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

   1 /*
   2  * Copyright (C) 1995-2009 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  * @version     $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "config.h"
  29 #include "irtypes.h"
  30 #include "vrp.h"
  31 #include "irouts.h"
  32 #include "irgraph_t.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
  40
  41 static char v;
  42 static void *VISITED = &v;
  43
  44 struct vrp_env_t {
  45         waitq *workqueue;
  46 };
  47
  48 static int update_vrp_data(ir_node *node)
  49 {
  50
  51         tarval *new_bits_set = get_tarval_bad();
  52         tarval *new_bits_not_set = get_tarval_bad();
  53         tarval *new_range_bottom = get_tarval_bad();
  54         tarval *new_range_top = get_tarval_bad();
  55         ir_node *new_bits_node = NULL;
  56         ir_node *new_range_node = NULL;
  57         enum range_types new_range_type = VRP_UNDEFINED;
  58         enum range_ops new_range_op = VRP_NONE;
  59         int something_changed = 0;
  60         tarval *tmp_tv, *tv;
  61         ir_node *left, *right, *pred, *bound;
  62         int overflow_top, overflow_bottom;
  63         tarval *new_top, *new_bottom;
  64
  65         pn_Cmp cmp;
  66
  67         node->vrp.valid = 1;
  68         /* TODO: Check if all predecessors have valid VRP information*/
  69
  70
  71         if (!mode_is_int(get_irn_mode(node))) {
  72                 return 0; /* we don't optimize for non-int-nodes*/
  73         }
  74
  75         switch (get_irn_opcode(node)) {
  76         case iro_Const:
  77                 tv = get_Const_tarval(node);
  78
  79                 new_bits_set = tv;
  80                 new_bits_not_set = tarval_not(tv);
  81                 new_range_bottom = tv;
  82                 new_range_top = tv;
  83                 new_range_type = VRP_RANGE;
  84                 break;
  85
  86         case iro_And:
  87                 left = get_And_left(node);
  88                 right = get_And_right(node);
  89
  90                 new_bits_set = tarval_and(left->vrp.bits_set, right->vrp.bits_set);
  91                 new_bits_not_set = tarval_or(left->vrp.bits_not_set, right->vrp.bits_not_set);
  92
  93                 tmp_tv = tarval_not(left->vrp.bits_set);
  94                 tmp_tv = tarval_eor(left->vrp.bits_not_set, tmp_tv);
  95                 /*check if one of the predecessors is completely determined*/
  96                 if (tarval_is_null(tmp_tv)) {
  97                         new_bits_node = right;
  98                 }
  99
 100                 tmp_tv = tarval_not(right->vrp.bits_set);
 101                 tmp_tv = tarval_eor(right->vrp.bits_not_set, tmp_tv);
 102                 if (tarval_is_null(tmp_tv)) {
 103                         new_bits_node = left;
 104                 }
 105                 break;
 106
 107         case iro_Add:
 108                 left = get_Add_left(node);
 109                 right = get_Add_right(node);
 110
 111
 112                 if (left->vrp.range_type == VRP_UNDEFINED || right->vrp.range_type ==
 113                                 VRP_UNDEFINED || left->vrp.range_type == VRP_VARYING ||
 114                                 right->vrp.range_type == VRP_VARYING) {
 115                         return 0;
 116                 }
 117
 118                 new_top = tarval_add(left->vrp.range_top, right->vrp.range_top);
 119                 overflow_top = tarval_carry();
 120                 new_bottom = tarval_add(left->vrp.range_bottom, right->vrp.range_bottom);
 121                 overflow_bottom = tarval_carry();
 122
 123                 if (!overflow_top && !overflow_bottom && left->vrp.range_type == VRP_RANGE
 124                                 &&right->vrp.range_type == VRP_RANGE) {
 125                         new_range_bottom = new_bottom;
 126                         new_range_top = new_top;
 127                         new_range_type = VRP_RANGE;
 128                 }
 129
 130                 if (overflow_top || overflow_bottom) {
 131                         /* TODO Implement overflow handling*/
 132                         new_range_type = VRP_UNDEFINED;
 133                 }
 134                 break;
 135
 136         case iro_Sub:
 137                 left = get_Sub_left(node);
 138                 right = get_Sub_right(node);
 139
 140                 if (left->vrp.range_type == VRP_UNDEFINED || right->vrp.range_type ==
 141                                 VRP_UNDEFINED) {
 142                         return 0;
 143                 }
 144
 145                 new_top = tarval_sub(left->vrp.range_top, right->vrp.range_top, NULL);
 146                 overflow_top = tarval_carry();
 147                 new_bottom = tarval_sub(left->vrp.range_bottom, right->vrp.range_bottom, NULL);
