nsz Git - libfirm/blob - ir/be/bespillutil.c

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   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.
  10  *
  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.
  14  *
  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
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       implementation of the spill/reload placement abstraction layer
  23  * @author      Daniel Grund, Sebastian Hack, Matthias Braun
  24  * @date        29.09.2005
  25  * @version     $Id$
  26  */
  27 #include "config.h"
  28
  29 #include <stdlib.h>
  30 #include <stdbool.h>
  31
  32 #include "pset.h"
  33 #include "irnode_t.h"
  34 #include "ircons_t.h"
  35 #include "iredges_t.h"
  36 #include "irbackedge_t.h"
  37 #include "irprintf.h"
  38 #include "ident_t.h"
  39 #include "type_t.h"
  40 #include "entity_t.h"
  41 #include "debug.h"
  42 #include "irgwalk.h"
  43 #include "array.h"
  44 #include "pdeq.h"
  45 #include "execfreq.h"
  46 #include "irnodeset.h"
  47 #include "error.h"
  48
  49 #include "bearch.h"
  50 #include "belive_t.h"
  51 #include "besched.h"
  52 #include "bespill.h"
  53 #include "bespillutil.h"
  54 #include "belive_t.h"
  55 #include "benode.h"
  56 #include "bechordal_t.h"
  57 #include "bestatevent.h"
  58 #include "bessaconstr.h"
  59 #include "beirg.h"
  60 #include "beirgmod.h"
  61 #include "beintlive_t.h"
  62 #include "bemodule.h"
  63 #include "be_t.h"
  64
  65 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  66
  67 #define REMAT_COST_INFINITE  1000
  68
  69 typedef struct reloader_t reloader_t;
  70 struct reloader_t {
  71         reloader_t *next;
  72         ir_node    *can_spill_after;
  73         ir_node    *reloader;
  74         ir_node    *rematted_node;
  75         int         remat_cost_delta; /** costs needed for rematerialization,
  76                                            compared to placing a reload */
  77 };
  78
  79 typedef struct spill_t spill_t;
  80 struct spill_t {
  81         spill_t *next;
  82         ir_node *after;  /**< spill has to be placed after this node (or earlier) */
  83         ir_node *spill;
  84 };
  85
  86 typedef struct spill_info_t spill_info_t;
  87 struct spill_info_t {
  88         ir_node    *to_spill;  /**< the value that should get spilled */
  89         reloader_t *reloaders; /**< list of places where the value should get
  90                                     reloaded */
  91         spill_t    *spills;    /**< list of latest places where spill must be
  92                                     placed */
  93         double      spill_costs; /**< costs needed for spilling the value */
  94         const arch_register_class_t *reload_cls; /** the register class in which the
  95                                                      reload should be placed */
  96 };
  97
  98 struct spill_env_t {
  99         const arch_env_t *arch_env;
 100         ir_graph         *irg;
 101         struct obstack    obst;
 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
 105                                                placed */
 106         ir_nodeset_t      mem_phis;       /**< set of all spilled phis. */
 107         ir_exec_freq     *exec_freq;
 108
 109 #ifdef FIRM_STATISTICS
 110         unsigned          spill_count;
 111         unsigned          reload_count;
 112         unsigned          remat_count;
 113         unsigned          spilled_phi_count;
 114 #endif
 115 };
 116
 117 /**
 118  * Compare two spill infos.
