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

   1 /*
   2  * Copyright (C) 1995-2010 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief       analyze graph to provide value range information
  23  * @author      Jonas Fietz
  24  * @version     $Id$
  25  */
  26 #include "config.h"
  27
  28 #include "irtypes.h"
  29 #include "vrp.h"
  30 #include "irouts.h"
  31 #include "irgraph_t.h"
  32 #include "irgopt.h"
  33 #include "irpass.h"
  34 #include "irgwalk.h"
  35 #include "iredges.h"
  36 #include "tv.h"
  37 #include "irop.h"
  38 #include "pdeq.h"
  39 #include "irphase_t.h"
  40
  41
  42 static char v;
  43 static void *VISITED = &v;
  44
  45 struct vrp_env_t {
  46         waitq *workqueue;
  47 };
  48
  49 static int vrp_update_node(ir_node *node)
  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         enum range_types new_range_type = VRP_UNDEFINED;
  56         int something_changed = 0;
  57         vrp_attr *vrp;
  58         ir_phase *phase;
  59
  60         if (!mode_is_int(get_irn_mode(node))) {
  61                 return 0; /* we don't optimize for non-int-nodes*/
  62         }
  63
  64         phase = get_irg_phase(get_irn_irg(node), PHASE_VRP);
  65
  66         ir_printf("update_vrp for %d called\n", get_irn_node_nr(node));
  67         vrp = phase_get_or_set_irn_data(phase, node);
  68
  69         /* TODO: Check if all predecessors have valid VRP information*/
  70
  71
  72
  73         switch (get_irn_opcode(node)) {
  74         case iro_Const: {
  75                 tarval *tv = get_Const_tarval(node);
  76                 new_bits_set = tv;
  77                 new_bits_not_set = tarval_not(tv);
  78                 new_range_bottom = tv;
  79                 new_range_top = tv;
  80                 new_range_type = VRP_RANGE;
  81                 break;
  82         }
  83
  84         case iro_And: {
  85                 vrp_attr *vrp_left, *vrp_right;
  86                 ir_node *left, *right;
  87
  88                 left = get_And_left(node);
  89                 right = get_And_right(node);
  90                 vrp_left = phase_get_or_set_irn_data(phase, left);
  91                 vrp_right = phase_get_or_set_irn_data(phase, right);
  92                 new_bits_set = tarval_and(vrp_left->bits_set, vrp_right->bits_set);
  93                 new_bits_not_set = tarval_or(vrp_left->bits_not_set, vrp_right->bits_not_set);
  94
  95                 break;
  96         }
  97
  98         case iro_Add: {
  99                 int overflow_top, overflow_bottom;
 100                 tarval *new_top, *new_bottom;
 101                 vrp_attr *vrp_left, *vrp_right;
 102                 vrp_left = phase_get_or_set_irn_data(phase, get_Add_left(node));
 103                 vrp_right = phase_get_or_set_irn_data(phase, get_Add_right(node));
 104
 105                 if (vrp_left->range_type == VRP_UNDEFINED || vrp_right->range_type ==
 106                                 VRP_UNDEFINED || vrp_left->range_type == VRP_VARYING ||
 107                                 vrp_right->range_type == VRP_VARYING) {
 108                         return 0;
 109                 }
 110
 111                 new_top = tarval_add(vrp_left->range_top, vrp_right->range_top);
 112                 overflow_top = tarval_carry();
 113                 new_bottom = tarval_add(vrp_left->range_bottom, vrp_right->range_bottom);
 114                 overflow_bottom = tarval_carry();
 115
 116                 if (!overflow_top && !overflow_bottom && vrp_left->range_type == VRP_RANGE
 117                                 &&vrp_right->range_type == VRP_RANGE) {
 118                         new_range_bottom = new_bottom;
 119                         new_range_top = new_top;
 120                         new_range_type = VRP_RANGE;
 121                 }
 122
 123                 if (overflow_top || overflow_bottom) {
 124                         /* TODO Implement overflow handling*/
 125                         new_range_type = VRP_UNDEFINED;
 126                 }
 127                 break;
 128         }
 129
 130         case iro_Sub: {
 131                 int overflow_top, overflow_bottom;
 132                 tarval *new_top, *new_bottom;
 133                 vrp_attr *vrp_left, *vrp_right;
 134                 vrp_left = phase_get_or_set_irn_data(phase, get_Sub_left(node));
 135                 vrp_right = phase_get_or_set_irn_data(phase, get_Sub_right(node));
 136
 137                 if (vrp_left->range_type == VRP_UNDEFINED || vrp_right->range_type ==
 138                                 VRP_UNDEFINED) {
 139                         return 0;
 140                 }
 141
 142                 new_top = tarval_sub(vrp_left->range_top, vrp_right->range_top, NULL);
 143                 overflow_top = tarval_carry();
 144                 new_bottom = tarval_sub(vrp_left->range_bottom, vrp_right->range_bottom, NULL);
