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  * @version     $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "irtypes.h"
  29 #include "vrp.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 "irphase_t.h"
  40 #include "irprintf.h"
  41
  42 static char v;
  43 static void *VISITED = &v;
  44
  45 struct vrp_env_t {
  46         waitq *workqueue;
  47 };
  48
  49 static vrp_attr *get_vrp_attr(const ir_node *node)
  50 {
  51         return (vrp_attr*) get_or_set_irn_phase_info(node, PHASE_VRP);
  52 }
  53
  54 static int vrp_update_node(ir_node *node)
  55 {
  56         tarval *new_bits_set = get_tarval_bad();
  57         tarval *new_bits_not_set = get_tarval_bad();
  58         tarval *new_range_bottom = get_tarval_bad();
  59         tarval *new_range_top = get_tarval_bad();
  60         enum range_types new_range_type = VRP_UNDEFINED;
  61         int something_changed = 0;
  62         vrp_attr *vrp;
  63
  64         if (!mode_is_int(get_irn_mode(node))) {
  65                 return 0; /* we don't optimize for non-int-nodes*/
  66         }
  67
  68         ir_printf("update_vrp for %d called\n", get_irn_node_nr(node));
  69         vrp = get_vrp_attr(node);
  70
  71         /* TODO: Check if all predecessors have valid VRP information*/
  72
  73         switch (get_irn_opcode(node)) {
  74         case iro_Const: {
  75                 tarval *tv = get_Const_tarval(node);
  76                 new_bits_set = tv;
  77                 new_bits_not_set = tarval_not(tv);
  78                 new_range_bottom = tv;
  79                 new_range_top = tv;
  80                 new_range_type = VRP_RANGE;
  81                 break;
  82         }
  83
  84         case iro_And: {
  85                 vrp_attr *vrp_left, *vrp_right;
  86                 ir_node *left, *right;
  87
  88                 left = get_And_left(node);
  89                 right = get_And_right(node);
  90                 vrp_left = get_vrp_attr(left);
  91                 vrp_right = get_vrp_attr(right);
  92                 new_bits_set = tarval_and(vrp_left->bits_set, vrp_right->bits_set);
  93                 new_bits_not_set = tarval_or(vrp_left->bits_not_set, vrp_right->bits_not_set);
  94
  95                 break;
  96         }
  97
  98         case iro_Add: {
  99                 int overflow_top, overflow_bottom;
 100                 tarval *new_top, *new_bottom;
 101                 vrp_attr *vrp_left, *vrp_right;
 102                 vrp_left = get_vrp_attr(get_Add_left(node));
 103                 vrp_right = get_vrp_attr(get_Add_right(node));
 104
 105                 if (vrp_left->range_type == VRP_UNDEFINED || vrp_right->range_type ==
 106                                 VRP_UNDEFINED || vrp_left->range_type == VRP_VARYING ||
 107                                 vrp_right->range_type == VRP_VARYING) {
 108                         return 0;
 109                 }
 110
 111                 new_top = tarval_add(vrp_left->range_top, vrp_right->range_top);
 112                 overflow_top = tarval_carry();
 113                 new_bottom = tarval_add(vrp_left->range_bottom, vrp_right->range_bottom);
 114                 overflow_bottom = tarval_carry();
 115
 116                 if (!overflow_top && !overflow_bottom && vrp_left->range_type == VRP_RANGE
 117                                 &&vrp_right->range_type == VRP_RANGE) {
 118                         new_range_bottom = new_bottom;
 119                         new_range_top = new_top;
 120                         new_range_type = VRP_RANGE;
 121                 }
 122
 123                 if (overflow_top || overflow_bottom) {
 124                         /* TODO Implement overflow handling*/
 125                         new_range_type = VRP_UNDEFINED;
 126                 }
 127                 break;
 128         }
 129
 130         case iro_Sub: {
 131                 int overflow_top, overflow_bottom;
 132                 tarval *new_top, *new_bottom;
 133                 vrp_attr *vrp_left, *vrp_right;
 134                 vrp_left = get_vrp_attr(get_Sub_left(node));
 135                 vrp_right = get_vrp_attr(get_Sub_right(node));
 136
 137                 if (vrp_left->range_type == VRP_UNDEFINED || vrp_right->range_type ==
 138                                 VRP_UNDEFINED) {
 139                         return 0;
 140                 }
 141
 142                 new_top = tarval_sub(vrp_left->range_top, vrp_right->range_top, NULL);
 143                 overflow_top = tarval_carry();
 144                 new_bottom = tarval_sub(vrp_left->range_bottom, vrp_right->range_bottom, NULL);
