nsz Git - libfirm/blob - ir/ana/vrp.c

   1 /*
   2  * Copyright (C) 1995-2010 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   analyze graph to provide value range information
  23  * @author  Jonas Fietz
  24  */
  25 #include "config.h"
  26
  27 #include "irtypes.h"
  28 #include "vrp.h"
  29 #include "iroptimize.h"
  30 #include "irouts.h"
  31 #include "irgraph_t.h"
  32 #include "irgopt.h"
  33 #include "irpass.h"
  34 #include "irgwalk.h"
  35 #include "iredges.h"
  36 #include "tv.h"
  37 #include "irop.h"
  38 #include "pdeq.h"
  39 #include "irnodemap.h"
  40 #include "irhooks.h"
  41 #include "bitset.h"
  42 #include "debug.h"
  43
  44 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  45
  46 typedef struct vrp_env_t {
  47         waitq       *workqueue;
  48         bitset_t    *visited;
  49         ir_vrp_info *info;
  50 } vrp_env_t;
  51
  52 static vrp_attr *vrp_get_or_set_info(ir_vrp_info *info, const ir_node *node)
  53 {
  54         vrp_attr *attr = ir_nodemap_get(vrp_attr, &info->infos, node);
  55         if (attr == NULL) {
  56                 ir_mode *mode = get_irn_mode(node);
  57                 assert(mode_is_int(mode));
  58
  59                 attr = OALLOCZ(&info->obst, vrp_attr);
  60                 attr->range_type   = VRP_UNDEFINED;
  61                 attr->bits_set     = get_mode_null(mode);
  62                 attr->bits_not_set = get_mode_all_one(mode);
  63                 attr->range_bottom = get_tarval_top();
  64                 attr->range_top    = get_tarval_top();
  65
  66                 ir_nodemap_insert(&info->infos, node, attr);
  67         }
  68         return attr;
  69 }
  70
  71 vrp_attr *vrp_get_info(const ir_node *node)
  72 {
  73         ir_graph *irg = get_irn_irg(node);
  74         if (irg->vrp.infos.data == NULL)
  75                 return NULL;
  76         return ir_nodemap_get(vrp_attr, &irg->vrp.infos, node);
  77 }
  78
  79 static int vrp_update_node(ir_vrp_info *info, ir_node *node)
  80 {
  81         ir_tarval *new_bits_set = get_tarval_bad();
  82         ir_tarval *new_bits_not_set = get_tarval_bad();
  83         ir_tarval *new_range_bottom = get_tarval_bad();
  84         ir_tarval *new_range_top = get_tarval_bad();
  85         enum range_types new_range_type = VRP_UNDEFINED;
  86         int something_changed = 0;
  87         vrp_attr *vrp;
  88
  89         if (!mode_is_int(get_irn_mode(node))) {
  90                 return 0; /* we don't optimize for non-int-nodes*/
  91         }
  92
  93         vrp = vrp_get_or_set_info(info, node);
  94
  95         /* TODO: Check if all predecessors have valid VRP information*/
  96
  97         switch (get_irn_opcode(node)) {
  98         case iro_Const: {
  99                 ir_tarval *tv = get_Const_tarval(node);
 100                 new_bits_set = tv;
 101                 new_bits_not_set = tv;
 102                 new_range_bottom = tv;
 103                 new_range_top = tv;
 104                 new_range_type = VRP_RANGE;
 105                 break;
 106         }
 107         case iro_And: {
 108                 const vrp_attr *vrp_left, *vrp_right;
 109                 const ir_node *left, *right;
 110
 111                 left = get_And_left(node);
 112                 right = get_And_right(node);
 113                 vrp_left = vrp_get_or_set_info(info, left);
 114                 vrp_right = vrp_get_or_set_info(info, right);
 115                 new_bits_set = tarval_and(vrp_left->bits_set, vrp_right->bits_set);
 116                 new_bits_not_set = tarval_and(vrp_left->bits_not_set, vrp_right->bits_not_set);
 117
 118                 break;
 119         }
 120
 121         case iro_Add: {
 122                 const vrp_attr *vrp_left  = vrp_get_or_set_info(info, get_Add_left(node));
 123                 const vrp_attr *vrp_right = vrp_get_or_set_info(info, get_Add_right(node));
 124
 125                 if (vrp_left->range_type == VRP_UNDEFINED
 126                  || vrp_right->range_type == VRP_UNDEFINED
 127                  || vrp_left->range_type == VRP_VARYING
 128                  || vrp_right->range_type == VRP_VARYING) {
 129                         return 0;
 130                 }
 131
 132                 if (vrp_left->range_type == VRP_RANGE
 133                  && vrp_right->range_type == VRP_RANGE) {
 134                         tarval_int_overflow_mode_t rem = tarval_get_integer_overflow_mode();
 135                         tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
 136                         ir_tarval *new_top
 137                                 = tarval_add(vrp_left->range_top, vrp_right->range_top);
