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

   1 /*
   2  * Author:      Matthias Braun
   3  * Date:                26.7.06
   4  * Copyright:   (c) Universitaet Karlsruhe
   5  * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
   6  */
   7 #ifdef HAVE_CONFIG_H
   8 #include <config.h>
   9 #endif
  10
  11 #include <stdlib.h>
  12
  13 #include "set.h"
  14
  15 #include "irgwalk.h"
  16 #include "ircons.h"
  17 #include "irprintf.h"
  18 #include "execfreq.h"
  19 #include "unionfind.h"
  20 #include "type.h"
  21 #include "irdump_t.h"
  22
  23 #include "benode_t.h"
  24 #include "besched.h"
  25 #include "bespillslots.h"
  26 #include "bechordal_t.h"
  27 #include "bejavacoal.h"
  28 #include "benodesets.h"
  29 #include "bestatevent.h"
  30 #include "bespilloptions.h"
  31
  32 #define DBG_COALESCING          1
  33 #define DBG_INTERFERENCES       2
  34
  35 DEBUG_ONLY(
  36 static firm_dbg_module_t *dbg = NULL;
  37 )
  38
  39 typedef struct _spill_t {
  40         ir_node *spill;
  41         /** mode of the spilled value */
  42         const ir_mode *mode;
  43         /** alignment for the spilled value */
  44         int alignment;
  45         /** index into spillslot_unionfind unionfind structure */
  46         int spillslot;
  47 } spill_t;
  48
  49 typedef struct _affinity_edge_t {
  50         double affinity;
  51         int slot1, slot2;
  52 } affinity_edge_t;
  53
  54 struct _be_fec_env_t {
  55         struct obstack obst;
  56         const arch_env_t *arch_env;
  57         be_irg_t *birg;
  58         set *spills;
  59         ir_node **reloads;
  60         affinity_edge_t **affinity_edges;
  61         set *memperms;
  62 };
  63
  64 /** Compare 2 affinity edges (used in quicksort) */
  65 static int cmp_affinity(const void *d1, const void *d2)
  66 {
  67         const affinity_edge_t * const *e1 = d1;
  68         const affinity_edge_t * const *e2 = d2;
  69
  70         // sort in descending order
  71         return (*e1)->affinity < (*e2)->affinity ? 1 : -1;
  72 }
  73
  74 static int cmp_spill(const void* d1, const void* d2, size_t size)
  75 {
  76         const spill_t* s1 = d1;
  77         const spill_t* s2 = d2;
  78         return s1->spill != s2->spill;
  79 }
  80
  81 static spill_t *get_spill(be_fec_env_t *env, ir_node *node)
  82 {
  83         spill_t spill, *res;
  84         int hash = nodeset_hash(node);
  85
  86         spill.spill = node;
  87         res = set_find(env->spills, &spill, sizeof(spill), hash);
  88
  89         return res;
  90 }
  91
  92 /*
  93  *   ____      _ _           _     ____        _ _ _
  94  *  / ___|___ | | | ___  ___| |_  / ___| _ __ (_) | |___
  95  * | |   / _ \| | |/ _ \/ __| __| \___ \| '_ \| | | / __|
  96  * | |__| (_) | | |  __/ (__| |_   ___) | |_) | | | \__ \
  97  *  \____\___/|_|_|\___|\___|\__| |____/| .__/|_|_|_|___/
  98  *                                      |_|
  99  */
 100
 101 static INLINE ir_node *get_memory_edge(const ir_node *node)
 102 {
 103         int i, arity;
 104
 105         arity = get_irn_arity(node);
 106         for(i = arity - 1; i >= 0; --i) {
 107                 ir_node *arg = get_irn_n(node, i);
 108                 if(get_irn_mode(arg) == mode_M)
 109                         return arg;
 110         }
 111
 112         return NULL;
 113 }
 114
 115 static spill_t *collect_spill(be_fec_env_t *env, ir_node *node,
 116                                       const ir_mode *mode, int align)
 117 {
 118         spill_t spill, *res;
 119         int hash = nodeset_hash(node);
 120
 121         /* insert into set of spills if not already there */
 122         spill.spill = node;
 123         res = set_find(env->spills, &spill, sizeof(spill), hash);
 124
 125         if(res == NULL) {