 145                 overflow_bottom = tarval_carry();
 146
 147                 if (!overflow_top && !overflow_bottom && vrp_left->range_type == VRP_RANGE
 148                                 &&vrp_right->range_type == VRP_RANGE) {
 149                         new_range_bottom = new_bottom;
 150                         new_range_top = new_top;
 151                         new_range_type = VRP_RANGE;
 152                 }
 153
 154                 if (overflow_top || overflow_bottom) {
 155                         /* TODO Implement overflow handling*/
 156                 }
 157                 break;
 158         }
 159
 160         case iro_Or: {
 161                 vrp_attr *vrp_left, *vrp_right;
 162
 163                 vrp_left = get_vrp_attr(get_Or_left(node));
 164                 vrp_right = get_vrp_attr(get_Or_right(node));
 165
 166                 new_bits_set = tarval_or(vrp_left->bits_set, vrp_right->bits_set);
 167                 new_bits_not_set = tarval_and(vrp_left->bits_not_set, vrp_right->bits_not_set);
 168
 169                 break;
 170         }
 171
 172         case iro_Rotl: {
 173                 vrp_attr *vrp_left, *vrp_right;
 174                 ir_node *right = get_Rotl_right(node);
 175
 176                 vrp_left = get_vrp_attr(get_Rotl_left(node));
 177                 vrp_right = get_vrp_attr(get_Rotl_right(node));
 178
 179                 /* We can only compute this if the right value is a constant*/
 180                 if (is_Const(right)) {
 181                         tarval *bits_set, *bits_not_set;
 182                         bits_set = tarval_rotl(vrp_left->bits_set, get_Const_tarval(right));
 183                         bits_not_set = tarval_rotl(vrp_left->bits_not_set, get_Const_tarval(right));
 184
 185                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 186                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 187                 }
 188                 break;
 189         }
 190
 191         case iro_Shl: {
 192                 vrp_attr *vrp_left, *vrp_right;
 193                 ir_node *right = get_Shl_right(node);
 194                 vrp_left = get_vrp_attr(get_Shl_left(node));
 195                 vrp_right = get_vrp_attr(get_Shl_right(node));
 196
 197                 /* We can only compute this if the right value is a constant*/
 198                 if (is_Const(right)) {
 199                         tarval *bits_set, *bits_not_set;
 200                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 201                         bits_set = tarval_shl(vrp_left->bits_set, get_Const_tarval(right));
 202                         bits_not_set = tarval_shl(vrp_left->bits_not_set, get_Const_tarval(right));
 203
 204                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 205                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 206
 207                         bits_not_set = tarval_not( tarval_shl(
 208                                                                                 get_mode_all_one(m),
 209                                                                                 get_Const_tarval(right)));
 210                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 211
 212                 }
 213                 break;
 214         }
 215
 216         case iro_Shr: {
 217                 vrp_attr *vrp_left, *vrp_right;
 218                 ir_node *right = get_Shr_right(node);
 219
 220                 vrp_left = get_vrp_attr(get_Shr_left(node));
 221                 vrp_right = get_vrp_attr(get_Shr_right(node));
 222
 223                 /* We can only compute this if the right value is a constant*/
 224                 if (is_Const(right)) {
 225                         tarval *bits_set, *bits_not_set;
 226                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 227                         bits_set = tarval_shr(vrp_left->bits_set, get_Const_tarval(right));
 228                         bits_not_set = tarval_shr(vrp_left->bits_not_set, get_Const_tarval(right));
 229
 230                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 231                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 232
 233                         bits_not_set = tarval_not( tarval_shr(
 234                                                                                 get_mode_all_one(m),
 235                                                                                 get_Const_tarval(right)));