 138                         ir_tarval *new_bottom
 139                                 = tarval_add(vrp_left->range_bottom, vrp_right->range_bottom);
 140                         tarval_set_integer_overflow_mode(rem);
 141
 142                         if (new_top != tarval_bad && new_bottom != tarval_bad) {
 143                                 new_range_bottom = new_bottom;
 144                                 new_range_top    = new_top;
 145                                 new_range_type   = VRP_RANGE;
 146                         } else {
 147                                 /* TODO Implement overflow handling*/
 148                                 new_range_type = VRP_UNDEFINED;
 149                         }
 150                 }
 151                 break;
 152         }
 153
 154         case iro_Sub: {
 155                 ir_node *left  = get_Sub_left(node);
 156                 ir_node *right = get_Sub_right(node);
 157
 158                 if (!mode_is_int(get_irn_mode(left)))
 159                         return 0;
 160
 161                 const vrp_attr *vrp_left  = vrp_get_or_set_info(info, left);
 162                 const vrp_attr *vrp_right = vrp_get_or_set_info(info, right);
 163
 164                 if (vrp_left->range_type == VRP_UNDEFINED
 165                  || vrp_right->range_type == VRP_UNDEFINED
 166                  || vrp_left->range_type == VRP_VARYING
 167                  || vrp_right->range_type == VRP_VARYING) {
 168                         return 0;
 169                 }
 170
 171                 if (vrp_left->range_type == VRP_RANGE
 172                  && vrp_right->range_type == VRP_RANGE) {
 173                         tarval_int_overflow_mode_t rem = tarval_get_integer_overflow_mode();
 174                         tarval_set_integer_overflow_mode(TV_OVERFLOW_BAD);
 175                         ir_tarval *new_top = tarval_sub(vrp_left->range_top, vrp_right->range_top, NULL);
 176                         ir_tarval *new_bottom = tarval_sub(vrp_left->range_bottom, vrp_right->range_bottom, NULL);
 177                         tarval_set_integer_overflow_mode(rem);
 178
 179                         if (new_top != tarval_bad && new_bottom != tarval_bad) {
 180                                 new_range_bottom = new_bottom;
 181                                 new_range_top = new_top;
 182                                 new_range_type = VRP_RANGE;
 183                         } else {
 184                                 /* TODO Implement overflow handling*/
 185                                 new_range_type = VRP_UNDEFINED;
 186                         }
 187                 }
 188                 break;
 189         }
 190
 191         case iro_Or: {
 192                 const vrp_attr *vrp_left, *vrp_right;
 193
 194                 vrp_left = vrp_get_or_set_info(info, get_Or_left(node));
 195                 vrp_right = vrp_get_or_set_info(info, get_Or_right(node));
 196
 197                 new_bits_set = tarval_or(vrp_left->bits_set, vrp_right->bits_set);
 198                 new_bits_not_set = tarval_or(vrp_left->bits_not_set, vrp_right->bits_not_set);
 199
 200                 break;
 201         }
 202
 203         case iro_Rotl: {
 204                 const vrp_attr *vrp_left;
 205                 const ir_node *right = get_Rotl_right(node);
 206
 207                 vrp_left = vrp_get_or_set_info(info, get_Rotl_left(node));
 208
 209                 /* We can only compute this if the right value is a constant*/
 210                 if (is_Const(right)) {
 211                         new_bits_set = tarval_rotl(vrp_left->bits_set, get_Const_tarval(right));
 212                         new_bits_not_set = tarval_rotl(vrp_left->bits_not_set, get_Const_tarval(right));
 213                 }
 214                 break;
 215         }
 216
 217         case iro_Shl: {
 218                 const vrp_attr *vrp_left;
 219                 const ir_node *right = get_Shl_right(node);
 220                 vrp_left = vrp_get_or_set_info(info, get_Shl_left(node));
 221
 222                 /* We can only compute this if the right value is a constant*/
 223                 if (is_Const(right)) {
 224                         new_bits_set = tarval_shl(vrp_left->bits_set, get_Const_tarval(right));
 225                         new_bits_not_set = tarval_shl(vrp_left->bits_not_set, get_Const_tarval(right));
 226                 }
 227                 break;
 228         }
 229
 230         case iro_Shr: {
 231                 const vrp_attr *vrp_left;
 232                 const ir_node *right = get_Shr_right(node);
 233
