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_t.h"
  56 #include "bechordal_t.h"
  57 #include "bestatevent.h"
  58 #include "bessaconstr.h"
  59 #include "beirg.h"
  60 #include "beintlive_t.h"
  61 #include "bemodule.h"
  62 #include "be_t.h"
  63
  64 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  65
  66 #define REMAT_COST_INFINITE  1000
  67
  68 typedef struct reloader_t reloader_t;
  69 struct reloader_t {
  70         reloader_t *next;
  71         ir_node    *can_spill_after;
  72         ir_node    *reloader;
  73         ir_node    *rematted_node;
  74         int         remat_cost_delta; /** costs needed for rematerialization,
  75                                            compared to placing a reload */
  76 };
  77
  78 typedef struct spill_t spill_t;
  79 struct spill_t {
  80         spill_t *next;
  81         ir_node *after;  /**< spill has to be placed after this node (or earlier) */
  82         ir_node *spill;
  83 };
  84
  85 typedef struct spill_info_t spill_info_t;
  86 struct 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
  89                                     reloaded */
  90         spill_t    *spills;    /**< list of latest places where spill must be
  91                                     placed */
  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 };
  96
  97 struct spill_env_t {
  98         const arch_env_t *arch_env;
  99         ir_graph         *irg;
 100         struct obstack    obst;
 101         be_irg_t         *birg;
 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 = x;
 123         const spill_info_t *yy = 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 = 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 = set_insert(env->spills, &info, sizeof(info), hash);
 146         }
 147
 148         return res;
 149 }
 150
 151 spill_env_t *be_new_spill_env(be_irg_t *birg)
 152 {
 153         const arch_env_t *arch_env = birg->main_env->arch_env;
 154
 155         spill_env_t *env = XMALLOC(spill_env_t);
 156         env->spills                     = new_set(cmp_spillinfo, 1024);
 157         env->irg            = be_get_birg_irg(birg);
 158         env->birg           = birg;
 159         env->arch_env       = arch_env;
 160         ir_nodeset_init(&env->mem_phis);
 161         env->spill_cost     = arch_env->spill_cost;
 162         env->reload_cost    = arch_env->reload_cost;
 163         env->exec_freq      = be_get_birg_exec_freq(birg);
 164         obstack_init(&env->obst);
 165
 166 #ifdef FIRM_STATISTICS
 167         env->spill_count       = 0;
 168         env->reload_count      = 0;
 169         env->remat_count       = 0;
 170         env->spilled_phi_count = 0;
 171 #endif
 172
 173         return env;
 174 }
 175
 176 void be_delete_spill_env(spill_env_t *env)
 177 {
 178         del_set(env->spills);
 179         ir_nodeset_destroy(&env->mem_phis);
 180         obstack_free(&env->obst, NULL);
 181         free(env);
 182 }
 183
 184 /*
 185  *  ____  _                  ____      _                 _
 186  * |  _ \| | __ _  ___ ___  |  _ \ ___| | ___   __ _  __| |___
 187  * | |_) | |/ _` |/ __/ _ \ | |_) / _ \ |/ _ \ / _` |/ _` / __|
 188  * |  __/| | (_| | (_|  __/ |  _ <  __/ | (_) | (_| | (_| \__ \
 189  * |_|   |_|\__,_|\___\___| |_| \_\___|_|\___/ \__,_|\__,_|___/
 190  *
 191  */
 192
 193 void be_add_spill(spill_env_t *env, ir_node *to_spill, ir_node *after)
 194 {
 195         spill_info_t  *spill_info = get_spillinfo(env, to_spill);
 196         const ir_node *insn       = skip_Proj_const(to_spill);
 197         spill_t       *spill;
 198         spill_t       *s;
 199         spill_t       *last;
 200
 201         assert(!arch_irn_is(insn, dont_spill));
 202         DB((dbg, LEVEL_1, "Add spill of %+F after %+F\n", to_spill, after));
 203
 204         /* Just for safety make sure that we do not insert the spill in front of a phi */
 205         assert(!is_Phi(sched_next(after)));
 206
 207         /* spills that are dominated by others are not needed */
 208         last = NULL;
 209         s    = spill_info->spills;
 210         for( ; s != NULL; s = s->next) {
 211                 /* no need to add this spill if it is dominated by another */
 212                 if(value_dominates(s->after, after)) {
 213                         DB((dbg, LEVEL_1, "...dominated by %+F, not added\n", s->after));
 214                         return;
 215                 }
 216                 /* remove spills that we dominate */
 217                 if(value_dominates(after, s->after)) {