 119  */
 120 static int cmp_spillinfo(const void *x, const void *y, size_t size)
 121 {
 122         const spill_info_t *xx = (const spill_info_t*)x;
 123         const spill_info_t *yy = (const spill_info_t*)y;
 124         (void) size;
 125
 126         return xx->to_spill != yy->to_spill;
 127 }
 128
 129 /**
 130  * Returns spill info for a specific value (the value that is to be spilled)
 131  */
 132 static spill_info_t *get_spillinfo(const spill_env_t *env, ir_node *value)
 133 {
 134         spill_info_t info, *res;
 135         int hash = hash_irn(value);
 136
 137         info.to_spill = value;
 138         res = (spill_info_t*)set_find(env->spills, &info, sizeof(info), hash);
 139
 140         if (res == NULL) {
 141                 info.reloaders   = NULL;
 142                 info.spills      = NULL;
 143                 info.spill_costs = -1;
 144                 info.reload_cls  = NULL;
 145                 res = (spill_info_t*)set_insert(env->spills, &info, sizeof(info), hash);
 146         }
 147
 148         return res;
 149 }
 150
 151 spill_env_t *be_new_spill_env(ir_graph *irg)
 152 {
 153         const arch_env_t *arch_env = be_get_irg_arch_env(irg);
 154
 155         spill_env_t *env = XMALLOC(spill_env_t);
 156         env->spills         = new_set(cmp_spillinfo, 1024);
 157         env->irg            = irg;
 158         env->arch_env       = arch_env;
 159         ir_nodeset_init(&env->mem_phis);
 160         env->spill_cost     = arch_env->spill_cost;
 161         env->reload_cost    = arch_env->reload_cost;
 162         env->exec_freq      = be_get_irg_exec_freq(irg);
 163         obstack_init(&env->obst);
 164
 165 #ifdef FIRM_STATISTICS
 166         env->spill_count       = 0;
 167         env->reload_count      = 0;
 168         env->remat_count       = 0;
 169         env->spilled_phi_count = 0;
 170 #endif
 171
 172         return env;
 173 }
 174
 175 void be_delete_spill_env(spill_env_t *env)
 176 {
 177         del_set(env->spills);
 178         ir_nodeset_destroy(&env->mem_phis);
 179         obstack_free(&env->obst, NULL);
 180         free(env);
 181 }
 182
 183 /*
 184  *  ____  _                  ____      _                 _
 185  * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
 186  * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
 187  * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
 188  * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
 189  *
 190  */
 191
 192 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
 193 {
 194         spill_info_t  *spill_info = get_spillinfo(env, to_spill);
 195         spill_t       *spill;
 196         spill_t       *s;
 197         spill_t       *last;
 198
 199         assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
 200         DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
 201
 202         /* Just for safety make sure that we do not insert the spill in front of a phi */
 203         assert(!is_Phi(sched_next(after)));
 204
 205         /* spills that are dominated by others are not needed */
 206         last = NULL;
 207         s    = spill_info->spills;
 208         for ( ; s != NULL; s = s->next) {
 209                 /* no need to add this spill if it is dominated by another */
 210                 if (value_dominates(s->after, after)) {
 211                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
 212                         return;
 213                 }
 214                 /* remove spills that we dominate */
 215                 if (value_dominates(after, s->after)) {
 216                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
 217                         if (last != NULL) {
 218                                 last->next         = s->next;
 219                         } else {
 220                                 spill_info->spills = s->next;
 221                         }
 222                 } else {
 223                         last = s;
 224                 }
 225         }
 226
 227         spill         = OALLOC(&env->obst, spill_t);
 228         spill->after  = after;
 229         spill->next   = spill_info->spills;
 230         spill->spill  = NULL;
 231
 232         spill_info->spills = spill;
 233 }
 234
 235 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 236                   ir_node *rematted_node)
 237 {
 238         spill_info_t *spill_info;
 239         reloader_t *reloader;
 240
 241         spill_info = get_spillinfo(env, to_spill);
 242
 243         /* add the remat information */
 244         reloader                   = OALLOC(&env->obst, reloader_t);
 245         reloader->next             = spill_info->reloaders;
 246         reloader->reloader         = before;
 247         reloader->rematted_node    = rematted_node;
 248         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 249                                            reload since we're not even allowed to
 250                                            create a reload */
 251
 252         spill_info->reloaders  = reloader;
 253
 254         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 255                 to_spill, before));
 256 }
 257
 258 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 259                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 260                 int allow_remat)
 261 {
 262         spill_info_t  *info;
 263         reloader_t    *rel;
 264
