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 "irtypes.h"
  29 #include "vrp.h"
  30 #include "irouts.h"
  31 #include "irgraph_t.h"
  32 #include "irpass.h"
  33 #include "list.h"
  34 #include "irgwalk.h"
  35 #include "iredges.h"
  36 #include "tv.h"
  37
  38
  39 static char v;
  40 static void *VISITED = &v;
  41
  42 typedef struct worklist_t worklist_t;
  43 struct worklist_t {
  44          struct list_head nodes;
  45         ir_node *node;
  46 };
  47
  48 struct vrp_env_t {
  49         worklist_t *worklist;
  50 };
  51
  52 int update_vrp_data( ir_node *node)
  53 {
  54
  55         tarval *new_bits_set = get_tarval_bad();
  56         tarval *new_bits_not_set = get_tarval_bad();
  57         tarval *new_range_bottom = get_tarval_bad();
  58         tarval *new_range_top = get_tarval_bad();
  59         ir_node *new_bits_node = NULL;
  60         ir_node *new_range_node = NULL;
  61         enum range_types new_range_type = VRP_UNDEFINED;
  62         enum range_ops new_range_op = VRP_NONE;
  63         int something_changed = 0;
  64
  65         node->vrp.valid = 1;
  66         // TODO: Check if all predecessors have valid VRP information
  67
  68
  69         if (!mode_is_int(get_irn_mode(node))) {
  70                 return 0; // we don't optimize for non-int-nodes
  71         }
  72
  73         if (is_Const(node)) {
  74                 tarval *tv = get_Const_tarval(node);
  75
  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         } else if (is_And(node)) {
  82                 ir_node *pred0 = get_And_left(node);
  83                 ir_node *pred1 = get_And_right(node);
  84                 tarval *tmp;
  85
  86                 new_bits_set = tarval_and(pred0->vrp.bits_set, pred1->vrp.bits_set);
  87                 new_bits_not_set = tarval_or(pred0->vrp.bits_not_set, pred1->vrp.bits_not_set);
  88
  89                 tmp = tarval_not(pred0->vrp.bits_set);
  90                 tmp = tarval_eor(pred0->vrp.bits_not_set, tmp);
  91                 //check if one of the predecessors is completely determined
  92                 if (tarval_is_null(tmp)) {
  93                         new_bits_node = pred1;
  94                 }
  95
  96                 tmp = tarval_not(pred1->vrp.bits_set);
  97                 tmp = tarval_eor(pred1->vrp.bits_not_set, tmp);
  98                 if (tarval_is_null(tmp)) {
  99                         new_bits_node = pred0;
 100                 }
 101         } else if (is_Add(node)) {
 102                 ir_node *pred0 = get_Add_left(node);
 103                 ir_node *pred1 = get_Add_right(node);
 104                 int overflow_top, overflow_bottom;
 105                 tarval *new_top, *new_bottom;
 106
 107                 if (pred0->vrp.range_type == VRP_UNDEFINED || pred1->vrp.range_type ==
 108                                 VRP_UNDEFINED || pred0->vrp.range_type == VRP_VARYING ||
 109                                 pred1->vrp.range_type == VRP_VARYING) {
 110                         return 0;
 111                 }
 112
 113                 new_top = tarval_add(pred0->vrp.range_top, pred1->vrp.range_top);
 114                 overflow_top = tarval_carry();
 115                 new_bottom = tarval_add(pred0->vrp.range_bottom, pred1->vrp.range_bottom);
 116                 overflow_bottom = tarval_carry();
 117
 118                 if (!overflow_top && !overflow_bottom && pred0->vrp.range_type == VRP_RANGE
 119                                 &&pred1->vrp.range_type == VRP_RANGE) {
 120                         new_range_bottom = new_bottom;
 121                         new_range_top = new_top;
 122                         new_range_type = VRP_RANGE;
 123                 }
 124
 125                 if (overflow_top || overflow_bottom) {
 126                         // TODO Implement overflow handling
 127                         new_range_type = VRP_UNDEFINED;
 128                 }
 129         } else if (is_Sub(node)) {
 130                 ir_node *pred0 = get_Sub_left(node);
 131                 ir_node *pred1 = get_Sub_right(node);
 132                 int overflow_top, overflow_bottom;
 133                 tarval *new_top, *new_bottom;
 134
 135                 if (pred0->vrp.range_type == VRP_UNDEFINED || pred1->vrp.range_type ==
 136                                 VRP_UNDEFINED) {
 137                         return 0;
 138                 }
 139
 140                 new_top = tarval_sub(pred0->vrp.range_top, pred1->vrp.range_top, NULL);
 141                 overflow_top = tarval_carry();
 142                 new_bottom = tarval_sub(pred0->vrp.range_bottom, pred1->vrp.range_bottom, NULL);
 143                 overflow_bottom = tarval_carry();
 144
 145                 if (!overflow_top && !overflow_bottom && pred0->vrp.range_type == VRP_RANGE
 146                                 &&pred1->vrp.range_type == VRP_RANGE) {