 234                 vrp_left = vrp_get_or_set_info(info, get_Shr_left(node));
 235
 236                 /* We can only compute this if the right value is a constant*/
 237                 if (is_Const(right)) {
 238                         new_bits_set = tarval_shr(vrp_left->bits_set, get_Const_tarval(right));
 239                         new_bits_not_set = tarval_shr(vrp_left->bits_not_set, get_Const_tarval(right));
 240                 }
 241                 break;
 242         }
 243
 244         case iro_Shrs: {
 245                 const vrp_attr *vrp_left;
 246                 const ir_node *right = get_Shrs_right(node);
 247
 248                 vrp_left = vrp_get_or_set_info(info, get_Shrs_left(node));
 249
 250                 /* We can only compute this if the right value is a constant*/
 251                 if (is_Const(right)) {
 252                         new_bits_set = tarval_shrs(vrp_left->bits_set, get_Const_tarval(right));
 253                         new_bits_not_set = tarval_shrs(vrp_left->bits_not_set, get_Const_tarval(right));
 254                 }
 255                 break;
 256         }
 257
 258         case iro_Eor: {
 259                 const vrp_attr *vrp_left, *vrp_right;
 260
 261                 vrp_left = vrp_get_or_set_info(info, get_Eor_left(node));
 262                 vrp_right = vrp_get_or_set_info(info, get_Eor_right(node));
 263
 264                 new_bits_set = tarval_or(
 265                                                 tarval_and(vrp_left->bits_set, tarval_not(vrp_right->bits_not_set)),
 266                                                 tarval_and(tarval_not(vrp_left->bits_not_set), vrp_right->bits_set));
 267
 268                 new_bits_not_set = tarval_not(tarval_or(
 269                                 tarval_and(vrp_left->bits_set,vrp_right->bits_set),
 270                                                         tarval_and(tarval_not(vrp_left->bits_not_set),
 271                                                                 tarval_not(vrp_right->bits_not_set))));
 272
 273                 break;
 274         }
 275
 276         case iro_Id: {
 277                 const vrp_attr *vrp_pred = vrp_get_or_set_info(info, get_Id_pred(node));
 278                 new_bits_set = vrp_pred->bits_set;
 279                 new_bits_not_set = vrp_pred->bits_not_set;
 280                 new_range_top = vrp_pred->range_top;
 281                 new_range_bottom = vrp_pred->range_bottom;
 282                 new_range_type = vrp_pred->range_type;
 283                 break;
 284         }
 285
 286         case iro_Not: {
 287                 const vrp_attr *vrp_pred = vrp_get_or_set_info(info, get_Not_op(node));
 288                 new_bits_set = tarval_not(vrp_pred->bits_not_set);
 289                 new_bits_not_set = tarval_not(vrp_pred->bits_set);
 290                 break;
 291         }
 292
 293         case iro_Conv: {
 294                 const ir_node *pred = get_Conv_op(node);
 295                 ir_mode *old_mode = get_irn_mode(pred);
 296                 const vrp_attr *vrp_pred;
 297
 298                 ir_mode *new_mode;
 299
 300                 if (!mode_is_int(old_mode))
 301                         return 0;
 302
 303                 vrp_pred = vrp_get_or_set_info(info, pred);
 304                 new_mode = get_irn_mode(node);
 305
 306                 /* The second and is needed if target type is smaller*/
 307                 new_bits_not_set = tarval_convert_to(get_mode_all_one(old_mode), new_mode);
 308                 new_bits_not_set = tarval_and(new_bits_not_set, tarval_convert_to(vrp_pred->bits_not_set, new_mode));
 309                 new_bits_set = tarval_and(
 310                                 new_bits_not_set, tarval_convert_to(vrp_pred->bits_set, new_mode));
 311
 312                 /* Matze: TODO, BUGGY, tarval_cmp never returns ir_relation_less_equal */
 313                 if (tarval_cmp(vrp_pred->range_top, get_mode_max(new_mode)) == ir_relation_less_equal) {
 314                         vrp->range_top = vrp_pred->range_top;
 315                 }
 316
 317                 /* Matze: TODO, BUGGY, tarval_cmp never returns ir_relation_greater_equal */
 318                 if (tarval_cmp(vrp_pred->range_bottom, get_mode_min(new_mode)) == ir_relation_greater_equal) {
 319                         vrp->range_bottom = vrp_pred->range_bottom;
 320                 }
 321                 break;
 322         }
 323
 324         case iro_Confirm: {
 325                 const ir_relation relation = get_Confirm_relation(node);
 326                 const ir_node    *bound    = get_Confirm_bound(node);
 327
 328
 329                 if (relation == ir_relation_less_greater) {