 265         assert(!arch_irn_is(skip_Proj_const(to_spill), dont_spill));
 266
 267         info = get_spillinfo(env, to_spill);
 268
 269         if (is_Phi(to_spill)) {
 270                 int i, arity;
 271
 272                 /* create spillinfos for the phi arguments */
 273                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 274                         ir_node *arg = get_irn_n(to_spill, i);
 275                         get_spillinfo(env, arg);
 276                 }
 277         }
 278
 279         assert(!is_Proj(before) && !be_is_Keep(before));
 280
 281         /* put reload into list */
 282         rel                   = OALLOC(&env->obst, reloader_t);
 283         rel->next             = info->reloaders;
 284         rel->reloader         = before;
 285         rel->rematted_node    = NULL;
 286         rel->can_spill_after  = can_spill_after;
 287         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 288
 289         info->reloaders  = rel;
 290         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 291         info->reload_cls = reload_cls;
 292
 293         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 294                 to_spill, before, allow_remat ? "" : " not"));
 295 }
 296
 297 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 298                    const arch_register_class_t *reload_cls, int allow_remat)
 299 {
 300         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 301
 302 }
 303
 304 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 305 {
 306         ir_node *last = sched_last(block);
 307
 308         /* we might have keeps behind the jump... */
 309         while (be_is_Keep(last)) {
 310                 last = sched_prev(last);
 311                 assert(!sched_is_end(last));
 312         }
 313
 314         assert(is_cfop(last));
 315
 316         /* add the reload before the (cond-)jump */
 317         return last;
 318 }
 319
 320 static ir_node *skip_keeps_phis(ir_node *node)
 321 {
 322         while (true) {
 323                 ir_node *next = sched_next(node);
 324                 if (!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
 325                         break;
 326                 node = next;
 327         }
 328         return node;
 329 }
 330
 331 /**
 332  * Returns the point at which you can insert a node that should be executed
 333  * before block @p block when coming from pred @p pos.
 334  */
 335 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 336 {
 337         ir_node *predblock;
 338
 339         /* simply add the reload to the beginning of the block if we only have 1
 340          * predecessor. We don't need to check for phis as there can't be any in a
 341          * block with only 1 pred. */
 342         if (get_Block_n_cfgpreds(block) == 1) {
 343                 assert(!is_Phi(sched_first(block)));
 344                 return sched_first(block);
 345         }
 346
 347         /* We have to reload the value in pred-block */
 348         predblock = get_Block_cfgpred_block(block, pos);
 349         return be_get_end_of_block_insertion_point(predblock);
 350 }
 351
 352 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 353                           const ir_node *block,
 354                           const arch_register_class_t *reload_cls,
 355                           int allow_remat)
 356 {
 357         ir_node *before = be_get_end_of_block_insertion_point(block);
 358         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 359 }
 360
 361 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 362                            int pos, const arch_register_class_t *reload_cls,
 363                            int allow_remat)
 364 {
 365         ir_node *before = get_block_insertion_point(block, pos);
 366         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 367 }
 368
 369 void be_spill_phi(spill_env_t *env, ir_node *node)
 370 {
 371         ir_node *block;
 372         int i, arity;
 373
 374         assert(is_Phi(node));
 375
 376         ir_nodeset_insert(&env->mem_phis, node);
 377
 378         /* create spills for the phi arguments */
 379         block = get_nodes_block(node);
 380         for (i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 381                 ir_node *arg = get_irn_n(node, i);
 382                 ir_node *insert;
 383
 384                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 385                  * and simply always available. */
 386                 if (!sched_is_scheduled(arg)) {
 387                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 388                         insert = be_get_end_of_block_insertion_point(pred_block);
 389                         insert = sched_prev(insert);
 390                 } else {
 391                         insert = skip_keeps_phis(arg);
 392                 }
 393
 394                 be_add_spill(env, arg, insert);
 395         }
 396 }
 397
 398 /*
 399  *   ____                _         ____        _ _ _
 400  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 401  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 402  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 403  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 404  *                                      |_|
 405  */
 406
 407 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 408
 409 /**
 410  * Creates a spill.