 148                 overflow_bottom = tarval_carry();
 149
 150                 if (!overflow_top && !overflow_bottom && left->vrp.range_type == VRP_RANGE
 151                                 &&right->vrp.range_type == VRP_RANGE) {
 152                         new_range_bottom = new_bottom;
 153                         new_range_top = new_top;
 154                         new_range_type = VRP_RANGE;
 155                 }
 156
 157                 if (overflow_top || overflow_bottom) {
 158                         /* TODO Implement overflow handling*/
 159                 }
 160                 break;
 161
 162         case iro_Or:
 163                 left = get_Or_left(node);
 164                 right = get_Or_right(node);
 165
 166                 new_bits_set = tarval_or(left->vrp.bits_set, right->vrp.bits_set);
 167                 new_bits_not_set = tarval_and(left->vrp.bits_not_set, right->vrp.bits_not_set);
 168
 169                 tmp_tv = tarval_not(left->vrp.bits_set);
 170                 tmp_tv = tarval_eor(left->vrp.bits_not_set, tmp_tv);
 171                 /*check if one of the predecessors is completely determined*/
 172                 if (tarval_is_null(tmp_tv)) {
 173                         new_bits_node = right;
 174                 }
 175
 176                 tmp_tv = tarval_not(right->vrp.bits_set);
 177                 tmp_tv = tarval_eor(right->vrp.bits_not_set, tmp_tv);
 178                 if (tarval_is_null(tmp_tv)) {
 179                         new_bits_node = left;
 180                 }
 181                 break;
 182
 183         case iro_Rotl:
 184                 left = get_Rotl_left(node);
 185                 right = get_Rotl_right(node);
 186
 187                 /* We can only compute this if the right value is a constant*/
 188                 if (is_Const(right)) {
 189                         tarval *bits_set, *bits_not_set;
 190                         bits_set = tarval_rotl(left->vrp.bits_set, get_Const_tarval(right));
 191                         bits_not_set = tarval_rotl(left->vrp.bits_not_set, get_Const_tarval(right));
 192
 193                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 194                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 195                 }
 196                 break;
 197
 198         case iro_Shl:
 199                 left = get_Shl_left(node);
 200                 right = get_Shl_right(node);
 201
 202                 /* We can only compute this if the right value is a constant*/
 203                 if (is_Const(right)) {
 204                         tarval *bits_set, *bits_not_set;
 205                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 206                         bits_set = tarval_shl(left->vrp.bits_set, get_Const_tarval(right));
 207                         bits_not_set = tarval_shl(left->vrp.bits_not_set, get_Const_tarval(right));
 208
 209                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 210                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 211
 212                         bits_not_set = tarval_not( tarval_shl(
 213                                                                                 get_mode_all_one(m),
 214                                                                                 get_Const_tarval(right)));
 215                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 216
 217                 }
 218                 break;
 219
 220         case iro_Shr:
 221                 left = get_Shr_left(node);
 222                 right = get_Shr_right(node);
 223
 224                 /* We can only compute this if the right value is a constant*/
 225                 if (is_Const(right)) {
 226                         tarval *bits_set, *bits_not_set;
 227                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 228                         bits_set = tarval_shr(left->vrp.bits_set, get_Const_tarval(right));
 229                         bits_not_set = tarval_shr(left->vrp.bits_not_set, get_Const_tarval(right));
 230
 231                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 232                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 233
 234                         bits_not_set = tarval_not( tarval_shr(
 235                                                                                 get_mode_all_one(m),
 236                                                                                 get_Const_tarval(right)));
 237                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 238                 }
 239                 break;
 240
 241         case iro_Shrs:
 242                 left = get_Shrs_left(node);
 243                 right = get_Shrs_right(node);
 244
