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

   1 /*
   2  * Copyright (C) 1995-2011 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       Preference Guided Register Assignment
  23  * @author      Matthias Braun
  24  * @date        14.2.2009
  25  *
  26  * The idea is to allocate registers in 2 passes:
  27  * 1. A first pass to determine "preferred" registers for live-ranges. This
  28  *    calculates for each register and each live-range a value indicating
  29  *    the usefulness. (You can roughly think of the value as the negative
  30  *    costs needed for copies when the value is in the specific registers...)
  31  *
  32  * 2. Walk blocks and assigns registers in a greedy fashion. Preferring
  33  *    registers with high preferences. When register constraints are not met,
  34  *    add copies and split live-ranges.
  35  *
  36  * TODO:
  37  *  - make use of free registers in the permute_values code
  38  */
  39 #include "config.h"
  40
  41 #include <float.h>
  42 #include <stdbool.h>
  43 #include <math.h>
  44 #include "lpp.h"
  45
  46 #include "error.h"
  47 #include "execfreq.h"
  48 #include "ircons.h"
  49 #include "irdom.h"
  50 #include "iredges_t.h"
  51 #include "irgraph_t.h"
  52 #include "irgwalk.h"
  53 #include "irnode_t.h"
  54 #include "irprintf.h"
  55 #include "irdump.h"
  56 #include "irtools.h"
  57 #include "util.h"
  58 #include "obst.h"
  59 #include "raw_bitset.h"
  60 #include "unionfind.h"
  61 #include "pdeq.h"
  62 #include "hungarian.h"
  63
  64 #include "beabi.h"
  65 #include "bechordal_t.h"
  66 #include "be.h"
  67 #include "beirg.h"
  68 #include "belive_t.h"
  69 #include "bemodule.h"
  70 #include "benode.h"
  71 #include "bera.h"
  72 #include "besched.h"
  73 #include "bespill.h"
  74 #include "bespillutil.h"
  75 #include "beverify.h"
  76 #include "beutil.h"
  77 #include "bestack.h"
  78
  79 #define USE_FACTOR                     1.0f
  80 #define DEF_FACTOR                     1.0f
  81 #define NEIGHBOR_FACTOR                0.2f
  82 #define AFF_SHOULD_BE_SAME             0.5f
  83 #define AFF_PHI                        1.0f
  84 #define SPLIT_DELTA                    1.0f
  85 #define MAX_OPTIMISTIC_SPLIT_RECURSION 0
  86
  87 DEBUG_ONLY(static firm_dbg_module_t *dbg = NULL;)
  88
  89 static struct obstack               obst;
  90 static ir_graph                    *irg;
  91 static const arch_register_class_t *cls;
  92 static be_lv_t                     *lv;
  93 static const ir_exec_freq          *execfreqs;
  94 static unsigned                     n_regs;
  95 static unsigned                    *normal_regs;
  96 static int                         *congruence_classes;
  97 static ir_node                    **block_order;
  98 static size_t                       n_block_order;
  99 static int                          create_preferences        = true;
 100 static int                          create_congruence_classes = true;
 101 static int                          propagate_phi_registers   = true;
 102
 103 static const lc_opt_table_entry_t options[] = {
 104         LC_OPT_ENT_BOOL("prefs", "use preference based coloring", &create_preferences),
 105         LC_OPT_ENT_BOOL("congruences", "create congruence classes", &create_congruence_classes),
 106         LC_OPT_ENT_BOOL("prop_phi", "propagate phi registers", &propagate_phi_registers),
 107         LC_OPT_LAST
 108 };
 109
 110 /** currently active assignments (while processing a basic block)
 111  * maps registers to values(their current copies) */
 112 static ir_node **assignments;
 113
 114 /**
 115  * allocation information: last_uses, register preferences
 116  * the information is per firm-node.
 117  */
 118 struct allocation_info_t {
 119         unsigned  last_uses[2];   /**< bitset indicating last uses (input pos) */
 120         ir_node  *current_value;  /**< copy of the value that should be used */
 121         ir_node  *original_value; /**< for copies point to original value */
 122         float     prefs[];        /**< register preferences */
 123 };
 124 typedef struct allocation_info_t allocation_info_t;
 125
 126 /** helper datastructure used when sorting register preferences */
 127 struct reg_pref_t {
 128         unsigned num;
 129         float    pref;
 130 };
 131 typedef struct reg_pref_t reg_pref_t;
 132
 133 /** per basic-block information */
 134 struct block_info_t {
 135         bool     processed;       /**< indicate whether block is processed */
 136         ir_node *assignments[];   /**< register assignments at end of block */
 137 };
 138 typedef struct block_info_t block_info_t;
 139
 140 /**
 141  * Get the allocation info for a node.
 142  * The info is allocated on the first visit of a node.
 143  */
 144 static allocation_info_t *get_allocation_info(ir_node *node)
 145 {
 146         allocation_info_t *info = (allocation_info_t*)get_irn_link(node);
 147         if (info == NULL) {
 148                 info = OALLOCFZ(&obst, allocation_info_t, prefs, n_regs);
 149                 info->current_value  = node;
 150                 info->original_value = node;
 151                 set_irn_link(node, info);
 152         }
 153
 154         return info;
 155 }
 156
 157 static allocation_info_t *try_get_allocation_info(const ir_node *node)
 158 {
 159         return (allocation_info_t*) get_irn_link(node);
 160 }
 161
 162 /**
 163  * Get allocation information for a basic block
 164  */
 165 static block_info_t *get_block_info(ir_node *block)
 166 {
 167         block_info_t *info = (block_info_t*)get_irn_link(block);
 168
 169         assert(is_Block(block));
 170         if (info == NULL) {
 171                 info = OALLOCFZ(&obst, block_info_t, assignments, n_regs);
 172                 set_irn_link(block, info);
 173         }
 174
 175         return info;
 176 }
 177
 178 /**
 179  * Link the allocation info of a node to a copy.
 180  * Afterwards, both nodes uses the same allocation info.
 181  * Copy must not have an allocation info assigned yet.
 182  *
 183  * @param copy   the node that gets the allocation info assigned
 184  * @param value  the original node
 185  */
 186 static void mark_as_copy_of(ir_node *copy, ir_node *value)
 187 {
 188         ir_node           *original;
 189         allocation_info_t *info      = get_allocation_info(value);
 190         allocation_info_t *copy_info = get_allocation_info(copy);
 191
 192         /* find original value */
 193         original = info->original_value;
 194         if (original != value) {
 195                 info = get_allocation_info(original);
 196         }
 197
 198         assert(info->original_value == original);
 199         info->current_value = copy;
 200
 201         /* the copy should not be linked to something else yet */
 202         assert(copy_info->original_value == copy);
 203         copy_info->original_value = original;
 204
 205         /* copy over allocation preferences */
 206         memcpy(copy_info->prefs, info->prefs, n_regs * sizeof(copy_info->prefs[0]));
 207 }
 208
 209 /**
 210  * Calculate the penalties for every register on a node and its live neighbors.
 211  *
 212  * @param live_nodes  the set of live nodes at the current position, may be NULL
 213  * @param penalty     the penalty to subtract from
 214  * @param limited     a raw bitset containing the limited set for the node
 215  * @param node        the node
 216  */
 217 static void give_penalties_for_limits(const ir_nodeset_t *live_nodes,
 218                                       float penalty, const unsigned* limited,
 219                                       ir_node *node)
 220 {
 221         unsigned           r;
 222         size_t             n_allowed;
 223         allocation_info_t *info = get_allocation_info(node);
 224
 225         /* give penalty for all forbidden regs */
 226         for (r = 0; r < n_regs; ++r) {
 227                 if (rbitset_is_set(limited, r))
 228                         continue;
 229
 230                 info->prefs[r] -= penalty;
 231         }
 232
 233         /* all other live values should get a penalty for allowed regs */
 234         if (live_nodes == NULL)
 235                 return;
 236
 237         penalty   *= NEIGHBOR_FACTOR;
 238         n_allowed  = rbitset_popcount(limited, n_regs);
 239         if (n_allowed > 1) {
 240                 /* only create a very weak penalty if multiple regs are allowed */
 241                 penalty = (penalty * 0.8f) / n_allowed;
 242         }
 243         foreach_ir_nodeset(live_nodes, neighbor, iter) {
 244                 allocation_info_t *neighbor_info;
 245
 246                 /* TODO: if op is used on multiple inputs we might not do a
 247                  * continue here */
 248                 if (neighbor == node)
 249                         continue;
 250
 251                 neighbor_info = get_allocation_info(neighbor);
 252                 for (r = 0; r < n_regs; ++r) {
 253                         if (!rbitset_is_set(limited, r))
 254                                 continue;
 255
 256                         neighbor_info->prefs[r] -= penalty;
 257                 }
 258         }
 259 }
 260
 261 /**
 262  * Calculate the preferences of a definition for the current register class.
 263  * If the definition uses a limited set of registers, reduce the preferences
 264  * for the limited register on the node and its neighbors.
 265  *
 266  * @param live_nodes  the set of live nodes at the current node
 267  * @param weight      the weight
 268  * @param node        the current node
 269  */
 270 static void check_defs(const ir_nodeset_t *live_nodes, float weight,
 271                        ir_node *node)
 272 {
 273         const arch_register_req_t *req = arch_get_irn_register_req(node);
 274         if (req->type & arch_register_req_type_limited) {
 275                 const unsigned *limited = req->limited;
 276                 float           penalty = weight * DEF_FACTOR;
 277                 give_penalties_for_limits(live_nodes, penalty, limited, node);
 278         }
 279
 280         if (req->type & arch_register_req_type_should_be_same) {
 281                 ir_node           *insn  = skip_Proj(node);
 282                 allocation_info_t *info  = get_allocation_info(node);
 283                 int                arity = get_irn_arity(insn);
 284                 int                i;
 285
 286                 float factor = 1.0f / rbitset_popcount(&req->other_same, arity);
 287                 for (i = 0; i < arity; ++i) {
 288                         ir_node           *op;
 289                         unsigned           r;
 290                         allocation_info_t *op_info;
 291
 292                         if (!rbitset_is_set(&req->other_same, i))
 293                                 continue;
 294
 295                         op = get_irn_n(insn, i);
 296
 297                         /* if we the value at the should_be_same input doesn't die at the
 298                          * node, then it is no use to propagate the constraints (since a
 299                          * copy will emerge anyway) */
 300                         if (ir_nodeset_contains(live_nodes, op))
 301                                 continue;
 302
 303                         op_info = get_allocation_info(op);
 304                         for (r = 0; r < n_regs; ++r) {
 305                                 op_info->prefs[r] += info->prefs[r] * factor;
 306                         }
 307                 }
 308         }
 309 }
 310
 311 /**
 312  * Walker: Runs an a block calculates the preferences for any
 313  * node and every register from the considered register class.