 411  *
 412  * @param senv      the spill environment
 413  * @param irn       the node that should be spilled
 414  * @param ctx_irn   an user of the spilled node
 415  *
 416  * @return a be_Spill node
 417  */
 418 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 419 {
 420         ir_node       *to_spill = spillinfo->to_spill;
 421         const ir_node *insn     = skip_Proj_const(to_spill);
 422         spill_t *spill;
 423
 424         /* determine_spill_costs must have been run before */
 425         assert(spillinfo->spill_costs >= 0);
 426
 427         /* some backends have virtual noreg/unknown nodes that are not scheduled
 428          * and simply always available. */
 429         if (!sched_is_scheduled(insn)) {
 430                 /* override spillinfos or create a new one */
 431                 ir_graph *irg = get_irn_irg(to_spill);
 432                 spillinfo->spills->spill = new_r_NoMem(irg);
 433                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 434                 return;
 435         }
 436
 437         DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
 438         spill = spillinfo->spills;
 439         for ( ; spill != NULL; spill = spill->next) {
 440                 ir_node *after = spill->after;
 441                 ir_node *block = get_block(after);
 442
 443                 after = skip_keeps_phis(after);
 444
 445                 spill->spill = be_spill(block, to_spill);
 446                 sched_add_after(skip_Proj(after), spill->spill);
 447                 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
 448 #ifdef FIRM_STATISTICS
 449                 env->spill_count++;
 450 #endif
 451         }
 452         DBG((dbg, LEVEL_1, "\n"));
 453 }
 454
 455 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 456
 457 /**
 458  * If the first usage of a Phi result would be out of memory
 459  * there is no sense in allocating a register for it.
 460  * Thus we spill it and all its operands to the same spill slot.
 461  * Therefore the phi/dataB becomes a phi/Memory
 462  *
 463  * @param senv      the spill environment
 464  * @param phi       the Phi node that should be spilled
 465  * @param ctx_irn   an user of the spilled node
 466  */
 467 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 468 {
 469         ir_graph *irg   = env->irg;
 470         ir_node  *phi   = spillinfo->to_spill;
 471         ir_node  *block = get_nodes_block(phi);
 472         ir_node  *unknown;
 473         ir_node **ins;
 474         spill_t  *spill;
 475         int       i;
 476         int       arity;
 477
 478         assert(is_Phi(phi));
 479         assert(!get_opt_cse());
 480         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 481
 482         /* build a new PhiM */
 483         arity   = get_irn_arity(phi);
 484         ins     = ALLOCAN(ir_node*, arity);
 485         unknown = new_r_Unknown(irg, mode_M);
 486         for (i = 0; i < arity; ++i) {
 487                 ins[i] = unknown;
 488         }
 489
 490         /* override or replace spills list... */
 491         spill         = OALLOC(&env->obst, spill_t);
 492         spill->after  = skip_keeps_phis(phi);
 493         spill->spill  = be_new_Phi(block, arity, ins, mode_M, NULL);
 494         spill->next   = NULL;
 495         sched_add_after(block, spill->spill);
 496
 497         spillinfo->spills = spill;
 498 #ifdef FIRM_STATISTICS
 499         env->spilled_phi_count++;
 500 #endif
 501
 502         for (i = 0; i < arity; ++i) {
 503                 ir_node      *arg      = get_irn_n(phi, i);
 504                 spill_info_t *arg_info = get_spillinfo(env, arg);
 505
 506                 determine_spill_costs(env, arg_info);
 507                 spill_node(env, arg_info);
 508
 509                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 510         }
 511         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 512              spill->spill));
 513 }
 514
 515 /**
 516  * Spill a node.
 517  *
 518  * @param senv      the spill environment
 519  * @param to_spill  the node that should be spilled
 520  */
 521 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 522 {
 523         ir_node *to_spill;
 524
 525         /* node is already spilled */
 526         if (spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 527                 return;
 528
 529         to_spill = spillinfo->to_spill;
 530
 531         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 532                 spill_phi(env, spillinfo);
 533         } else {
 534                 spill_irn(env, spillinfo);
 535         }
 536 }
 537
 538 /*
 539  *
 540  *  ____                      _            _       _ _
 541  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 542  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 543  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 544  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 545  *
 546  */
 547
 548 /**
 549  * Tests whether value @p arg is available before node @p reloader
 550  * @returns 1 if value is available, 0 otherwise
 551  */
 552 static int is_value_available(spill_env_t *env, const ir_node *arg,
 553                               const ir_node *reloader)
 554 {
 555         if (is_Unknown(arg) || is_NoMem(arg))
 556                 return 1;
 557
 558         if (be_is_Spill(skip_Proj_const(arg)))
 559                 return 1;
 560
 561         if (arg == get_irg_frame(env->irg))
 562                 return 1;
 563
 564         (void)reloader;
 565
 566         if (get_irn_mode(arg) == mode_T)
 567                 return 0;
 568
 569         /*
 570          * Ignore registers are always available
 571          */
 572         if (arch_irn_is_ignore(arg))
 573                 return 1;
 574
 575         return 0;
 576 }
 577
 578 /**
 579  * Check if a node is rematerializable. This tests for the following conditions:
 580  *
 581  * - The node itself is rematerializable
 582  * - All arguments of the node are available or also rematerialisable
 583  * - The costs for the rematerialisation operation is less or equal a limit
 584  *
 585  * Returns the costs needed for rematerialisation or something
 586  * >= REMAT_COST_INFINITE if remat is not possible.