 147                         new_range_bottom = new_bottom;
 148                         new_range_top = new_top;
 149                         new_range_type = VRP_RANGE;
 150                 }
 151
 152                 if (overflow_top || overflow_bottom) {
 153                         // TODO Implement overflow handling
 154                 }
 155         } else if (is_Or(node)) {
 156                 ir_node *a = get_Or_left(node);
 157                 ir_node *b = get_Or_right(node);
 158                 tarval *tmp;
 159
 160                 new_bits_set = tarval_or(a->vrp.bits_set, b->vrp.bits_set);
 161                 new_bits_not_set = tarval_and(a->vrp.bits_not_set, b->vrp.bits_not_set);
 162
 163                 tmp = tarval_not(a->vrp.bits_set);
 164                 tmp = tarval_eor(a->vrp.bits_not_set, tmp);
 165                 //check if one of the predecessors is completely determined
 166                 if (tarval_is_null(tmp)) {
 167                         new_bits_node = b;
 168                 }
 169
 170                 tmp = tarval_not(b->vrp.bits_set);
 171                 tmp = tarval_eor(b->vrp.bits_not_set, tmp);
 172                 if (tarval_is_null(tmp)) {
 173                         new_bits_node = a;
 174                 }
 175
 176         } else if (is_Rotl(node)) {
 177                 ir_node *a = get_Rotl_left(node);
 178                 ir_node *b = get_Rotl_right(node);
 179
 180                 // We can only compute this if the right value is a constant
 181                 if (is_Const(b)) {
 182                         tarval *bits_set, *bits_not_set;
 183                         bits_set = tarval_rotl(a->vrp.bits_set, get_Const_tarval(b));
 184                         bits_not_set = tarval_rotl(a->vrp.bits_not_set, get_Const_tarval(b));
 185
 186                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 187                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 188                 }
 189
 190         } else if (is_Shl(node)) {
 191                 ir_node *a = get_Shl_left(node);
 192                 ir_node *b = get_Shl_right(node);
 193
 194                 // We can only compute this if the right value is a constant
 195                 if (is_Const(b)) {
 196                         tarval *bits_set, *bits_not_set;
 197                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 198                         bits_set = tarval_shl(a->vrp.bits_set, get_Const_tarval(b));
 199                         bits_not_set = tarval_shl(a->vrp.bits_not_set, get_Const_tarval(b));
 200
 201                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 202                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 203
 204                         bits_not_set = tarval_not( tarval_shl(
 205                                                                                 get_mode_all_one(m),
 206                                                                                 get_Const_tarval(b)));
 207                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 208
 209                 }
 210
 211         } else if (is_Shr(node)) {
 212                 ir_node *a = get_Shr_left(node);
 213                 ir_node *b = get_Shr_right(node);
 214
 215                 // We can only compute this if the right value is a constant
 216                 if (is_Const(b)) {
 217                         tarval *bits_set, *bits_not_set;
 218                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 219                         bits_set = tarval_shr(a->vrp.bits_set, get_Const_tarval(b));
 220                         bits_not_set = tarval_shr(a->vrp.bits_not_set, get_Const_tarval(b));
 221
 222                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 223                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 224
 225                         bits_not_set = tarval_not( tarval_shr(
 226                                                                                 get_mode_all_one(m),
 227                                                                                 get_Const_tarval(b)));
 228                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 229                 }
 230
 231         } else if (is_Shrs(node)) {
 232                 ir_node *a = get_Shrs_left(node);
 233                 ir_node *b = get_Shrs_right(node);
 234
 235                 // We can only compute this if the right value is a constant
 236                 if (is_Const(b)) {
 237                         tarval *bits_set, *bits_not_set;
 238                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 239                         bits_set = tarval_shrs(a->vrp.bits_set, get_Const_tarval(b));
 240                         bits_not_set = tarval_shrs(a->vrp.bits_not_set, get_Const_tarval(b));
 241
 242                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 243                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 244
