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
  27 #include "irtypes.h"
  28 #include "vrp.h"
  29 #include "irouts.h"
  30 #include "irgraph_t.h"
  31 #include "irpass.h"
  32 #include "list.h"
  33 #include "irgwalk.h"
  34 #include "iredges.h"
  35 #include "tv.h"
  36
  37
  38 static char v;
  39 static void *VISITED = &v;
  40
  41 typedef struct worklist_t worklist_t;
  42 struct worklist_t {
  43          struct list_head nodes;
  44         ir_node *node;
  45 };
  46
  47 struct vrp_env_t {
  48         worklist_t *worklist;
  49 };
  50
  51 int update_vrp_data( ir_node *node) {
  52
  53         tarval *new_bits_set = get_tarval_bad();
  54         tarval *new_bits_not_set = get_tarval_bad();
  55         tarval *new_range_bottom = get_tarval_bad();
  56         tarval *new_range_top = get_tarval_bad();
  57         ir_node *new_bits_node = NULL;
  58         ir_node *new_range_node = NULL;
  59         enum range_types new_range_type = VRP_UNDEFINED;
  60         enum range_ops new_range_op = VRP_NONE;
  61         int something_changed = 0;
  62
  63         node->vrp.valid = 1;
  64         // TODO: Check if all predecessors have valid VRP information
  65
  66
  67         if (!mode_is_int(get_irn_mode(node))) {
  68                 return 0; // we don't optimize for non-int-nodes
  69         }
  70
  71         if (is_Const(node)) {
  72                 tarval *tv = get_Const_tarval(node);
  73
  74                 new_bits_set = tv;
  75                 new_bits_not_set = tarval_not(tv);
  76                 new_range_bottom = tv;
  77                 new_range_top = tv;
  78                 new_range_type = VRP_RANGE;
  79         } else if (is_And(node)) {
  80                 ir_node *pred0 = get_And_left(node);
  81                 ir_node *pred1 = get_And_right(node);
  82                 tarval *tmp;
  83
  84                 new_bits_set = tarval_and(pred0->vrp.bits_set, pred1->vrp.bits_set);
  85                 new_bits_not_set = tarval_or(pred0->vrp.bits_not_set, pred1->vrp.bits_not_set);
  86
  87                 tmp = tarval_not(pred0->vrp.bits_set);
  88                 tmp = tarval_eor(pred0->vrp.bits_not_set, tmp);
  89                 //check if one of the predecessors is completely determined
  90                 if (tarval_is_null(tmp)) {
  91                         new_bits_node = pred1;
  92                 }
  93
  94                 tmp = tarval_not(pred1->vrp.bits_set);
  95                 tmp = tarval_eor(pred1->vrp.bits_not_set, tmp);
  96                 if (tarval_is_null(tmp)) {
  97                         new_bits_node = pred0;
  98                 }
  99         } else if (is_Add(node)) {
 100                 ir_node *pred0 = get_Add_left(node);
 101                 ir_node *pred1 = get_Add_right(node);
 102                 int overflow_top, overflow_bottom;
 103                 tarval *new_top, *new_bottom;
 104
 105                 if (pred0->vrp.range_type == VRP_UNDEFINED || pred1->vrp.range_type ==
 106                                 VRP_UNDEFINED || pred0->vrp.range_type == VRP_VARYING ||
 107                                 pred1->vrp.range_type == VRP_VARYING) {
 108                         return 0;
 109                 }
 110
 111                 new_top = tarval_add(pred0->vrp.range_top, pred1->vrp.range_top);
 112                 overflow_top = tarval_carry();
 113                 new_bottom = tarval_add(pred0->vrp.range_bottom, pred1->vrp.range_bottom);
 114                 overflow_bottom = tarval_carry();
 115
 116                 if (!overflow_top && !overflow_bottom && pred0->vrp.range_type == VRP_RANGE
 117                                 &&pred1->vrp.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         } else if (is_Sub(node)) {
 128                 ir_node *pred0 = get_Sub_left(node);
 129                 ir_node *pred1 = get_Sub_right(node);
 130                 int overflow_top, overflow_bottom;
 131                 tarval *new_top, *new_bottom;
 132
 133                 if (pred0->vrp.range_type == VRP_UNDEFINED || pred1->vrp.range_type ==
 134                                 VRP_UNDEFINED) {
 135                         return 0;
 136                 }
 137
 138                 new_top = tarval_sub(pred0->vrp.range_top, pred1->vrp.range_top, NULL);
 139                 overflow_top = tarval_carry();
 140                 new_bottom = tarval_sub(pred0->vrp.range_bottom, pred1->vrp.range_bottom, NULL);
 141                 overflow_bottom = tarval_carry();
 142
 143                 if (!overflow_top && !overflow_bottom && pred0->vrp.range_type == VRP_RANGE
 144                                 &&pred1->vrp.range_type == VRP_RANGE) {
 145                         new_range_bottom = new_bottom;
 146                         new_range_top = new_top;
 147                         new_range_type = VRP_RANGE;
 148                 }
 149
 150                 if (overflow_top || overflow_bottom) {
 151                         // TODO Implement overflow handling
 152                 }
 153         } else if (is_Or(node)) {
 154                 ir_node *a = get_Or_left(node);
 155                 ir_node *b = get_Or_right(node);
 156                 tarval *tmp;
 157
 158                 new_bits_set = tarval_or(a->vrp.bits_set, b->vrp.bits_set);