 126                 spill.spillslot = set_count(env->spills);
 127                 spill.mode = mode;
 128                 spill.alignment = align;
 129                 res = set_insert(env->spills, &spill, sizeof(spill), hash);
 130         } else {
 131                 assert(res->mode == mode);
 132                 assert(res->alignment == align);
 133         }
 134
 135         return res;
 136 }
 137
 138 static spill_t *collect_memphi(be_fec_env_t *env, ir_node *node,
 139                                const ir_mode *mode, int align)
 140 {
 141         int i, arity;
 142         spill_t spill, *res;
 143         int hash = nodeset_hash(node);
 144         const ir_exec_freq *exec_freq = be_get_birg_exec_freq(env->birg);
 145
 146         assert(is_Phi(node));
 147
 148         spill.spill = node;
 149         res = set_find(env->spills, &spill, sizeof(spill), hash);
 150         if(res != NULL) {
 151                 assert(res->mode == mode);
 152                 assert(res->alignment == align);
 153                 return res;
 154         }
 155
 156         spill.spillslot = set_count(env->spills);
 157         spill.mode = mode;
 158         spill.alignment = align;
 159         res = set_insert(env->spills, &spill, sizeof(spill), hash);
 160
 161         // collect attached spills and mem-phis
 162         arity = get_irn_arity(node);
 163         for(i = 0; i < arity; ++i) {
 164                 affinity_edge_t *affinty_edge;
 165                 ir_node *arg = get_irn_n(node, i);
 166                 spill_t *arg_spill;
 167
 168                 if(is_Phi(arg)) {
 169                         arg_spill = collect_memphi(env, arg, mode, align);
 170                 } else {
 171                         arg_spill = collect_spill(env, arg, mode, align);
 172                 }
 173
 174                 // add an affinity edge
 175                 affinty_edge = obstack_alloc(&env->obst, sizeof(affinty_edge[0]));
 176                 affinty_edge->affinity = get_block_execfreq(exec_freq, get_nodes_block(arg));
 177                 affinty_edge->slot1 = res->spillslot;
 178                 affinty_edge->slot2 = arg_spill->spillslot;
 179                 ARR_APP1(affinity_edge_t*, env->affinity_edges, affinty_edge);
 180         }
 181
 182         return res;
 183 }
 184
 185 void be_node_needs_frame_entity(be_fec_env_t *env, ir_node *node,
 186                                 const ir_mode *mode, int align)
 187 {
 188         ir_node *spillnode = get_memory_edge(node);
 189         spill_t *spill;
 190
 191         assert(spillnode != NULL);
 192
 193         if (is_Phi(spillnode)) {
 194                 spill = collect_memphi(env, spillnode, mode, align);
 195         } else {
 196                 spill = collect_spill(env, spillnode, mode, align);
 197         }
 198
 199         ARR_APP1(ir_node *, env->reloads, node);
 200 }
 201
 202 /*
 203  *   ____            _                      ____  _       _
 204  *  / ___|___   __ _| | ___  ___  ___ ___  / ___|| | ___ | |_ ___
 205  * | |   / _ \ / _` | |/ _ \/ __|/ __/ _ \ \___ \| |/ _ \| __/ __|
 206  * | |__| (_) | (_| | |  __/\__ \ (_|  __/  ___) | | (_) | |_\__ \
 207  *  \____\___/ \__,_|_|\___||___/\___\___| |____/|_|\___/ \__|___/
 208  */
 209
 210 static int merge_interferences(be_fec_env_t *env, bitset_t** interferences,
 211                                int* spillslot_unionfind, int s1, int s2)
 212 {
 213         int res;
 214         int i;
 215         int spillcount;
 216
 217         // merge spillslots and interferences
 218         res = uf_union(spillslot_unionfind, s1, s2);
 219         // we assume that we always merge s2 to s1 so swap s1, s2 if necessary
 220         if(res != 0) {
 221                 int t = s1;
 222                 s1 = s2;