 236                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 237                 }
 238                 break;
 239         }
 240
 241         case iro_Shrs: {
 242                 vrp_attr *vrp_left, *vrp_right;
 243                 ir_node *right = get_Shrs_right(node);
 244
 245                 vrp_left = get_vrp_attr(get_Shrs_left(node));
 246                 vrp_right = get_vrp_attr(get_Shrs_right(node));
 247
 248                 /* We can only compute this if the right value is a constant*/
 249                 if (is_Const(right)) {
 250                         tarval *bits_set, *bits_not_set;
 251                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 252                         bits_set = tarval_shrs(vrp_left->bits_set, get_Const_tarval(right));
 253                         bits_not_set = tarval_shrs(vrp_left->bits_not_set, get_Const_tarval(right));
 254
 255                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 256                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 257
 258                         bits_not_set = tarval_not( tarval_shrs(
 259                                                                                 get_mode_all_one(m),
 260                                                                                 get_Const_tarval(right)));
 261                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 262                 }
 263                 break;
 264         }
 265
 266         case iro_Eor: {
 267                 tarval *bits_set, *bits_not_set;
 268                 vrp_attr *vrp_left, *vrp_right;
 269
 270                 vrp_left = get_vrp_attr(get_Eor_left(node));
 271                 vrp_right = get_vrp_attr(get_Eor_right(node));
 272
 273                 bits_not_set = tarval_or(
 274                                                         tarval_and(vrp_left->bits_set, vrp_right->bits_set),
 275                                                         tarval_and(vrp_left->bits_not_set,
 276                                                                 vrp_right->bits_not_set));
 277
 278                 bits_set = tarval_or(
 279                                                 tarval_and(vrp_left->bits_set, vrp_right->bits_not_set),
 280                                                 tarval_and(vrp_left->bits_not_set, vrp_right->bits_set));
 281
 282                 new_bits_set = tarval_or(bits_set, vrp->bits_set);
 283                 new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 284                 break;
 285         }
 286
 287         case iro_Id: {
 288                 vrp_attr *vrp_pred = get_vrp_attr(get_Id_pred(node));
 289                 new_bits_set = vrp_pred->bits_set;
 290                 new_bits_not_set = vrp_pred->bits_not_set;
 291                 new_range_top = vrp_pred->range_top;
 292                 new_range_bottom = vrp_pred->range_bottom;
 293                 new_range_type = vrp_pred->range_type;
 294                 break;
 295         }
 296
 297         case iro_Not: {
 298                 vrp_attr *vrp_pred = get_vrp_attr(get_Not_op(node));
 299                 new_bits_set = tarval_or(vrp_pred->bits_not_set, vrp->bits_set);
 300                 new_bits_not_set = tarval_or(vrp_pred->bits_set, vrp->bits_not_set);
 301                 break;
 302         }
 303
 304         case iro_Conv: {
 305                 ir_node *pred = get_Conv_op(node);
 306                 ir_mode *old_mode = get_irn_mode(pred);
 307                 vrp_attr *vrp_pred = get_vrp_attr(pred);
 308
 309                 ir_mode *new_mode;
 310                 tarval *bits_not_set;
 311
 312                 if (!mode_is_int(old_mode))
 313                         return 0;
 314
 315                 new_mode = get_irn_mode(node);
 316
 317                 /* The second and is needed if target type is smaller*/
 318                 bits_not_set = tarval_not(
 319                                                         tarval_convert_to(get_mode_all_one(old_mode),
 320                                                                 new_mode
 321                                                                 ));
 322                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(vrp_pred->bits_not_set, new_mode));
 323                 new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 324                 new_bits_set = tarval_and(
 325                                 tarval_not(bits_not_set), tarval_convert_to(vrp_pred->bits_set, new_mode));
 326
 327                 if (tarval_cmp(vrp_pred->range_top, get_mode_max(new_mode)) == pn_Cmp_Le) {