 330                         /** @todo: Handle non-Const bounds */
 331                         if (is_Const(bound)) {
 332                                 new_range_type = VRP_ANTIRANGE;
 333                                 new_range_top = get_Const_tarval(bound);
 334                                 new_range_bottom = get_Const_tarval(bound);
 335                         }
 336                 } else if (relation == ir_relation_less_equal) {
 337                         if (is_Const(bound)) {
 338                                 new_range_type = VRP_RANGE;
 339                                 new_range_top = get_Const_tarval(bound);
 340                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 341                         }
 342                 }
 343                 break;
 344         }
 345
 346         case iro_Phi: {
 347                 /* combine all ranges*/
 348
 349                 int num = get_Phi_n_preds(node);
 350                 ir_relation relation;
 351                 int i;
 352
 353                 const ir_node *pred = get_Phi_pred(node,0);
 354                 const vrp_attr *vrp_pred = vrp_get_or_set_info(info, pred);
 355                 new_range_top = vrp_pred->range_top;
 356                 new_range_bottom = vrp_pred->range_bottom;
 357                 new_range_type = vrp_pred->range_type;
 358                 new_bits_set = vrp_pred->bits_set;
 359                 new_bits_not_set = vrp_pred->bits_not_set;
 360
 361                 assert(num > 0);
 362
 363                 for (i = 1; i < num; i++) {
 364                         pred = get_Phi_pred(node, i);
 365                         vrp_pred = vrp_get_or_set_info(info, pred);
 366                         if (new_range_type == VRP_RANGE && vrp_pred->range_type ==
 367                                         VRP_RANGE) {
 368                                 relation = tarval_cmp(new_range_top, vrp_pred->range_top);
 369                                 if (relation == ir_relation_less) {
 370                                         new_range_top = vrp_pred->range_top;
 371                                 }
 372                                 relation = tarval_cmp(new_range_bottom, vrp_pred->range_bottom);
 373                                 if (relation == ir_relation_greater) {
 374                                         new_range_bottom = vrp_pred->range_bottom;
 375                                 }
 376                         } else {
 377                                 new_range_type = VRP_VARYING;
 378                         }
 379                         new_bits_set = tarval_and(new_bits_set, vrp_pred->bits_set);
 380                         new_bits_not_set = tarval_or(new_bits_not_set,
 381                                         vrp_pred->bits_not_set);
 382                 }
 383
 384                 break;
 385         }
 386         default:
 387                 /* unhandled, therefore never updated */
 388                 break;
 389         }
 390
 391
 392
 393         /* TODO: Check, if there can be information derived from any of these:
 394         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 395         is_Break(node) is_Builtin(node) is_Call(node)
 396         is_Carry(node) is_Cmp(node) is_Cond(node)
 397         is_CopyB(node) is_Div(node) is_Dummy(node)
 398         is_End(node) is_Free(node)
 399         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 400         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 401         is_Pin(node) is_Proj(node)
 402         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 403         is_SymConst(node) is_Sync(node) is_Tuple(node)
 404         */
 405
 406         /* @todo: At this place, we check if the mode of the variable changed. A
 407          * better place for this might be in the convopt.c file
 408          */
 409
 410         if (new_bits_set != tarval_bad && get_tarval_mode(new_bits_set) != get_tarval_mode(vrp->bits_set)) {
 411                 vrp->bits_set = tarval_convert_to(vrp->bits_set, get_irn_mode(node));
 412         }
 413         if (new_bits_not_set != tarval_bad && get_tarval_mode(new_bits_not_set) != get_tarval_mode(vrp->bits_not_set)) {
 414                 vrp->bits_not_set = tarval_convert_to(vrp->bits_not_set, get_irn_mode(node));
 415         }
 416
 417         if (vrp->range_type != VRP_UNDEFINED && new_range_type != VRP_UNDEFINED && get_tarval_mode(new_range_top) != get_tarval_mode(vrp->range_top)) {
 418                 /* @todo: We might be able to preserve this range information if it
 419                  * fits in */
