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 */
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 unsigned spill_count;
109 unsigned reload_count;
110 unsigned remat_count;
111 unsigned spilled_phi_count;
115 * Compare two spill infos.
117 static int cmp_spillinfo(const void *x, const void *y, size_t size)
119 const spill_info_t *xx = (const spill_info_t*)x;
120 const spill_info_t *yy = (const spill_info_t*)y;
123 return xx->to_spill != yy->to_spill;
127 * Returns spill info for a specific value (the value that is to be spilled)
129 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
131 spill_info_t info, *res;
132 int hash = hash_irn(value);
134 info.to_spill = value;
135 res = (spill_info_t*)set_find(env->spills, &info, sizeof(info), hash);
138 info.reloaders = NULL;
140 info.spill_costs = -1;
141 info.reload_cls = NULL;
142 res = (spill_info_t*)set_insert(env->spills, &info, sizeof(info), hash);
148 spill_env_t *be_new_spill_env(ir_graph *irg)
150 const arch_env_t *arch_env = be_get_irg_arch_env(irg);
152 spill_env_t *env = XMALLOC(spill_env_t);
153 env->spills = new_set(cmp_spillinfo, 1024);
155 env->arch_env = arch_env;
156 ir_nodeset_init(&env->mem_phis);
157 env->spill_cost = arch_env->spill_cost;
158 env->reload_cost = arch_env->reload_cost;
159 env->exec_freq = be_get_irg_exec_freq(irg);
160 obstack_init(&env->obst);
162 env->spill_count = 0;
163 env->reload_count = 0;
164 env->remat_count = 0;
165 env->spilled_phi_count = 0;
170 void be_delete_spill_env(spill_env_t *env)
172 del_set(env->spills);
173 ir_nodeset_destroy(&env->mem_phis);
174 obstack_free(&env->obst, NULL);
180 * | _ \| | __ _ ___ ___ | _ \ ___| | ___ __ _ __| |___
181 * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
182 * | __/| | (_| | (_| __/ | _ < __/ | (_) | (_| | (_| \__ \
183 * |_| |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
187 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
189 spill_info_t *spill_info = get_spillinfo(env, to_spill);
194 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
195 DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
197 /* Just for safety make sure that we do not insert the spill in front of a phi */
198 assert(!is_Phi(sched_next(after)));
200 /* spills that are dominated by others are not needed */
202 s = spill_info->spills;
203 for ( ; s != NULL; s = s->next) {
204 /* no need to add this spill if it is dominated by another */
205 if (value_dominates(s->after, after)) {
206 DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
209 /* remove spills that we dominate */
210 if (value_dominates(after, s->after)) {
211 DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
213 last->next = s->next;
215 spill_info->spills = s->next;
222 spill = OALLOC(&env->obst, spill_t);
223 spill->after = after;
224 spill->next = spill_info->spills;
227 spill_info->spills = spill;
230 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
231 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
237 assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
239 info = get_spillinfo(env, to_spill);
241 if (is_Phi(to_spill)) {
244 /* create spillinfos for the phi arguments */
245 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
246 ir_node *arg = get_irn_n(to_spill, i);
247 get_spillinfo(env, arg);
251 assert(!is_Proj(before) && !be_is_Keep(before));
253 /* put reload into list */
254 rel = OALLOC(&env->obst, reloader_t);
255 rel->next = info->reloaders;
256 rel->reloader = before;
257 rel->rematted_node = NULL;
258 rel->can_spill_after = can_spill_after;
259 rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
261 info->reloaders = rel;
262 assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
263 info->reload_cls = reload_cls;
265 DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
266 to_spill, before, allow_remat ? "" : " not"));
269 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
270 const arch_register_class_t *reload_cls, int allow_remat)
272 be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
276 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
278 ir_node *last = sched_last(block);
280 /* we might have keeps behind the jump... */
281 while (be_is_Keep(last)) {
282 last = sched_prev(last);
283 assert(!sched_is_end(last));
286 assert(is_cfop(last));
288 /* add the reload before the (cond-)jump */
293 * determine final spill position: it should be after all phis, keep nodes
294 * and behind nodes marked as prolog
296 static ir_node *determine_spill_point(ir_node *node)
298 node = skip_Proj(node);
300 ir_node *next = sched_next(node);
301 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
309 * Returns the point at which you can insert a node that should be executed
310 * before block @p block when coming from pred @p pos.