 218                         DB((dbg, LEVEL_1, "...remove old spill at %+F\n", s->after));
 219                         if(last != NULL) {
 220                                 last->next         = s->next;
 221                         } else {
 222                                 spill_info->spills = s->next;
 223                         }
 224                 } else {
 225                         last = s;
 226                 }
 227         }
 228
 229         spill         = OALLOC(&env->obst, spill_t);
 230         spill->after  = after;
 231         spill->next   = spill_info->spills;
 232         spill->spill  = NULL;
 233
 234         spill_info->spills = spill;
 235 }
 236
 237 void be_add_remat(spill_env_t *env, ir_node *to_spill, ir_node *before,
 238                   ir_node *rematted_node)
 239 {
 240         spill_info_t *spill_info;
 241         reloader_t *reloader;
 242
 243         spill_info = get_spillinfo(env, to_spill);
 244
 245         /* add the remat information */
 246         reloader                   = OALLOC(&env->obst, reloader_t);
 247         reloader->next             = spill_info->reloaders;
 248         reloader->reloader         = before;
 249         reloader->rematted_node    = rematted_node;
 250         reloader->remat_cost_delta = 0; /* We will never have a cost win over a
 251                                            reload since we're not even allowed to
 252                                            create a reload */
 253
 254         spill_info->reloaders  = reloader;
 255
 256         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be rematerialized before %+F\n",
 257                 to_spill, before));
 258 }
 259
 260 void be_add_reload2(spill_env_t *env, ir_node *to_spill, ir_node *before,
 261                 ir_node *can_spill_after, const arch_register_class_t *reload_cls,
 262                 int allow_remat)
 263 {
 264         spill_info_t  *info;
 265         reloader_t    *rel;
 266         const ir_node *insn = skip_Proj_const(to_spill);
 267
 268         assert(!arch_irn_is(insn, dont_spill));
 269
 270         info = get_spillinfo(env, to_spill);
 271
 272         if (is_Phi(to_spill)) {
 273                 int i, arity;
 274
 275                 /* create spillinfos for the phi arguments */
 276                 for (i = 0, arity = get_irn_arity(to_spill); i < arity; ++i) {
 277                         ir_node *arg = get_irn_n(to_spill, i);
 278                         get_spillinfo(env, arg);
 279                 }
 280         }
 281
 282         assert(!is_Proj(before) && !be_is_Keep(before));
 283
 284         /* put reload into list */
 285         rel                   = OALLOC(&env->obst, reloader_t);
 286         rel->next             = info->reloaders;
 287         rel->reloader         = before;
 288         rel->rematted_node    = NULL;
 289         rel->can_spill_after  = can_spill_after;
 290         rel->remat_cost_delta = allow_remat ? 0 : REMAT_COST_INFINITE;
 291
 292         info->reloaders  = rel;
 293         assert(info->reload_cls == NULL || info->reload_cls == reload_cls);
 294         info->reload_cls = reload_cls;
 295
 296         DBG((dbg, LEVEL_1, "creating spillinfo for %+F, will be reloaded before %+F, may%s be rematerialized\n",
 297                 to_spill, before, allow_remat ? "" : " not"));
 298 }
 299
 300 void be_add_reload(spill_env_t *senv, ir_node *to_spill, ir_node *before,
 301                    const arch_register_class_t *reload_cls, int allow_remat)
 302 {
 303         be_add_reload2(senv, to_spill, before, to_spill, reload_cls, allow_remat);
 304
 305 }
 306
 307 ir_node *be_get_end_of_block_insertion_point(const ir_node *block)
 308 {
 309         ir_node *last = sched_last(block);
 310
 311         /* we might have keeps behind the jump... */
 312         while (be_is_Keep(last)) {
 313                 last = sched_prev(last);
 314                 assert(!sched_is_end(last));
 315         }
 316
 317         assert(is_cfop(last));
 318
 319         /* add the reload before the (cond-)jump */
 320         return last;
 321 }
 322
 323 static ir_node *skip_keeps_phis(ir_node *node)
 324 {
 325         while(true) {
 326                 ir_node *next = sched_next(node);
 327                 if(!is_Phi(next) && !be_is_Keep(next) && !be_is_CopyKeep(next))
 328                         break;
 329                 node = next;
 330         }
 331         return node;
 332 }
 333
 334 /**
 335  * Returns the point at which you can insert a node that should be executed
 336  * before block @p block when coming from pred @p pos.