 145                 overflow_bottom = tarval_carry();
 146
 147                 if (!overflow_top && !overflow_bottom && vrp_left->range_type == VRP_RANGE
 148                                 &&vrp_right->range_type == VRP_RANGE) {
 149                         new_range_bottom = new_bottom;
 150                         new_range_top = new_top;
 151                         new_range_type = VRP_RANGE;
 152                 }
 153
 154                 if (overflow_top || overflow_bottom) {
 155                         /* TODO Implement overflow handling*/
 156                 }
 157                 break;
 158         }
 159
 160         case iro_Or: {
 161                 vrp_attr *vrp_left, *vrp_right;
 162                 ir_node *left, *right;
 163
 164                 left = get_Or_left(node);
 165                 right = get_Or_right(node);
 166
 167                 vrp_left = phase_get_or_set_irn_data(phase, get_Or_left(node));
 168                 vrp_right = phase_get_or_set_irn_data(phase, get_Or_right(node));
 169
 170                 new_bits_set = tarval_or(vrp_left->bits_set, vrp_right->bits_set);
 171                 new_bits_not_set = tarval_and(vrp_left->bits_not_set, vrp_right->bits_not_set);
 172
 173                 break;
 174         }
 175
 176         case iro_Rotl: {
 177                 vrp_attr *vrp_left, *vrp_right;
 178                 ir_node *right = get_Rotl_right(node);
 179
 180                 vrp_left = phase_get_or_set_irn_data(phase, get_Rotl_left(node));
 181                 vrp_right = phase_get_or_set_irn_data(phase, get_Rotl_right(node));
 182
 183                 /* We can only compute this if the right value is a constant*/
 184                 if (is_Const(right)) {
 185                         tarval *bits_set, *bits_not_set;
 186                         bits_set = tarval_rotl(vrp_left->bits_set, get_Const_tarval(right));
 187                         bits_not_set = tarval_rotl(vrp_left->bits_not_set, get_Const_tarval(right));
 188
 189                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 190                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 191                 }
 192                 break;
 193         }
 194
 195         case iro_Shl: {
 196                 vrp_attr *vrp_left, *vrp_right;
 197                 ir_node *right = get_Shl_right(node);
 198                 vrp_left = phase_get_or_set_irn_data(phase, get_Shl_left(node));
 199                 vrp_right = phase_get_or_set_irn_data(phase, get_Shl_right(node));
 200
 201                 /* We can only compute this if the right value is a constant*/
 202                 if (is_Const(right)) {
 203                         tarval *bits_set, *bits_not_set;
 204                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 205                         bits_set = tarval_shl(vrp_left->bits_set, get_Const_tarval(right));
 206                         bits_not_set = tarval_shl(vrp_left->bits_not_set, get_Const_tarval(right));
 207
 208                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 209                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 210
 211                         bits_not_set = tarval_not( tarval_shl(
 212                                                                                 get_mode_all_one(m),
 213                                                                                 get_Const_tarval(right)));
 214                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 215
 216                 }
 217                 break;
 218         }
 219
 220         case iro_Shr: {
 221                 vrp_attr *vrp_left, *vrp_right;
 222                 ir_node *right = get_Shr_right(node);
 223
 224                 vrp_left = phase_get_or_set_irn_data(phase, get_Shr_left(node));
 225                 vrp_right = phase_get_or_set_irn_data(phase, get_Shr_right(node));
 226
 227                 /* We can only compute this if the right value is a constant*/
 228                 if (is_Const(right)) {
 229                         tarval *bits_set, *bits_not_set;
 230                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 231                         bits_set = tarval_shr(vrp_left->bits_set, get_Const_tarval(right));
 232                         bits_not_set = tarval_shr(vrp_left->bits_not_set, get_Const_tarval(right));
 233
 234                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 235                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 236
 237                         bits_not_set = tarval_not( tarval_shr(
 238                                                                                 get_mode_all_one(m),
 239                                                                                 get_Const_tarval(right)));