 223                 s2 = t;
 224         }
 225
 226         bitset_or(interferences[s1], interferences[s2]);
 227
 228         // update other interferences
 229         spillcount = set_count(env->spills);
 230         for(i = 0; i < spillcount; ++i) {
 231                 bitset_t *intfs = interferences[i];
 232                 if(bitset_is_set(intfs, s2))
 233                         bitset_set(intfs, s1);
 234         }
 235
 236         return res;
 237 }
 238
 239 /**
 240  * A greedy coalescing algorithm for spillslots:
 241  *  1. Sort the list of affinity edges
 242  *  2. Try to merge slots with affinity edges (most expensive slots first)
 243  *  3. Try to merge everything else that is possible
 244  */
 245 static void do_greedy_coalescing(be_fec_env_t *env)
 246 {
 247         int spillcount;
 248         spill_t **spilllist;
 249         spill_t *spill;
 250         int i, i2;
 251         int affinity_edge_count;
 252         bitset_t **interferences;
 253         int* spillslot_unionfind;
 254         const be_lv_t *lv = be_get_birg_liveness(env->birg);
 255
 256         spillcount = set_count(env->spills);
 257         if(spillcount == 0)
 258                 return;
 259
 260         DBG((dbg, DBG_COALESCING, "Coalescing %d spillslots\n", spillcount));
 261
 262         interferences = alloca(spillcount * sizeof(interferences[0]));
 263         spillslot_unionfind = alloca(spillcount * sizeof(spillslot_unionfind[0]));
 264         spilllist = alloca(spillcount * sizeof(spilllist[0]));
 265
 266         uf_init(spillslot_unionfind, 0, spillcount);
 267
 268         DEBUG_ONLY(
 269                 memset(spilllist, 0, spillcount * sizeof(spilllist[0]));
 270         );
 271
 272         for(spill = set_first(env->spills), i = 0; spill != NULL; spill = set_next(env->spills), ++i) {
 273                 assert(spill->spillslot < spillcount);
 274                 spilllist[spill->spillslot] = spill;
 275         }
 276
 277         for(i = 0; i < spillcount; ++i) {
 278                 interferences[i] = bitset_alloca(spillcount);
 279         }
 280
 281         // construct interferences
 282         for(i = 0; i < spillcount; ++i) {
 283                 for(i2 = i+1; i2 < spillcount; ++i2) {
 284                         if(values_interfere(lv, spilllist[i]->spill, spilllist[i2]->spill)) {
 285                                 DBG((dbg, DBG_INTERFERENCES, "Slot %d and %d interfere\n", i, i2));
 286                                 bitset_set(interferences[i], i2);
 287                                 bitset_set(interferences[i2], i);
 288                         }
 289                 }
 290         }
 291
 292         // sort affinity edges
 293         affinity_edge_count = ARR_LEN(env->affinity_edges);
 294         qsort(env->affinity_edges, affinity_edge_count, sizeof(env->affinity_edges[0]), cmp_affinity);
 295
 296         //dump_interference_graph(env, interferences, "before");
 297
 298         // try to merge affine nodes
 299         for(i = 0; i < affinity_edge_count; ++i) {
 300                 const affinity_edge_t *edge = env->affinity_edges[i];
 301                 int s1 = uf_find(spillslot_unionfind, edge->slot1);
 302                 int s2 = uf_find(spillslot_unionfind, edge->slot2);
 303
 304                 /* test if values interfere */
 305                 if(bitset_is_set(interferences[s1], s2)) {
 306                         assert(bitset_is_set(interferences[s2], s1));
 307                         continue;
 308                 }
 309
 310                 DBG((dbg, DBG_COALESCING, "Merging %d and %d because of affinity edge\n", s1, s2));
 311
 312                 merge_interferences(env, interferences, spillslot_unionfind, s1, s2);
 313         }
 314
 315         // try to merge as much remaining spillslots as possible