 245                 /* We can only compute this if the right value is a constant*/
 246                 if (is_Const(right)) {
 247                         tarval *bits_set, *bits_not_set;
 248                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 249                         bits_set = tarval_shrs(left->vrp.bits_set, get_Const_tarval(right));
 250                         bits_not_set = tarval_shrs(left->vrp.bits_not_set, get_Const_tarval(right));
 251
 252                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 253                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 254
 255                         bits_not_set = tarval_not( tarval_shrs(
 256                                                                                 get_mode_all_one(m),
 257                                                                                 get_Const_tarval(right)));
 258                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 259                 }
 260                 break;
 261
 262         case iro_Eor:
 263                 left = get_Eor_left(node);
 264                 right = get_Eor_right(node);
 265
 266                 tarval *bits_set, *bits_not_set;
 267                 bits_not_set = tarval_or(
 268                                                         tarval_and(left->vrp.bits_set, right->vrp.bits_set),
 269                                                         tarval_and(left->vrp.bits_not_set,
 270                                                                 right->vrp.bits_not_set));
 271
 272                 bits_set = tarval_or(
 273                                                 tarval_and(left->vrp.bits_set, right->vrp.bits_not_set),
 274                                                 tarval_and(left->vrp.bits_not_set, right->vrp.bits_set));
 275
 276                 new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 277                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 278                 break;
 279
 280         case iro_Id:
 281                 pred = get_Id_pred(node);
 282                 new_bits_set = pred->vrp.bits_set;
 283                 new_bits_not_set = pred->vrp.bits_not_set;
 284                 new_range_top = pred->vrp.range_top;
 285                 new_range_bottom = pred->vrp.range_bottom;
 286                 new_range_type = pred->vrp.range_type;
 287                 break;
 288
 289         case iro_Not:
 290                 pred = get_Not_op(node);
 291                 new_bits_set = tarval_or(pred->vrp.bits_not_set, node->vrp.bits_set);
 292                 new_bits_not_set = tarval_or(pred->vrp.bits_set, node->vrp.bits_not_set);
 293                 break;
 294
 295         case iro_Conv:
 296                 pred = get_Conv_op(node);
 297                 ir_mode *old_mode = get_irn_mode(pred);
 298                 ir_mode *new_mode;
 299
 300                 if (!mode_is_int(old_mode))
 301                         return 0;
 302
 303                 new_mode = get_irn_mode(node);
 304
 305                 /* The second and is needed if target type is smaller*/
 306                 bits_not_set = tarval_not(
 307                                                         tarval_convert_to(get_mode_all_one(old_mode),
 308                                                                 new_mode
 309                                                                 ));
 310                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(pred->vrp.bits_not_set, new_mode));
 311                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 312                 new_bits_set = tarval_and(
 313                                 tarval_not(bits_not_set), tarval_convert_to(pred->vrp.bits_set, new_mode));
 314
 315                 if (tarval_cmp(pred->vrp.range_top, get_mode_max(new_mode)) == pn_Cmp_Le) {
 316                         node->vrp.range_top = pred->vrp.range_top;
 317                 }
 318
 319                 if (tarval_cmp(pred->vrp.range_bottom, get_mode_min(new_mode)) == pn_Cmp_Ge) {
 320                         node->vrp.range_bottom = pred->vrp.range_bottom;
 321                 }
 322                 break;
 323
 324         case iro_Confirm:
 325                 cmp = get_Confirm_cmp(node);
 326                 bound = get_Confirm_bound(node);
 327
 328                 /** @todo: Handle non-Const bounds */
 329
 330                 if (cmp == pn_Cmp_Lg) {
 331                         /** @todo: Is there some way to preserve the information? */
 332                         new_range_type = VRP_ANTIRANGE;
 333                         if (is_Const(bound)) {
 334                                 new_range_top = get_Const_tarval(bound);
 335                                 new_range_bottom = get_Const_tarval(bound);
