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
  61
  62         node->vrp.valid = 1;
  63         /* TODO: Check if all predecessors have valid VRP information*/
  64
  65
  66         if (!mode_is_int(get_irn_mode(node))) {
  67                 return 0; /* we don't optimize for non-int-nodes*/
  68         }
  69
  70         switch (get_irn_opcode(node)) {
  71         case iro_Const: {
  72                 tarval *tv = get_Const_tarval(node);
  73                 new_bits_set = tv;
  74                 new_bits_not_set = tarval_not(tv);
  75                 new_range_bottom = tv;
  76                 new_range_top = tv;
  77                 new_range_type = VRP_RANGE;
  78                 break;
  79         }
  80
  81         case iro_And: {
  82                 ir_node *left, *right;
  83                 tarval *tmp_tv;
  84
  85                 left = get_And_left(node);
  86                 right = get_And_right(node);
  87
  88                 new_bits_set = tarval_and(left->vrp.bits_set, right->vrp.bits_set);
  89                 new_bits_not_set = tarval_or(left->vrp.bits_not_set, right->vrp.bits_not_set);
  90
  91                 tmp_tv = tarval_not(left->vrp.bits_set);
  92                 tmp_tv = tarval_eor(left->vrp.bits_not_set, tmp_tv);
  93                 /*check if one of the predecessors is completely determined*/
  94                 if (tarval_is_null(tmp_tv)) {
  95                         new_bits_node = right;
  96                 }
  97
  98                 tmp_tv = tarval_not(right->vrp.bits_set);
  99                 tmp_tv = tarval_eor(right->vrp.bits_not_set, tmp_tv);
 100                 if (tarval_is_null(tmp_tv)) {
 101                         new_bits_node = left;
 102                 }
 103                 break;
 104         }
 105
 106         case iro_Add: {
 107                 ir_node *left, *right;
 108                 left = get_Add_left(node);
 109                 right = get_Add_right(node);
 110                 int overflow_top, overflow_bottom;
 111                 tarval *new_top, *new_bottom;
 112
 113                 if (left->vrp.range_type == VRP_UNDEFINED || right->vrp.range_type ==
 114                                 VRP_UNDEFINED || left->vrp.range_type == VRP_VARYING ||
 115                                 right->vrp.range_type == VRP_VARYING) {
 116                         return 0;
 117                 }
 118
 119                 new_top = tarval_add(left->vrp.range_top, right->vrp.range_top);
 120                 overflow_top = tarval_carry();
 121                 new_bottom = tarval_add(left->vrp.range_bottom, right->vrp.range_bottom);
 122                 overflow_bottom = tarval_carry();
 123
 124                 if (!overflow_top && !overflow_bottom && left->vrp.range_type == VRP_RANGE
 125                                 &&right->vrp.range_type == VRP_RANGE) {
 126                         new_range_bottom = new_bottom;
 127                         new_range_top = new_top;
 128                         new_range_type = VRP_RANGE;
 129                 }
 130
 131                 if (overflow_top || overflow_bottom) {
 132                         /* TODO Implement overflow handling*/
 133                         new_range_type = VRP_UNDEFINED;
 134                 }
 135                 break;
 136         }
 137
 138         case iro_Sub: {
 139                 ir_node *left, *right;
 140                 left = get_Sub_left(node);
 141                 right = get_Sub_right(node);
 142                 int overflow_top, overflow_bottom;
 143                 tarval *new_top, *new_bottom;
 144
 145                 if (left->vrp.range_type == VRP_UNDEFINED || right->vrp.range_type ==
 146                                 VRP_UNDEFINED) {
 147                         return 0;
 148                 }
 149
 150                 new_top = tarval_sub(left->vrp.range_top, right->vrp.range_top, NULL);
 151                 overflow_top = tarval_carry();
 152                 new_bottom = tarval_sub(left->vrp.range_bottom, right->vrp.range_bottom, NULL);
 153                 overflow_bottom = tarval_carry();
 154
 155                 if (!overflow_top && !overflow_bottom && left->vrp.range_type == VRP_RANGE
 156                                 &&right->vrp.range_type == VRP_RANGE) {
 157                         new_range_bottom = new_bottom;
 158                         new_range_top = new_top;
 159                         new_range_type = VRP_RANGE;
 160                 }
 161
 162                 if (overflow_top || overflow_bottom) {
 163                         /* TODO Implement overflow handling*/
 164                 }
 165                 break;
 166         }
 167
 168         case iro_Or: {
 169                 ir_node *left, *right;
 170                 tarval *tmp_tv;
 171
 172                 left = get_Or_left(node);
 173                 right = get_Or_right(node);
 174
 175                 new_bits_set = tarval_or(left->vrp.bits_set, right->vrp.bits_set);
 176                 new_bits_not_set = tarval_and(left->vrp.bits_not_set, right->vrp.bits_not_set);
 177
 178                 tmp_tv = tarval_not(left->vrp.bits_set);
 179                 tmp_tv = tarval_eor(left->vrp.bits_not_set, tmp_tv);
 180                 /*check if one of the predecessors is completely determined*/
 181                 if (tarval_is_null(tmp_tv)) {
 182                         new_bits_node = right;
 183                 }
 184
 185                 tmp_tv = tarval_not(right->vrp.bits_set);
 186                 tmp_tv = tarval_eor(right->vrp.bits_not_set, tmp_tv);
 187                 if (tarval_is_null(tmp_tv)) {
 188                         new_bits_node = left;
 189                 }
 190                 break;