 328                         vrp->range_top = vrp_pred->range_top;
 329                 }
 330
 331                 if (tarval_cmp(vrp_pred->range_bottom, get_mode_min(new_mode)) == pn_Cmp_Ge) {
 332                         vrp->range_bottom = vrp_pred->range_bottom;
 333                 }
 334                 break;
 335         }
 336
 337         case iro_Confirm: {
 338                 pn_Cmp cmp = get_Confirm_cmp(node);
 339                 ir_node *bound = get_Confirm_bound(node);
 340
 341
 342                 if (cmp == pn_Cmp_Lg) {
 343                         /** @todo: Handle non-Const bounds */
 344                         if (is_Const(bound)) {
 345                                 new_range_type = VRP_ANTIRANGE;
 346                                 new_range_top = get_Const_tarval(bound);
 347                                 new_range_bottom = get_Const_tarval(bound);
 348                         }
 349                 } else if (cmp == pn_Cmp_Le) {
 350                         if (is_Const(bound)) {
 351                                 new_range_type = VRP_RANGE;
 352                                 new_range_top = get_Const_tarval(bound);
 353                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 354                         }
 355                 }
 356                 break;
 357         }
 358
 359         case iro_Phi: {
 360                 /* combine all ranges*/
 361
 362                 int num = get_Phi_n_preds(node);
 363                 pn_Cmp cmp;
 364                 int i;
 365
 366                 ir_node *pred = get_Phi_pred(node,0);
 367                 vrp_attr *vrp_pred = get_vrp_attr(pred);
 368                 new_range_top = vrp_pred->range_top;
 369                 new_range_bottom = vrp_pred->range_bottom;
 370                 new_range_type = vrp_pred->range_type;
 371                 new_bits_set = vrp_pred->bits_set;
 372                 new_bits_not_set = vrp_pred->bits_not_set;
 373
 374                 assert(num > 0);
 375
 376
 377                 for (i = 1; i < num; i++) {
 378                         pred = get_Phi_pred(node, i);
 379                         vrp_pred = get_vrp_attr(pred);
 380                         if (new_range_type == VRP_RANGE && vrp_pred->range_type ==
 381                                         VRP_RANGE) {
 382                                 cmp = tarval_cmp(new_range_top, vrp_pred->range_top);
 383                                 if (cmp == pn_Cmp_Lt) {
 384                                         new_range_top = vrp_pred->range_top;
 385                                 }
 386                                 cmp = tarval_cmp(new_range_bottom, vrp_pred->range_bottom);
 387                                 if (cmp == pn_Cmp_Gt) {
 388                                         new_range_bottom = vrp_pred->range_bottom;
 389                                 }
 390                         } else {
 391                                 new_range_type = VRP_VARYING;
 392                                 break;
 393                         }
 394                 }
 395
 396                 break;
 397         }
 398         default:
 399                 /* unhandled, therefore never updated */
 400                 break;
 401         }
 402
 403
 404
 405         /* TODO: Check, if there can be information derived from any of these:
 406         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 407         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 408         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 409         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 410         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 411         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 412         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 413         is_Pin(node) is_Proj(node) is_Quot(node)
 414         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 415         is_SymConst(node) is_Sync(node) is_Tuple(node)
 416         */
 417
 418         /* Merge the newly calculated values with those that might already exist*/
 419         if (new_bits_set != tarval_bad) {
 420                 new_bits_set = tarval_or(new_bits_set, vrp->bits_set);
 421                 if (tarval_cmp(new_bits_set, vrp->bits_set) != pn_Cmp_Eq) {
 422                         something_changed = 1;
 423                         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, vrp->bits_not_set);
 429
 430                 if (tarval_cmp(new_bits_not_set, vrp->bits_not_set) != pn_Cmp_Eq) {