 587  */
 588 static int check_remat_conditions_costs(spill_env_t *env,
 589                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 590 {
 591         int i, arity;
 592         int argremats;
 593         int costs = 0;
 594         const ir_node *insn = skip_Proj_const(spilled);
 595
 596         assert(!be_is_Spill(insn));
 597         if (!arch_irn_is(insn, rematerializable))
 598                 return REMAT_COST_INFINITE;
 599
 600         if (be_is_Reload(insn)) {
 601                 costs += 2;
 602         } else {
 603                 costs += arch_get_op_estimated_cost(insn);
 604         }
 605         if (parentcosts + costs >= env->reload_cost + env->spill_cost) {
 606                 return REMAT_COST_INFINITE;
 607         }
 608         /* never rematerialize a node which modifies the flags.
 609          * (would be better to test wether the flags are actually live at point
 610          * reloader...)
 611          */
 612         if (arch_irn_is(insn, modify_flags)) {
 613                 return REMAT_COST_INFINITE;
 614         }
 615
 616         argremats = 0;
 617         for (i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
 618                 ir_node *arg = get_irn_n(insn, i);
 619
 620                 if (is_value_available(env, arg, reloader))
 621                         continue;
 622
 623                 /* we have to rematerialize the argument as well */
 624                 ++argremats;
 625                 if (argremats > 1) {
 626                         /* we only support rematerializing 1 argument at the moment,
 627                          * as multiple arguments could increase register pressure */
 628                         return REMAT_COST_INFINITE;
 629                 }
 630
 631                 costs += check_remat_conditions_costs(env, arg, reloader,
 632                                                       parentcosts + costs);
 633                 if (parentcosts + costs >= env->reload_cost + env->spill_cost)
 634                         return REMAT_COST_INFINITE;
 635         }
 636
 637         return costs;
 638 }
 639
 640 /**
 641  * Re-materialize a node.
 642  *
 643  * @param senv      the spill environment
 644  * @param spilled   the node that was spilled
 645  * @param reloader  a irn that requires a reload
 646  */
 647 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 648 {
 649         int i, arity;
 650         ir_node *res;
 651         ir_node *bl;
 652         ir_node **ins;
 653
 654         if (is_Block(reloader)) {
 655                 bl = reloader;
 656         } else {
 657                 bl = get_nodes_block(reloader);
 658         }
 659
 660         ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
 661         for (i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 662                 ir_node *arg = get_irn_n(spilled, i);
 663
 664                 if (is_value_available(env, arg, reloader)) {
 665                         ins[i] = arg;
 666                 } else {
 667                         ins[i] = do_remat(env, arg, reloader);
 668 #ifdef FIRM_STATISTICS
 669                         /* don't count the recursive call as remat */
 670                         env->remat_count--;
 671 #endif
 672                 }
 673         }
 674
 675         /* create a copy of the node */
 676         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 677                           get_irn_op(spilled), get_irn_mode(spilled),
 678                           get_irn_arity(spilled), ins);
 679         copy_node_attr(env->irg, spilled, res);
 680         arch_env_mark_remat(env->arch_env, res);
 681
 682         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 683
 684         if (! is_Proj(res)) {
 685                 /* insert in schedule */
 686                 sched_reset(res);
 687                 sched_add_before(reloader, res);
 688 #ifdef FIRM_STATISTICS
 689                 env->remat_count++;
 690 #endif
 691         }
 692
 693         return res;
 694 }
 695
 696 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 697 {
 698         ir_node *block = get_nodes_block(before);
 699         double   freq  = get_block_execfreq(env->exec_freq, block);
 700         (void) to_spill;
 701
 702         return env->spill_cost * freq;
 703 }
 704
 705 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
 706                                        const ir_node *before)
 707 {
 708         if (be_do_remats) {
 709                 /* is the node rematerializable? */
 710                 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
 711                 if (costs < (unsigned) env->reload_cost)
 712                         return costs;
 713         }
 714
 715         return env->reload_cost;
 716 }
 717
 718 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 719 {
 720         ir_node      *block = get_nodes_block(before);
 721         double        freq  = get_block_execfreq(env->exec_freq, block);
 722
 723         if (be_do_remats) {
 724                 /* is the node rematerializable? */
 725                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 726                 if (costs < env->reload_cost)
 727                         return costs * freq;
 728         }
 729
 730         return env->reload_cost * freq;