 314  */
 315 static void analyze_block(ir_node *block, void *data)
 316 {
 317         float        weight = (float)get_block_execfreq(execfreqs, block);
 318         ir_nodeset_t live_nodes;
 319         (void) data;
 320
 321         ir_nodeset_init(&live_nodes);
 322         be_liveness_end_of_block(lv, cls, block, &live_nodes);
 323
 324         sched_foreach_reverse(block, node) {
 325                 allocation_info_t *info;
 326                 int                i;
 327                 int                arity;
 328
 329                 if (is_Phi(node))
 330                         break;
 331
 332                 if (create_preferences) {
 333                         ir_node *value;
 334                         be_foreach_definition(node, cls, value,
 335                                 check_defs(&live_nodes, weight, value);
 336                         );
 337                 }
 338
 339                 /* mark last uses */
 340                 arity = get_irn_arity(node);
 341
 342                 /* the allocation info node currently only uses 1 unsigned value
 343                    to mark last used inputs. So we will fail for a node with more than
 344                    32 inputs. */
 345                 if (arity >= (int) sizeof(info->last_uses) * 8) {
 346                         panic("Node with more than %d inputs not supported yet",
 347                                         (int) sizeof(info->last_uses) * 8);
 348                 }
 349
 350                 info = get_allocation_info(node);
 351                 for (i = 0; i < arity; ++i) {
 352                         ir_node                   *op  = get_irn_n(node, i);
 353                         const arch_register_req_t *req = arch_get_irn_register_req(op);
 354                         if (req->cls != cls)
 355                                 continue;
 356
 357                         /* last usage of a value? */
 358                         if (!ir_nodeset_contains(&live_nodes, op)) {
 359                                 rbitset_set(info->last_uses, i);
 360                         }
 361                 }
 362
 363                 be_liveness_transfer(cls, node, &live_nodes);
 364
 365                 if (create_preferences) {
 366                         /* update weights based on usage constraints */
 367                         for (i = 0; i < arity; ++i) {
 368                                 const arch_register_req_t *req;
 369                                 const unsigned            *limited;
 370                                 ir_node                   *op = get_irn_n(node, i);
 371
 372                                 if (!arch_irn_consider_in_reg_alloc(cls, op))
 373                                         continue;
 374
 375                                 req = arch_get_irn_register_req_in(node, i);
 376                                 if (!(req->type & arch_register_req_type_limited))
 377                                         continue;
 378
 379                                 limited = req->limited;
 380                                 give_penalties_for_limits(&live_nodes, weight * USE_FACTOR,
 381                                                           limited, op);
 382                         }
 383                 }
 384         }
 385
 386         ir_nodeset_destroy(&live_nodes);
 387 }
 388
 389 static void congruence_def(ir_nodeset_t *live_nodes, const ir_node *node)
 390 {
 391         const arch_register_req_t *req = arch_get_irn_register_req(node);
 392
 393         /* should be same constraint? */
 394         if (req->type & arch_register_req_type_should_be_same) {
 395                 const ir_node *insn  = skip_Proj_const(node);
 396                 int      arity = get_irn_arity(insn);
 397                 int      i;
 398                 unsigned node_idx = get_irn_idx(node);
 399                 node_idx          = uf_find(congruence_classes, node_idx);
 400
 401                 for (i = 0; i < arity; ++i) {
 402                         ir_node *op;
 403                         int      op_idx;
 404                         bool     interferes = false;
 405
 406                         if (!rbitset_is_set(&req->other_same, i))
 407                                 continue;
 408
 409                         op     = get_irn_n(insn, i);
 410                         op_idx = get_irn_idx(op);
 411                         op_idx = uf_find(congruence_classes, op_idx);
 412
 413                         /* do we interfere with the value */
 414                         foreach_ir_nodeset(live_nodes, live, iter) {
 415                                 int lv_idx = get_irn_idx(live);
 416                                 lv_idx     = uf_find(congruence_classes, lv_idx);
 417                                 if (lv_idx == op_idx) {
 418                                         interferes = true;
 419                                         break;
 420                                 }
 421                         }
 422                         /* don't put in same affinity class if we interfere */
 423                         if (interferes)
 424                                 continue;
 425
 426                         node_idx = uf_union(congruence_classes, node_idx, op_idx);
 427                         DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
 428                             node, op));
 429                         /* one should_be_same is enough... */
 430                         break;
 431                 }
 432         }
 433 }
 434
 435 static void create_congruence_class(ir_node *block, void *data)
 436 {
 437         ir_nodeset_t live_nodes;
 438
 439         (void) data;
 440         ir_nodeset_init(&live_nodes);
 441         be_liveness_end_of_block(lv, cls, block, &live_nodes);
 442
 443         /* check should be same constraints */
 444         ir_node *last_phi = NULL;
 445         sched_foreach_reverse(block, node) {
 446                 ir_node *value;
 447                 if (is_Phi(node)) {
 448                         last_phi = node;
 449                         break;
 450                 }
 451
 452                 be_foreach_definition(node, cls, value,
 453                         congruence_def(&live_nodes, value);
 454                 );
 455                 be_liveness_transfer(cls, node, &live_nodes);
 456         }
 457         if (!last_phi)
 458                 return;
 459
 460         /* check phi congruence classes */
 461         sched_foreach_reverse_from(last_phi, phi) {
 462                 int i;
 463                 int arity;
 464                 int node_idx;
 465                 assert(is_Phi(phi));
 466
 467                 if (!arch_irn_consider_in_reg_alloc(cls, phi))
 468                         continue;
 469
 470                 node_idx = get_irn_idx(phi);
 471                 node_idx = uf_find(congruence_classes, node_idx);
 472
 473                 arity = get_irn_arity(phi);
 474                 for (i = 0; i < arity; ++i) {
 475                         bool               interferes = false;
 476                         unsigned           r;
 477                         int                old_node_idx;
 478                         allocation_info_t *head_info;
 479                         allocation_info_t *other_info;
 480                         ir_node           *op     = get_Phi_pred(phi, i);
 481                         int                op_idx = get_irn_idx(op);
 482                         op_idx = uf_find(congruence_classes, op_idx);
 483
 484                         /* do we interfere with the value */
 485                         foreach_ir_nodeset(&live_nodes, live, iter) {
 486                                 int lv_idx = get_irn_idx(live);
 487                                 lv_idx     = uf_find(congruence_classes, lv_idx);
 488                                 if (lv_idx == op_idx) {
 489                                         interferes = true;
 490                                         break;
 491                                 }
 492                         }
 493                         /* don't put in same affinity class if we interfere */
 494                         if (interferes)
 495                                 continue;
 496                         /* any other phi has the same input? */
 497                         sched_foreach(block, phi) {
 498                                 ir_node *oop;
 499                                 int      oop_idx;
 500                                 if (!is_Phi(phi))
 501                                         break;
 502                                 if (!arch_irn_consider_in_reg_alloc(cls, phi))
 503                                         continue;
 504                                 oop = get_Phi_pred(phi, i);
 505                                 if (oop == op)
 506                                         continue;
 507                                 oop_idx = get_irn_idx(oop);
 508                                 oop_idx = uf_find(congruence_classes, oop_idx);
 509                                 if (oop_idx == op_idx) {
 510                                         interferes = true;
 511                                         break;
 512                                 }
 513                         }
 514                         if (interferes)
 515                                 continue;
 516
 517                         /* merge the 2 congruence classes and sum up their preferences */
 518                         old_node_idx = node_idx;
 519                         node_idx = uf_union(congruence_classes, node_idx, op_idx);
 520                         DB((dbg, LEVEL_3, "Merge %+F and %+F congruence classes\n",
 521                             phi, op));
 522
 523                         old_node_idx = node_idx == old_node_idx ? op_idx : old_node_idx;
 524                         head_info  = get_allocation_info(get_idx_irn(irg, node_idx));
 525                         other_info = get_allocation_info(get_idx_irn(irg, old_node_idx));
 526                         for (r = 0; r < n_regs; ++r) {
 527                                 head_info->prefs[r] += other_info->prefs[r];
 528                         }
 529                 }
 530         }
 531 }
 532
 533 static void set_congruence_prefs(ir_node *node, void *data)
 534 {
 535         allocation_info_t *info;
 536         allocation_info_t *head_info;
 537         unsigned node_idx = get_irn_idx(node);
 538         unsigned node_set = uf_find(congruence_classes, node_idx);
 539
 540         (void) data;
 541
 542         /* head of congruence class or not in any class */
 543         if (node_set == node_idx)
 544                 return;
 545
 546         if (!arch_irn_consider_in_reg_alloc(cls, node))
 547                 return;
 548
 549         head_info = get_allocation_info(get_idx_irn(irg, node_set));
 550         info      = get_allocation_info(node);
 551
 552         memcpy(info->prefs, head_info->prefs, n_regs * sizeof(info->prefs[0]));
 553 }
 554
 555 static void combine_congruence_classes(void)
 556 {
 557         size_t n = get_irg_last_idx(irg);
 558         congruence_classes = XMALLOCN(int, n);
 559         uf_init(congruence_classes, n);
 560
 561         /* create congruence classes */
 562         irg_block_walk_graph(irg, create_congruence_class, NULL, NULL);
 563         /* merge preferences */
 564         irg_walk_graph(irg, set_congruence_prefs, NULL, NULL);
 565         free(congruence_classes);
 566 }
 567
 568
 569
 570 /**
 571  * Assign register reg to the given node.