 191         }
 192
 193         case iro_Rotl: {
 194                 ir_node *left, *right;
 195
 196                 left = get_Rotl_left(node);
 197                 right = get_Rotl_right(node);
 198
 199                 /* We can only compute this if the right value is a constant*/
 200                 if (is_Const(right)) {
 201                         tarval *bits_set, *bits_not_set;
 202                         bits_set = tarval_rotl(left->vrp.bits_set, get_Const_tarval(right));
 203                         bits_not_set = tarval_rotl(left->vrp.bits_not_set, get_Const_tarval(right));
 204
 205                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 206                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 207                 }
 208                 break;
 209         }
 210
 211         case iro_Shl: {
 212                 ir_node *left, *right;
 213                 left = get_Shl_left(node);
 214                 right = get_Shl_right(node);
 215
 216                 /* We can only compute this if the right value is a constant*/
 217                 if (is_Const(right)) {
 218                         tarval *bits_set, *bits_not_set;
 219                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 220                         bits_set = tarval_shl(left->vrp.bits_set, get_Const_tarval(right));
 221                         bits_not_set = tarval_shl(left->vrp.bits_not_set, get_Const_tarval(right));
 222
 223                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 224                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 225
 226                         bits_not_set = tarval_not( tarval_shl(
 227                                                                                 get_mode_all_one(m),
 228                                                                                 get_Const_tarval(right)));
 229                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 230
 231                 }
 232                 break;
 233         }
 234
 235         case iro_Shr: {
 236                 ir_node *left, *right;
 237
 238                 left = get_Shr_left(node);
 239                 right = get_Shr_right(node);
 240
 241                 /* We can only compute this if the right value is a constant*/
 242                 if (is_Const(right)) {
 243                         tarval *bits_set, *bits_not_set;
 244                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 245                         bits_set = tarval_shr(left->vrp.bits_set, get_Const_tarval(right));
 246                         bits_not_set = tarval_shr(left->vrp.bits_not_set, get_Const_tarval(right));
 247
 248                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 249                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 250
 251                         bits_not_set = tarval_not( tarval_shr(
 252                                                                                 get_mode_all_one(m),
 253                                                                                 get_Const_tarval(right)));
 254                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 255                 }
 256                 break;
 257         }
 258
 259         case iro_Shrs: {
 260                 ir_node *left, *right;
 261
 262                 left = get_Shrs_left(node);
 263                 right = get_Shrs_right(node);
 264
 265                 /* We can only compute this if the right value is a constant*/
 266                 if (is_Const(right)) {
 267                         tarval *bits_set, *bits_not_set;
 268                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 269                         bits_set = tarval_shrs(left->vrp.bits_set, get_Const_tarval(right));
 270                         bits_not_set = tarval_shrs(left->vrp.bits_not_set, get_Const_tarval(right));
 271
 272                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 273                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 274
 275                         bits_not_set = tarval_not( tarval_shrs(
 276                                                                                 get_mode_all_one(m),
 277                                                                                 get_Const_tarval(right)));
 278                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 279                 }
 280                 break;
 281         }
 282
 283         case iro_Eor: {
 284                 ir_node *left, *right;
 285
 286                 left = get_Eor_left(node);
 287                 right = get_Eor_right(node);
 288
 289                 tarval *bits_set, *bits_not_set;
 290                 bits_not_set = tarval_or(
 291                                                         tarval_and(left->vrp.bits_set, right->vrp.bits_set),
 292                                                         tarval_and(left->vrp.bits_not_set,
 293                                                                 right->vrp.bits_not_set));
 294
 295                 bits_set = tarval_or(
 296                                                 tarval_and(left->vrp.bits_set, right->vrp.bits_not_set),
 297                                                 tarval_and(left->vrp.bits_not_set, right->vrp.bits_set));
 298
 299                 new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 300                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 301                 break;
 302         }
 303
 304         case iro_Id: {
 305                 ir_node *pred = get_Id_pred(node);
 306                 new_bits_set = pred->vrp.bits_set;