 316         for(i = 0; i < spillcount; ++i) {
 317                 int s1 = uf_find(spillslot_unionfind, i);
 318                 if(s1 != i)
 319                         continue;
 320
 321                 for(i2 = i+1; i2 < spillcount; ++i2) {
 322                         int s2 = uf_find(spillslot_unionfind, i2);
 323                         if(s2 != i2)
 324                                 continue;
 325
 326                         /* test if values interfere
 327                          * we have to test n1-n2 and n2-n1, because only 1 side gets updated
 328                          * when node merging occurs
 329                          */
 330                         if(bitset_is_set(interferences[s1], s2)) {
 331                                 assert(bitset_is_set(interferences[s2], s1));
 332                                 continue;
 333                         }
 334
 335                         DBG((dbg, DBG_COALESCING, "Merging %d and %d because it is possible\n", s1, s2));
 336
 337                         if(merge_interferences(env, interferences, spillslot_unionfind, s1, s2) != 0) {
 338                                 // we can break the loop here, because s2 is the new supernode now
 339                                 // and we'll test s2 again later anyway
 340                                 break;
 341                         }
 342                 }
 343         }
 344
 345         // assign spillslots to spills
 346         for(i = 0; i < spillcount; ++i) {
 347                 spill_t *spill = spilllist[i];
 348
 349                 spill->spillslot = uf_find(spillslot_unionfind, i);
 350         }
 351
 352         //dump_interference_graph(env, interferences, "after");
 353 }
 354
 355 /*
 356  *     _            _               _____       _   _ _   _
 357  *    / \   ___ ___(_) __ _ _ __   | ____|_ __ | |_(_) |_(_) ___  ___
 358  *   / _ \ / __/ __| |/ _` | '_ \  |  _| | '_ \| __| | __| |/ _ \/ __|
 359  *  / ___ \\__ \__ \ | (_| | | | | | |___| | | | |_| | |_| |  __/\__ \
 360  * /_/   \_\___/___/_|\__, |_| |_| |_____|_| |_|\__|_|\__|_|\___||___/
 361  *                    |___/
 362  */
 363
 364 typedef struct _spill_slot_t {
 365         int size;
 366         int align;
 367         ir_entity *entity;
 368 } spill_slot_t;
 369
 370 typedef struct _memperm_entry_t {
 371         ir_node* node;
 372         int pos;
 373         ir_entity *in;
 374         ir_entity *out;
 375         struct _memperm_entry_t *next;
 376 } memperm_entry_t;
 377
 378 typedef struct _memperm_t {
 379         ir_node *block;
 380         int entrycount;
 381         memperm_entry_t *entries;
 382 } memperm_t;
 383
 384 static int cmp_memperm(const void* d1, const void* d2, size_t size)
 385 {
 386         const memperm_t* e1 = d1;
 387         const memperm_t* e2 = d2;
 388         return e1->block != e2->block;
 389 }
 390
 391 static memperm_t *get_memperm(be_fec_env_t *env, ir_node *block)
 392 {
 393         memperm_t entry, *res;
 394         int hash;
 395
 396         entry.block = block;
 397         hash = nodeset_hash(block);
 398
 399         res = set_find(env->memperms, &entry, sizeof(entry), hash);
 400
 401         if(res == NULL) {
 402                 entry.entrycount = 0;
 403                 entry.entries = NULL;
 404                 res = set_insert(env->memperms, &entry, sizeof(entry), hash);
 405         }
 406
 407         return res;
 408 }
 409
 410 static ir_entity* create_stack_entity(be_fec_env_t *env, spill_slot_t *slot)
 411 {
 412         ir_graph *irg = be_get_birg_irg(env->birg);
 413         ir_type *frame = get_irg_frame_type(irg);
 414         ir_entity *res = frame_alloc_area(frame, slot->size, slot->align, 0);
 415
 416         // adjust size of the entity type...