 240                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 241                 }
 242                 break;
 243         }
 244
 245         case iro_Shrs: {
 246                 vrp_attr *vrp_left, *vrp_right;
 247                 ir_node *right = get_Shrs_right(node);
 248
 249                 vrp_left = phase_get_or_set_irn_data(phase, get_Shrs_left(node));
 250                 vrp_right = phase_get_or_set_irn_data(phase, get_Shrs_right(node));
 251
 252                 /* We can only compute this if the right value is a constant*/
 253                 if (is_Const(right)) {
 254                         tarval *bits_set, *bits_not_set;
 255                         ir_mode *m = get_tarval_mode(vrp->bits_not_set);
 256                         bits_set = tarval_shrs(vrp_left->bits_set, get_Const_tarval(right));
 257                         bits_not_set = tarval_shrs(vrp_left->bits_not_set, get_Const_tarval(right));
 258
 259                         new_bits_set = tarval_or(bits_set, vrp->bits_set);
 260                         new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 261
 262                         bits_not_set = tarval_not( tarval_shrs(
 263                                                                                 get_mode_all_one(m),
 264                                                                                 get_Const_tarval(right)));
 265                         new_bits_not_set = tarval_or(bits_not_set, new_bits_not_set);
 266                 }
 267                 break;
 268         }
 269
 270         case iro_Eor: {
 271                 tarval *bits_set, *bits_not_set;
 272                 vrp_attr *vrp_left, *vrp_right;
 273
 274                 vrp_left = phase_get_or_set_irn_data(phase, get_Eor_left(node));
 275                 vrp_right = phase_get_or_set_irn_data(phase, get_Eor_right(node));
 276
 277                 bits_not_set = tarval_or(
 278                                                         tarval_and(vrp_left->bits_set, vrp_right->bits_set),
 279                                                         tarval_and(vrp_left->bits_not_set,
 280                                                                 vrp_right->bits_not_set));
 281
 282                 bits_set = tarval_or(
 283                                                 tarval_and(vrp_left->bits_set, vrp_right->bits_not_set),
 284                                                 tarval_and(vrp_left->bits_not_set, vrp_right->bits_set));
 285
 286                 new_bits_set = tarval_or(bits_set, vrp->bits_set);
 287                 new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 288                 break;
 289         }
 290
 291         case iro_Id: {
 292                 vrp_attr *vrp_pred = phase_get_or_set_irn_data(phase, get_Id_pred(node));
 293                 new_bits_set = vrp_pred->bits_set;
 294                 new_bits_not_set = vrp_pred->bits_not_set;
 295                 new_range_top = vrp_pred->range_top;
 296                 new_range_bottom = vrp_pred->range_bottom;
 297                 new_range_type = vrp_pred->range_type;
 298                 break;
 299         }
 300
 301         case iro_Not: {
 302                 vrp_attr *vrp_pred = phase_get_or_set_irn_data(phase, get_Not_op(node));
 303                 new_bits_set = tarval_or(vrp_pred->bits_not_set, vrp->bits_set);
 304                 new_bits_not_set = tarval_or(vrp_pred->bits_set, vrp->bits_not_set);
 305                 break;
 306         }
 307
 308         case iro_Conv: {
 309                 ir_node *pred = get_Conv_op(node);
 310                 ir_mode *old_mode = get_irn_mode(pred);
 311                 vrp_attr *vrp_pred = phase_get_or_set_irn_data(phase, pred);
 312
 313                 ir_mode *new_mode;
 314                 tarval *bits_not_set;
 315
 316                 if (!mode_is_int(old_mode))
 317                         return 0;
 318
 319                 new_mode = get_irn_mode(node);
 320
 321                 /* The second and is needed if target type is smaller*/
 322                 bits_not_set = tarval_not(
 323                                                         tarval_convert_to(get_mode_all_one(old_mode),
 324                                                                 new_mode
 325                                                                 ));
 326                 bits_not_set = tarval_or(bits_not_set, tarval_convert_to(vrp_pred->bits_not_set, new_mode));
 327                 new_bits_not_set = tarval_or(bits_not_set, vrp->bits_not_set);
 328                 new_bits_set = tarval_and(
 329                                 tarval_not(bits_not_set), tarval_convert_to(vrp_pred->bits_set, new_mode));
 330
 331                 if (tarval_cmp(vrp_pred->range_top, get_mode_max(new_mode)) == pn_Cmp_Le) {
 332                         vrp->range_top = vrp_pred->range_top;