 159                 new_bits_not_set = tarval_and(a->vrp.bits_not_set, b->vrp.bits_not_set);
 160
 161                 tmp = tarval_not(a->vrp.bits_set);
 162                 tmp = tarval_eor(a->vrp.bits_not_set, tmp);
 163                 //check if one of the predecessors is completely determined
 164                 if (tarval_is_null(tmp)) {
 165                         new_bits_node = b;
 166                 }
 167
 168                 tmp = tarval_not(b->vrp.bits_set);
 169                 tmp = tarval_eor(b->vrp.bits_not_set, tmp);
 170                 if (tarval_is_null(tmp)) {
 171                         new_bits_node = a;
 172                 }
 173
 174         } else if (is_Rotl(node)) {
 175                 ir_node *a = get_Rotl_left(node);
 176                 ir_node *b = get_Rotl_right(node);
 177
 178                 // We can only compute this if the right value is a constant
 179                 if (is_Const(b)) {
 180                         tarval *bits_set, *bits_not_set;
 181                         bits_set = tarval_rotl(a->vrp.bits_set, get_Const_tarval(b));
 182                         bits_not_set = tarval_rotl(a->vrp.bits_not_set, get_Const_tarval(b));
 183
 184                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 185                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 186                 }
 187
 188         } else if (is_Shl(node)) {
 189                 ir_node *a = get_Shl_left(node);
 190                 ir_node *b = get_Shl_right(node);
 191
 192                 // We can only compute this if the right value is a constant
 193                 if (is_Const(b)) {
 194                         tarval *bits_set, *bits_not_set;
 195                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 196                         bits_set = tarval_shl(a->vrp.bits_set, get_Const_tarval(b));
 197                         bits_not_set = tarval_shl(a->vrp.bits_not_set, get_Const_tarval(b));
 198
 199                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 200                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 201
 202                         bits_not_set = tarval_not( tarval_shl(
 203                                                                                 get_tarval_all_one(m),
 204                                                                                 get_Const_tarval(b)));
 205                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 206
 207                 }
 208
 209         } else if (is_Shr(node)) {
 210                 ir_node *a = get_Shr_left(node);
 211                 ir_node *b = get_Shr_right(node);
 212
 213                 // We can only compute this if the right value is a constant
 214                 if (is_Const(b)) {
 215                         tarval *bits_set, *bits_not_set;
 216                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 217                         bits_set = tarval_shr(a->vrp.bits_set, get_Const_tarval(b));
 218                         bits_not_set = tarval_shr(a->vrp.bits_not_set, get_Const_tarval(b));
 219
 220                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 221                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 222
 223                         bits_not_set = tarval_not( tarval_shr(
 224                                                                                 get_tarval_all_one(m),
 225                                                                                 get_Const_tarval(b)));
 226                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 227                 }
 228
 229         } else if (is_Shrs(node)) {
 230                 ir_node *a = get_Shrs_left(node);
 231                 ir_node *b = get_Shrs_right(node);
 232
 233                 // We can only compute this if the right value is a constant
 234                 if (is_Const(b)) {
 235                         tarval *bits_set, *bits_not_set;
 236                         ir_mode *m = get_tarval_mode(node->vrp.bits_not_set);
 237                         bits_set = tarval_shrs(a->vrp.bits_set, get_Const_tarval(b));
 238                         bits_not_set = tarval_shrs(a->vrp.bits_not_set, get_Const_tarval(b));
 239
 240                         new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 241                         new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 242
 243                         bits_not_set = tarval_not( tarval_shrs(
 244                                                                                 get_tarval_all_one(m),
 245                                                                                 get_Const_tarval(b)));
 246                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 247                 }
 248
 249         } else if (is_Eor(node)) {
 250                 ir_node *a = get_Eor_left(node);
 251                 ir_node *b = get_Eor_right(node);
 252
 253                 tarval *bits_set, *bits_not_set;
 254                 bits_not_set = tarval_or(
 255                                                         tarval_and(a->vrp.bits_set, b->vrp.bits_set),
 256                                                         tarval_and(a->vrp.bits_not_set,
