_cost_delta = remat_cost_delta;
939 block = is_Block(reloader) ? reloader : get_nodes_block(reloader);
940 freq = get_block_execfreq(exec_freq, block);
941 all_remat_costs += remat_cost_delta * freq;
942 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
943 "%d (rel %f)\n", reloader, remat_cost_delta,
944 remat_cost_delta * freq));
946 if (all_remat_costs < REMAT_COST_INFINITE) {
947 /* we don't need the costs for the spill if we can remat
949 all_remat_costs -= si->spill_costs;
951 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
952 env->spill_cost, si->spill_costs));
955 if (all_remat_costs < 0) {
956 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
962 /* go through all reloads for this spill */
963 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
964 ir_node *copy; /* a reload is a "copy" of the original value */
966 if (rld->rematted_node != NULL) {
967 copy = rld->rematted_node;
968 sched_add_before(rld->reloader, copy);
969 } else if (be_do_remats &&
970 (force_remat || rld->remat_cost_delta < 0)) {
971 copy = do_remat(env, to_spill, rld->reloader);
973 /* make sure we have a spill */
976 /* create a reload, use the first spill for now SSA
977 * reconstruction for memory comes below */
978 assert(si->spills != NULL);
979 copy = arch_env_new_reload(env->arch_env, si->to_spill,
980 si->spills->spill, rld->reloader);
984 DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
985 copy, to_spill, rld->reloader));
986 ARR_APP1(ir_node*, copies, copy);
989 /* if we had any reloads or remats, then we need to reconstruct the
990 * SSA form for the spilled value */
991 if (ARR_LEN(copies) > 0) {
992 be_ssa_construction_env_t senv;
993 /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
995 be_ssa_construction_init(&senv, env->irg);
996 be_ssa_construction_add_copy(&senv, to_spill);
997 be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
998 be_ssa_construction_fix_users(&senv, to_spill);
1001 /* no need to enable this as long as we invalidate liveness
1002 after this function... */
1003 be_ssa_construction_update_liveness_phis(&senv);
1004 be_liveness_update(to_spill);
1005 len = ARR_LEN(copies);
1006 for (i = 0; i < len; ++i) {
1007 be_liveness_update(lv, copies[i]);
1010 be_ssa_construction_destroy(&senv);
1012 /* need to reconstruct SSA form if we had multiple spills */
1013 if (si->spills != NULL && si->spills->next != NULL) {
1015 int spill_count = 0;
1017 be_ssa_construction_env_t senv;
1019 be_ssa_construction_init(&senv, env->irg);
1021 for ( ; spill != NULL; spill = spill->next) {
1022 /* maybe we rematerialized the value and need no spill */
1023 if (spill->spill == NULL)
1025 be_ssa_construction_add_copy(&senv, spill->spill);
1028 if (spill_count > 1) {
1029 /* all reloads are attached to the first spill, fix them now */
1030 be_ssa_construction_fix_users(&senv, si->spills->spill);
1033 be_ssa_construction_destroy(&senv);
1037 si->reloaders = NULL;
1040 stat_ev_dbl("spill_spills", env->spill_count);
1041 stat_ev_dbl("spill_reloads", env->reload_count);
1042 stat_ev_dbl("spill_remats", env->remat_count);
1043 stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1045 /* Matze: In theory be_ssa_construction should take care of the liveness...
1046 * try to disable this again in the future */
1047 be_invalidate_live_sets(env->irg);
1049 be_remove_dead_nodes_from_schedule(env->irg);
1051 be_timer_pop(T_RA_SPILL_APPLY);
1054 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill)
1055 void be_init_spill(void)
1057 FIRM_DBG_REGISTER(dbg, "firm.be.spill");