312 static ir_node *get_block_insertion_point(ir_node *block, int pos)
316 /* simply add the reload to the beginning of the block if we only have 1
317 * predecessor. We don't need to check for phis as there can't be any in a
318 * block with only 1 pred. */
319 if (get_Block_n_cfgpreds(block) == 1) {
320 assert(!is_Phi(sched_first(block)));
321 return sched_first(block);
324 /* We have to reload the value in pred-block */
325 predblock = get_Block_cfgpred_block(block, pos);
326 return be_get_end_of_block_insertion_point(predblock);
329 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
330 const ir_node *block,
331 const arch_register_class_t *reload_cls,
334 ir_node *before = be_get_end_of_block_insertion_point(block);
335 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
338 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
339 int pos, const arch_register_class_t *reload_cls,
342 ir_node *before = get_block_insertion_point(block, pos);
343 be_add_reload(env, to_spill, before, reload_cls, allow_remat);
346 void be_spill_phi(spill_env_t *env, ir_node *node)
351 assert(is_Phi(node));
353 ir_nodeset_insert(&env->mem_phis, node);
355 /* create spills for the phi arguments */
356 block = get_nodes_block(node);
357 for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
358 ir_node *arg = get_irn_n(node, i);
361 /* some backends have virtual noreg/unknown nodes that are not scheduled
362 * and simply always available. */
363 if (!sched_is_scheduled(arg)) {
364 ir_node *pred_block = get_Block_cfgpred_block(block, i);
365 insert = be_get_end_of_block_insertion_point(pred_block);
366 insert = sched_prev(insert);
368 insert = determine_spill_point(arg);
371 be_add_spill(env, arg, insert);
377 * / ___|_ __ ___ __ _| |_ ___ / ___| _ __ (_) | |___
378 * | | | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
379 * | |___| | | __/ (_| | || __/ ___) | |_) | | | \__ \
380 * \____|_| \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
384 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
389 * @param senv the spill environment
390 * @param irn the node that should be spilled
391 * @param ctx_irn an user of the spilled node
393 * @return a be_Spill node
395 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
397 ir_node *to_spill = spillinfo->to_spill;
398 const ir_node *insn = skip_Proj_const(to_spill);
401 /* determine_spill_costs must have been run before */
402 assert(spillinfo->spill_costs >= 0);
404 /* some backends have virtual noreg/unknown nodes that are not scheduled
405 * and simply always available. */
406 if (!sched_is_scheduled(insn)) {
407 /* override spillinfos or create a new one */
408 ir_graph *irg = get_irn_irg(to_spill);
409 spillinfo->spills->spill = get_irg_no_mem(irg);
410 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
414 DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
415 spill = spillinfo->spills;
416 for ( ; spill != NULL; spill = spill->next) {
417 ir_node *after = spill->after;
418 after = determine_spill_point(after);
420 spill->spill = arch_env_new_spill(env->arch_env, to_spill, after);
421 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
424 DBG((dbg, LEVEL_1, "\n"));
427 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
430 * If the first usage of a Phi result would be out of memory
431 * there is no sense in allocating a register for it.
432 * Thus we spill it and all its operands to the same spill slot.