 245                         bits_not_set = tarval_not( tarval_shrs(
 246                                                                                 get_mode_all_one(m),
 247                                                                                 get_Const_tarval(b)));
 248                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 249                 }
 250
 251         } else if (is_Eor(node)) {
 252                 ir_node *a = get_Eor_left(node);
 253                 ir_node *b = get_Eor_right(node);
 254
 255                 tarval *bits_set, *bits_not_set;
 256                 bits_not_set = tarval_or(
 257                                                         tarval_and(a->vrp.bits_set, b->vrp.bits_set),
 258                                                         tarval_and(a->vrp.bits_not_set,
 259                                                                 b->vrp.bits_not_set));
 260
 261                 bits_set = tarval_or(
 262                                                 tarval_and(a->vrp.bits_set, b->vrp.bits_not_set),
 263                                                 tarval_and(a->vrp.bits_not_set, b->vrp.bits_set));
 264
 265                 new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 266                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 267
 268         } else if (is_Id(node)) {
 269                 ir_node *pred = get_Id_pred(node);
 270                 new_bits_set = pred->vrp.bits_set;
 271                 new_bits_not_set = pred->vrp.bits_not_set;
 272                 new_range_top = pred->vrp.range_top;
 273                 new_range_bottom = pred->vrp.range_bottom;
 274                 new_range_type = pred->vrp.range_type;
 275
 276         } else if (is_Not(node)) {
 277                 ir_node *pred = get_Not_op(node);
 278                 new_bits_set = tarval_or(pred->vrp.bits_not_set, node->vrp.bits_set);
 279                 new_bits_not_set = tarval_or(pred->vrp.bits_set, node->vrp.bits_not_set);
 280
 281         } else if (is_Conv(node)) {
 282                 ir_node *pred = get_Conv_op(node);
 283                 ir_mode *old_mode = get_irn_mode(pred);
 284                 ir_mode *new_mode;
 285                 tarval *bits_not_set;
 286
 287                 if (!mode_is_int(old_mode))
 288                         return 0;
 289
 290                 new_mode = get_irn_mode(node);
 291
 292                 // The second and is needed if target type is smaller
 293                 bits_not_set = tarval_not(
 294                                                         tarval_convert_to(get_mode_all_one(old_mode),
 295                                                                 new_mode
 296                                                                 ));
 297                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(pred->vrp.bits_not_set, new_mode));
 298                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 299                 new_bits_set = tarval_and(
 300                                 tarval_not(bits_not_set), tarval_convert_to(pred->vrp.bits_set, new_mode));
 301
 302                 if (tarval_cmp(pred->vrp.range_top, get_mode_max(new_mode)) == pn_Cmp_Le) {
 303                         node->vrp.range_top = pred->vrp.range_top;
 304                 }
 305
 306                 if (tarval_cmp(pred->vrp.range_bottom, get_mode_min(new_mode)) == pn_Cmp_Ge) {
 307                         node->vrp.range_bottom = pred->vrp.range_bottom;
 308                 }
 309
 310         } else if (is_Confirm(node)) {
 311                 pn_Cmp cmp = get_Confirm_cmp(node);
 312                 ir_node *bound = get_Confirm_bound(node);
 313
 314                 /** @todo: Handle non-Const bounds */
 315
 316                 if (cmp == pn_Cmp_Lg) {
 317                         /** @todo: Is there some way to preserve the information? */
 318                         new_range_type = VRP_ANTIRANGE;
 319                         if (is_Const(bound)) {
 320                                 new_range_top = get_Const_tarval(bound);
 321                                 new_range_bottom = get_Const_tarval(bound);
 322                         }
 323                 } else if (cmp == pn_Cmp_Le) {
 324                         if (node->vrp.range_type == VRP_UNDEFINED) {
 325                                 new_range_type = VRP_RANGE;
 326                                 if (is_Const(bound)) {
 327                                         new_range_top = get_Const_tarval(bound);
 328                                 }
 329                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 330                         } else if (node->vrp.range_type == VRP_RANGE) {
 331                                 if (is_Const(bound)) {
 332                                         if (tarval_cmp(node->vrp.range_top,