 337  */
 338 static ir_node *get_block_insertion_point(ir_node *block, int pos)
 339 {
 340         ir_node *predblock;
 341
 342         /* simply add the reload to the beginning of the block if we only have 1
 343          * predecessor. We don't need to check for phis as there can't be any in a
 344          * block with only 1 pred. */
 345         if(get_Block_n_cfgpreds(block) == 1) {
 346                 assert(!is_Phi(sched_first(block)));
 347                 return sched_first(block);
 348         }
 349
 350         /* We have to reload the value in pred-block */
 351         predblock = get_Block_cfgpred_block(block, pos);
 352         return be_get_end_of_block_insertion_point(predblock);
 353 }
 354
 355 void be_add_reload_at_end(spill_env_t *env, ir_node *to_spill,
 356                           const ir_node *block,
 357                           const arch_register_class_t *reload_cls,
 358                           int allow_remat)
 359 {
 360         ir_node *before = be_get_end_of_block_insertion_point(block);
 361         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 362 }
 363
 364 void be_add_reload_on_edge(spill_env_t *env, ir_node *to_spill, ir_node *block,
 365                            int pos,     const arch_register_class_t *reload_cls,
 366                            int allow_remat)
 367 {
 368         ir_node *before = get_block_insertion_point(block, pos);
 369         be_add_reload(env, to_spill, before, reload_cls, allow_remat);
 370 }
 371
 372 void be_spill_phi(spill_env_t *env, ir_node *node)
 373 {
 374         ir_node *block;
 375         spill_info_t* spill;
 376         int i, arity;
 377
 378         assert(is_Phi(node));
 379
 380         ir_nodeset_insert(&env->mem_phis, node);
 381
 382         /* create spills for the phi arguments */
 383         block = get_nodes_block(node);
 384         spill = get_spillinfo(env, node);
 385         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 386                 ir_node *arg = get_irn_n(node, i);
 387                 ir_node *insert;
 388                 //get_spillinfo(env, arg);
 389
 390                 /* some backends have virtual noreg/unknown nodes that are not scheduled
 391                  * and simply always available. */
 392                 if(!sched_is_scheduled(arg)) {
 393                         ir_node *pred_block = get_Block_cfgpred_block(block, i);
 394                         insert = be_get_end_of_block_insertion_point(pred_block);
 395                         insert = sched_prev(insert);
 396                 } else {
 397                         insert = skip_keeps_phis(arg);
 398                 }
 399
 400                 be_add_spill(env, arg, insert);
 401         }
 402 }
 403
 404 /*
 405  *   ____                _         ____        _ _ _
 406  *  / ___|_ __ ___  __ _| |_ ___  / ___| _ __ (_) | |___
 407  * | |   | '__/ _ \/ _` | __/ _ \ \___ \| '_ \| | | / __|
 408  * | |___| | |  __/ (_| | ||  __/  ___) | |_) | | | \__ \
 409  *  \____|_|  \___|\__,_|\__\___| |____/| .__/|_|_|_|___/
 410  *                                      |_|
 411  */
 412
 413 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo);
 414
 415 /**
 416  * Creates a spill.
 417  *
 418  * @param senv      the spill environment
 419  * @param irn       the node that should be spilled
 420  * @param ctx_irn   an user of the spilled node
 421  *
 422  * @return a be_Spill node
 423  */
 424 static void spill_irn(spill_env_t *env, spill_info_t *spillinfo)
 425 {
 426         ir_node       *to_spill = spillinfo->to_spill;
 427         const ir_node *insn     = skip_Proj_const(to_spill);
 428         spill_t *spill;
 429
 430         /* determine_spill_costs must have been run before */
 431         assert(spillinfo->spill_costs >= 0);
 432
 433         /* some backends have virtual noreg/unknown nodes that are not scheduled
 434          * and simply always available. */
 435         if(!sched_is_scheduled(insn)) {
 436                 /* override spillinfos or create a new one */
 437                 spillinfo->spills->spill = new_NoMem();
 438                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 439                 return;
 440         }
 441
 442         DBG((dbg, LEVEL_1, "spilling %+F ... \n", to_spill));
 443         spill = spillinfo->spills;
 444         for( ; spill != NULL; spill = spill->next) {
 445                 ir_node *after = spill->after;
 446                 ir_node *block = get_block(after);
 447
 448                 after = skip_keeps_phis(after);
 449
 450                 spill->spill = be_spill(block, to_spill);
 451                 sched_add_after(skip_Proj(after), spill->spill);
 452                 DB((dbg, LEVEL_1, "\t%+F after %+F\n", spill->spill, after));
 453 #ifdef FIRM_STATISTICS
 454                 env->spill_count++;
 455 #endif
 456         }
 457         DBG((dbg, LEVEL_1, "\n"));
 458 }
 459
 460 static void spill_node(spill_env_t *env, spill_info_t *spillinfo);
 461
 462 /**
 463  * If the first usage of a Phi result would be out of memory
 464  * there is no sense in allocating a register for it.