 572  *
 573  * @param node  the node
 574  * @param reg   the register
 575  */
 576 static void use_reg(ir_node *node, const arch_register_t *reg)
 577 {
 578         unsigned r = arch_register_get_index(reg);
 579         assignments[r] = node;
 580         arch_set_irn_register(node, reg);
 581 }
 582
 583 static void free_reg_of_value(ir_node *node)
 584 {
 585         const arch_register_t *reg;
 586         unsigned               r;
 587
 588         if (!arch_irn_consider_in_reg_alloc(cls, node))
 589                 return;
 590
 591         reg        = arch_get_irn_register(node);
 592         r          = arch_register_get_index(reg);
 593         /* assignment->value may be NULL if a value is used at 2 inputs
 594            so it gets freed twice. */
 595         assert(assignments[r] == node || assignments[r] == NULL);
 596         assignments[r] = NULL;
 597 }
 598
 599 /**
 600  * Compare two register preferences in decreasing order.
 601  */
 602 static int compare_reg_pref(const void *e1, const void *e2)
 603 {
 604         const reg_pref_t *rp1 = (const reg_pref_t*) e1;
 605         const reg_pref_t *rp2 = (const reg_pref_t*) e2;
 606         if (rp1->pref < rp2->pref)
 607                 return 1;
 608         if (rp1->pref > rp2->pref)
 609                 return -1;
 610         return 0;
 611 }
 612
 613 static void fill_sort_candidates(reg_pref_t *regprefs,
 614                                  const allocation_info_t *info)
 615 {
 616         unsigned r;
 617
 618         for (r = 0; r < n_regs; ++r) {
 619                 float pref = info->prefs[r];
 620                 regprefs[r].num  = r;
 621                 regprefs[r].pref = pref;
 622         }
 623         /* TODO: use a stable sort here to avoid unnecessary register jumping */
 624         qsort(regprefs, n_regs, sizeof(regprefs[0]), compare_reg_pref);
 625 }
 626
 627 static bool try_optimistic_split(ir_node *to_split, ir_node *before,
 628                                  float pref, float pref_delta,
 629                                  unsigned *forbidden_regs, int recursion)
 630 {
 631         const arch_register_t *from_reg;
 632         const arch_register_t *reg;
 633         ir_node               *original_insn;
 634         ir_node               *block;
 635         ir_node               *copy;
 636         unsigned               r = 0;
 637         unsigned               from_r;
 638         unsigned               i;
 639         allocation_info_t     *info = get_allocation_info(to_split);
 640         reg_pref_t            *prefs;
 641         float                  delta = 0;
 642         float                  split_threshold;
 643
 644         (void) pref;
 645
 646         /* stupid hack: don't optimisticallt split don't spill nodes...
 647          * (so we don't split away the values produced because of
 648          *  must_be_different constraints) */
 649         original_insn = skip_Proj(info->original_value);
 650         if (arch_get_irn_flags(original_insn) & arch_irn_flags_dont_spill)
 651                 return false;
 652
 653         from_reg        = arch_get_irn_register(to_split);
 654         from_r          = arch_register_get_index(from_reg);
 655         block           = get_nodes_block(before);
 656         split_threshold = (float)get_block_execfreq(execfreqs, block) * SPLIT_DELTA;
 657
 658         if (pref_delta < split_threshold*0.5)
 659                 return false;
 660
 661         /* find the best free position where we could move to */
 662         prefs = ALLOCAN(reg_pref_t, n_regs);
 663         fill_sort_candidates(prefs, info);
 664         for (i = 0; i < n_regs; ++i) {
 665                 float apref;
 666                 float apref_delta;
 667                 bool  res;
 668                 bool  old_source_state;
 669
 670                 /* we need a normal register which is not an output register
 671                    an different from the current register of to_split */
 672                 r = prefs[i].num;
 673                 if (!rbitset_is_set(normal_regs, r))
 674                         continue;
 675                 if (rbitset_is_set(forbidden_regs, r))
 676                         continue;
 677                 if (r == from_r)
 678                         continue;
 679
 680                 /* is the split worth it? */
 681                 delta = pref_delta + prefs[i].pref;
 682                 if (delta < split_threshold) {
 683                         DB((dbg, LEVEL_3, "Not doing optimistical split of %+F (depth %d), win %f too low\n",
 684                                 to_split, recursion, delta));
 685                         return false;
 686                 }
 687
 688                 /* if the register is free then we can do the split */
 689                 if (assignments[r] == NULL)
 690                         break;
 691
 692                 /* otherwise we might try recursively calling optimistic_split */
 693                 if (recursion+1 > MAX_OPTIMISTIC_SPLIT_RECURSION)
 694                         continue;
 695
 696                 apref        = prefs[i].pref;
 697                 apref_delta  = i+1 < n_regs ? apref - prefs[i+1].pref : 0;
 698                 apref_delta += pref_delta - split_threshold;
 699
 700                 /* our source register isn't a useful destination for recursive
 701                    splits */
 702                 old_source_state = rbitset_is_set(forbidden_regs, from_r);
 703                 rbitset_set(forbidden_regs, from_r);
 704                 /* try recursive split */
 705                 res = try_optimistic_split(assignments[r], before, apref,
 706                                            apref_delta, forbidden_regs, recursion+1);
 707                 /* restore our destination */
 708                 if (old_source_state) {
 709                         rbitset_set(forbidden_regs, from_r);
 710                 } else {
 711                         rbitset_clear(forbidden_regs, from_r);
 712                 }
 713
 714                 if (res)
 715                         break;
 716         }
 717         if (i >= n_regs)
 718                 return false;
 719
 720         reg  = arch_register_for_index(cls, r);
 721         copy = be_new_Copy(block, to_split);
 722         mark_as_copy_of(copy, to_split);
 723         /* hacky, but correct here */
 724         if (assignments[arch_register_get_index(from_reg)] == to_split)
 725                 free_reg_of_value(to_split);
 726         use_reg(copy, reg);
 727         sched_add_before(before, copy);
 728
 729         DB((dbg, LEVEL_3,
 730             "Optimistic live-range split %+F move %+F(%s) -> %s before %+F (win %f, depth %d)\n",
 731             copy, to_split, from_reg->name, reg->name, before, delta, recursion));
 732         return true;
 733 }
 734
 735 /**
 736  * Determine and assign a register for node @p node
 737  */
 738 static void assign_reg(const ir_node *block, ir_node *node,
 739                        unsigned *forbidden_regs)
 740 {
 741         const arch_register_t     *final_reg;
 742         allocation_info_t         *info;
 743         const arch_register_req_t *req;
 744         reg_pref_t                *reg_prefs;
 745         ir_node                   *in_node;
 746         unsigned                   r;
 747         const unsigned            *allowed_regs;
 748         unsigned                   final_reg_index = 0;
 749
 750         assert(!is_Phi(node));
 751         /* preassigned register? */
 752         final_reg = arch_get_irn_register(node);
 753         if (final_reg != NULL) {
 754                 DB((dbg, LEVEL_2, "Preassignment %+F -> %s\n", node, final_reg->name));
 755                 use_reg(node, final_reg);
 756                 return;
 757         }
 758
 759         req = arch_get_irn_register_req(node);
 760         /* ignore reqs must be preassigned */
 761         assert (! (req->type & arch_register_req_type_ignore));
 762
 763         /* give should_be_same boni */
 764         info    = get_allocation_info(node);
 765         in_node = skip_Proj(node);
 766         if (req->type & arch_register_req_type_should_be_same) {
 767                 float weight = (float)get_block_execfreq(execfreqs, block);
 768                 int   arity  = get_irn_arity(in_node);
 769                 int   i;
 770
 771                 assert(arity <= (int) sizeof(req->other_same) * 8);
 772                 for (i = 0; i < arity; ++i) {
 773                         ir_node               *in;
 774                         const arch_register_t *reg;
 775                         unsigned               reg_index;
 776                         if (!rbitset_is_set(&req->other_same, i))
 777                                 continue;
 778
 779                         in  = get_irn_n(in_node, i);
 780                         reg = arch_get_irn_register(in);
 781                         assert(reg != NULL);
 782                         reg_index = arch_register_get_index(reg);
 783
 784                         /* if the value didn't die here then we should not propagate the
 785                          * should_be_same info */
 786                         if (assignments[reg_index] == in)
 787                                 continue;
 788
 789                         info->prefs[reg_index] += weight * AFF_SHOULD_BE_SAME;
 790                 }
 791         }
 792
 793         /* create list of register candidates and sort by their preference */
 794         DB((dbg, LEVEL_2, "Candidates for %+F:", node));
 795         reg_prefs = ALLOCAN(reg_pref_t, n_regs);
 796         fill_sort_candidates(reg_prefs, info);
 797         for (r = 0; r < n_regs; ++r) {
 798                 unsigned num = reg_prefs[r].num;
 799                 const arch_register_t *reg;
 800
 801                 if (!rbitset_is_set(normal_regs, num))
 802                         continue;
 803                 reg = arch_register_for_index(cls, num);
 804                 DB((dbg, LEVEL_2, " %s(%f)", reg->name, reg_prefs[r].pref));
 805         }
 806         DB((dbg, LEVEL_2, "\n"));
 807
 808         allowed_regs = normal_regs;
 809         if (req->type & arch_register_req_type_limited) {
 810                 allowed_regs = req->limited;
 811         }
 812
 813         for (r = 0; r < n_regs; ++r) {
 814                 float   pref, delta;
 815                 ir_node *before;
 816                 bool    res;
 817
 818                 final_reg_index = reg_prefs[r].num;
 819                 if (!rbitset_is_set(allowed_regs, final_reg_index))
 820                         continue;
 821                 /* alignment constraint? */
 822                 if (req->width > 1 && (req->type & arch_register_req_type_aligned)
 823                                 && (final_reg_index % req->width) != 0)
 824                         continue;
 825
 826                 if (assignments[final_reg_index] == NULL)
 827                         break;
 828                 pref   = reg_prefs[r].pref;
 829                 delta  = r+1 < n_regs ? pref - reg_prefs[r+1].pref : 0;
 830                 before = skip_Proj(node);
 831                 res    = try_optimistic_split(assignments[final_reg_index], before,
 832                                               pref, delta, forbidden_regs, 0);
 833                 if (res)
 834                         break;
 835         }
 836         if (r >= n_regs) {
 837                 /* the common reason to hit this panic is when 1 of your nodes is not
 838                  * register pressure faithful */
 839                 panic("No register left for %+F\n", node);
 840         }
 841
 842         final_reg = arch_register_for_index(cls, final_reg_index);
 843         DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, final_reg->name));
 844         use_reg(node, final_reg);
 845 }
 846
 847 /**
 848  * Add an permutation in front of a node and change the assignments
 849  * due to this permutation.