 731 }
 732
 733 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 734                            const ir_node *before)
 735 {
 736         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 737 }
 738
 739 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 740                                    ir_node *block, int pos)
 741 {
 742         ir_node *before = get_block_insertion_point(block, pos);
 743         return be_get_reload_costs(env, to_spill, before);
 744 }
 745
 746 /*
 747  *  ___                     _     ____      _                 _
 748  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 749  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 750  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 751  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 752  *
 753  */
 754
 755 /**
 756  * analyzes how to best spill a node and determine costs for that
 757  */
 758 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 759 {
 760         ir_node       *to_spill = spillinfo->to_spill;
 761         const ir_node *insn     = skip_Proj_const(to_spill);
 762         ir_node       *spill_block;
 763         spill_t       *spill;
 764         double         spill_execfreq;
 765
 766         /* already calculated? */
 767         if (spillinfo->spill_costs >= 0)
 768                 return;
 769
 770         assert(!arch_irn_is(insn, dont_spill));
 771         assert(!be_is_Reload(insn));
 772
 773         /* some backends have virtual noreg/unknown nodes that are not scheduled
 774          * and simply always available.
 775          * TODO: this is kinda hairy, the NoMem is correct for an Unknown as Phi
 776          * predecessor (of a PhiM) but this test might match other things too...
 777          */
 778         if (!sched_is_scheduled(insn)) {
 779                 ir_graph *irg = get_irn_irg(to_spill);
 780                 /* override spillinfos or create a new one */
 781                 spill_t *spill = OALLOC(&env->obst, spill_t);
 782                 spill->after = NULL;
 783                 spill->next  = NULL;
 784                 spill->spill = new_r_NoMem(irg);
 785
 786                 spillinfo->spills      = spill;
 787                 spillinfo->spill_costs = 0;
 788
 789                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 790                 return;
 791         }
 792
 793         spill_block    = get_nodes_block(insn);
 794         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 795
 796         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 797                 /* TODO calculate correct costs...
 798                  * (though we can't remat this node anyway so no big problem) */
 799                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 800                 return;
 801         }
 802
 803         if (spillinfo->spills != NULL) {
 804                 spill_t *s;
 805                 double   spills_execfreq;
 806
 807                 /* calculate sum of execution frequencies of individual spills */
 808                 spills_execfreq = 0;
 809                 s               = spillinfo->spills;
 810                 for ( ; s != NULL; s = s->next) {
 811                         ir_node *spill_block = get_block(s->after);
 812                         double   freq = get_block_execfreq(env->exec_freq, spill_block);
 813
 814                         spills_execfreq += freq;
 815                 }
 816
 817                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 818                     spills_execfreq * env->spill_cost,
 819                     spill_execfreq * env->spill_cost));
 820
 821                 /* multi-/latespill is advantageous -> return*/
 822                 if (spills_execfreq < spill_execfreq) {
 823                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 824                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 825                         return;
 826                 }
 827         }
 828
 829         /* override spillinfos or create a new one */
 830         spill        = OALLOC(&env->obst, spill_t);
 831         spill->after = skip_keeps_phis(to_spill);
 832         spill->next  = NULL;
 833         spill->spill = NULL;
 834
 835         spillinfo->spills      = spill;
 836         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 837         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 838 }
 839
 840 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
 841 {
 842         const spill_info_t *si = get_spillinfo(env, irn);
 843         ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
 844         int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
 845         bitset_t *reloads      = bitset_alloca(n_blocks);
 846         reloader_t *r;
 847         spill_t *s;
 848
 849         if (si == NULL)
 850                 return;
 851
 852         /* Fill the bitset with the dominance pre-order numbers
 853          * of the blocks the reloads are located in. */
 854         for (r = si->reloaders; r != NULL; r = r->next) {
 855                 ir_node *bl = get_nodes_block(r->reloader);
 856                 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 857         }
 858
 859         /* Now, cancel out all the blocks that are dominated by each spill.