 465  * Thus we spill it and all its operands to the same spill slot.
 466  * Therefore the phi/dataB becomes a phi/Memory
 467  *
 468  * @param senv      the spill environment
 469  * @param phi       the Phi node that should be spilled
 470  * @param ctx_irn   an user of the spilled node
 471  */
 472 static void spill_phi(spill_env_t *env, spill_info_t *spillinfo)
 473 {
 474         ir_graph *irg   = env->irg;
 475         ir_node  *phi   = spillinfo->to_spill;
 476         ir_node  *block = get_nodes_block(phi);
 477         ir_node  *unknown;
 478         ir_node **ins;
 479         spill_t  *spill;
 480         int       i;
 481         int       arity;
 482
 483         assert(is_Phi(phi));
 484         assert(!get_opt_cse());
 485         DBG((dbg, LEVEL_1, "spilling Phi %+F:\n", phi));
 486
 487         /* build a new PhiM */
 488         arity   = get_irn_arity(phi);
 489         ins     = ALLOCAN(ir_node*, arity);
 490         unknown = new_r_Unknown(irg, mode_M);
 491         for(i = 0; i < arity; ++i) {
 492                 ins[i] = unknown;
 493         }
 494
 495         /* override or replace spills list... */
 496         spill         = OALLOC(&env->obst, spill_t);
 497         spill->after  = skip_keeps_phis(phi);
 498         spill->spill  = new_r_Phi(block, arity, ins, mode_M);
 499         spill->next   = NULL;
 500
 501         spillinfo->spills = spill;
 502 #ifdef FIRM_STATISTICS
 503         env->spilled_phi_count++;
 504 #endif
 505
 506         for(i = 0; i < arity; ++i) {
 507                 ir_node      *arg      = get_irn_n(phi, i);
 508                 spill_info_t *arg_info = get_spillinfo(env, arg);
 509
 510                 determine_spill_costs(env, arg_info);
 511                 spill_node(env, arg_info);
 512
 513                 set_irn_n(spill->spill, i, arg_info->spills->spill);
 514         }
 515         DBG((dbg, LEVEL_1, "... done spilling Phi %+F, created PhiM %+F\n", phi,
 516              spill->spill));
 517 }
 518
 519 /**
 520  * Spill a node.
 521  *
 522  * @param senv      the spill environment
 523  * @param to_spill  the node that should be spilled
 524  */
 525 static void spill_node(spill_env_t *env, spill_info_t *spillinfo)
 526 {
 527         ir_node *to_spill;
 528
 529         /* node is already spilled */
 530         if(spillinfo->spills != NULL && spillinfo->spills->spill != NULL)
 531                 return;
 532
 533         to_spill = spillinfo->to_spill;
 534
 535         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 536                 spill_phi(env, spillinfo);
 537         } else {
 538                 spill_irn(env, spillinfo);
 539         }
 540 }
 541
 542 /*
 543  *
 544  *  ____                      _            _       _ _
 545  * |  _ \ ___ _ __ ___   __ _| |_ ___ _ __(_) __ _| (_)_______
 546  * | |_) / _ \ '_ ` _ \ / _` | __/ _ \ '__| |/ _` | | |_  / _ \
 547  * |  _ <  __/ | | | | | (_| | ||  __/ |  | | (_| | | |/ /  __/
 548  * |_| \_\___|_| |_| |_|\__,_|\__\___|_|  |_|\__,_|_|_/___\___|
 549  *
 550  */
 551
 552 /**
 553  * Tests whether value @p arg is available before node @p reloader
 554  * @returns 1 if value is available, 0 otherwise
 555  */
 556 static int is_value_available(spill_env_t *env, const ir_node *arg,
 557                               const ir_node *reloader)
 558 {
 559         if(is_Unknown(arg) || arg == new_NoMem())
 560                 return 1;
 561
 562         if(be_is_Spill(skip_Proj_const(arg)))
 563                 return 1;
 564
 565         if(arg == get_irg_frame(env->irg))
 566                 return 1;
 567
 568         (void)reloader;
 569
 570         /*
 571          * Ignore registers are always available
 572          */
 573         if (arch_irn_is_ignore(arg))
 574                 return 1;
 575
 576         return 0;
 577 }
 578
 579 /**
 580  * Check if a node is rematerializable. This tests for the following conditions:
 581  *
 582  * - The node itself is rematerializable
 583  * - All arguments of the node are available or also rematerialisable
 584  * - The costs for the rematerialisation operation is less or equal a limit
 585  *
 586  * Returns the costs needed for rematerialisation or something
 587  * >= REMAT_COST_INFINITE if remat is not possible.