433 * Therefore the phi/dataB becomes a phi/Memory
435 * @param senv the spill environment
436 * @param phi the Phi node that should be spilled
437 * @param ctx_irn an user of the spilled node
439 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
441 ir_graph *irg = env->irg;
442 ir_node *phi = spillinfo->to_spill;
443 ir_node *block = get_nodes_block(phi);
451 assert(!get_opt_cse());
452 DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
454 /* build a new PhiM */
455 arity = get_irn_arity(phi);
456 ins = ALLOCAN(ir_node*, arity);
457 unknown = new_r_Unknown(irg, mode_M);
458 for (i = 0; i < arity; ++i) {
462 /* override or replace spills list... */
463 spill = OALLOC(&env->obst, spill_t);
464 spill->after = determine_spill_point(phi);
465 spill->spill = be_new_Phi(block, arity, ins, mode_M, NULL);
467 sched_add_after(block, spill->spill);
469 spillinfo->spills = spill;
470 env->spilled_phi_count++;
472 for (i = 0; i < arity; ++i) {
473 ir_node *arg = get_irn_n(phi, i);
474 spill_info_t *arg_info = get_spillinfo(env, arg);
476 determine_spill_costs(env, arg_info);
477 spill_node(env, arg_info);
479 set_irn_n(spill->spill, i, arg_info->spills->spill);
481 DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
488 * @param senv the spill environment
489 * @param to_spill the node that should be spilled
491 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
495 /* node is already spilled */
496 if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
499 to_spill = spillinfo->to_spill;
501 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
502 spill_phi(env, spillinfo);
504 spill_irn(env, spillinfo);
511 * | _ \ ___ _ __ ___ __ _| |_ ___ _ __(_) __ _| (_)_______
512 * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_ / _ \
513 * | _ < __/ | | | | | (_| | || __/ | | | (_| | | |/ / __/
514 * |_| \_\___|_| |_| |_|\__,_|\__\___|_| |_|\__,_|_|_/___\___|
519 * Tests whether value @p arg is available before node @p reloader
520 * @returns 1 if value is available, 0 otherwise
522 static int is_value_available(spill_env_t *env, const ir_node *arg,
523 const ir_node *reloader)
525 if (is_Unknown(arg) || is_NoMem(arg))
528 if (be_is_Spill(skip_Proj_const(arg)))
531 if (arg == get_irg_frame(env->irg))
536 if (get_irn_mode(arg) == mode_T)
540 * Ignore registers are always available
542 if (arch_irn_is_ignore(arg))
549 * Check if a node is rematerializable. This tests for the following conditions:
551 * - The node itself is rematerializable
552 * - All arguments of the node are available or also rematerialisable
553 * - The costs for the rematerialisation operation is less or equal a limit
555 * Returns the costs needed for rematerialisation or something
556 * >= REMAT_COST_INFINITE if remat is not possible.
558 static int check_remat_conditions_costs(spill_env_t *env,
559 const ir_node *spilled, const ir_node *reloader, int parentcosts)
564 const ir_node *insn = skip_Proj_const(spilled);
566 assert(!be_is_Spill(insn));
567 if (!arch_irn_is(insn, rematerializable))
568 return REMAT_COST_INFINITE;
570 if (be_is_Reload(insn)) {
573 costs += arch_get_op_estimated_cost(insn);
575 if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
576 return REMAT_COST_INFINITE;
578 /* never rematerialize a node which modifies the flags.
579 * (would be better to test whether the flags are actually live at point
582 if (arch_irn_is(insn, modify_flags)) {
583 return REMAT_COST_INFINITE;
587 for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
588 ir_node *arg = get_irn_n(insn, i);
590 if (is_value_available(env, arg, reloader))
593 /* we have to rematerialize the argument as well */
596 /* we only support rematerializing 1 argument at the moment,
597 * as multiple arguments could increase register pressure */
598 return REMAT_COST_INFINITE;
601 costs += check_remat_conditions_costs(env, arg, reloader,
602 parentcosts + costs);
603 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
604 return REMAT_COST_INFINITE;
611 * Re-materialize a node.