 431                         something_changed = 1;
 432                         vrp->bits_not_set = new_bits_not_set;
 433                 }
 434         }
 435
 436         if (vrp->range_type == VRP_UNDEFINED &&
 437                         new_range_type != VRP_UNDEFINED) {
 438                 something_changed = 1;
 439                 vrp->range_type = new_range_type;
 440                 vrp->range_bottom = new_range_bottom;
 441                 vrp->range_top = new_range_top;
 442
 443         } else if (vrp->range_type == VRP_RANGE) {
 444                 if (new_range_type == VRP_RANGE) {
 445                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 446                                 something_changed = 1;
 447                                 vrp->range_bottom = new_range_bottom;
 448                         }
 449                         if (tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Gt) {
 450                                 something_changed = 1;
 451                                 vrp->range_top = new_range_top;
 452                         }
 453                 }
 454
 455                 if (new_range_type == VRP_ANTIRANGE) {
 456                         /* if they are overlapping, cut the range.*/
 457                         /* TODO: Maybe we can preserve more information here*/
 458                         if (tarval_cmp(vrp->range_bottom, new_range_top) == pn_Cmp_Gt &&
 459                                         tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 460                                 something_changed = 1;
 461                                 vrp->range_bottom = new_range_top;
 462
 463                         } else if (tarval_cmp(vrp->range_top, new_range_bottom) == pn_Cmp_Gt &&
 464                                         tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Lt) {
 465                                 something_changed = 1;
 466                                 vrp->range_top = new_range_bottom;
 467                         }
 468
 469                         /* We can not handle the case where the anti range is in the*/
 470                         /* range*/
 471
 472                 }
 473         } else if (vrp->range_type == VRP_ANTIRANGE) {
 474                 if (new_range_type == VRP_ANTIRANGE) {
 475                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 476                                 something_changed = 1;
 477                                 vrp->range_bottom = new_range_bottom;
 478                         }
 479                         if (tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Lt) {
 480                                 something_changed = 1;
 481                                 vrp->range_top = new_range_top;
 482                         }
 483                 }
 484
 485                 if (new_range_type == VRP_RANGE) {
 486                         if (tarval_cmp(vrp->range_bottom, new_range_top) == pn_Cmp_Gt) {
 487                                 something_changed = 1;
 488                                 vrp->range_bottom = new_range_top;
 489                         }
 490                         if (tarval_cmp(vrp->range_top, new_range_bottom) == pn_Cmp_Lt) {
 491                                 something_changed = 1;
 492                                 vrp->range_top = new_range_bottom;
 493                         }
 494                 }
 495         }
 496
 497         assert(tarval_is_null(
 498                                 tarval_and(vrp->bits_set, vrp->bits_not_set)));
 499         return something_changed;
 500 }
 501
 502 static void vrp_first_pass(ir_node *n, void *e)
 503 {
 504         ir_node *succ;
 505         int i;
 506         struct vrp_env_t *env = e;
 507
 508         if (is_Block(n))
 509                 return;
 510
 511         set_irn_link(n, VISITED);
 512
 513         vrp_update_node(n);
 514
 515         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 516                 succ =  get_irn_out(n, i);
 517                 if (get_irn_link(succ) == VISITED) {
 518                         /* we found a loop*/
 519                         waitq_put(env->workqueue, n);
 520                 }
 521         }
 522 }
 523
 524 static void *vrp_init_node(ir_phase *phase, const ir_node *n, void *old)
 525 {
 526         ir_mode *mode;
 527         vrp_attr *vrp;
 528
 529         ir_printf("initialized node nr: %d\n", get_irn_node_nr(n));
 530         if (old) {
 531                 assert(1==0 && "init called for node already initialized");
 532         }