 417         ir_type *enttype = get_entity_type(res);
 418         set_type_size_bytes(enttype, slot->size);
 419
 420         slot->entity = res;
 421
 422         return res;
 423 }
 424
 425 /**
 426  * Enlarges a spillslot (if necessary) so that it can carry a value of size
 427  * @p othersize and alignment @p otheralign.
 428  */
 429 static void enlarge_spillslot(spill_slot_t *slot, int otheralign, int othersize)
 430 {
 431         if(othersize > slot->size) {
 432                 slot->size = othersize;
 433         }
 434         if(otheralign > slot->align) {
 435                 if(otheralign % slot->align != 0)
 436                         slot->align *= otheralign;
 437                 else
 438                         slot->align = otheralign;
 439         } else if(slot->align % otheralign != 0) {
 440                 slot->align *= otheralign;
 441         }
 442 }
 443
 444 /**
 445  * Create stack entities for the spillslots and assign them to the spill and
 446  * reload nodes.
 447  */
 448 static void assign_spillslots(be_fec_env_t *env)
 449 {
 450         const arch_env_t *arch_env = env->arch_env;
 451         int i;
 452         int spillcount;
 453         spill_t *spill;
 454         spill_slot_t* spillslots;
 455
 456         spillcount = set_count(env->spills);
 457         spillslots = alloca(spillcount * sizeof(spillslots[0]));
 458
 459         memset(spillslots, 0, spillcount * sizeof(spillslots[0]));
 460
 461         // construct spillslots
 462         for(spill = set_first(env->spills); spill != NULL; spill = set_next(env->spills)) {
 463                 int slotid = spill->spillslot;
 464                 const ir_mode *mode = spill->mode;
 465                 spill_slot_t *slot = & (spillslots[slotid]);
 466                 int size = get_mode_size_bytes(mode);
 467                 int align = spill->alignment;
 468
 469                 if(slot->align == 0 && slot->size == 0) {
 470                         slot->align = align;
 471                         slot->size = size;
 472                 } else {
 473                         enlarge_spillslot(slot, align, size);
 474                 }
 475         }
 476
 477         for(spill = set_first(env->spills); spill != NULL; spill = set_next(env->spills)) {
 478                 spill_slot_t *slot;
 479                 ir_node *node = spill->spill;
 480                 int slotid = spill->spillslot;
 481
 482                 slot = &spillslots[slotid];
 483                 if(slot->entity == NULL) {
 484                         create_stack_entity(env, slot);
 485                 }
 486
 487                 if(is_Phi(node)) {
 488                         int i, arity;
 489                         ir_node *block = get_nodes_block(node);
 490
 491                         // should be a PhiM
 492                         assert(is_Phi(node));
 493
 494                         for(i = 0, arity = get_irn_arity(node); i < arity; ++i) {
 495                                 ir_node *arg = get_irn_n(node, i);
 496                                 ir_node *predblock = get_Block_cfgpred_block(block, i);
 497                                 spill_t *argspill;
 498                                 int argslotid;
 499
 500                                 argspill = get_spill(env, arg);
 501                                 assert(argspill != NULL);
 502
 503                                 argslotid = argspill->spillslot;
 504                                 if(slotid != argslotid) {
 505                                         memperm_t *memperm;
 506                                         memperm_entry_t *entry;
 507                                         spill_slot_t *argslot = &spillslots[argslotid];
 508                                         if(argslot->entity == NULL) {
 509                                                 create_stack_entity(env, argslot);