 588  */
 589 static int check_remat_conditions_costs(spill_env_t *env,
 590                 const ir_node *spilled, const ir_node *reloader, int parentcosts)
 591 {
 592         int i, arity;
 593         int argremats;
 594         int costs = 0;
 595         const ir_node *insn = skip_Proj_const(spilled);
 596
 597         assert(!be_is_Spill(insn));
 598         if (!arch_irn_is(insn, rematerializable))
 599                 return REMAT_COST_INFINITE;
 600
 601         if(be_is_Reload(insn)) {
 602                 costs += 2;
 603         } else {
 604                 costs += arch_get_op_estimated_cost(insn);
 605         }
 606         if(parentcosts + costs >= env->reload_cost + env->spill_cost) {
 607                 return REMAT_COST_INFINITE;
 608         }
 609         /* never rematerialize a node which modifies the flags.
 610          * (would be better to test wether the flags are actually live at point
 611          * reloader...)
 612          */
 613         if (arch_irn_is(insn, modify_flags)) {
 614                 return REMAT_COST_INFINITE;
 615         }
 616
 617         argremats = 0;
 618         for(i = 0, arity = get_irn_arity(insn); i < arity; ++i) {
 619                 ir_node *arg = get_irn_n(insn, i);
 620
 621                 if(is_value_available(env, arg, reloader))
 622                         continue;
 623
 624                 /* we have to rematerialize the argument as well */
 625                 ++argremats;
 626                 if(argremats > 1) {
 627                         /* we only support rematerializing 1 argument at the moment,
 628                          * as multiple arguments could increase register pressure */
 629                         return REMAT_COST_INFINITE;
 630                 }
 631
 632                 costs += check_remat_conditions_costs(env, arg, reloader,
 633                                                       parentcosts + costs);
 634                 if(parentcosts + costs >= env->reload_cost + env->spill_cost)
 635                         return REMAT_COST_INFINITE;
 636         }
 637
 638         return costs;
 639 }
 640
 641 /**
 642  * Re-materialize a node.
 643  *
 644  * @param senv      the spill environment
 645  * @param spilled   the node that was spilled
 646  * @param reloader  a irn that requires a reload
 647  */
 648 static ir_node *do_remat(spill_env_t *env, ir_node *spilled, ir_node *reloader)
 649 {
 650         int i, arity;
 651         ir_node *res;
 652         ir_node *bl;
 653         ir_node **ins;
 654
 655         if(is_Block(reloader)) {
 656                 bl = reloader;
 657         } else {
 658                 bl = get_nodes_block(reloader);
 659         }
 660
 661         ins = ALLOCAN(ir_node*, get_irn_arity(spilled));
 662         for(i = 0, arity = get_irn_arity(spilled); i < arity; ++i) {
 663                 ir_node *arg = get_irn_n(spilled, i);
 664
 665                 if(is_value_available(env, arg, reloader)) {
 666                         ins[i] = arg;
 667                 } else {
 668                         ins[i] = do_remat(env, arg, reloader);
 669 #ifdef FIRM_STATISTICS
 670                         /* don't count the recursive call as remat */
 671                         env->remat_count--;
 672 #endif
 673                 }
 674         }
 675
 676         /* create a copy of the node */
 677         res = new_ir_node(get_irn_dbg_info(spilled), env->irg, bl,
 678                           get_irn_op(spilled), get_irn_mode(spilled),
 679                           get_irn_arity(spilled), ins);
 680         copy_node_attr(spilled, res);
 681         arch_env_mark_remat(env->arch_env, res);
 682         new_backedge_info(res);
 683
 684         DBG((dbg, LEVEL_1, "Insert remat %+F of %+F before reloader %+F\n", res, spilled, reloader));
 685
 686         if (! is_Proj(res)) {
 687                 /* insert in schedule */
 688                 sched_reset(res);
 689                 sched_add_before(reloader, res);
 690 #ifdef FIRM_STATISTICS