 860          * If the bitset is not empty after that, we have reloads that are
 861          * not dominated by any spill. */
 862         for (s = si->spills; s != NULL; s = s->next) {
 863                 ir_node *bl = get_nodes_block(s->after);
 864                 int start   = get_Block_dom_tree_pre_num(bl);
 865                 int end     = get_Block_dom_max_subtree_pre_num(bl);
 866
 867                 bitset_clear_range(reloads, start, end);
 868         }
 869
 870         if (!bitset_is_empty(reloads))
 871                 be_add_spill(env, si->to_spill, si->to_spill);
 872 }
 873
 874 void be_insert_spills_reloads(spill_env_t *env)
 875 {
 876         const ir_exec_freq    *exec_freq = env->exec_freq;
 877         spill_info_t          *si;
 878         ir_nodeset_iterator_t  iter;
 879         ir_node               *node;
 880
 881         be_timer_push(T_RA_SPILL_APPLY);
 882
 883         /* create all phi-ms first, this is needed so, that phis, hanging on
 884            spilled phis work correctly */
 885         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 886                 spill_info_t *info = get_spillinfo(env, node);
 887                 spill_node(env, info);
 888         }
 889
 890         /* process each spilled node */
 891         foreach_set(env->spills, spill_info_t*, si) {
 892                 reloader_t *rld;
 893                 ir_node  *to_spill        = si->to_spill;
 894                 ir_mode  *mode            = get_irn_mode(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                 int       force_remat     = 0;
 898
 899                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 900
 901                 determine_spill_costs(env, si);
 902
 903                 /* determine possibility of rematerialisations */
 904                 if (be_do_remats) {
 905                         /* calculate cost savings for each indivial value when it would
 906                            be rematted instead of reloaded */
 907                         for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 908                                 double   freq;
 909                                 int      remat_cost;
 910                                 int      remat_cost_delta;
 911                                 ir_node *block;
 912                                 ir_node *reloader = rld->reloader;
 913
 914                                 if (rld->rematted_node != NULL) {
 915                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 916                                              rld->rematted_node, reloader));
 917                                         continue;
 918                                 }
 919                                 if (rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 920                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 921                                              reloader));
 922                                         all_remat_costs = REMAT_COST_INFINITE;
 923                                         continue;
 924                                 }
 925
 926                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 927                                                                            reloader, 0);
 928                                 if (remat_cost >= REMAT_COST_INFINITE) {
 929                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 930                                              reloader));
 931                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 932                                         all_remat_costs       = REMAT_COST_INFINITE;
 933                                         continue;
 934                                 }
 935
 936                                 remat_cost_delta      = remat_cost - env->reload_cost;
 937                                 rld->remat_cost_delta = remat_cost_delta;
 938                                 block                 = is_Block(reloader) ? reloader : get_nodes_block(reloader);
 939                                 freq                  = get_block_execfreq(exec_freq, block);
 940                                 all_remat_costs      += remat_cost_delta * freq;
 941                                 DBG((dbg, LEVEL_2, "\tremat costs delta before %+F: "
 942                                      "%d (rel %f)\n", reloader, remat_cost_delta,
 943                                      remat_cost_delta * freq));
 944                         }
 945                         if (all_remat_costs < REMAT_COST_INFINITE) {
 946                                 /* we don't need the costs for the spill if we can remat
 947                                    all reloaders */
 948                                 all_remat_costs -= si->spill_costs;
 949
 950                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 951                                      env->spill_cost, si->spill_costs));
 952                         }
 953
 954                         if (all_remat_costs < 0) {
 955                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 956                                      all_remat_costs));