613 * @param env the spill environment
614 * @param spilled the node that was spilled
615 * @param reloader a irn that requires a reload
617 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
624 if (is_Block(reloader)) {
627 bl = get_nodes_block(reloader);
630 ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
631 for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
632 ir_node *arg = get_irn_n(spilled, i);
634 if (is_value_available(env, arg, reloader)) {
637 ins[i] = do_remat(env, arg, reloader);
638 /* don't count the argument rematerialization as an extra remat */
643 /* create a copy of the node */
644 res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
645 get_irn_op(spilled), get_irn_mode(spilled),
646 get_irn_arity(spilled), ins);
647 copy_node_attr(env->irg, spilled, res);
648 arch_env_mark_remat(env->arch_env, res);
650 DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
652 if (! is_Proj(res)) {
653 /* insert in schedule */
655 sched_add_before(reloader, res);
662 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
664 ir_node *block = get_nodes_block(before);
665 double freq = get_block_execfreq(env->exec_freq, block);
668 return env->spill_cost * freq;
671 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
672 const ir_node *before)
675 /* is the node rematerializable? */
676 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
677 if (costs < (unsigned) env->reload_cost)
681 return env->reload_cost;
684 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
686 ir_node *block = get_nodes_block(before);
687 double freq = get_block_execfreq(env->exec_freq, block);
690 /* is the node rematerializable? */
691 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
692 if (costs < env->reload_cost)
696 return env->reload_cost * freq;
699 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
700 const ir_node *before)
702 return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
705 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
706 ir_node *block, int pos)
708 ir_node *before = get_block_insertion_point(block, pos);
709 return be_get_reload_costs(env, to_spill, before);
712 ir_node *be_new_spill(ir_node *value, ir_node *after)
714 ir_graph *irg = get_irn_irg(value);
715 ir_node *frame = get_irg_frame(irg);
716 const arch_register_class_t *cls = arch_get_irn_reg_class(value);
717 const arch_register_class_t *cls_frame = arch_get_irn_reg_class(frame);
718 ir_node *block = get_block(after);
720 = be_new_Spill(cls, cls_frame, block, frame, value);
722 sched_add_after(after, spill);
726 ir_node *be_new_reload(ir_node *value, ir_node *spill, ir_node *before)
728 ir_graph *irg = get_irn_irg(value);
729 ir_node *frame = get_irg_frame(irg);
730 ir_node *block = get_block(before);
731 const arch_register_class_t *cls = arch_get_irn_reg_class(value);
732 const arch_register_class_t *cls_frame = arch_get_irn_reg_class(frame);
733 ir_mode *mode = get_irn_mode(value);
736 assert(be_is_Spill(spill) || is_Phi(spill));
737 assert(get_irn_mode(spill) == mode_M);
739 reload = be_new_Reload(cls, cls_frame, block, frame, spill, mode);
740 sched_add_before(before, reload);
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 ir_graph *irg = get_irn_irg(to_spill);
779 /* override spillinfos or create a new one */
780 spill_t *spill = OALLOC(&env->obst, spill_t);
783 spill->spill = get_irg_no_mem(irg);
785 spillinfo->spills = spill;
786 spillinfo->spill_costs = 0;
788 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
792 spill_block = get_nodes_block(insn);
793 spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
795 if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
796 /* TODO calculate correct costs...
797 * (though we can't remat this node anyway so no big problem) */
798 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
802 if (spillinfo->spills != NULL) {
804 double spills_execfreq;
806 /* calculate sum of execution frequencies of individual spills */
808 s = spillinfo->spills;
809 for ( ; s != NULL; s = s->next) {
810 ir_node *spill_block = get_block(s->after);
811 double freq = get_block_execfreq(env->exec_freq, spill_block);
813 spills_execfreq += freq;
816 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
817 spills_execfreq * env->spill_cost,
818 spill_execfreq * env->spill_cost));
820 /* multi-/latespill is advantageous -> return*/
821 if (spills_execfreq < spill_execfreq) {
822 DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
823 spillinfo->spill_costs = spills_execfreq * env->spill_cost;
828 /* override spillinfos or create a new one */
829 spill = OALLOC(&env->obst, spill_t);
830 spill->after = determine_spill_point(to_spill);
834 spillinfo->spills = spill;
835 spillinfo->spill_costs = spill_execfreq * env->spill_cost;
836 DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
839 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
841 const spill_info_t *si = get_spillinfo(env, irn);
842 ir_node *start_block = get_irg_start_block(get_irn_irg(irn));
843 int n_blocks = get_Block_dom_max_subtree_pre_num(start_block);
844 bitset_t *reloads = bitset_alloca(n_blocks);
851 /* Fill the bitset with the dominance pre-order numbers
852 * of the blocks the reloads are located in. */
853 for (r = si->reloaders; r != NULL; r = r->next) {
854 ir_node *bl = get_nodes_block(r->reloader);
855 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
858 /* Now, cancel out all the blocks that are dominated by each spill.