 420                 vrp->range_type = VRP_VARYING;
 421         }
 422
 423         /* Merge the newly calculated values with those that might already exist*/
 424         if (new_bits_set != tarval_bad) {
 425                 new_bits_set = tarval_or(new_bits_set, vrp->bits_set);
 426                 if (new_bits_set != vrp->bits_set) {
 427                         something_changed = 1;
 428                         vrp->bits_set = new_bits_set;
 429                 }
 430         }
 431         if (new_bits_not_set != tarval_bad) {
 432                 new_bits_not_set = tarval_and(new_bits_not_set, vrp->bits_not_set);
 433
 434                 if (new_bits_not_set != vrp->bits_not_set) {
 435                         something_changed = 1;
 436                         vrp->bits_not_set = new_bits_not_set;
 437                 }
 438         }
 439
 440         if (vrp->range_type == VRP_UNDEFINED &&
 441                         new_range_type != VRP_UNDEFINED) {
 442                 something_changed = 1;
 443                 vrp->range_type = new_range_type;
 444                 vrp->range_bottom = new_range_bottom;
 445                 vrp->range_top = new_range_top;
 446
 447         } else if (vrp->range_type == VRP_RANGE) {
 448                 if (new_range_type == VRP_RANGE) {
 449                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == ir_relation_less) {
 450                                 something_changed = 1;
 451                                 vrp->range_bottom = new_range_bottom;
 452                         }
 453                         if (tarval_cmp(vrp->range_top, new_range_top) == ir_relation_greater) {
 454                                 something_changed = 1;
 455                                 vrp->range_top = new_range_top;
 456                         }
 457                 }
 458
 459                 if (new_range_type == VRP_ANTIRANGE) {
 460                         /* if they are overlapping, cut the range.*/
 461                         /* TODO: Maybe we can preserve more information here*/
 462                         if (tarval_cmp(vrp->range_bottom, new_range_top) == ir_relation_greater &&
 463                                         tarval_cmp(vrp->range_bottom, new_range_bottom) == ir_relation_greater) {
 464                                 something_changed = 1;
 465                                 vrp->range_bottom = new_range_top;
 466
 467                         } else if (tarval_cmp(vrp->range_top, new_range_bottom) == ir_relation_greater &&
 468                                         tarval_cmp(vrp->range_top, new_range_top) == ir_relation_less) {
 469                                 something_changed = 1;
 470                                 vrp->range_top = new_range_bottom;
 471                         }
 472
 473                         /* We can not handle the case where the anti range is in the*/
 474                         /* range*/
 475
 476                 }
 477         } else if (vrp->range_type == VRP_ANTIRANGE) {
 478                 if (new_range_type == VRP_ANTIRANGE) {
 479                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == ir_relation_greater) {
 480                                 something_changed = 1;
 481                                 vrp->range_bottom = new_range_bottom;
 482                         }
 483                         if (tarval_cmp(vrp->range_top, new_range_top) == ir_relation_less) {
 484                                 something_changed = 1;
 485                                 vrp->range_top = new_range_top;
 486                         }
 487                 }
 488
 489                 if (new_range_type == VRP_RANGE) {
 490                         if (tarval_cmp(vrp->range_bottom, new_range_top) == ir_relation_greater) {
 491                                 something_changed = 1;
 492                                 vrp->range_bottom = new_range_top;
 493                         }
 494                         if (tarval_cmp(vrp->range_top, new_range_bottom) == ir_relation_less) {
 495                                 something_changed = 1;
 496                                 vrp->range_top = new_range_bottom;
 497                         }
 498                 }
 499         }
 500
 501         assert(tarval_is_null(
 502                                 tarval_and(vrp->bits_set, tarval_not(vrp->bits_not_set))));
 503         return something_changed;
 504 }
 505
 506 static void vrp_first_pass(ir_node *n, void *e)
 507 {
 508         int i;
 509         vrp_env_t *env = (vrp_env_t*) e;
 510
 511         if (is_Block(n))
 512                 return;
 513