 333                                                                 get_Const_tarval(bound)) == pn_Cmp_Le) {
 334                                                 new_range_top = get_Const_tarval(bound);
 335                                         }
 336                                         new_range_bottom = get_tarval_min(get_irn_mode(node));
 337
 338                                 } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 339                                         /** @todo: How do we manage not to get a never ending loop? */
 340                                 }
 341                         }
 342                 }
 343
 344         } else if (is_Phi(node)) {
 345                 // combine all ranges
 346                 ir_node *pred;
 347                 int num = get_Phi_n_preds(node);
 348                 pn_Cmp cmp;
 349                 int i;
 350                 tarval *range_top, *range_bottom, *bits_set, *bits_not_set;
 351                 enum range_types range_type;
 352
 353                 assert(num > 0);
 354
 355                 pred = get_Phi_pred(node,0);
 356                 range_top = pred->vrp.range_top;
 357                 range_bottom = pred->vrp.range_bottom;
 358                 range_type = pred->vrp.range_type;
 359                 bits_set = pred->vrp.bits_set;
 360                 bits_not_set = pred->vrp.bits_not_set;
 361
 362                 for (i = 1; i < num; i++) {
 363                         pred = get_Phi_pred(node, i);
 364                         if (range_type == VRP_RANGE && pred->vrp.range_type ==
 365                                         VRP_RANGE) {
 366                                 cmp = tarval_cmp(range_top, pred->vrp.range_top);
 367                                 if (cmp == pn_Cmp_Lt) {
 368                                         range_top = pred->vrp.range_top;
 369                                 }
 370                                 cmp = tarval_cmp(range_bottom, pred->vrp.range_bottom);
 371                                 if (cmp == pn_Cmp_Gt) {
 372                                         range_bottom = pred->vrp.range_bottom;
 373                                 }
 374                         } else {
 375                                 range_type = VRP_VARYING;
 376                                 break;
 377                         }
 378                 }
 379
 380                 new_range_type = range_type;
 381                 new_range_top = range_top;
 382                 new_range_bottom = range_bottom;
 383
 384         } else {
 385                 // unhandled, therefore never updated
 386                 return 0;
 387         }
 388
 389
 390
 391         /* TODO: Check, if there can be information derived from any of these:
 392         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 393         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 394         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 395         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 396         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 397         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 398         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 399         is_Pin(node) is_Proj(node) is_Quot(node)
 400         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 401         is_SymConst(node) is_Sync(node) is_Tuple(node)
 402         */
 403
 404         // Merge the newly calculated values with those that might already exist
 405
 406         if (new_bits_set != tarval_bad) {
 407                 new_bits_set = tarval_or(new_bits_set, node->vrp.bits_set);
 408                 if (tarval_cmp(new_bits_set, node->vrp.bits_set) != pn_Cmp_Eq) {
 409                         something_changed = 1;
 410                         node->vrp.bits_set = new_bits_set;
 411                 }
 412         }
 413
 414         if (new_bits_not_set != tarval_bad) {
 415                 new_bits_not_set = tarval_or(new_bits_not_set, node->vrp.bits_not_set);
 416
 417                 if (tarval_cmp(new_bits_not_set, node->vrp.bits_not_set) != pn_Cmp_Eq) {
 418                         something_changed = 1;
 419                         node->vrp.bits_not_set = new_bits_not_set;
 420                 }
 421         }
 422
 423         if (node->vrp.bits_node == NULL && new_bits_node != NULL) {
 424                 something_changed = 1;
 425                 node->vrp.bits_node = new_bits_node;
 426         }
 427
 428         if (node->vrp.range_type == VRP_UNDEFINED &&
 429                         new_range_type != VRP_UNDEFINED) {
 430                 something_changed = 1;
 431                 node->vrp.range_type = new_range_type;
 432                 node->vrp.range_bottom = new_range_bottom;
 433                 node->vrp.range_top = new_range_top;
 434                 node->vrp.range_op = new_range_op;