 510                                         }
 511
 512                                         memperm = get_memperm(env, predblock);
 513
 514                                         entry = obstack_alloc(&env->obst, sizeof(entry[0]));
 515                                         entry->node = node;
 516                                         entry->pos = i;
 517                                         entry->in = argslot->entity;
 518                                         entry->out = slot->entity;
 519                                         entry->next = memperm->entries;
 520                                         memperm->entrycount++;
 521                                         memperm->entries = entry;
 522                                 }
 523                         }
 524                 } else {
 525                         arch_set_frame_entity(arch_env, node, slot->entity);
 526                 }
 527         }
 528
 529         for(i = 0; i < ARR_LEN(env->reloads); ++i) {
 530                 ir_node* reload = env->reloads[i];
 531                 ir_node* spillnode = get_memory_edge(reload);
 532                 spill_t *spill = get_spill(env, spillnode);
 533                 const spill_slot_t *slot = & spillslots[spill->spillslot];
 534
 535                 assert(slot->entity != NULL);
 536
 537                 arch_set_frame_entity(arch_env, reload, slot->entity);
 538         }
 539 }
 540
 541 /**
 542  * Returns the last node in a block which is no control flow changing node
 543  */
 544 static ir_node *get_end_of_block_insertion_point(ir_node* block)
 545 {
 546         ir_node* ins = sched_last(block);
 547         while(is_Proj(ins) && get_irn_mode(ins) == mode_X) {
 548                 ins = sched_prev(ins);
 549                 assert(ins != NULL);
 550         }
 551
 552         if(is_cfop(ins)) {
 553                 while(1) {
 554                         ir_node *prev = sched_prev(ins);
 555                         if(!is_cfop(prev))
 556                                 break;
 557                         ins = prev;
 558                 }
 559         }
 560
 561         return ins;
 562 }
 563
 564 static void create_memperms(be_fec_env_t *env)
 565 {
 566         const arch_env_t *arch_env = env->arch_env;
 567         ir_graph *irg = be_get_birg_irg(env->birg);
 568         memperm_t *memperm;
 569
 570         for(memperm = set_first(env->memperms); memperm != NULL; memperm = set_next(env->memperms)) {
 571                 int i;
 572                 memperm_entry_t *entry;
 573                 ir_node *blockend;
 574                 ir_node** nodes = alloca(memperm->entrycount * sizeof(nodes[0]));
 575                 ir_node* mempermnode;
 576
 577                 assert(memperm->entrycount > 0);
 578
 579                 for(entry = memperm->entries, i = 0; entry != NULL; entry = entry->next, ++i) {
 580                         ir_node* arg = get_irn_n(entry->node, entry->pos);
 581                         nodes[i] = arg;
 582                 }
 583
 584                 mempermnode = be_new_MemPerm(arch_env, irg, memperm->block,
 585                                              memperm->entrycount, nodes);
 586
 587                 // insert node into schedule
 588                 blockend = get_end_of_block_insertion_point(memperm->block);
 589                 sched_add_before(blockend, mempermnode);
 590                 be_stat_ev("mem_perm", memperm->entrycount);
 591
 592                 i = 0;
 593                 for(entry = memperm->entries; entry != NULL; entry = entry->next, ++i) {
 594                         ir_node *proj;
 595                         ir_node* arg = get_irn_n(entry->node, entry->pos);
 596
 597                         be_set_MemPerm_in_entity(mempermnode, i, entry->in);
 598                         be_set_MemPerm_out_entity(mempermnode, i, entry->out);