 257                                                                 b->vrp.bits_not_set));
 258
 259                 bits_set = tarval_or(
 260                                                 tarval_and(a->vrp.bits_set, b->vrp.bits_not_set),
 261                                                 tarval_and(a->vrp.bits_not_set, b->vrp.bits_set));
 262
 263                 new_bits_set = tarval_or(bits_set, node->vrp.bits_set);
 264                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 265
 266         } else if (is_Id(node)) {
 267                 ir_node *pred = get_Id_pred(node);
 268                 new_bits_set = pred->vrp.bits_set;
 269                 new_bits_not_set = pred->vrp.bits_not_set;
 270                 new_range_top = pred->vrp.range_top;
 271                 new_range_bottom = pred->vrp.range_bottom;
 272                 new_range_type = pred->vrp.range_type;
 273
 274         } else if (is_Not(node)) {
 275                 ir_node *pred = get_Not_op(node);
 276                 new_bits_set = tarval_or(pred->vrp.bits_not_set, node->vrp.bits_set);
 277                 new_bits_not_set = tarval_or(pred->vrp.bits_set, node->vrp.bits_not_set);
 278
 279         } else if (is_Conv(node)) {
 280                 ir_node *pred = get_Conv_op(node);
 281                 ir_mode *old_mode = get_irn_mode(pred);
 282                 ir_mode *new_mode;
 283                 tarval *bits_not_set;
 284
 285                 if (!mode_is_int(old_mode))
 286                         return 0;
 287
 288                 new_mode = get_irn_mode(node);
 289
 290                 // The second and is needed if target type is smaller
 291                 bits_not_set = tarval_not(
 292                                                         tarval_convert_to(get_tarval_all_one(old_mode),
 293                                                                 new_mode
 294                                                                 ));
 295                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(pred->vrp.bits_not_set, new_mode));
 296                 new_bits_not_set = tarval_or(bits_not_set, node->vrp.bits_not_set);
 297                 new_bits_set = tarval_and(
 298                                 tarval_not(bits_not_set), tarval_convert_to(pred->vrp.bits_set, new_mode));
 299
 300                 if (tarval_cmp(pred->vrp.range_top, get_tarval_max(new_mode)) == pn_Cmp_Le) {
 301                         node->vrp.range_top = pred->vrp.range_top;
 302                 }
 303
 304                 if (tarval_cmp(pred->vrp.range_bottom, get_tarval_min(new_mode)) == pn_Cmp_Ge) {
 305                         node->vrp.range_bottom = pred->vrp.range_bottom;
 306                 }
 307
 308         } else if (is_Confirm(node)) {
 309                 pn_Cmp cmp = get_Confirm_cmp(node);
 310                 ir_node *bound = get_Confirm_bound(node);
 311
 312                 /** @todo: Handle non-Const bounds */
 313
 314                 if (cmp == pn_Cmp_Lg) {
 315                         /** @todo: Is there some way to preserve the information? */
 316                         new_range_type = VRP_ANTIRANGE;
 317                         if (is_Const(bound)) {
 318                                 new_range_top = get_Const_tarval(bound);
 319                                 new_range_bottom = get_Const_tarval(bound);
 320                         }
 321                 } else if (cmp == pn_Cmp_Le) {
 322                         if (node->vrp.range_type == VRP_UNDEFINED) {
 323                                 new_range_type = VRP_RANGE;
 324                                 if (is_Const(bound)) {
 325                                         new_range_top = get_Const_tarval(bound);
 326                                 }
 327                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 328                         } else if (node->vrp.range_type == VRP_RANGE) {
 329                                 if (is_Const(bound)) {
 330                                         if (tarval_cmp(node->vrp.range_top,
 331                                                                 get_Const_tarval(bound)) == pn_Cmp_Le) {
 332                                                 new_range_top = get_Const_tarval(bound);
 333                                         }
 334                                         new_range_bottom = get_tarval_min(get_irn_mode(node));
 335
 336                                 } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 337                                         /** @todo: How do we manage not to get a never ending loop? */
 338                                 }
 339                         }
 340                 }
 341
 342         } else if (is_Phi(node)) {
 343                 // combine all ranges
 344                 ir_node *pred;
 345                 int num = get_Phi_n_preds(node);
 346                 pn_Cmp cmp;
 347                 int i;
 348                 tarval *range_top, *range_bottom, *bits_set, *bits_not_set;
 349                 enum range_types range_type;
 350
 351                 assert(num > 0);
 352
 353                 pred = get_Phi_pred(node,0);
 354                 range_top = pred->vrp.range_top;
 355                 range_bottom = pred->vrp.range_bottom;