 533         vrp = phase_alloc(phase, sizeof(vrp_attr));
 534
 535         memset(vrp, 0, sizeof(vrp_attr));
 536         /* Initialize the vrp information to default */
 537
 538         mode = get_irn_mode(n);
 539
 540         vrp->range_type = VRP_UNDEFINED;
 541
 542         /* TODO: We might be able to optimize space usage if we do not allocate
 543          * vrp space for non-int nodes. (currently caught by vrp_update_node)
 544          */
 545         if (mode_is_int(mode)) {
 546                 /* We are assuming that 0 is always represented as this modes null */
 547                 vrp->valid = 1;
 548                 vrp->bits_set = get_mode_null(mode);
 549                 vrp->bits_not_set = get_mode_null(mode);
 550                 vrp->range_bottom = get_tarval_top();
 551                 vrp->range_top = get_tarval_top();
 552         } else {
 553                 vrp->valid = 0;
 554                 vrp->bits_set = get_tarval_bad();
 555                 vrp->bits_not_set = get_tarval_bad();
 556                 vrp->range_bottom = get_tarval_bad();
 557                 vrp->range_top = get_tarval_bad();
 558         }
 559
 560         /* TODO: We might be able to set better vrp info at this time, if this is
 561          * a node which is newly created in an already initialized irg
 562          *
 563          * maybe just call vrp_update_node and if it returns one, iterate over
 564          * successors
 565          */
 566         return vrp;
 567 }
 568
 569 void set_vrp_data(ir_graph *irg)
 570 {
 571         ir_node *succ, *node;
 572         int i;
 573         struct vrp_env_t *env;
 574         ir_phase *phase;
 575
 576         assure_irg_outs(irg); /* ensure that out edges are consistent*/
 577         phase = irg_get_phase(irg, PHASE_VRP);
 578         if (phase == NULL) {
 579                 /* this is our first run */
 580                 phase = new_phase(irg, vrp_init_node);
 581                 irg_register_phase(irg, PHASE_VRP, phase);
 582                 env = phase_alloc(phase, sizeof(*env));
 583                 phase->priv = env;
 584         } else {
 585                 env = phase->priv;
 586         }
 587
 588         env->workqueue = new_waitq();
 589
 590         irg_walk_graph(irg, NULL, vrp_first_pass, env);
 591
 592         /* while there are entries in the worklist, continue*/
 593         while (!waitq_empty(env->workqueue)) {
 594                 node = waitq_get(env->workqueue);
 595
 596                 if (vrp_update_node(node)) {
 597                         /* if something changed, add successors to worklist*/
 598                         for (i = get_irn_n_outs(node) - 1; i >=0; --i) {
 599                                 succ =  get_irn_out(node, i);
 600                                 waitq_put(env->workqueue, node);
 601                         }
 602                 }
 603         }
 604         del_waitq(env->workqueue);
 605 }
 606
 607
 608 ir_graph_pass_t *set_vrp_pass(const char *name)
 609 {
 610         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 611 }
 612
 613 pn_Cmp vrp_cmp(const ir_node *left, const ir_node *right)
 614 {
 615         vrp_attr *vrp_left, *vrp_right;
 616
 617         vrp_left = vrp_get_info(left);
 618         vrp_right = vrp_get_info(right);
 619
 620         if (!vrp_left || !vrp_right) {
 621                 return pn_Cmp_False;
 622         }
 623
 624         if (vrp_left->range_type == VRP_RANGE && vrp_right->range_type == VRP_RANGE) {
 625                 if (tarval_cmp(vrp_left->range_top, vrp_right->range_bottom) == pn_Cmp_Lt) {
 626                         return pn_Cmp_Lt;
 627                 }
 628                 if (tarval_cmp(vrp_left->range_bottom, vrp_right->range_top) == pn_Cmp_Gt) {
 629                         return pn_Cmp_Gt;
 630                 }
 631         }
 632
 633         if (!tarval_is_null(tarval_and(vrp_left->bits_set, vrp_right->bits_not_set)) ||
 634                         !tarval_is_null(tarval_and(vrp_left->bits_not_set, vrp_right->bits_set))) {
 635                 return pn_Cmp_Lg;
 636         }
 637         /* TODO: We can get way more information here*/
 638
 639         return pn_Cmp_False;
 640 }
 641
 642 vrp_attr *vrp_get_info(const ir_node *node)
 643 {
 644         const ir_graph *irg   = get_irn_irg(node);
 645         const ir_phase *phase = irg_get_phase(irg, PHASE_VRP);
 646
 647         if (phase == NULL) {
 648                 /* phase has not yet been initialized */
 649                 return NULL;
 650         }
 651
 652         return phase_get_irn_data(phase, node);
 653 }