 599                         set_irg_current_block(irg, memperm->block);
 600                         proj = new_Proj(mempermnode, get_irn_mode(arg), i);
 601                         sched_add_before(blockend, proj);
 602
 603                         set_irn_n(entry->node, entry->pos, proj);
 604                 }
 605         }
 606 }
 607
 608 static int count_spillslots(const be_fec_env_t *env)
 609 {
 610         const spill_t *spill;
 611         int spillcount = set_count(env->spills);
 612         bitset_t *counted = bitset_alloca(spillcount);
 613         int slotcount;
 614
 615         slotcount = 0;
 616         for(spill = set_first(env->spills); spill != NULL;
 617             spill = set_next(env->spills)) {
 618                 int spillslot = spill->spillslot;
 619                 if(!bitset_is_set(counted, spillslot)) {
 620                         slotcount++;
 621                         bitset_set(counted, spillslot);
 622                 }
 623         }
 624
 625         return slotcount;
 626 }
 627
 628 be_fec_env_t *be_new_frame_entity_coalescer(be_irg_t *birg)
 629 {
 630         const arch_env_t *arch_env = birg->main_env->arch_env;
 631
 632         be_fec_env_t *env = xmalloc(sizeof(env[0]));
 633
 634         be_assure_liveness(birg);
 635
 636         obstack_init(&env->obst);
 637         env->arch_env = arch_env;
 638         env->birg = birg;
 639         env->spills = new_set(cmp_spill, 10);
 640         env->reloads = NEW_ARR_F(ir_node*, 0);
 641         env->affinity_edges = NEW_ARR_F(affinity_edge_t*, 0);
 642         env->memperms = new_set(cmp_memperm, 10);
 643         FIRM_DBG_REGISTER(dbg, "firm.be.spillslots");
 644
 645         return env;
 646 }
 647
 648 void be_free_frame_entity_coalescer(be_fec_env_t *env)
 649 {
 650         del_set(env->memperms);
 651         DEL_ARR_F(env->reloads);
 652         DEL_ARR_F(env->affinity_edges);
 653         del_set(env->spills);
 654         obstack_free(&env->obst, NULL);
 655
 656         free(env);
 657 }
 658
 659 void be_assign_entities(be_fec_env_t *env)
 660 {
 661         if(be_stat_ev_is_active()) {
 662                 int count = set_count(env->spills);
 663                 be_stat_ev("spillslots", count);
 664         }
 665
 666         if(be_coalesce_spill_slots) {
 667                 do_greedy_coalescing(env);
 668         }
 669
 670         if(be_stat_ev_is_active()) {
 671                 int count = count_spillslots(env);
 672                 be_stat_ev("spillslots_after_coalescing", count);
 673         }
 674
 675         assign_spillslots(env);
 676
 677         create_memperms(env);
 678 }
 679
 680 /**
 681  * This walker function searches for reloads and collects all the spills
 682  * and memphis attached to them.
 683  */
 684 static void collect_spills_walker(ir_node *node, void *data)
 685 {
 686         be_fec_env_t *env = data;
 687         const arch_env_t *arch_env = env->arch_env;
 688         const ir_mode *mode;
 689         const arch_register_class_t *cls;
 690         int align;
 691
 692         /* classify returns classification of the irn the proj is attached to */
 693         if (is_Proj(node))
 694                 return;
 695
 696         if (!arch_irn_class_is(arch_env, node, reload))
 697                 return;
 698
 699         mode = get_irn_mode(node);
 700         cls = arch_get_irn_reg_class(arch_env, node, -1);
 701         align = arch_isa_get_reg_class_alignment(arch_env_get_isa(arch_env), cls);
 702
 703         be_node_needs_frame_entity(env, node, mode, align);
 704 }
 705
 706 void be_coalesce_spillslots(be_irg_t *birg)
 707 {
 708         be_fec_env_t *env = be_new_frame_entity_coalescer(birg);
 709
 710         /* collect reloads */
 711         irg_walk_graph(birg->irg, NULL, collect_spills_walker, env);
 712
 713         be_assign_entities(env);
 714
 715         be_free_frame_entity_coalescer(env);
 716 }