 336                         }
 337                 } else if (cmp == pn_Cmp_Le) {
 338                         if (node->vrp.range_type == VRP_UNDEFINED) {
 339                                 new_range_type = VRP_RANGE;
 340                                 if (is_Const(bound)) {
 341                                         new_range_top = get_Const_tarval(bound);
 342                                 }
 343                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 344                         } else if (node->vrp.range_type == VRP_RANGE) {
 345                                 if (is_Const(bound)) {
 346                                         if (tarval_cmp(node->vrp.range_top,
 347                                                                 get_Const_tarval(bound)) == pn_Cmp_Le) {
 348                                                 new_range_top = get_Const_tarval(bound);
 349                                         }
 350                                         new_range_bottom = get_tarval_min(get_irn_mode(node));
 351
 352                                 } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 353                                         /** @todo: How do we manage not to get a never ending loop? */
 354                                 }
 355                         }
 356                 }
 357                 break;
 358
 359         case iro_Phi:
 360                 /* combine all ranges*/
 361
 362                 pred = get_Phi_pred(node,0);
 363                 new_range_top = pred->vrp.range_top;
 364                 new_range_bottom = pred->vrp.range_bottom;
 365                 new_range_type = pred->vrp.range_type;
 366                 new_bits_set = pred->vrp.bits_set;
 367                 new_bits_not_set = pred->vrp.bits_not_set;
 368
 369                 int num = get_Phi_n_preds(node);
 370                 pn_Cmp cmp;
 371                 int i;
 372
 373                 assert(num > 0);
 374
 375
 376                 for (i = 1; i < num; i++) {
 377                         pred = get_Phi_pred(node, i);
 378                         if (new_range_type == VRP_RANGE && pred->vrp.range_type ==
 379                                         VRP_RANGE) {
 380                                 cmp = tarval_cmp(new_range_top, pred->vrp.range_top);
 381                                 if (cmp == pn_Cmp_Lt) {
 382                                         new_range_top = pred->vrp.range_top;
 383                                 }
 384                                 cmp = tarval_cmp(new_range_bottom, pred->vrp.range_bottom);
 385                                 if (cmp == pn_Cmp_Gt) {
 386                                         new_range_bottom = pred->vrp.range_bottom;
 387                                 }
 388                         } else {
 389                                 new_range_type = VRP_VARYING;
 390                                 break;
 391                         }
 392                 }
 393
 394                 break;
 395
 396
 397         default:
 398                 /* unhandled, therefore never updated */
 399                 break;
 400         }
 401
 402
 403
 404         /* TODO: Check, if there can be information derived from any of these:
 405         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 406         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 407         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 408         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 409         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 410         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 411         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 412         is_Pin(node) is_Proj(node) is_Quot(node)
 413         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 414         is_SymConst(node) is_Sync(node) is_Tuple(node)
 415         */
 416
 417         /* Merge the newly calculated values with those that might already exist*/
 418
 419         if (new_bits_set != tarval_bad) {
 420                 new_bits_set = tarval_or(new_bits_set, node->vrp.bits_set);
 421                 if (tarval_cmp(new_bits_set, node->vrp.bits_set) != pn_Cmp_Eq) {
 422                         something_changed = 1;
 423                         node->vrp.bits_set = new_bits_set;
 424                 }
 425         }
 426
 427         if (new_bits_not_set != tarval_bad) {
 428                 new_bits_not_set = tarval_or(new_bits_not_set, node->vrp.bits_not_set);
 429
 430                 if (tarval_cmp(new_bits_not_set, node->vrp.bits_not_set) != pn_Cmp_Eq) {
 431                         something_changed = 1;
 432                         node->vrp.bits_not_set = new_bits_not_set;
 433                 }
 434         }