 957                                 force_remat = 1;
 958                         }
 959                 }
 960
 961                 /* go through all reloads for this spill */
 962                 for (rld = si->reloaders; rld != NULL; rld = rld->next) {
 963                         ir_node *copy; /* a reload is a "copy" of the original value */
 964
 965                         if (rld->rematted_node != NULL) {
 966                                 copy = rld->rematted_node;
 967                                 sched_add_before(rld->reloader, copy);
 968                         } else if (be_do_remats &&
 969                                         (force_remat || rld->remat_cost_delta < 0)) {
 970                                 copy = do_remat(env, to_spill, rld->reloader);
 971                         } else {
 972                                 /* make sure we have a spill */
 973                                 spill_node(env, si);
 974
 975                                 /* create a reload, use the first spill for now SSA
 976                                  * reconstruction for memory comes below */
 977                                 assert(si->spills != NULL);
 978                                 copy = be_reload(si->reload_cls, rld->reloader, mode,
 979                                                  si->spills->spill);
 980 #ifdef FIRM_STATISTICS
 981                                 env->reload_count++;
 982 #endif
 983                         }
 984
 985                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 986                              copy, to_spill, rld->reloader));
 987                         ARR_APP1(ir_node*, copies, copy);
 988                 }
 989
 990                 /* if we had any reloads or remats, then we need to reconstruct the
 991                  * SSA form for the spilled value */
 992                 if (ARR_LEN(copies) > 0) {
 993                         be_ssa_construction_env_t senv;
 994                         /* be_lv_t *lv = be_get_irg_liveness(env->irg); */
 995
 996                         be_ssa_construction_init(&senv, env->irg);
 997                         be_ssa_construction_add_copy(&senv, to_spill);
 998                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
 999                         be_ssa_construction_fix_users(&senv, to_spill);
1000
1001 #if 0
1002                         /* no need to enable this as long as we invalidate liveness
1003                            after this function... */
1004                         be_ssa_construction_update_liveness_phis(&senv);
1005                         be_liveness_update(to_spill);
1006                         len = ARR_LEN(copies);
1007                         for (i = 0; i < len; ++i) {
1008                                 be_liveness_update(lv, copies[i]);
1009                         }
1010 #endif
1011                         be_ssa_construction_destroy(&senv);
1012                 }
1013                 /* need to reconstruct SSA form if we had multiple spills */
1014                 if (si->spills != NULL && si->spills->next != NULL) {
1015                         spill_t *spill;
1016                         int      spill_count = 0;
1017
1018                         be_ssa_construction_env_t senv;
1019
1020                         be_ssa_construction_init(&senv, env->irg);
1021                         spill = si->spills;
1022                         for ( ; spill != NULL; spill = spill->next) {
1023                                 /* maybe we rematerialized the value and need no spill */
1024                                 if (spill->spill == NULL)
1025                                         continue;
1026                                 be_ssa_construction_add_copy(&senv, spill->spill);
1027                                 spill_count++;
1028                         }
1029                         if (spill_count > 1) {
1030                                 /* all reloads are attached to the first spill, fix them now */
1031                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1032                         }
1033
1034                         be_ssa_construction_destroy(&senv);
1035                 }
1036
1037                 DEL_ARR_F(copies);
1038                 si->reloaders = NULL;
1039         }
1040
1041         stat_ev_dbl("spill_spills", env->spill_count);
1042         stat_ev_dbl("spill_reloads", env->reload_count);
1043         stat_ev_dbl("spill_remats", env->remat_count);
1044         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1045
1046         /* Matze: In theory be_ssa_construction should take care of the liveness...
1047          * try to disable this again in the future */
1048         be_liveness_invalidate(be_get_irg_liveness(env->irg));
1049
1050         be_remove_dead_nodes_from_schedule(env->irg);
1051
1052         be_timer_pop(T_RA_SPILL_APPLY);
1053 }
1054
1055 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);
1056 void be_init_spill(void)
1057 {
1058         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1059 }