 850  *
 851  * To understand this imagine a permutation like this:
 852  *
 853  * 1 -> 2
 854  * 2 -> 3
 855  * 3 -> 1, 5
 856  * 4 -> 6
 857  * 5
 858  * 6
 859  * 7 -> 7
 860  *
 861  * First we count how many destinations a single value has. At the same time
 862  * we can be sure that each destination register has at most 1 source register
 863  * (it can have 0 which means we don't care what value is in it).
 864  * We ignore all fulfilled permuations (like 7->7)
 865  * In a first pass we create as much copy instructions as possible as they
 866  * are generally cheaper than exchanges. We do this by counting into how many
 867  * destinations a register has to be copied (in the example it's 2 for register
 868  * 3, or 1 for the registers 1,2,4 and 7).
 869  * We can then create a copy into every destination register when the usecount
 870  * of that register is 0 (= noone else needs the value in the register).
 871  *
 872  * After this step we should only have cycles left. We implement a cyclic
 873  * permutation of n registers with n-1 transpositions.
 874  *
 875  * @param live_nodes   the set of live nodes, updated due to live range split
 876  * @param before       the node before we add the permutation
 877  * @param permutation  the permutation array indices are the destination
 878  *                     registers, the values in the array are the source
 879  *                     registers.
 880  */
 881 static void permute_values(ir_nodeset_t *live_nodes, ir_node *before,
 882                            unsigned *permutation)
 883 {
 884         unsigned  *n_used = ALLOCANZ(unsigned, n_regs);
 885         ir_node   *block;
 886         unsigned   r;
 887
 888         /* determine how often each source register needs to be read */
 889         for (r = 0; r < n_regs; ++r) {
 890                 unsigned  old_reg = permutation[r];
 891                 ir_node  *value;
 892
 893                 value = assignments[old_reg];
 894                 if (value == NULL) {
 895                         /* nothing to do here, reg is not live. Mark it as fixpoint
 896                          * so we ignore it in the next steps */
 897                         permutation[r] = r;
 898                         continue;
 899                 }
 900
 901                 ++n_used[old_reg];
 902         }
 903
 904         block = get_nodes_block(before);
 905
 906         /* step1: create copies where immediately possible */
 907         for (r = 0; r < n_regs; /* empty */) {
 908                 ir_node *copy;
 909                 ir_node *src;
 910                 const arch_register_t *reg;
 911                 unsigned               old_r = permutation[r];
 912
 913                 /* - no need to do anything for fixed points.
 914                    - we can't copy if the value in the dest reg is still needed */
 915                 if (old_r == r || n_used[r] > 0) {
 916                         ++r;
 917                         continue;
 918                 }
 919
 920                 /* create a copy */
 921                 src  = assignments[old_r];
 922                 copy = be_new_Copy(block, src);
 923                 sched_add_before(before, copy);
 924                 reg = arch_register_for_index(cls, r);
 925                 DB((dbg, LEVEL_2, "Copy %+F (from %+F, before %+F) -> %s\n",
 926                     copy, src, before, reg->name));
 927                 mark_as_copy_of(copy, src);
 928                 use_reg(copy, reg);
 929
 930                 if (live_nodes != NULL) {
 931                         ir_nodeset_insert(live_nodes, copy);
 932                 }
 933
 934                 /* old register has 1 user less, permutation is resolved */
 935                 assert(arch_register_get_index(arch_get_irn_register(src)) == old_r);
 936                 permutation[r] = r;
 937
 938                 assert(n_used[old_r] > 0);
 939                 --n_used[old_r];
 940                 if (n_used[old_r] == 0) {
 941                         if (live_nodes != NULL) {
 942                                 ir_nodeset_remove(live_nodes, src);
 943                         }
 944                         free_reg_of_value(src);
 945                 }
 946
 947                 /* advance or jump back (if this copy enabled another copy) */
 948                 if (old_r < r && n_used[old_r] == 0) {
 949                         r = old_r;
 950                 } else {
 951                         ++r;
 952                 }
 953         }
 954
 955         /* at this point we only have "cycles" left which we have to resolve with
 956          * perm instructions
 957          * TODO: if we have free registers left, then we should really use copy
 958          * instructions for any cycle longer than 2 registers...
 959          * (this is probably architecture dependent, there might be archs where
 960          *  copies are preferable even for 2-cycles) */
 961
 962         /* create perms with the rest */
 963         for (r = 0; r < n_regs; /* empty */) {
 964                 const arch_register_t *reg;
 965                 unsigned  old_r = permutation[r];
 966                 unsigned  r2;
 967                 ir_node  *in[2];
 968                 ir_node  *perm;
 969                 ir_node  *proj0;
 970                 ir_node  *proj1;
 971
 972                 if (old_r == r) {
 973                         ++r;
 974                         continue;
 975                 }
 976
 977                 /* we shouldn't have copies from 1 value to multiple destinations left*/
 978                 assert(n_used[old_r] == 1);
 979
 980                 /* exchange old_r and r2; after that old_r is a fixed point */
 981                 r2 = permutation[old_r];
 982
 983                 in[0] = assignments[r2];
 984                 in[1] = assignments[old_r];
 985                 perm = be_new_Perm(cls, block, 2, in);
 986                 sched_add_before(before, perm);
 987                 DB((dbg, LEVEL_2, "Perm %+F (perm %+F,%+F, before %+F)\n",
 988                     perm, in[0], in[1], before));
 989
 990                 proj0 = new_r_Proj(perm, get_irn_mode(in[0]), 0);
 991                 mark_as_copy_of(proj0, in[0]);
 992                 reg = arch_register_for_index(cls, old_r);
 993                 use_reg(proj0, reg);
 994
 995                 proj1 = new_r_Proj(perm, get_irn_mode(in[1]), 1);
 996                 mark_as_copy_of(proj1, in[1]);
 997                 reg = arch_register_for_index(cls, r2);
 998                 use_reg(proj1, reg);
 999
1000                 /* 1 value is now in the correct register */
1001                 permutation[old_r] = old_r;
1002                 /* the source of r changed to r2 */
1003                 permutation[r] = r2;
1004
1005                 /* if we have reached a fixpoint update data structures */
1006                 if (live_nodes != NULL) {
1007                         ir_nodeset_remove(live_nodes, in[0]);
1008                         ir_nodeset_remove(live_nodes, in[1]);
1009                         ir_nodeset_remove(live_nodes, proj0);
1010                         ir_nodeset_insert(live_nodes, proj1);
1011                 }
1012         }
1013
1014 #ifdef DEBUG_libfirm
1015         /* now we should only have fixpoints left */
1016         for (r = 0; r < n_regs; ++r) {
1017                 assert(permutation[r] == r);
1018         }
1019 #endif
1020 }
1021
1022 /**
1023  * Free regs for values last used.