 691                 env->remat_count++;
 692 #endif
 693         }
 694
 695         return res;
 696 }
 697
 698 double be_get_spill_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 699 {
 700         ir_node *block = get_nodes_block(before);
 701         double   freq  = get_block_execfreq(env->exec_freq, block);
 702         (void) to_spill;
 703
 704         return env->spill_cost * freq;
 705 }
 706
 707 unsigned be_get_reload_costs_no_weight(spill_env_t *env, const ir_node *to_spill,
 708                                        const ir_node *before)
 709 {
 710         if(be_do_remats) {
 711                 /* is the node rematerializable? */
 712                 unsigned costs = check_remat_conditions_costs(env, to_spill, before, 0);
 713                 if(costs < (unsigned) env->reload_cost)
 714                         return costs;
 715         }
 716
 717         return env->reload_cost;
 718 }
 719
 720 double be_get_reload_costs(spill_env_t *env, ir_node *to_spill, ir_node *before)
 721 {
 722         ir_node      *block = get_nodes_block(before);
 723         double        freq  = get_block_execfreq(env->exec_freq, block);
 724
 725         if(be_do_remats) {
 726                 /* is the node rematerializable? */
 727                 int costs = check_remat_conditions_costs(env, to_spill, before, 0);
 728                 if(costs < env->reload_cost)
 729                         return costs * freq;
 730         }
 731
 732         return env->reload_cost * freq;
 733 }
 734
 735 int be_is_rematerializable(spill_env_t *env, const ir_node *to_remat,
 736                            const ir_node *before)
 737 {
 738         return check_remat_conditions_costs(env, to_remat, before, 0) < REMAT_COST_INFINITE;
 739 }
 740
 741 double be_get_reload_costs_on_edge(spill_env_t *env, ir_node *to_spill,
 742                                    ir_node *block, int pos)
 743 {
 744         ir_node *before = get_block_insertion_point(block, pos);
 745         return be_get_reload_costs(env, to_spill, before);
 746 }
 747
 748 /*
 749  *  ___                     _     ____      _                 _
 750  * |_ _|_ __  ___  ___ _ __| |_  |  _ \ ___| | ___   __ _  __| |___
 751  *  | || '_ \/ __|/ _ \ '__| __| | |_) / _ \ |/ _ \ / _` |/ _` / __|
 752  *  | || | | \__ \  __/ |  | |_  |  _ <  __/ | (_) | (_| | (_| \__ \
 753  * |___|_| |_|___/\___|_|   \__| |_| \_\___|_|\___/ \__,_|\__,_|___/
 754  *
 755  */
 756
 757 /**
 758  * analyzes how to best spill a node and determine costs for that
 759  */
 760 static void determine_spill_costs(spill_env_t *env, spill_info_t *spillinfo)
 761 {
 762         ir_node       *to_spill = spillinfo->to_spill;
 763         const ir_node *insn     = skip_Proj_const(to_spill);
 764         ir_node       *spill_block;
 765         spill_t       *spill;
 766         double         spill_execfreq;
 767
 768         /* already calculated? */
 769         if(spillinfo->spill_costs >= 0)
 770                 return;
 771
 772         assert(!arch_irn_is(insn, dont_spill));
 773         assert(!be_is_Reload(insn));
 774
 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...
 779          */
 780         if(!sched_is_scheduled(insn)) {
 781                 /* override spillinfos or create a new one */
 782                 spill_t *spill = OALLOC(&env->obst, spill_t);
 783                 spill->after = NULL;
 784                 spill->next  = NULL;
 785                 spill->spill = new_NoMem();
 786
 787                 spillinfo->spills      = spill;
 788                 spillinfo->spill_costs = 0;
 789
 790                 DB((dbg, LEVEL_1, "don't spill %+F use NoMem\n", to_spill));
 791                 return;
 792         }
 793
 794         spill_block    = get_nodes_block(insn);
 795         spill_execfreq = get_block_execfreq(env->exec_freq, spill_block);
 796
 797         if (is_Phi(to_spill) && ir_nodeset_contains(&env->mem_phis, to_spill)) {
 798                 /* TODO calculate correct costs...