 307                 new_bits_not_set = pred->vrp.bits_not_set;
 308                 new_range_top = pred->vrp.range_top;
 309                 new_range_bottom = pred->vrp.range_bottom;
 310                 new_range_type = pred->vrp.range_type;
 311                 break;
 312         }
 313
 314         case iro_Not: {
 315                 ir_node *pred = get_Not_op(node);
 316                 new_bits_set = tarval_or(pred->vrp.bits_not_set, node->vrp.bits_set);
 317                 new_bits_not_set = tarval_or(pred->vrp.bits_set, node->vrp.bits_not_set);
 318                 break;
 319         }
 320
 321         case iro_Conv: {
 322                 ir_node *pred = get_Conv_op(node);
 323                 ir_mode *old_mode = get_irn_mode(pred);
 324
 325                 ir_mode *new_mode;
 326                 tarval *bits_not_set;
 327
 328                 if (!mode_is_int(old_mode))
 329                         return 0;
 330
 331                 new_mode = get_irn_mode(node);
 332
 333                 /* The second and is needed if target type is smaller*/
 334                 bits_not_set = tarval_not(
 335                                                         tarval_convert_to(get_mode_all_one(old_mode),
 336                                                                 new_mode
 337                                                                 ));
 338                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(pred->vrp.bits_not_set, new_mode));
 339                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 340                 new_bits_set = tarval_and(
 341                                 tarval_not(bits_not_set), tarval_convert_to(pred->vrp.bits_set, new_mode));
 342
 343                 if (tarval_cmp(pred->vrp.range_top, get_mode_max(new_mode)) == pn_Cmp_Le) {
 344                         node->vrp.range_top = pred->vrp.range_top;
 345                 }
 346
 347                 if (tarval_cmp(pred->vrp.range_bottom, get_mode_min(new_mode)) == pn_Cmp_Ge) {
 348                         node->vrp.range_bottom = pred->vrp.range_bottom;
 349                 }
 350                 break;
 351         }
 352
 353         case iro_Confirm: {
 354                 pn_Cmp cmp = get_Confirm_cmp(node);
 355                 ir_node *bound = get_Confirm_bound(node);
 356
 357                 /** @todo: Handle non-Const bounds */
 358
 359                 if (cmp == pn_Cmp_Lg) {
 360                         /** @todo: Is there some way to preserve the information? */
 361                         new_range_type = VRP_ANTIRANGE;
 362                         if (is_Const(bound)) {
 363                                 new_range_top = get_Const_tarval(bound);
 364                                 new_range_bottom = get_Const_tarval(bound);
 365                         }
 366                 } else if (cmp == pn_Cmp_Le) {
 367                         if (node->vrp.range_type == VRP_UNDEFINED) {
 368                                 new_range_type = VRP_RANGE;
 369                                 if (is_Const(bound)) {
 370                                         new_range_top = get_Const_tarval(bound);
 371                                 }
 372                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 373                         } else if (node->vrp.range_type == VRP_RANGE) {
 374                                 if (is_Const(bound)) {
 375                                         if (tarval_cmp(node->vrp.range_top,
 376                                                                 get_Const_tarval(bound)) == pn_Cmp_Le) {
 377                                                 new_range_top = get_Const_tarval(bound);
 378                                         }
 379                                         new_range_bottom = get_tarval_min(get_irn_mode(node));
 380
 381                                 } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 382                                         /** @todo: How do we manage not to get a never ending loop? */
 383                                 }
 384                         }
 385                 }
 386                 break;
 387         }
 388
 389         case iro_Phi: {
 390                 /* combine all ranges*/
 391
 392                 ir_node *pred = get_Phi_pred(node,0);
 393                 new_range_top = pred->vrp.range_top;
 394                 new_range_bottom = pred->vrp.range_bottom;
 395                 new_range_type = pred->vrp.range_type;
 396                 new_bits_set = pred->vrp.bits_set;
 397                 new_bits_not_set = pred->vrp.bits_not_set;
 398
 399                 int num = get_Phi_n_preds(node);
 400                 pn_Cmp cmp;
 401                 int i;
 402
 403                 assert(num > 0);
 404
 405
 406                 for (i = 1; i < num; i++) {
 407                         pred = get_Phi_pred(node, i);
 408                         if (new_range_type == VRP_RANGE && pred->vrp.range_type ==
 409                                         VRP_RANGE) {
 410                                 cmp = tarval_cmp(new_range_top, pred->vrp.range_top);
 411                                 if (cmp == pn_Cmp_Lt) {
 412                                         new_range_top = pred->vrp.range_top;
 413                                 }
 414                                 cmp = tarval_cmp(new_range_bottom, pred->vrp.range_bottom);
 415                                 if (cmp == pn_Cmp_Gt) {
 416                                         new_range_bottom = pred->vrp.range_bottom;
 417                                 }
 418                         } else {
 419                                 new_range_type = VRP_VARYING;
 420                                 break;