1024  *
1025  * @param live_nodes   set of live nodes, will be updated
1026  * @param node         the node to consider
1027  */
1028 static void free_last_uses(ir_nodeset_t *live_nodes, ir_node *node)
1029 {
1030         allocation_info_t *info      = get_allocation_info(node);
1031         const unsigned    *last_uses = info->last_uses;
1032         int                arity     = get_irn_arity(node);
1033         int                i;
1034
1035         for (i = 0; i < arity; ++i) {
1036                 ir_node *op;
1037
1038                 /* check if one operand is the last use */
1039                 if (!rbitset_is_set(last_uses, i))
1040                         continue;
1041
1042                 op = get_irn_n(node, i);
1043                 free_reg_of_value(op);
1044                 ir_nodeset_remove(live_nodes, op);
1045         }
1046 }
1047
1048 /**
1049  * change inputs of a node to the current value (copies/perms)
1050  */
1051 static void rewire_inputs(ir_node *node)
1052 {
1053         int i;
1054         int arity = get_irn_arity(node);
1055
1056         for (i = 0; i < arity; ++i) {
1057                 ir_node           *op = get_irn_n(node, i);
1058                 allocation_info_t *info = try_get_allocation_info(op);
1059
1060                 if (info == NULL)
1061                         continue;
1062
1063                 info = get_allocation_info(info->original_value);
1064                 if (info->current_value != op) {
1065                         set_irn_n(node, i, info->current_value);
1066                 }
1067         }
1068 }
1069
1070 /**
1071  * Create a bitset of registers occupied with value living through an
1072  * instruction
1073  */
1074 static void determine_live_through_regs(unsigned *bitset, ir_node *node)
1075 {
1076         const allocation_info_t *info = get_allocation_info(node);
1077         unsigned r;
1078         int i;
1079         int arity;
1080
1081         /* mark all used registers as potentially live-through */
1082         for (r = 0; r < n_regs; ++r) {
1083                 if (assignments[r] == NULL)
1084                         continue;
1085                 if (!rbitset_is_set(normal_regs, r))
1086                         continue;
1087
1088                 rbitset_set(bitset, r);
1089         }
1090
1091         /* remove registers of value dying at the instruction */
1092         arity = get_irn_arity(node);
1093         for (i = 0; i < arity; ++i) {
1094                 ir_node               *op;
1095                 const arch_register_t *reg;
1096
1097                 if (!rbitset_is_set(info->last_uses, i))
1098                         continue;
1099
1100                 op  = get_irn_n(node, i);
1101                 reg = arch_get_irn_register(op);
1102                 rbitset_clear(bitset, arch_register_get_index(reg));
1103         }
1104 }
1105
1106 static void solve_lpp(ir_nodeset_t *live_nodes, ir_node *node,
1107                       unsigned *forbidden_regs, unsigned *live_through_regs)
1108 {
1109         unsigned *forbidden_edges = rbitset_malloc(n_regs * n_regs);
1110         int      *lpp_vars        = XMALLOCNZ(int, n_regs*n_regs);
1111         int       arity           = get_irn_arity(node);
1112         int       i;
1113         unsigned  l;
1114         unsigned  r;
1115
1116         lpp_t *lpp = lpp_new("prefalloc", lpp_minimize);
1117         //lpp_set_time_limit(lpp, 20);
1118         lpp_set_log(lpp, stdout);
1119
1120         /** mark some edges as forbidden */
1121         for (i = 0; i < arity; ++i) {
1122                 ir_node                   *op = get_irn_n(node, i);
1123                 const arch_register_t     *reg;
1124                 const arch_register_req_t *req;
1125                 const unsigned            *limited;
1126                 unsigned                   current_reg;
1127
1128                 if (!arch_irn_consider_in_reg_alloc(cls, op))
1129                         continue;
1130
1131                 req = arch_get_irn_register_req_in(node, i);
1132                 if (!(req->type & arch_register_req_type_limited))
1133                         continue;
1134
1135                 limited     = req->limited;
1136                 reg         = arch_get_irn_register(op);
1137                 current_reg = arch_register_get_index(reg);
1138                 for (r = 0; r < n_regs; ++r) {
1139                         if (rbitset_is_set(limited, r))
1140                                 continue;
1141
1142                         rbitset_set(forbidden_edges, current_reg*n_regs + r);
1143                 }
1144         }
1145
1146         /* add all combinations, except for not allowed ones */
1147         for (l = 0; l < n_regs; ++l) {
1148                 if (!rbitset_is_set(normal_regs, l)) {
1149                         char name[15];
1150                         snprintf(name, sizeof(name), "%u_to_%u", l, l);
1151                         lpp_vars[l*n_regs+l] = lpp_add_var(lpp, name, lpp_binary, 1);
1152                         continue;
1153                 }
1154
1155                 for (r = 0; r < n_regs; ++r) {
1156                         if (!rbitset_is_set(normal_regs, r))
1157                                 continue;
1158                         if (rbitset_is_set(forbidden_edges, l*n_regs + r))
1159                                 continue;
1160                         /* livethrough values may not use constrained output registers */
1161                         if (rbitset_is_set(live_through_regs, l)
1162                             && rbitset_is_set(forbidden_regs, r))
1163                                 continue;
1164
1165                         char name[15];
1166                         snprintf(name, sizeof(name), "%u_to_%u", l, r);
1167
1168                         double costs = l==r ? 9 : 8;
1169                         lpp_vars[l*n_regs+r]
1170                                 = lpp_add_var(lpp, name, lpp_binary, costs);
1171                         assert(lpp_vars[l*n_regs+r] > 0);
1172                 }
1173         }
1174         /* add constraints */
1175         for (l = 0; l < n_regs; ++l) {
1176                 int constraint;
1177                 /* only 1 destination per register */
1178                 constraint = -1;
1179                 for (r = 0; r < n_regs; ++r) {
1180                         int var = lpp_vars[l*n_regs+r];
1181                         if (var == 0)
1182                                 continue;
1183                         if (constraint < 0) {
1184                                 char name[64];
1185                                 snprintf(name, sizeof(name), "%u_to_dest", l);
1186                                 constraint = lpp_add_cst(lpp, name, lpp_equal, 1);
1187                         }
1188                         lpp_set_factor_fast(lpp, constraint, var, 1);
1189                 }
1190                 /* each destination used by at most 1 value */
1191                 constraint = -1;
1192                 for (r = 0; r < n_regs; ++r) {
1193                         int var = lpp_vars[r*n_regs+l];
1194                         if (var == 0)
1195                                 continue;
1196                         if (constraint < 0) {
1197                                 char name[64];
1198                                 snprintf(name, sizeof(name), "one_to_%u", l);
1199                                 constraint = lpp_add_cst(lpp, name, lpp_less_equal, 1);
1200                         }
1201                         lpp_set_factor_fast(lpp, constraint, var, 1);
1202                 }
1203         }
1204
1205         lpp_dump_plain(lpp, fopen("lppdump.txt", "w"));
1206
1207         /* solve lpp */
1208         {
1209                 unsigned *assignment;
1210                 lpp_solve(lpp, be_options.ilp_server, be_options.ilp_solver);
1211                 if (!lpp_is_sol_valid(lpp))
1212                         panic("ilp solution not valid!");
1213
1214                 assignment = ALLOCAN(unsigned, n_regs);
1215                 for (l = 0; l < n_regs; ++l) {
1216                         unsigned dest_reg = (unsigned)-1;
1217                         for (r = 0; r < n_regs; ++r) {
1218                                 int var = lpp_vars[l*n_regs+r];
1219                                 if (var == 0)
1220                                         continue;
1221                                 double val = lpp_get_var_sol(lpp, var);
1222                                 if (val == 1) {
1223                                         assert(dest_reg == (unsigned)-1);
1224                                         dest_reg = r;
1225                                 }
1226                         }
1227                         assert(dest_reg != (unsigned)-1);
1228                         assignment[dest_reg] = l;
1229                 }
1230
1231                 fprintf(stderr, "Assignment: ");
1232                 for (l = 0; l < n_regs; ++l) {
1233                         fprintf(stderr, "%u ", assignment[l]);
1234                 }
1235                 fprintf(stderr, "\n");
1236                 fflush(stdout);
1237                 permute_values(live_nodes, node, assignment);
1238         }
1239         lpp_free(lpp);
1240 }
1241
1242 static bool is_aligned(unsigned num, unsigned alignment)
1243 {
1244         unsigned mask = alignment-1;
1245         assert(is_po2(alignment));
1246         return (num&mask) == 0;
1247 }
1248
1249 /**
1250  * Enforce constraints at a node by live range splits.
1251  *
1252  * @param  live_nodes  the set of live nodes, might be changed
1253  * @param  node        the current node
1254  */
1255 static void enforce_constraints(ir_nodeset_t *live_nodes, ir_node *node,
1256                                 unsigned *forbidden_regs)
1257 {
1258         int arity = get_irn_arity(node);
1259         int i, res;
1260         hungarian_problem_t *bp;
1261         unsigned l, r;
1262         unsigned *assignment;
1263         ir_node  *value;
1264
1265         /* construct a list of register occupied by live-through values */
1266         unsigned *live_through_regs = NULL;
1267
1268         /* see if any use constraints are not met and whether double-width
1269          * values are involved */
1270         bool double_width = false;
1271         bool good = true;
1272         for (i = 0; i < arity; ++i) {
1273                 ir_node                   *op = get_irn_n(node, i);
1274                 const arch_register_t     *reg;
1275                 const arch_register_req_t *req;
1276                 const unsigned            *limited;
1277                 unsigned                   reg_index;
1278
1279                 if (!arch_irn_consider_in_reg_alloc(cls, op))
1280                         continue;
1281
1282                 /* are there any limitations for the i'th operand? */
1283                 req = arch_get_irn_register_req_in(node, i);
1284                 if (req->width > 1)
1285                         double_width = true;
1286                 reg       = arch_get_irn_register(op);
1287                 reg_index = arch_register_get_index(reg);
1288                 if (req->type & arch_register_req_type_aligned) {
1289                         if (!is_aligned(reg_index, req->width)) {
1290                                 good = false;
1291                                 continue;
1292                         }
1293                 }
1294                 if (!(req->type & arch_register_req_type_limited))
1295                         continue;
1296
1297                 limited   = req->limited;
1298                 if (!rbitset_is_set(limited, reg_index)) {
1299                         /* found an assignment outside the limited set */
1300                         good = false;
1301                         continue;
1302                 }
1303         }
1304
1305         /* is any of the live-throughs using a constrained output register? */
1306         be_foreach_definition(node, cls, value,
1307                 if (req_->width > 1)
1308                         double_width = true;
1309                 if (! (req_->type & arch_register_req_type_limited))
1310                         continue;
1311                 if (live_through_regs == NULL) {
1312                         rbitset_alloca(live_through_regs, n_regs);
1313                         determine_live_through_regs(live_through_regs, node);
1314                 }
1315                 rbitset_or(forbidden_regs, req_->limited, n_regs);
1316                 if (rbitsets_have_common(req_->limited, live_through_regs, n_regs))
1317                         good = false;
1318         );
1319
1320         if (good)
1321                 return;
1322
1323         /* create these arrays if we haven't yet */
1324         if (live_through_regs == NULL) {
1325                 rbitset_alloca(live_through_regs, n_regs);
1326         }
1327
1328         if (double_width) {
1329                 /* only the ILP variant can solve this yet */
1330                 solve_lpp(live_nodes, node, forbidden_regs, live_through_regs);
1331                 return;
1332         }
1333
1334         /* at this point we have to construct a bipartite matching problem to see
1335          * which values should go to which registers
1336          * Note: We're building the matrix in "reverse" - source registers are
1337          *       right, destinations left because this will produce the solution
1338          *       in the format required for permute_values.