 799                  * (though we can't remat this node anyway so no big problem) */
 800                 spillinfo->spill_costs = env->spill_cost * spill_execfreq;
 801                 return;
 802         }
 803
 804         if(spillinfo->spills != NULL) {
 805                 spill_t *s;
 806                 double   spills_execfreq;
 807
 808                 /* calculate sum of execution frequencies of individual spills */
 809                 spills_execfreq = 0;
 810                 s               = spillinfo->spills;
 811                 for( ; s != NULL; s = s->next) {
 812                         ir_node *spill_block = get_block(s->after);
 813                         double   freq = get_block_execfreq(env->exec_freq, spill_block);
 814
 815                         spills_execfreq += freq;
 816                 }
 817
 818                 DB((dbg, LEVEL_1, "%+F: latespillcosts %f after def: %f\n", to_spill,
 819                     spills_execfreq * env->spill_cost,
 820                     spill_execfreq * env->spill_cost));
 821
 822                 /* multi-/latespill is advantageous -> return*/
 823                 if(spills_execfreq < spill_execfreq) {
 824                         DB((dbg, LEVEL_1, "use latespills for %+F\n", to_spill));
 825                         spillinfo->spill_costs = spills_execfreq * env->spill_cost;
 826                         return;
 827                 }
 828         }
 829
 830         /* override spillinfos or create a new one */
 831         spill        = OALLOC(&env->obst, spill_t);
 832         spill->after = skip_keeps_phis(to_spill);
 833         spill->next  = NULL;
 834         spill->spill = NULL;
 835
 836         spillinfo->spills      = spill;
 837         spillinfo->spill_costs = spill_execfreq * env->spill_cost;
 838         DB((dbg, LEVEL_1, "spill %+F after definition\n", to_spill));
 839 }
 840
 841 void make_spill_locations_dominate_irn(spill_env_t *env, ir_node *irn)
 842 {
 843         const spill_info_t *si = get_spillinfo(env, irn);
 844         ir_node *start_block   = get_irg_start_block(get_irn_irg(irn));
 845         int n_blocks           = get_Block_dom_max_subtree_pre_num(start_block);
 846         bitset_t *reloads      = bitset_alloca(n_blocks);
 847         reloader_t *r;
 848         spill_t *s;
 849
 850         if (si == NULL)
 851                 return;
 852
 853         /* Fill the bitset with the dominance pre-order numbers
 854          * of the blocks the reloads are located in. */
 855         for (r = si->reloaders; r != NULL; r = r->next) {
 856                 ir_node *bl = get_nodes_block(r->reloader);
 857                 bitset_set(reloads, get_Block_dom_tree_pre_num(bl));
 858         }
 859
 860         /* Now, cancel out all the blocks that are dominated by each spill.
 861          * If the bitset is not empty after that, we have reloads that are
 862          * not dominated by any spill. */
 863         for (s = si->spills; s != NULL; s = s->next) {
 864                 ir_node *bl = get_nodes_block(s->after);
 865                 int start   = get_Block_dom_tree_pre_num(bl);
 866                 int end     = get_Block_dom_max_subtree_pre_num(bl);
 867
 868                 bitset_clear_range(reloads, start, end);
 869         }
 870
 871         if (!bitset_is_empty(reloads))
 872                 be_add_spill(env, si->to_spill, si->to_spill);
 873 }
 874
 875 void be_insert_spills_reloads(spill_env_t *env)
 876 {
 877         const ir_exec_freq    *exec_freq = env->exec_freq;
 878         spill_info_t          *si;
 879         ir_nodeset_iterator_t  iter;
 880         ir_node               *node;
 881
 882         BE_TIMER_PUSH(t_ra_spill_apply);
 883
 884         /* create all phi-ms first, this is needed so, that phis, hanging on
 885            spilled phis work correctly */
 886         foreach_ir_nodeset(&env->mem_phis, node, iter) {
 887                 spill_info_t *info = get_spillinfo(env, node);
 888                 spill_node(env, info);
 889         }
 890
 891         /* process each spilled node */
 892         for (si = set_first(env->spills); si; si = set_next(env->spills)) {
 893                 reloader_t *rld;
 894                 ir_node  *to_spill        = si->to_spill;
 895                 ir_mode  *mode            = get_irn_mode(to_spill);
 896                 ir_node **copies          = NEW_ARR_F(ir_node*, 0);
 897                 double    all_remat_costs = 0; /** costs when we would remat all nodes */
 898                 int       force_remat     = 0;
 899
 900                 DBG((dbg, LEVEL_1, "\nhandling all reloaders of %+F:\n", to_spill));
 901
 902                 determine_spill_costs(env, si);
 903
 904                 /* determine possibility of rematerialisations */
 905                 if(be_do_remats) {
 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) {
 909                                 double   freq;
 910                                 int      remat_cost;
 911                                 int      remat_cost_delta;
 912                                 ir_node *block;
 913                                 ir_node *reloader = rld->reloader;
 914
 915                                 if(rld->rematted_node != NULL) {
 916                                         DBG((dbg, LEVEL_2, "\tforced remat %+F before %+F\n",
 917                                              rld->rematted_node, reloader));
 918                                         continue;
 919                                 }
 920                                 if(rld->remat_cost_delta >= REMAT_COST_INFINITE) {
 921                                         DBG((dbg, LEVEL_2, "\treload before %+F is forbidden\n",
 922                                              reloader));
 923                                         all_remat_costs = REMAT_COST_INFINITE;
 924                                         continue;
 925                                 }
 926
 927                                 remat_cost  = check_remat_conditions_costs(env, to_spill,