 421                         }
 422                 }
 423
 424                 break;
 425         }
 426
 427         default:
 428                 /* unhandled, therefore never updated */
 429                 break;
 430         }
 431
 432
 433
 434         /* TODO: Check, if there can be information derived from any of these:
 435         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 436         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 437         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 438         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 439         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 440         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 441         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 442         is_Pin(node) is_Proj(node) is_Quot(node)
 443         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 444         is_SymConst(node) is_Sync(node) is_Tuple(node)
 445         */
 446
 447         /* Merge the newly calculated values with those that might already exist*/
 448
 449         if (new_bits_set != tarval_bad) {
 450                 new_bits_set = tarval_or(new_bits_set, node->vrp.bits_set);
 451                 if (tarval_cmp(new_bits_set, node->vrp.bits_set) != pn_Cmp_Eq) {
 452                         something_changed = 1;
 453                         node->vrp.bits_set = new_bits_set;
 454                 }
 455         }
 456
 457         if (new_bits_not_set != tarval_bad) {
 458                 new_bits_not_set = tarval_or(new_bits_not_set, node->vrp.bits_not_set);
 459
 460                 if (tarval_cmp(new_bits_not_set, node->vrp.bits_not_set) != pn_Cmp_Eq) {
 461                         something_changed = 1;
 462                         node->vrp.bits_not_set = new_bits_not_set;
 463                 }
 464         }
 465
 466         if (node->vrp.bits_node == NULL && new_bits_node != NULL) {
 467                 something_changed = 1;
 468                 node->vrp.bits_node = new_bits_node;
 469         }
 470
 471         if (node->vrp.range_type == VRP_UNDEFINED &&
 472                         new_range_type != VRP_UNDEFINED) {
 473                 something_changed = 1;
 474                 node->vrp.range_type = new_range_type;
 475                 node->vrp.range_bottom = new_range_bottom;
 476                 node->vrp.range_top = new_range_top;
 477                 node->vrp.range_op = new_range_op;
 478                 node->vrp.range_node = new_range_node;
 479
 480         } else if (node->vrp.range_type == VRP_RANGE) {
 481                 if (new_range_type == VRP_RANGE) {
 482                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 483                                         (new_range_node == node->vrp.range_node &&
 484                                          new_range_op == node->vrp.range_op)) {
 485                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 486                                         something_changed = 1;
 487                                         node->vrp.range_bottom = new_range_bottom;
 488                                 }
 489                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Gt) {
 490                                         something_changed = 1;
 491                                         node->vrp.range_top = new_range_top;
 492                                 }
 493                         }
 494
 495                         /* prefer the absolute value*/
 496                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 497                                 something_changed = 1;
 498                                 node->vrp.range_node = NULL;
 499                                 node->vrp.range_top = new_range_top;
 500                                 node->vrp.range_bottom = new_range_bottom;
 501                         }
 502                 }
 503
 504                 if (new_range_type == VRP_ANTIRANGE) {
 505                         /* if they are overlapping, cut the range.*/
 506                         /* TODO: Maybe we can preserve more information here*/
 507                         if (new_range_node == NULL && node->vrp.range_node == NULL) {
 508                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt &&
 509                                                 tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 510                                         something_changed = 1;
 511                                         node->vrp.range_bottom = new_range_top;
 512
 513                                 } else if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Gt &&
 514                                                 tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 515                                         something_changed = 1;
 516                                         node->vrp.range_top = new_range_bottom;
 517                                 }
 518
 519                                 /* We can not handle the case where the anti range is in the*/
 520                                 /* range*/
 521                         }
 522
 523                         /* prefer the absolute value*/
 524                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 525                                 something_changed = 1;
 526                                 node->vrp.range_node = NULL;
 527                                 node->vrp.range_top = new_range_top;
 528                                 node->vrp.range_bottom = new_range_bottom;
 529                         }
 530                 }
 531         } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 532                 if (new_range_type == VRP_ANTIRANGE) {