 356                 range_type = pred->vrp.range_type;
 357                 bits_set = pred->vrp.bits_set;
 358                 bits_not_set = pred->vrp.bits_not_set;
 359
 360                 for(i = 1; i < num; i++) {
 361                         pred = get_Phi_pred(node, i);
 362                         if (range_type == VRP_RANGE && pred->vrp.range_type ==
 363                                         VRP_RANGE) {
 364                                 cmp = tarval_cmp(range_top, pred->vrp.range_top);
 365                                 if (cmp == pn_Cmp_Lt) {
 366                                         range_top = pred->vrp.range_top;
 367                                 }
 368                                 cmp = tarval_cmp(range_bottom, pred->vrp.range_bottom);
 369                                 if (cmp == pn_Cmp_Gt) {
 370                                         range_bottom = pred->vrp.range_bottom;
 371                                 }
 372                         } else {
 373                                 range_type = VRP_VARYING;
 374                                 break;
 375                         }
 376                 }
 377
 378                 new_range_type = range_type;
 379                 new_range_top = range_top;
 380                 new_range_bottom = range_bottom;
 381
 382         } else {
 383                 // unhandled, therefore never updated
 384                 return 0;
 385         }
 386
 387
 388
 389         /* TODO: Check, if there can be information derived from any of these:
 390         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 391         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 392         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 393         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 394         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 395         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 396         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 397         is_Pin(node) is_Proj(node) is_Quot(node)
 398         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 399         is_SymConst(node) is_Sync(node) is_Tuple(node)
 400         */
 401
 402         // Merge the newly calculated values with those that might already exist
 403
 404         if (new_bits_set != tarval_bad) {
 405                 new_bits_set = tarval_or(new_bits_set, node->vrp.bits_set);
 406                 if (tarval_cmp(new_bits_set, node->vrp.bits_set) != pn_Cmp_Eq) {
 407                         something_changed = 1;
 408                         node->vrp.bits_set = new_bits_set;
 409                 }
 410         }
 411
 412         if (new_bits_not_set != tarval_bad) {
 413                 new_bits_not_set = tarval_or(new_bits_not_set, node->vrp.bits_not_set);
 414
 415                 if (tarval_cmp(new_bits_not_set, node->vrp.bits_not_set) != pn_Cmp_Eq) {
 416                         something_changed = 1;
 417                         node->vrp.bits_not_set = new_bits_not_set;
 418                 }
 419         }
 420
 421         if (node->vrp.bits_node == NULL && new_bits_node != NULL) {
 422                 something_changed = 1;
 423                 node->vrp.bits_node = new_bits_node;
 424         }
 425
 426         if (node->vrp.range_type == VRP_UNDEFINED &&
 427                         new_range_type != VRP_UNDEFINED) {
 428                 something_changed = 1;
 429                 node->vrp.range_type = new_range_type;
 430                 node->vrp.range_bottom = new_range_bottom;
 431                 node->vrp.range_top = new_range_top;
 432                 node->vrp.range_op = new_range_op;
 433                 node->vrp.range_node = new_range_node;
 434
 435         } else if (node->vrp.range_type == VRP_RANGE) {
 436                 if (new_range_type == VRP_RANGE) {
 437                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 438                                         (new_range_node == node->vrp.range_node &&
 439                                          new_range_op == node->vrp.range_op)) {
 440                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 441                                         something_changed = 1;
 442                                         node->vrp.range_bottom = new_range_bottom;
 443                                 }
 444                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Gt) {
 445                                         something_changed = 1;
 446                                         node->vrp.range_top = new_range_top;
 447                                 }
 448                         }
 449
 450                         // prefer the absolute value
 451                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 452                                 something_changed = 1;
 453                                 node->vrp.range_node = NULL;
 454                                 node->vrp.range_top = new_range_top;
 455                                 node->vrp.range_bottom = new_range_bottom;
 456                         }
 457                 }
 458
 459                 if (new_range_type == VRP_ANTIRANGE) {
 460                         // if they are overlapping, cut the range.