 435
 436         if (node->vrp.bits_node == NULL && new_bits_node != NULL) {
 437                 something_changed = 1;
 438                 node->vrp.bits_node = new_bits_node;
 439         }
 440
 441         if (node->vrp.range_type == VRP_UNDEFINED &&
 442                         new_range_type != VRP_UNDEFINED) {
 443                 something_changed = 1;
 444                 node->vrp.range_type = new_range_type;
 445                 node->vrp.range_bottom = new_range_bottom;
 446                 node->vrp.range_top = new_range_top;
 447                 node->vrp.range_op = new_range_op;
 448                 node->vrp.range_node = new_range_node;
 449
 450         } else if (node->vrp.range_type == VRP_RANGE) {
 451                 if (new_range_type == VRP_RANGE) {
 452                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 453                                         (new_range_node == node->vrp.range_node &&
 454                                          new_range_op == node->vrp.range_op)) {
 455                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 456                                         something_changed = 1;
 457                                         node->vrp.range_bottom = new_range_bottom;
 458                                 }
 459                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Gt) {
 460                                         something_changed = 1;
 461                                         node->vrp.range_top = new_range_top;
 462                                 }
 463                         }
 464
 465                         /* prefer the absolute value*/
 466                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 467                                 something_changed = 1;
 468                                 node->vrp.range_node = NULL;
 469                                 node->vrp.range_top = new_range_top;
 470                                 node->vrp.range_bottom = new_range_bottom;
 471                         }
 472                 }
 473
 474                 if (new_range_type == VRP_ANTIRANGE) {
 475                         /* if they are overlapping, cut the range.*/
 476                         /* TODO: Maybe we can preserve more information here*/
 477                         if (new_range_node == NULL && node->vrp.range_node == NULL) {
 478                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt &&
 479                                                 tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 480                                         something_changed = 1;
 481                                         node->vrp.range_bottom = new_range_top;
 482
 483                                 } else if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Gt &&
 484                                                 tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 485                                         something_changed = 1;
 486                                         node->vrp.range_top = new_range_bottom;
 487                                 }
 488
 489                                 /* We can not handle the case where the anti range is in the*/
 490                                 /* range*/
 491                         }
 492
 493                         /* prefer the absolute value*/
 494                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 495                                 something_changed = 1;
 496                                 node->vrp.range_node = NULL;
 497                                 node->vrp.range_top = new_range_top;
 498                                 node->vrp.range_bottom = new_range_bottom;
 499                         }
 500                 }
 501         } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 502                 if (new_range_type == VRP_ANTIRANGE) {
 503                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 504                                         (new_range_node == node->vrp.range_node &&
 505                                          new_range_op == node->vrp.range_op)) {
 506                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 507                                         something_changed = 1;
 508                                         node->vrp.range_bottom = new_range_bottom;
 509                                 }
 510                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 511                                         something_changed = 1;
 512                                         node->vrp.range_top = new_range_top;
 513                                 }
 514                         }
 515
 516                         /* prefer the absolute value*/