859 * If the bitset is not empty after that, we have reloads that are
860 * not dominated by any spill. */
861 for (s = si->spills; s != NULL; s = s->next) {
862 ir_node *bl = get_nodes_block(s->after);
863 int start = get_Block_dom_tree_pre_num(bl);
864 int end = get_Block_dom_max_subtree_pre_num(bl);
866 bitset_clear_range(reloads, start, end);
869 if (!bitset_is_empty(reloads))
870 be_add_spill(env, si->to_spill, si->to_spill);
873 void be_insert_spills_reloads(spill_env_t *env)
875 const ir_exec_freq *exec_freq = env->exec_freq;
877 ir_nodeset_iterator_t iter;
880 be_timer_push(T_RA_SPILL_APPLY);
882 /* create all phi-ms first, this is needed so, that phis, hanging on
883 spilled phis work correctly */
884 foreach_ir_nodeset(&env->mem_phis, node, iter) {
885 spill_info_t *info = get_spillinfo(env, node);
886 spill_node(env, info);
889 /* process each spilled node */
890 foreach_set(env->spills, spill_info_t*, si) {
891 ir_node *to_spill = si->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 */
894 bool force_remat = false;
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 = arch_env_new_reload(env->arch_env, si->to_spill,
977 si->spills->spill, rld->reloader);
981 DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
982 copy, to_spill, rld->reloader));
983 ARR_APP1(ir_node*, copies, copy);
986 /* if we had any reloads or remats, then we need to reconstruct the
987 * SSA form for the spilled value */
988 if (ARR_LEN(copies) > 0) {
989 be_ssa_construction_env_t senv;
990 /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
992 be_ssa_construction_init(&senv, env->irg);
993 be_ssa_construction_add_copy(&senv, to_spill);
994 be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
995 be_ssa_construction_fix_users(&senv, to_spill);
998 /* no need to enable this as long as we invalidate liveness
999 after this function... */
1000 be_ssa_construction_update_liveness_phis(&senv);
1001 be_liveness_update(to_spill);
1002 len = ARR_LEN(copies);
1003 for (i = 0; i < len; ++i) {
1004 be_liveness_update(lv, copies[i]);
1007 be_ssa_construction_destroy(&senv);
1009 /* need to reconstruct SSA form if we had multiple spills */
1010 if (si->spills != NULL && si->spills->next != NULL) {
1012 int spill_count = 0;
1014 be_ssa_construction_env_t senv;
1016 be_ssa_construction_init(&senv, env->irg);
1018 for ( ; spill != NULL; spill = spill->next) {
1019 /* maybe we rematerialized the value and need no spill */
1020 if (spill->spill == NULL)
1022 be_ssa_construction_add_copy(&senv, spill->spill);
1025 if (spill_count > 1) {
1026 /* all reloads are attached to the first spill, fix them now */
1027 be_ssa_construction_fix_users(&senv, si->spills->spill);
1030 be_ssa_construction_destroy(&senv);
1034 si->reloaders = NULL;
1037 stat_ev_dbl("spill_spills", env->spill_count);
1038 stat_ev_dbl("spill_reloads", env->reload_count);
1039 stat_ev_dbl("spill_remats", env->remat_count);
1040 stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1042 /* Matze: In theory be_ssa_construction should take care of the liveness...
1043 * try to disable this again in the future */
1044 be_invalidate_live_sets(env->irg);
1046 be_remove_dead_nodes_from_schedule(env->irg);
1048 be_timer_pop(T_RA_SPILL_APPLY);
1051 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill)
1052 void be_init_spill(void)
1054 FIRM_DBG_REGISTER(dbg, "firm.be.spill");