 461                         // TODO: Maybe we can preserve more information here
 462                         if (new_range_node == NULL && node->vrp.range_node == NULL) {
 463                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt &&
 464                                                 tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 465                                         something_changed = 1;
 466                                         node->vrp.range_bottom = new_range_top;
 467
 468                                 } else if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Gt &&
 469                                                 tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 470                                         something_changed = 1;
 471                                         node->vrp.range_top = new_range_bottom;
 472                                 }
 473
 474                                 // We can not handle the case where the anti range is in the
 475                                 // range
 476                         }
 477
 478                         // prefer the absolute value
 479                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 480                                 something_changed = 1;
 481                                 node->vrp.range_node = NULL;
 482                                 node->vrp.range_top = new_range_top;
 483                                 node->vrp.range_bottom = new_range_bottom;
 484                         }
 485                 }
 486         } else if (node->vrp.range_type == VRP_ANTIRANGE) {
 487                 if (new_range_type == VRP_ANTIRANGE) {
 488                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 489                                         (new_range_node == node->vrp.range_node &&
 490                                          new_range_op == node->vrp.range_op)) {
 491                                 if (tarval_cmp(node->vrp.range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 492                                         something_changed = 1;
 493                                         node->vrp.range_bottom = new_range_bottom;
 494                                 }
 495                                 if (tarval_cmp(node->vrp.range_top, new_range_top) == pn_Cmp_Lt) {
 496                                         something_changed = 1;
 497                                         node->vrp.range_top = new_range_top;
 498                                 }
 499                         }
 500
 501                         // prefer the absolute value
 502                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 503                                 something_changed = 1;
 504                                 node->vrp.range_node = NULL;
 505                                 node->vrp.range_top = new_range_top;
 506                                 node->vrp.range_bottom = new_range_bottom;
 507                         }
 508                 }
 509
 510                 if (new_range_type == VRP_RANGE) {
 511                         if ((new_range_node == NULL && node->vrp.range_node == NULL) ||
 512                                         (new_range_node == node->vrp.range_node &&
 513                                          new_range_op == node->vrp.range_op)) {
 514                                 if (tarval_cmp(node->vrp.range_bottom, new_range_top) == pn_Cmp_Gt) {
 515                                         something_changed = 1;
 516                                         node->vrp.range_bottom = new_range_top;
 517                                 }
 518                                 if (tarval_cmp(node->vrp.range_top, new_range_bottom) == pn_Cmp_Lt) {
 519                                         something_changed = 1;
 520                                         node->vrp.range_top = new_range_bottom;
 521                                 }
 522                         }
 523
 524                         // prefer the absolute value
 525                         if (new_range_node == NULL && node->vrp.range_node != NULL) {
 526                                 something_changed = 1;
 527                                 node->vrp.range_node = NULL;
 528                                 node->vrp.range_top = new_range_top;
 529                                 node->vrp.range_bottom = new_range_bottom;
 530                         }
 531                 }