 517                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 518                                 something_changed = 1;
 519                                 node->vrp.range_node = NULL;
 520                                 node->vrp.range_top = new_range_top;
 521                                 node->vrp.range_bottom = new_range_bottom;
 522                         }
 523                 }
 524
 525                 if (new_range_type == VRP_RANGE) {
 526                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 527                                         (new_range_node == node->vrp.range_node &&
 528                                          new_range_op == node->vrp.range_op)) {
 529                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt) {
 530                                         something_changed = 1;
 531                                         node->vrp.range_bottom = new_range_top;
 532                                 }
 533                                 if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Lt) {
 534                                         something_changed = 1;
 535                                         node->vrp.range_top = new_range_bottom;
 536                                 }
 537                         }
 538
 539                         /* prefer the absolute value*/
 540                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 541                                 something_changed = 1;
 542                                 node->vrp.range_node = NULL;
 543                                 node->vrp.range_top = new_range_top;
 544                                 node->vrp.range_bottom = new_range_bottom;
 545                         }
 546                 }
 547         }
 548
 549         assert(tarval_is_null(
 550                                 tarval_and(node->vrp.bits_set, node->vrp.bits_not_set)));
 551
 552         return something_changed;
 553 }
 554
 555 static void vrp_first_pass(ir_node *n, void *e)
 556 {
 557         ir_node *succ;
 558         int i;
 559         struct vrp_env_t *env = e;
 560
 561         if (is_Block(n))
 562                 return;
 563
 564         set_irn_link(n, VISITED);
 565
 566         update_vrp_data(n);
 567
 568         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 569                 succ =  get_irn_out(n, i);
 570                 if (get_irn_link(succ) == VISITED) {
 571                         /* we found a loop*/
 572                         waitq_put(env->workqueue, n);
 573                 }
 574         }
 575 }
 576
 577
 578 void set_vrp_data(ir_graph *irg)
 579 {
 580
 581         ir_node *succ, *node;
 582         int i;
 583         struct vrp_env_t env;
 584
 585         if (!irg) {
 586                 /* no graph, skip */
 587                 return;
 588         }
 589
 590         assure_irg_outs(irg); /* ensure that out edges are consistent*/
 591
 592         env.workqueue = new_waitq();
 593         irg_walk_graph(irg, NULL, vrp_first_pass, &env);
 594
 595         /* while there are entries in the worklist, continue*/
 596         while (!waitq_empty(env.workqueue)) {
 597                 node = waitq_get(env.workqueue);
 598
 599                 if (update_vrp_data(node)) {
 600                         /* if something changed, add successors to worklist*/
 601                         for (i = get_irn_n_outs(node) - 1; i >=0; --i) {
 602                                 succ =  get_irn_out(node, i);
 603                                 waitq_put(env.workqueue, node);
 604                         }
 605                 }
 606         }
 607         del_waitq(env.workqueue);
 608 }
 609
 610
 611 ir_graph_pass_t *set_vrp_pass(const char *name)
 612 {
 613         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 614 }
 615
 616 pn_Cmp vrp_cmp(ir_node *left, ir_node *right)
 617 {
 618         if (!left->vrp.valid || !right->vrp.valid) {
 619                 return pn_Cmp_False;
 620         }
 621
 622         if (left->vrp.range_type == VRP_RANGE && right->vrp.range_type == VRP_RANGE) {
 623                 if (tarval_cmp(left->vrp.range_top, right->vrp.range_bottom) == pn_Cmp_Lt) {
 624                         return pn_Cmp_Lt;
 625                 }
 626                 if (tarval_cmp(left->vrp.range_bottom, right->vrp.range_top) == pn_Cmp_Gt) {
 627                         return pn_Cmp_Gt;
 628                 }
 629         }
 630
 631         if (!tarval_is_null(tarval_and(left->vrp.bits_set, right->vrp.bits_not_set)) ||
 632                         !tarval_is_null(tarval_and(left->vrp.bits_not_set, right->vrp.bits_set))) {
 633                 return pn_Cmp_Lg;
 634         }
 635         /* TODO: We can get way more information here*/
 636
 637         return pn_Cmp_False;
 638 }