 533                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 534                                         (new_range_node == node->vrp.range_node &&
 535                                          new_range_op == node->vrp.range_op)) {
 536                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 537                                         something_changed = 1;
 538                                         node->vrp.range_bottom = new_range_bottom;
 539                                 }
 540                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 541                                         something_changed = 1;
 542                                         node->vrp.range_top = new_range_top;
 543                                 }
 544                         }
 545
 546                         /* prefer the absolute value*/
 547                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 548                                 something_changed = 1;
 549                                 node->vrp.range_node = NULL;
 550                                 node->vrp.range_top = new_range_top;
 551                                 node->vrp.range_bottom = new_range_bottom;
 552                         }
 553                 }
 554
 555                 if (new_range_type == VRP_RANGE) {
 556                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 557                                         (new_range_node == node->vrp.range_node &&
 558                                          new_range_op == node->vrp.range_op)) {
 559                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt) {
 560                                         something_changed = 1;
 561                                         node->vrp.range_bottom = new_range_top;
 562                                 }
 563                                 if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Lt) {
 564                                         something_changed = 1;
 565                                         node->vrp.range_top = new_range_bottom;
 566                                 }
 567                         }
 568
 569                         /* prefer the absolute value*/
 570                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 571                                 something_changed = 1;
 572                                 node->vrp.range_node = NULL;
 573                                 node->vrp.range_top = new_range_top;
 574                                 node->vrp.range_bottom = new_range_bottom;
 575                         }
 576                 }
 577         }
 578
 579         assert(tarval_is_null(
 580                                 tarval_and(node->vrp.bits_set, node->vrp.bits_not_set)));
 581
 582         return something_changed;
 583 }
 584
 585 static void vrp_first_pass(ir_node *n, void *e)
 586 {
 587         ir_node *succ;
 588         int i;
 589         struct vrp_env_t *env = e;
 590
 591         if (is_Block(n))
 592                 return;
 593
 594         set_irn_link(n, VISITED);
 595
 596         update_vrp_data(n);
 597
 598         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 599                 succ =  get_irn_out(n, i);
 600                 if (get_irn_link(succ) == VISITED) {
 601                         /* we found a loop*/
 602                         waitq_put(env->workqueue, n);
 603                 }
 604         }
 605 }
 606
 607
 608 void set_vrp_data(ir_graph *irg)
 609 {
 610
 611         ir_node *succ, *node;
 612         int i;
 613         struct vrp_env_t env;
 614
 615         if (!irg) {
 616                 /* no graph, skip */
 617                 return;
 618         }
 619
 620         assure_irg_outs(irg); /* ensure that out edges are consistent*/
 621
 622         env.workqueue = new_waitq();
 623         irg_walk_graph(irg, NULL, vrp_first_pass, &env);
 624
 625         /* while there are entries in the worklist, continue*/
 626         while (!waitq_empty(env.workqueue)) {
 627                 node = waitq_get(env.workqueue);
 628
 629                 if (update_vrp_data(node)) {
 630                         /* if something changed, add successors to worklist*/
 631                         for (i = get_irn_n_outs(node) - 1; i >=0; --i) {
 632                                 succ =  get_irn_out(node, i);
 633                                 waitq_put(env.workqueue, node);
 634                         }
 635                 }
 636         }
 637         del_waitq(env.workqueue);
 638 }
 639
 640
 641 ir_graph_pass_t *set_vrp_pass(const char *name)
 642 {
 643         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 644 }
 645
 646 pn_Cmp vrp_cmp(ir_node *left, ir_node *right)
 647 {
 648         if (!left->vrp.valid || !right->vrp.valid) {
 649                 return pn_Cmp_False;
 650         }
 651
 652         if (left->vrp.range_type == VRP_RANGE && right->vrp.range_type == VRP_RANGE) {
 653                 if (tarval_cmp(left->vrp.range_top, right->vrp.range_bottom) == pn_Cmp_Lt) {
 654                         return pn_Cmp_Lt;
 655                 }
 656                 if (tarval_cmp(left->vrp.range_bottom, right->vrp.range_top) == pn_Cmp_Gt) {
 657                         return pn_Cmp_Gt;
 658                 }
 659         }
 660
 661         if (!tarval_is_null(tarval_and(left->vrp.bits_set, right->vrp.bits_not_set)) ||
 662                         !tarval_is_null(tarval_and(left->vrp.bits_not_set, right->vrp.bits_set))) {
 663                 return pn_Cmp_Lg;
 664         }
 665         /* TODO: We can get way more information here*/
 666
 667         return pn_Cmp_False;
 668 }