 435                 node->vrp.range_node = new_range_node;
 436
 437         } else if (node->vrp.range_type == VRP_RANGE) {
 438                 if (new_range_type == VRP_RANGE) {
 439                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 440                                         (new_range_node == node->vrp.range_node &&
 441                                          new_range_op == node->vrp.range_op)) {
 442                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 443                                         something_changed = 1;
 444                                         node->vrp.range_bottom = new_range_bottom;
 445                                 }
 446                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Gt) {
 447                                         something_changed = 1;
 448                                         node->vrp.range_top = new_range_top;
 449                                 }
 450                         }
 451
 452                         // prefer the absolute value
 453                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 454                                 something_changed = 1;
 455                                 node->vrp.range_node = NULL;
 456                                 node->vrp.range_top = new_range_top;
 457                                 node->vrp.range_bottom = new_range_bottom;
 458                         }
 459                 }
 460
 461                 if (new_range_type == VRP_ANTIRANGE) {
 462                         // if they are overlapping, cut the range.
 463                         // TODO: Maybe we can preserve more information here
 464                         if (new_range_node == NULL && node->vrp.range_node == NULL) {
 465                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt &&
 466                                                 tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 467                                         something_changed = 1;
 468                                         node->vrp.range_bottom = new_range_top;
 469
 470                                 } else if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Gt &&
 471                                                 tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 472                                         something_changed = 1;
 473                                         node->vrp.range_top = new_range_bottom;
 474                                 }
 475
 476                                 // We can not handle the case where the anti range is in the
 477                                 // range
 478                         }
 479
 480                         // prefer the absolute value
 481                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 482                                 something_changed = 1;
 483                                 node->vrp.range_node = NULL;
 484                                 node->vrp.range_top = new_range_top;
 485                                 node->vrp.range_bottom = new_range_bottom;
 486                         }
 487                 }
 488         } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 489                 if (new_range_type == VRP_ANTIRANGE) {
 490                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 491                                         (new_range_node == node->vrp.range_node &&
 492                                          new_range_op == node->vrp.range_op)) {
 493                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 494                                         something_changed = 1;
 495                                         node->vrp.range_bottom = new_range_bottom;
 496                                 }
 497                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 498                                         something_changed = 1;
 499                                         node->vrp.range_top = new_range_top;
 500                                 }
 501                         }
 502
 503                         // prefer the absolute value
 504                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 505                                 something_changed = 1;
 506                                 node->vrp.range_node = NULL;
 507                                 node->vrp.range_top = new_range_top;
 508                                 node->vrp.range_bottom = new_range_bottom;
 509                         }
 510                 }
 511
 512                 if (new_range_type == VRP_RANGE) {
 513                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 514                                         (new_range_node == node->vrp.range_node &&
 515                                          new_range_op == node->vrp.range_op)) {