1339          */
1340         bp = hungarian_new(n_regs, n_regs, HUNGARIAN_MATCH_PERFECT);
1341
1342         /* add all combinations, then remove not allowed ones */
1343         for (l = 0; l < n_regs; ++l) {
1344                 if (!rbitset_is_set(normal_regs, l)) {
1345                         hungarian_add(bp, l, l, 1);
1346                         continue;
1347                 }
1348
1349                 for (r = 0; r < n_regs; ++r) {
1350                         if (!rbitset_is_set(normal_regs, r))
1351                                 continue;
1352                         /* livethrough values may not use constrainted output registers */
1353                         if (rbitset_is_set(live_through_regs, l)
1354                                         && rbitset_is_set(forbidden_regs, r))
1355                                 continue;
1356
1357                         hungarian_add(bp, r, l, l == r ? 9 : 8);
1358                 }
1359         }
1360
1361         for (i = 0; i < arity; ++i) {
1362                 ir_node                   *op = get_irn_n(node, i);
1363                 const arch_register_t     *reg;
1364                 const arch_register_req_t *req;
1365                 const unsigned            *limited;
1366                 unsigned                   current_reg;
1367
1368                 if (!arch_irn_consider_in_reg_alloc(cls, op))
1369                         continue;
1370
1371                 req = arch_get_irn_register_req_in(node, i);
1372                 if (!(req->type & arch_register_req_type_limited))
1373                         continue;
1374
1375                 limited     = req->limited;
1376                 reg         = arch_get_irn_register(op);
1377                 current_reg = arch_register_get_index(reg);
1378                 for (r = 0; r < n_regs; ++r) {
1379                         if (rbitset_is_set(limited, r))
1380                                 continue;
1381                         hungarian_remove(bp, r, current_reg);
1382                 }
1383         }
1384
1385         //hungarian_print_cost_matrix(bp, 1);
1386         hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1387
1388         assignment = ALLOCAN(unsigned, n_regs);
1389         res = hungarian_solve(bp, assignment, NULL, 0);
1390         assert(res == 0);
1391
1392 #if 0
1393         fprintf(stderr, "Swap result:");
1394         for (i = 0; i < (int) n_regs; ++i) {
1395                 fprintf(stderr, " %d", assignment[i]);
1396         }
1397         fprintf(stderr, "\n");
1398 #endif
1399
1400         hungarian_free(bp);
1401
1402         permute_values(live_nodes, node, assignment);
1403 }
1404
1405 /** test whether a node @p n is a copy of the value of node @p of */
1406 static bool is_copy_of(ir_node *value, ir_node *test_value)
1407 {
1408         allocation_info_t *test_info;
1409         allocation_info_t *info;
1410
1411         if (value == test_value)
1412                 return true;
1413
1414         info      = get_allocation_info(value);
1415         test_info = get_allocation_info(test_value);
1416         return test_info->original_value == info->original_value;
1417 }
1418
1419 /**
1420  * find a value in the end-assignment of a basic block
1421  * @returns the index into the assignment array if found
1422  *          -1 if not found
1423  */
1424 static int find_value_in_block_info(block_info_t *info, ir_node *value)
1425 {
1426         unsigned   r;
1427         ir_node  **end_assignments = info->assignments;
1428         for (r = 0; r < n_regs; ++r) {
1429                 ir_node *a_value = end_assignments[r];
1430
1431                 if (a_value == NULL)
1432                         continue;
1433                 if (is_copy_of(a_value, value))
1434                         return (int) r;
1435         }
1436
1437         return -1;
1438 }
1439
1440 /**
1441  * Create the necessary permutations at the end of a basic block to fullfill
1442  * the register assignment for phi-nodes in the next block
1443  */
1444 static void add_phi_permutations(ir_node *block, int p)
1445 {
1446         unsigned   r;
1447         unsigned  *permutation;
1448         ir_node  **old_assignments;
1449         bool       need_permutation;
1450         ir_node   *phi;
1451         ir_node   *pred = get_Block_cfgpred_block(block, p);
1452
1453         block_info_t *pred_info = get_block_info(pred);
1454
1455         /* predecessor not processed yet? nothing to do */
1456         if (!pred_info->processed)
1457                 return;
1458
1459         permutation = ALLOCAN(unsigned, n_regs);
1460         for (r = 0; r < n_regs; ++r) {
1461                 permutation[r] = r;
1462         }
1463
1464         /* check phi nodes */
1465         need_permutation = false;
1466         phi = sched_first(block);
1467         for ( ; is_Phi(phi); phi = sched_next(phi)) {
1468                 const arch_register_t *reg;
1469                 const arch_register_t *op_reg;
1470                 int                    regn;
1471                 int                    a;
1472                 ir_node               *op;
1473
1474                 if (!arch_irn_consider_in_reg_alloc(cls, phi))
1475                         continue;
1476
1477                 op = get_Phi_pred(phi, p);
1478                 a  = find_value_in_block_info(pred_info, op);
1479                 assert(a >= 0);
1480
1481                 reg  = arch_get_irn_register(phi);
1482                 regn = arch_register_get_index(reg);
1483                 /* same register? nothing to do */
1484                 if (regn == a)
1485                         continue;
1486
1487                 op     = pred_info->assignments[a];
1488                 op_reg = arch_get_irn_register(op);
1489                 /* virtual or joker registers are ok too */
1490                 if ((op_reg->type & arch_register_type_joker)
1491                                 || (op_reg->type & arch_register_type_virtual))
1492                         continue;
1493
1494                 permutation[regn] = a;
1495                 need_permutation  = true;
1496         }
1497
1498         if (need_permutation) {
1499                 /* permute values at end of predecessor */
1500                 old_assignments = assignments;
1501                 assignments     = pred_info->assignments;
1502                 permute_values(NULL, be_get_end_of_block_insertion_point(pred),
1503                                permutation);
1504                 assignments = old_assignments;
1505         }
1506
1507         /* change phi nodes to use the copied values */
1508         phi = sched_first(block);
1509         for ( ; is_Phi(phi); phi = sched_next(phi)) {
1510                 int      a;
1511                 ir_node *op;
1512
1513                 if (!arch_irn_consider_in_reg_alloc(cls, phi))
1514                         continue;
1515
1516                 op = get_Phi_pred(phi, p);
1517
1518                 /* we have permuted all values into the correct registers so we can
1519                    simply query which value occupies the phis register in the
1520                    predecessor */
1521                 a  = arch_register_get_index(arch_get_irn_register(phi));
1522                 op = pred_info->assignments[a];
1523                 set_Phi_pred(phi, p, op);
1524         }
1525 }
1526
1527 /**
1528  * Set preferences for a phis register based on the registers used on the
1529  * phi inputs.
1530  */
1531 static void adapt_phi_prefs(ir_node *phi)
1532 {
1533         int i;
1534         int arity = get_irn_arity(phi);
1535         ir_node           *block = get_nodes_block(phi);
1536         allocation_info_t *info  = get_allocation_info(phi);
1537
1538         for (i = 0; i < arity; ++i) {
1539                 ir_node               *op  = get_irn_n(phi, i);
1540                 const arch_register_t *reg = arch_get_irn_register(op);
1541                 ir_node               *pred_block;
1542                 block_info_t          *pred_block_info;
1543                 float                  weight;
1544                 unsigned               r;
1545
1546                 if (reg == NULL)
1547                         continue;
1548                 /* we only give the bonus if the predecessor already has registers
1549                  * assigned, otherwise we only see a dummy value
1550                  * and any conclusions about its register are useless */
1551                 pred_block = get_Block_cfgpred_block(block, i);
1552                 pred_block_info = get_block_info(pred_block);
1553                 if (!pred_block_info->processed)
1554                         continue;
1555
1556                 /* give bonus for already assigned register */
1557                 weight = (float)get_block_execfreq(execfreqs, pred_block);
1558                 r      = arch_register_get_index(reg);
1559                 info->prefs[r] += weight * AFF_PHI;
1560         }
1561 }
1562
1563 /**
1564  * After a phi has been assigned a register propagate preference inputs
1565  * to the phi inputs.