 532         }
 533
 534         assert(tarval_is_null(
 535                                 tarval_and(node->vrp.bits_set, node->vrp.bits_not_set)));
 536
 537         return something_changed;
 538 }
 539
 540 void vrp_first_pass(ir_node *n, void *e) {
 541         ir_node *succ;
 542         worklist_t *tmp_entry;
 543         int i;
 544         struct vrp_env_t *env = e;
 545
 546         if (is_Block(n))
 547                 return;
 548
 549         set_irn_link(n, VISITED);
 550
 551         update_vrp_data(n);
 552
 553         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 554                 succ =  get_irn_out(n, i);
 555                 if (get_irn_link(succ) == VISITED) {
 556                         // we found a loop
 557
 558                         tmp_entry = XMALLOC(worklist_t);
 559                         tmp_entry->node = n;
 560                         list_add(&(tmp_entry->nodes), &(env->worklist->nodes));
 561
 562
 563                 }
 564         }
 565 }
 566
 567
 568 void set_vrp_data(ir_graph *irg) {
 569
 570         ir_node *succ;
 571         int i;
 572         worklist_t worklist;
 573         worklist_t *tmp_entry, *tmp_entry2;
 574         struct vrp_env_t env;
 575
 576         if (!irg) {
 577                 /* no graph, skip */
 578                 return;
 579         }
 580
 581         assure_irg_outs(irg); // ensure that out edges are consistent
 582
 583 //      edges_activate(irg);
 584
 585         INIT_LIST_HEAD(&worklist.nodes);
 586
 587         env.worklist = &worklist;
 588         irg_walk_graph(irg, NULL, vrp_first_pass, &env);
 589
 590
 591
 592         // while there are entries in the worklist, continue
 593         while( !list_empty(&worklist.nodes) ) {
 594
 595                 list_head *pos, *next;
 596                 list_for_each_safe(pos, next, &worklist.nodes) {
 597
 598                         tmp_entry = list_entry(pos, worklist_t, nodes);
 599
 600                         if (update_vrp_data(tmp_entry->node)) {
 601                                 // if something changed, add successors to worklist
 602                                 for (i = get_irn_n_outs(tmp_entry->node) - 1; i >=0; --i) {
 603                                         succ =  get_irn_out(tmp_entry->node, i);
 604
 605                                         tmp_entry2 = XMALLOC(worklist_t);
 606                                         tmp_entry2->node = succ;
 607                                         list_add(&(tmp_entry2->nodes), &worklist.nodes);
 608                                 }
 609                         }
 610
 611                         list_del(pos);
 612                         xfree(tmp_entry);
 613                 }
 614         }
 615 }
 616
 617
 618 ir_graph_pass_t *set_vrp_pass(const char *name) {
 619         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 620 }
 621
 622 pn_Cmp vrp_cmp(ir_node *left, ir_node *right) {
 623         if (!left->vrp.valid || !right->vrp.valid) {
 624                 return pn_Cmp_False;
 625         }
 626
 627         if (!(left->vrp.range_type == VRP_UNDEFINED ||
 628                         left->vrp.range_type == VRP_VARYING) && !(
 629                         right->vrp.range_type == VRP_UNDEFINED ||
 630                         right->vrp.range_type == VRP_VARYING)) {
 631
 632                 tarval *lefttop = left->vrp.range_top;
 633                 tarval *leftbottom = left->vrp.range_bottom;
 634                 tarval *righttop = right->vrp.range_top;
 635                 tarval *rightbottom = right->vrp.range_bottom;
 636                 if (left->vrp.range_type == VRP_RANGE && right->vrp.range_type ==
 637                                 VRP_RANGE) {
 638                         if (tarval_cmp(lefttop, rightbottom) == pn_Cmp_Lt) {
 639                                 return pn_Cmp_Lt;
 640                         }
 641                         if (tarval_cmp(leftbottom, righttop) == pn_Cmp_Gt) {
 642                                 return pn_Cmp_Gt;
 643                         }
 644
 645                 }
 646         }
 647
 648         if (!tarval_is_null(tarval_and(left->vrp.bits_set, right->vrp.bits_not_set)) ||
 649                         !tarval_is_null(tarval_and(left->vrp.bits_not_set, right->vrp.bits_set))) {
 650                 return pn_Cmp_Lg;
 651         }
 652         // TODO: We can get way more information here
 653
 654         return pn_Cmp_False;
 655 }