 514         bitset_set(env->visited, get_irn_idx(n));
 515
 516         vrp_update_node(env->info, n);
 517
 518         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 519                 ir_node *succ = get_irn_out(n, i);
 520                 if (bitset_is_set(env->visited, get_irn_idx(succ))) {
 521                         /* we found a loop*/
 522                         waitq_put(env->workqueue, succ);
 523                 }
 524         }
 525 }
 526
 527 static void dump_vrp_info(void *ctx, FILE *F, const ir_node *node)
 528 {
 529         vrp_attr *vrp;
 530
 531         (void) ctx;
 532         if (!mode_is_int(get_irn_mode(node)))
 533                 return;
 534
 535         vrp = vrp_get_info(node);
 536         if (vrp == NULL)
 537                 return;
 538
 539         fprintf(F, "vrp range type: %d\n", (int) vrp->range_type);
 540         if (vrp->range_type == VRP_RANGE || vrp->range_type == VRP_ANTIRANGE) {
 541                 ir_fprintf(F, "vrp range bottom: %T\n",vrp->range_bottom);
 542                 ir_fprintf(F, "vrp range top: %T\n", vrp->range_top);
 543         }
 544         ir_fprintf(F, "vrp bits set: %T\n", vrp->bits_set);
 545         ir_fprintf(F, "vrp bits not set: %T\n", vrp->bits_not_set);
 546 }
 547
 548 static hook_entry_t dump_hook;
 549
 550 void set_vrp_data(ir_graph *irg)
 551 {
 552         ir_node *succ, *node;
 553         int i;
 554         vrp_env_t *env;
 555         ir_vrp_info *info;
 556
 557         if (irg->vrp.infos.data != NULL)
 558                 free_vrp_data(irg);
 559
 560         FIRM_DBG_REGISTER(dbg, "ir.ana.vrp");
 561
 562         assure_irg_outs(irg); /* ensure that out edges are consistent*/
 563         ir_nodemap_init(&irg->vrp.infos, irg);
 564         obstack_init(&irg->vrp.obst);
 565         info = &irg->vrp;
 566
 567         if (dump_hook.hook._hook_node_info == NULL) {
 568                 dump_hook.hook._hook_node_info = dump_vrp_info;
 569                 register_hook(hook_node_info, &dump_hook);
 570         }
 571
 572         env = OALLOCZ(&irg->vrp.obst, vrp_env_t);
 573         env->workqueue = new_waitq();
 574         env->info      = info;
 575
 576         env->visited = bitset_malloc(get_irg_last_idx(irg));
 577         irg_walk_graph(irg, NULL, vrp_first_pass, env);
 578         bitset_free(env->visited);
 579
 580         /* while there are entries in the worklist, continue*/
 581         while (!waitq_empty(env->workqueue)) {
 582                 node = (ir_node*) waitq_get(env->workqueue);
 583
 584                 if (vrp_update_node(info, node)) {
 585                         /* if something changed, add successors to worklist*/
 586                         for (i = get_irn_n_outs(node) - 1; i >= 0; --i) {
 587                                 succ =  get_irn_out(node, i);
 588                                 waitq_put(env->workqueue, succ);
 589                         }
 590                 }
 591         }
 592         del_waitq(env->workqueue);
 593 }
 594
 595 void free_vrp_data(ir_graph *irg)
 596 {
 597         if (irg->vrp.infos.data == NULL)
 598                 return;
 599         obstack_free(&irg->vrp.obst, NULL);
 600         ir_nodemap_destroy(&irg->vrp.infos);
 601 }
 602
 603 ir_graph_pass_t *set_vrp_pass(const char *name)
 604 {
 605         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 606 }
 607
 608 ir_relation vrp_cmp(const ir_node *left, const ir_node *right)
 609 {
 610         vrp_attr *vrp_left, *vrp_right;
 611
 612         if (!mode_is_int(get_irn_mode(left)))
 613                 return ir_relation_true;
 614
 615         vrp_left = vrp_get_info(left);
 616         vrp_right = vrp_get_info(right);
 617
 618         if (!vrp_left || !vrp_right)
 619                 return ir_relation_true;
 620
 621         if (vrp_left->range_type == VRP_RANGE && vrp_right->range_type == VRP_RANGE) {
 622                 if (tarval_cmp(vrp_left->range_top, vrp_right->range_bottom) == ir_relation_less) {
 623                         return ir_relation_less;
 624                 }
 625                 if (tarval_cmp(vrp_left->range_bottom, vrp_right->range_top) == ir_relation_greater) {
 626                         return ir_relation_greater;
 627                 }
 628         }
 629
 630         if (!tarval_is_null(tarval_and(vrp_left->bits_set, tarval_not(vrp_right->bits_not_set))) ||
 631                         !tarval_is_null(tarval_and(tarval_not(vrp_left->bits_not_set), vrp_right->bits_set))) {
 632                 return ir_relation_less_greater;
 633         }
 634
 635         /* TODO: We can get way more information here*/
 636         return ir_relation_true;
 637 }