1566  */
1567 static void propagate_phi_register(ir_node *phi, unsigned assigned_r)
1568 {
1569         int      i;
1570         ir_node *block = get_nodes_block(phi);
1571         int      arity = get_irn_arity(phi);
1572
1573         for (i = 0; i < arity; ++i) {
1574                 ir_node           *op         = get_Phi_pred(phi, i);
1575                 allocation_info_t *info       = get_allocation_info(op);
1576                 ir_node           *pred_block = get_Block_cfgpred_block(block, i);
1577                 unsigned           r;
1578                 float              weight
1579                         = (float)get_block_execfreq(execfreqs, pred_block) * AFF_PHI;
1580
1581                 if (info->prefs[assigned_r] >= weight)
1582                         continue;
1583
1584                 /* promote the prefered register */
1585                 for (r = 0; r < n_regs; ++r) {
1586                         if (info->prefs[r] > -weight) {
1587                                 info->prefs[r] = -weight;
1588                         }
1589                 }
1590                 info->prefs[assigned_r] = weight;
1591
1592                 if (is_Phi(op))
1593                         propagate_phi_register(op, assigned_r);
1594         }
1595 }
1596
1597 static void assign_phi_registers(ir_node *block)
1598 {
1599         int                  n_phis = 0;
1600         int                  n;
1601         int                  res;
1602         unsigned            *assignment;
1603         hungarian_problem_t *bp;
1604
1605         /* count phi nodes */
1606         sched_foreach(block, node) {
1607                 if (!is_Phi(node))
1608                         break;
1609                 if (!arch_irn_consider_in_reg_alloc(cls, node))
1610                         continue;
1611                 ++n_phis;
1612         }
1613
1614         if (n_phis == 0)
1615                 return;
1616
1617         /* build a bipartite matching problem for all phi nodes */
1618         bp = hungarian_new(n_phis, n_regs, HUNGARIAN_MATCH_PERFECT);
1619         n  = 0;
1620         sched_foreach(block, node) {
1621                 unsigned r;
1622
1623                 allocation_info_t *info;
1624                 if (!is_Phi(node))
1625                         break;
1626                 if (!arch_irn_consider_in_reg_alloc(cls, node))
1627                         continue;
1628
1629                 /* give boni for predecessor colorings */
1630                 adapt_phi_prefs(node);
1631                 /* add stuff to bipartite problem */
1632                 info = get_allocation_info(node);
1633                 DB((dbg, LEVEL_3, "Prefs for %+F: ", node));
1634                 for (r = 0; r < n_regs; ++r) {
1635                         float costs;
1636
1637                         if (!rbitset_is_set(normal_regs, r))
1638                                 continue;
1639
1640                         costs = info->prefs[r];
1641                         costs = costs < 0 ? -logf(-costs+1) : logf(costs+1);
1642                         costs *= 100;
1643                         costs += 10000;
1644                         hungarian_add(bp, n, r, (int)costs);
1645                         DB((dbg, LEVEL_3, " %s(%f)", arch_register_for_index(cls, r)->name,
1646                                                 info->prefs[r]));
1647                 }
1648                 DB((dbg, LEVEL_3, "\n"));
1649                 ++n;
1650         }
1651
1652         //hungarian_print_cost_matrix(bp, 7);
1653         hungarian_prepare_cost_matrix(bp, HUNGARIAN_MODE_MAXIMIZE_UTIL);
1654
1655         assignment = ALLOCAN(unsigned, n_regs);
1656         res        = hungarian_solve(bp, assignment, NULL, 0);
1657         assert(res == 0);
1658
1659         /* apply results */
1660         n = 0;
1661         sched_foreach(block, node) {
1662                 unsigned               r;
1663                 const arch_register_t *reg;
1664
1665                 if (!is_Phi(node))
1666                         break;
1667                 if (!arch_irn_consider_in_reg_alloc(cls, node))
1668                         continue;
1669
1670                 r = assignment[n++];
1671                 assert(rbitset_is_set(normal_regs, r));
1672                 reg = arch_register_for_index(cls, r);
1673                 DB((dbg, LEVEL_2, "Assign %+F -> %s\n", node, reg->name));
1674                 use_reg(node, reg);
1675
1676                 /* adapt preferences for phi inputs */
1677                 if (propagate_phi_registers)
1678                         propagate_phi_register(node, r);
1679         }
1680 }
1681
1682 /**
1683  * Walker: assign registers to all nodes of a block that
1684  * need registers from the currently considered register class.
1685  */
1686 static void allocate_coalesce_block(ir_node *block, void *data)
1687 {
1688         ir_nodeset_t   live_nodes;
1689         int            n_preds;
1690         block_info_t  *block_info;
1691         block_info_t **pred_block_infos;
1692         ir_node      **phi_ins;
1693         unsigned      *forbidden_regs; /**< collects registers which must
1694                                                 not be used for optimistic splits */
1695
1696         (void) data;
1697         DB((dbg, LEVEL_2, "* Block %+F\n", block));
1698
1699         /* clear assignments */
1700         block_info  = get_block_info(block);
1701         assignments = block_info->assignments;
1702
1703         ir_nodeset_init(&live_nodes);
1704
1705         /* gather regalloc infos of predecessor blocks */
1706         n_preds          = get_Block_n_cfgpreds(block);
1707         pred_block_infos = ALLOCAN(block_info_t*, n_preds);
1708         for (int i = 0; i < n_preds; ++i) {
1709                 ir_node      *pred      = get_Block_cfgpred_block(block, i);
1710                 block_info_t *pred_info = get_block_info(pred);
1711                 pred_block_infos[i]     = pred_info;
1712         }
1713
1714         phi_ins = ALLOCAN(ir_node*, n_preds);
1715
1716         /* collect live-in nodes and preassigned values */
1717         be_lv_foreach(lv, block, be_lv_state_in, node) {
1718                 bool                       need_phi = false;
1719                 const arch_register_req_t *req;
1720                 const arch_register_t     *reg;
1721                 int                        p;
1722
1723                 req  = arch_get_irn_register_req(node);
1724                 if (req->cls != cls)
1725                         continue;
1726
1727                 if (req->type & arch_register_req_type_ignore) {
1728                         allocation_info_t *info = get_allocation_info(node);
1729                         info->current_value = node;
1730
1731                         reg = arch_get_irn_register(node);
1732                         assert(reg != NULL); /* ignore values must be preassigned */
1733                         use_reg(node, reg);
1734                         continue;
1735                 }
1736
1737                 /* check all predecessors for this value, if it is not everywhere the
1738                    same or unknown then we have to construct a phi
1739                    (we collect the potential phi inputs here) */
1740                 for (p = 0; p < n_preds; ++p) {
1741                         block_info_t *pred_info = pred_block_infos[p];
1742
1743                         if (!pred_info->processed) {
1744                                 /* use node for now, it will get fixed later */
1745                                 phi_ins[p] = node;
1746                                 need_phi   = true;
1747                         } else {
1748                                 int a = find_value_in_block_info(pred_info, node);
1749
1750                                 /* must live out of predecessor */
1751                                 assert(a >= 0);
1752                                 phi_ins[p] = pred_info->assignments[a];
1753                                 /* different value from last time? then we need a phi */
1754                                 if (p > 0 && phi_ins[p-1] != phi_ins[p]) {
1755                                         need_phi = true;
1756                                 }
1757                         }
1758                 }
1759
1760                 if (need_phi) {
1761                         ir_mode *mode = get_irn_mode(node);
1762                         ir_node *phi  = be_new_Phi(block, n_preds, phi_ins, mode,
1763                                                    cls->class_req);
1764
1765                         DB((dbg, LEVEL_3, "Create Phi %+F (for %+F) -", phi, node));
1766 #ifdef DEBUG_libfirm
1767                         {
1768                                 int pi;
1769                                 for (pi = 0; pi < n_preds; ++pi) {
1770                                         DB((dbg, LEVEL_3, " %+F", phi_ins[pi]));
1771                                 }
1772                                 DB((dbg, LEVEL_3, "\n"));
1773                         }
1774 #endif
1775                         mark_as_copy_of(phi, node);
1776                         sched_add_after(block, phi);
1777
1778                         node = phi;
1779                 } else {
1780                         allocation_info_t *info = get_allocation_info(node);
1781                         info->current_value = phi_ins[0];
1782
1783                         /* Grab 1 of the inputs we constructed (might not be the same as
1784                          * "node" as we could see the same copy of the value in all
1785                          * predecessors */
1786                         node = phi_ins[0];
1787                 }
1788
1789                 /* if the node already has a register assigned use it */
1790                 reg = arch_get_irn_register(node);
1791                 if (reg != NULL) {
1792                         use_reg(node, reg);
1793                 }
1794
1795                 /* remember that this node is live at the beginning of the block */
1796                 ir_nodeset_insert(&live_nodes, node);
1797         }
1798
1799         rbitset_alloca(forbidden_regs, n_regs);
1800
1801         /* handle phis... */
1802         assign_phi_registers(block);
1803
1804         /* all live-ins must have a register */
1805 #ifdef DEBUG_libfirm
1806         foreach_ir_nodeset(&live_nodes, node, iter) {
1807                 const arch_register_t *reg = arch_get_irn_register(node);
1808                 assert(reg != NULL);
1809         }
1810 #endif
1811
1812         /* assign instructions in the block */
1813         sched_foreach(block, node) {
1814                 int arity;
1815                 ir_node *value;
1816
1817                 /* phis are already assigned */
1818                 if (is_Phi(node))
1819                         continue;
1820
1821                 rewire_inputs(node);
1822
1823                 /* enforce use constraints */
1824                 rbitset_clear_all(forbidden_regs, n_regs);
1825                 enforce_constraints(&live_nodes, node, forbidden_regs);
1826
1827                 rewire_inputs(node);
1828
1829                 /* we may not use registers used for inputs for optimistic splits */
1830                 arity = get_irn_arity(node);
1831                 for (int i = 0; i < arity; ++i) {
1832                         ir_node *op = get_irn_n(node, i);
1833                         const arch_register_t *reg;
1834                         if (!arch_irn_consider_in_reg_alloc(cls, op))
1835                                 continue;
1836
1837                         reg = arch_get_irn_register(op);
1838                         rbitset_set(forbidden_regs, arch_register_get_index(reg));
1839                 }
1840
1841                 /* free registers of values last used at this instruction */