 516                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt) {
 517                                         something_changed = 1;
 518                                         node->vrp.range_bottom = new_range_top;
 519                                 }
 520                                 if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Lt) {
 521                                         something_changed = 1;
 522                                         node->vrp.range_top = new_range_bottom;
 523                                 }
 524                         }
 525
 526                         // prefer the absolute value
 527                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 528                                 something_changed = 1;
 529                                 node->vrp.range_node = NULL;
 530                                 node->vrp.range_top = new_range_top;
 531                                 node->vrp.range_bottom = new_range_bottom;
 532                         }
 533                 }
 534         }
 535
 536         assert(tarval_is_null(
 537                                 tarval_and(node->vrp.bits_set, node->vrp.bits_not_set)));
 538
 539         return something_changed;
 540 }
 541
 542 void vrp_first_pass(ir_node *n, void *e)
 543 {
 544         ir_node *succ;
 545         worklist_t *tmp_entry;
 546         int i;
 547         struct vrp_env_t *env = e;
 548
 549         if (is_Block(n))
 550                 return;
 551
 552         set_irn_link(n, VISITED);
 553
 554         update_vrp_data(n);
 555
 556         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 557                 succ =  get_irn_out(n, i);
 558                 if (get_irn_link(succ) == VISITED) {
 559                         // we found a loop
 560
 561                         tmp_entry = XMALLOC(worklist_t);
 562                         tmp_entry->node = n;
 563                         list_add(&(tmp_entry->nodes), &(env->worklist->nodes));
 564
 565
 566                 }
 567         }
 568 }
 569
 570
 571 void set_vrp_data(ir_graph *irg)
 572 {
 573
 574         ir_node *succ;
 575         int i;
 576         worklist_t worklist;
 577         worklist_t *tmp_entry, *tmp_entry2;
 578         struct vrp_env_t env;
 579
 580         if (!irg) {
 581                 /* no graph, skip */
 582                 return;
 583         }
 584
 585         assure_irg_outs(irg); // ensure that out edges are consistent
 586
 587 //      edges_activate(irg);
 588
 589         INIT_LIST_HEAD(&worklist.nodes);
 590
 591         env.worklist = &worklist;
 592         irg_walk_graph(irg, NULL, vrp_first_pass, &env);
 593
 594
 595
 596         // while there are entries in the worklist, continue
 597         while ( !list_empty(&worklist.nodes) ) {
 598
 599                 list_head *pos, *next;
 600                 list_for_each_safe(pos, next, &worklist.nodes) {
 601
 602                         tmp_entry = list_entry(pos, worklist_t, nodes);
 603
 604                         if (update_vrp_data(tmp_entry->node)) {
 605                                 // if something changed, add successors to worklist
 606                                 for (i = get_irn_n_outs(tmp_entry->node) - 1; i >=0; --i) {
 607                                         succ =  get_irn_out(tmp_entry->node, i);
 608
 609                                         tmp_entry2 = XMALLOC(worklist_t);
 610                                         tmp_entry2->node = succ;
 611                                         list_add(&(tmp_entry2->nodes), &worklist.nodes);
 612                                 }
 613                         }
 614
 615                         list_del(pos);
 616                         xfree(tmp_entry);
 617                 }
 618         }
 619 }
 620
 621
 622 ir_graph_pass_t *set_vrp_pass(const char *name)
 623 {
 624         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 625 }
 626
 627 pn_Cmp vrp_cmp(ir_node *left, ir_node *right)
 628 {
 629         if (!left->vrp.valid || !right->vrp.valid) {
 630                 return pn_Cmp_False;
 631         }
 632
 633         if (left->vrp.range_type == VRP_RANGE && right->vrp.range_type == VRP_RANGE) {
 634                 if (tarval_cmp(left->vrp.range_top, right->vrp.range_bottom) == pn_Cmp_Lt) {
 635                         return pn_Cmp_Lt;
 636                 }
 637                 if (tarval_cmp(left->vrp.range_bottom, right->vrp.range_top) == pn_Cmp_Gt) {
 638                         return pn_Cmp_Gt;
 639                 }
 640         }
 641
 642         if (!tarval_is_null(tarval_and(left->vrp.bits_set, right->vrp.bits_not_set)) ||
 643                         !tarval_is_null(tarval_and(left->vrp.bits_not_set, right->vrp.bits_set))) {
 644                 return pn_Cmp_Lg;
 645         }
 646         // TODO: We can get way more information here
 647
 648         return pn_Cmp_False;
 649 }