 928                                                                            reloader, 0);
 929                                 if(remat_cost >= REMAT_COST_INFINITE) {
 930                                         DBG((dbg, LEVEL_2, "\tremat before %+F not possible\n",
 931                                              reloader));
 932                                         rld->remat_cost_delta = REMAT_COST_INFINITE;
 933                                         all_remat_costs       = REMAT_COST_INFINITE;
 934                                         continue;
 935                                 }
 936
 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));
 945                         }
 946                         if(all_remat_costs < REMAT_COST_INFINITE) {
 947                                 /* we don't need the costs for the spill if we can remat
 948                                    all reloaders */
 949                                 all_remat_costs -= si->spill_costs;
 950
 951                                 DBG((dbg, LEVEL_2, "\tspill costs %d (rel %f)\n",
 952                                      env->spill_cost, si->spill_costs));
 953                         }
 954
 955                         if(all_remat_costs < 0) {
 956                                 DBG((dbg, LEVEL_1, "\nforcing remats of all reloaders (%f)\n",
 957                                      all_remat_costs));
 958                                 force_remat = 1;
 959                         }
 960                 }
 961
 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 */
 965
 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);
 972                         } else {
 973                                 /* make sure we have a spill */
 974                                 spill_node(env, si);
 975
 976                                 /* create a reload, use the first spill for now SSA
 977                                  * reconstruction for memory comes below */
 978                                 assert(si->spills != NULL);
 979                                 copy = be_reload(si->reload_cls, rld->reloader, mode,
 980                                                  si->spills->spill);
 981 #ifdef FIRM_STATISTICS
 982                                 env->reload_count++;
 983 #endif
 984                         }
 985
 986                         DBG((dbg, LEVEL_1, " %+F of %+F before %+F\n",
 987                              copy, to_spill, rld->reloader));
 988                         ARR_APP1(ir_node*, copies, copy);
 989                 }
 990
 991                 /* if we had any reloads or remats, then we need to reconstruct the
 992                  * SSA form for the spilled value */
 993                 if (ARR_LEN(copies) > 0) {
 994                         be_ssa_construction_env_t senv;
 995                         /* be_lv_t *lv = be_get_birg_liveness(env->birg); */
 996
 997                         be_ssa_construction_init(&senv, env->birg);
 998                         be_ssa_construction_add_copy(&senv, to_spill);
 999                         be_ssa_construction_add_copies(&senv, copies, ARR_LEN(copies));
1000                         be_ssa_construction_fix_users(&senv, to_spill);
1001
1002 #if 0
1003                         /* no need to enable this as long as we invalidate liveness
1004                            after this function... */
1005                         be_ssa_construction_update_liveness_phis(&senv);
1006                         be_liveness_update(to_spill);
1007                         len = ARR_LEN(copies);
1008                         for(i = 0; i < len; ++i) {
1009                                 be_liveness_update(lv, copies[i]);
1010                         }
1011 #endif
1012                         be_ssa_construction_destroy(&senv);
1013                 }
1014                 /* need to reconstruct SSA form if we had multiple spills */
1015                 if (si->spills != NULL && si->spills->next != NULL) {
1016                         spill_t *spill;
1017                         int      spill_count = 0;
1018
1019                         be_ssa_construction_env_t senv;
1020
1021                         be_ssa_construction_init(&senv, env->birg);
1022                         spill = si->spills;
1023                         for( ; spill != NULL; spill = spill->next) {
1024                                 /* maybe we rematerialized the value and need no spill */
1025                                 if(spill->spill == NULL)
1026                                         continue;
1027                                 be_ssa_construction_add_copy(&senv, spill->spill);
1028                                 spill_count++;
1029                         }
1030                         if(spill_count > 1) {
1031                                 /* all reloads are attached to the first spill, fix them now */
1032                                 be_ssa_construction_fix_users(&senv, si->spills->spill);
1033                         }
1034
1035                         be_ssa_construction_destroy(&senv);
1036                 }
1037
1038                 DEL_ARR_F(copies);
1039                 si->reloaders = NULL;
1040         }
1041
1042         stat_ev_dbl("spill_spills", env->spill_count);
1043         stat_ev_dbl("spill_reloads", env->reload_count);
1044         stat_ev_dbl("spill_remats", env->remat_count);
1045         stat_ev_dbl("spill_spilled_phis", env->spilled_phi_count);
1046
1047         /* Matze: In theory be_ssa_construction should take care of the liveness...
1048          * try to disable this again in the future */
1049         be_liveness_invalidate(env->birg->lv);
1050
1051         be_remove_dead_nodes_from_schedule(env->birg);
1052
1053         BE_TIMER_POP(t_ra_spill_apply);
1054 }
1055
1056 void be_init_spill(void)
1057 {
1058         FIRM_DBG_REGISTER(dbg, "firm.be.spill");
1059 }
1060
1061 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_spill);