1842                 free_last_uses(&live_nodes, node);
1843
1844                 /* assign output registers */
1845                 be_foreach_definition_(node, cls, value,
1846                         assign_reg(block, value, forbidden_regs);
1847                 );
1848         }
1849
1850         ir_nodeset_destroy(&live_nodes);
1851         assignments = NULL;
1852
1853         block_info->processed = true;
1854
1855         /* permute values at end of predecessor blocks in case of phi-nodes */
1856         if (n_preds > 1) {
1857                 int p;
1858                 for (p = 0; p < n_preds; ++p) {
1859                         add_phi_permutations(block, p);
1860                 }
1861         }
1862
1863         /* if we have exactly 1 successor then we might be able to produce phi
1864            copies now */
1865         if (get_irn_n_edges_kind(block, EDGE_KIND_BLOCK) == 1) {
1866                 const ir_edge_t *edge
1867                         = get_irn_out_edge_first_kind(block, EDGE_KIND_BLOCK);
1868                 ir_node      *succ      = get_edge_src_irn(edge);
1869                 int           p         = get_edge_src_pos(edge);
1870                 block_info_t *succ_info = get_block_info(succ);
1871
1872                 if (succ_info->processed) {
1873                         add_phi_permutations(succ, p);
1874                 }
1875         }
1876 }
1877
1878 typedef struct block_costs_t block_costs_t;
1879 struct block_costs_t {
1880         float costs;   /**< costs of the block */
1881         int   dfs_num; /**< depth first search number (to detect backedges) */
1882 };
1883
1884 static int cmp_block_costs(const void *d1, const void *d2)
1885 {
1886         const ir_node       * const *block1 = (const ir_node**)d1;
1887         const ir_node       * const *block2 = (const ir_node**)d2;
1888         const block_costs_t *info1  = (const block_costs_t*)get_irn_link(*block1);
1889         const block_costs_t *info2  = (const block_costs_t*)get_irn_link(*block2);
1890         return QSORT_CMP(info2->costs, info1->costs);
1891 }
1892
1893 static void determine_block_order(void)
1894 {
1895         size_t    p;
1896         ir_node **blocklist = be_get_cfgpostorder(irg);
1897         size_t    n_blocks  = ARR_LEN(blocklist);
1898         int       dfs_num   = 0;
1899         pdeq     *worklist  = new_pdeq();
1900         ir_node **order     = XMALLOCN(ir_node*, n_blocks);
1901         size_t    order_p   = 0;
1902
1903         /* clear block links... */
1904         for (p = 0; p < n_blocks; ++p) {
1905                 ir_node *block = blocklist[p];
1906                 set_irn_link(block, NULL);
1907         }
1908
1909         /* walk blocks in reverse postorder, the costs for each block are the
1910          * sum of the costs of its predecessors (excluding the costs on backedges
1911          * which we can't determine) */
1912         for (p = n_blocks; p > 0;) {
1913                 block_costs_t *cost_info;
1914                 ir_node *block = blocklist[--p];
1915
1916                 float execfreq   = (float)get_block_execfreq(execfreqs, block);
1917                 float costs      = execfreq;
1918                 int   n_cfgpreds = get_Block_n_cfgpreds(block);
1919                 int   p2;
1920                 for (p2 = 0; p2 < n_cfgpreds; ++p2) {
1921                         ir_node       *pred_block = get_Block_cfgpred_block(block, p2);
1922                         block_costs_t *pred_costs = (block_costs_t*)get_irn_link(pred_block);
1923                         /* we don't have any info for backedges */
1924                         if (pred_costs == NULL)
1925                                 continue;
1926                         costs += pred_costs->costs;
1927                 }
1928
1929                 cost_info          = OALLOCZ(&obst, block_costs_t);
1930                 cost_info->costs   = costs;
1931                 cost_info->dfs_num = dfs_num++;
1932                 set_irn_link(block, cost_info);
1933         }
1934
1935         /* sort array by block costs */
1936         qsort(blocklist, n_blocks, sizeof(blocklist[0]), cmp_block_costs);
1937
1938         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1939         inc_irg_block_visited(irg);
1940
1941         for (p = 0; p < n_blocks; ++p) {
1942                 ir_node       *block = blocklist[p];
1943                 if (Block_block_visited(block))
1944                         continue;
1945
1946                 /* continually add predecessors with highest costs to worklist
1947                  * (without using backedges) */
1948                 do {
1949                         block_costs_t *info       = (block_costs_t*)get_irn_link(block);
1950                         ir_node       *best_pred  = NULL;
1951                         float          best_costs = -1;
1952                         int            n_cfgpred  = get_Block_n_cfgpreds(block);
1953                         int            i;
1954
1955                         pdeq_putr(worklist, block);
1956                         mark_Block_block_visited(block);
1957                         for (i = 0; i < n_cfgpred; ++i) {
1958                                 ir_node       *pred_block = get_Block_cfgpred_block(block, i);
1959                                 block_costs_t *pred_info  = (block_costs_t*)get_irn_link(pred_block);
1960
1961                                 /* ignore backedges */
1962                                 if (pred_info->dfs_num > info->dfs_num)
1963                                         continue;
1964
1965                                 if (info->costs > best_costs) {
1966                                         best_costs = info->costs;
1967                                         best_pred  = pred_block;
1968                                 }
1969                         }
1970                         block = best_pred;
1971                 } while (block != NULL && !Block_block_visited(block));
1972
1973                 /* now put all nodes in the worklist in our final order */
1974                 while (!pdeq_empty(worklist)) {
1975                         ir_node *pblock = (ir_node*)pdeq_getr(worklist);
1976                         assert(order_p < n_blocks);
1977                         order[order_p++] = pblock;
1978                 }
1979         }
1980         assert(order_p == n_blocks);
1981         del_pdeq(worklist);
1982
1983         ir_free_resources(irg, IR_RESOURCE_BLOCK_VISITED);
1984
1985         DEL_ARR_F(blocklist);
1986
1987         obstack_free(&obst, NULL);
1988         obstack_init(&obst);
1989
1990         block_order   = order;
1991         n_block_order = n_blocks;
1992 }
1993
1994 /**
1995  * Run the register allocator for the current register class.
1996  */
1997 static void be_pref_alloc_cls(void)
1998 {
1999         size_t i;
2000
2001         be_assure_live_sets(irg);
2002         lv = be_get_irg_liveness(irg);
2003
2004         ir_reserve_resources(irg, IR_RESOURCE_IRN_LINK);
2005
2006         DB((dbg, LEVEL_2, "=== Allocating registers of %s ===\n", cls->name));
2007
2008         be_clear_links(irg);
2009
2010         irg_block_walk_graph(irg, NULL, analyze_block, NULL);
2011         if (create_congruence_classes)
2012                 combine_congruence_classes();
2013
2014         for (i = 0; i < n_block_order; ++i) {
2015                 ir_node *block = block_order[i];
2016                 allocate_coalesce_block(block, NULL);
2017         }
2018
2019         ir_free_resources(irg, IR_RESOURCE_IRN_LINK);
2020 }
2021
2022 static void dump(int mask, ir_graph *irg, const char *suffix)
2023 {
2024         if (be_options.dump_flags & mask)
2025                 dump_ir_graph(irg, suffix);
2026 }
2027
2028 /**
2029  * Run the spiller on the current graph.
2030  */
2031 static void spill(void)
2032 {
2033         /* make sure all nodes show their real register pressure */
2034         be_timer_push(T_RA_CONSTR);
2035         be_pre_spill_prepare_constr(irg, cls);
2036         be_timer_pop(T_RA_CONSTR);
2037
2038         dump(DUMP_RA, irg, "spillprepare");
2039
2040         /* spill */
2041         be_timer_push(T_RA_SPILL);
2042         be_do_spill(irg, cls);
2043         be_timer_pop(T_RA_SPILL);
2044
2045         be_timer_push(T_RA_SPILL_APPLY);
2046         check_for_memory_operands(irg);
2047         be_timer_pop(T_RA_SPILL_APPLY);
2048
2049         dump(DUMP_RA, irg, "spill");
2050 }
2051
2052 /**
2053  * The pref register allocator for a whole procedure.
2054  */
2055 static void be_pref_alloc(ir_graph *new_irg)
2056 {
2057         const arch_env_t *arch_env = be_get_irg_arch_env(new_irg);
2058         int   n_cls                = arch_env->n_register_classes;
2059         int   c;
2060
2061         obstack_init(&obst);
2062
2063         irg       = new_irg;
2064         execfreqs = be_get_irg_exec_freq(irg);
2065
2066         /* determine a good coloring order */
2067         determine_block_order();
2068
2069         for (c = 0; c < n_cls; ++c) {
2070                 cls = &arch_env->register_classes[c];
2071                 if (arch_register_class_flags(cls) & arch_register_class_flag_manual_ra)
2072                         continue;
2073
2074                 stat_ev_ctx_push_str("regcls", cls->name);
2075
2076                 n_regs      = arch_register_class_n_regs(cls);
2077                 normal_regs = rbitset_malloc(n_regs);
2078                 be_set_allocatable_regs(irg, cls, normal_regs);
2079
2080                 spill();
2081
2082                 /* verify schedule and register pressure */
2083                 be_timer_push(T_VERIFY);
2084                 if (be_options.verify_option == BE_VERIFY_WARN) {
2085                         be_verify_schedule(irg);
2086                         be_verify_register_pressure(irg, cls);
2087                 } else if (be_options.verify_option == BE_VERIFY_ASSERT) {
2088                         assert(be_verify_schedule(irg) && "Schedule verification failed");
2089                         assert(be_verify_register_pressure(irg, cls)
2090                                 && "Register pressure verification failed");
2091                 }
2092                 be_timer_pop(T_VERIFY);
2093
2094                 be_timer_push(T_RA_COLOR);
2095                 be_pref_alloc_cls();
2096                 be_timer_pop(T_RA_COLOR);
2097
2098                 /* we most probably constructed new Phis so liveness info is invalid
2099                  * now */
2100                 be_invalidate_live_sets(irg);
2101                 free(normal_regs);
2102
2103                 stat_ev_ctx_pop("regcls");
2104         }
2105
2106         be_timer_push(T_RA_SPILL_APPLY);
2107         be_abi_fix_stack_nodes(irg);
2108         be_timer_pop(T_RA_SPILL_APPLY);
2109
2110         be_timer_push(T_VERIFY);
2111         if (be_options.verify_option == BE_VERIFY_WARN) {
2112                 be_verify_register_allocation(irg);
2113         } else if (be_options.verify_option == BE_VERIFY_ASSERT) {
2114                 assert(be_verify_register_allocation(irg)
2115                        && "Register allocation invalid");
2116         }
2117         be_timer_pop(T_VERIFY);
2118
2119         obstack_free(&obst, NULL);
2120 }
2121
2122 BE_REGISTER_MODULE_CONSTRUCTOR(be_init_pref_alloc)
2123 void be_init_pref_alloc(void)
2124 {
2125         static be_ra_t be_ra_pref = {
2126                 be_pref_alloc,
2127         };
2128         lc_opt_entry_t *be_grp              = lc_opt_get_grp(firm_opt_get_root(), "be");
2129         lc_opt_entry_t *prefalloc_group = lc_opt_get_grp(be_grp, "prefalloc");
2130         lc_opt_add_table(prefalloc_group, options);
2131
2132         be_register_allocator("pref", &be_ra_pref);
2133         FIRM_DBG_REGISTER(dbg, "firm.be.prefalloc");
2134 }