 333                 }
 334
 335                 if (tarval_cmp(vrp_pred->range_bottom, get_mode_min(new_mode)) == pn_Cmp_Ge) {
 336                         vrp->range_bottom = vrp_pred->range_bottom;
 337                 }
 338                 break;
 339         }
 340
 341         case iro_Confirm: {
 342                 pn_Cmp cmp = get_Confirm_cmp(node);
 343                 ir_node *bound = get_Confirm_bound(node);
 344
 345                 /** @todo: Handle non-Const bounds */
 346
 347                 if (cmp == pn_Cmp_Lg) {
 348                         /** @todo: Is there some way to preserve the information? */
 349                         new_range_type = VRP_ANTIRANGE;
 350                         if (is_Const(bound)) {
 351                                 new_range_top = get_Const_tarval(bound);
 352                                 new_range_bottom = get_Const_tarval(bound);
 353                         }
 354                 } else if (cmp == pn_Cmp_Le) {
 355                         if (vrp->range_type == VRP_UNDEFINED) {
 356                                 new_range_type = VRP_RANGE;
 357                                 if (is_Const(bound)) {
 358                                         new_range_top = get_Const_tarval(bound);
 359                                 }
 360                                 new_range_bottom = get_tarval_min(get_irn_mode(node));
 361                         } else if (vrp->range_type == VRP_RANGE) {
 362                                 if (is_Const(bound)) {
 363                                         if (tarval_cmp(vrp->range_top,
 364                                                                 get_Const_tarval(bound)) == pn_Cmp_Le) {
 365                                                 new_range_top = get_Const_tarval(bound);
 366                                         }
 367                                         new_range_bottom = get_tarval_min(get_irn_mode(node));
 368
 369                                 } else if (vrp->range_type == VRP_ANTIRANGE) {
 370                                         /** @todo: How do we manage not to get a never ending loop? */
 371                                 }
 372                         }
 373                 }
 374                 break;
 375         }
 376
 377         case iro_Phi: {
 378                 /* combine all ranges*/
 379
 380                 int num = get_Phi_n_preds(node);
 381                 pn_Cmp cmp;
 382                 int i;
 383
 384                 ir_node *pred = get_Phi_pred(node,0);
 385                 vrp_attr *vrp_pred = phase_get_or_set_irn_data(phase, pred);
 386                 new_range_top = vrp_pred->range_top;
 387                 new_range_bottom = vrp_pred->range_bottom;
 388                 new_range_type = vrp_pred->range_type;
 389                 new_bits_set = vrp_pred->bits_set;
 390                 new_bits_not_set = vrp_pred->bits_not_set;
 391
 392                 assert(num > 0);
 393
 394
 395                 for (i = 1; i < num; i++) {
 396                         pred = get_Phi_pred(node, i);
 397                         vrp_pred = phase_get_or_set_irn_data(phase, pred);
 398                         if (new_range_type == VRP_RANGE && vrp_pred->range_type ==
 399                                         VRP_RANGE) {
 400                                 cmp = tarval_cmp(new_range_top, vrp_pred->range_top);
 401                                 if (cmp == pn_Cmp_Lt) {
 402                                         new_range_top = vrp_pred->range_top;
 403                                 }
 404                                 cmp = tarval_cmp(new_range_bottom, vrp_pred->range_bottom);
 405                                 if (cmp == pn_Cmp_Gt) {
 406                                         new_range_bottom = vrp_pred->range_bottom;
 407                                 }
 408                         } else {
 409                                 new_range_type = VRP_VARYING;
 410                                 break;
 411                         }
 412                 }
 413
 414                 break;
 415         }
 416         default:
 417                 /* unhandled, therefore never updated */
 418                 break;
 419         }
 420
 421
 422
 423         /* TODO: Check, if there can be information derived from any of these:
 424         is_Abs(node) is_Alloc(node) is_Anchor(node) is_Borrow(node) is_Bound(node)
 425         is_Break(node) is_Builtin(node) is_Call(node) is_CallBegin(node)
 426         is_Carry(node) is_Cast(node) is_Cmp(node) is_Cond(node)
 427         is_CopyB(node) is_Div(node) is_DivMod(node) is_Dummy(node)
 428         is_End(node) is_EndExcept(node) is_EndReg(node) is_Filter(node) is_Free(node)
 429         is_IJmp(node) is_InstOf(node) is_Jmp(node) is_Load(node) is_Minus(node)
 430         is_Mod(node) is_Mul(node) is_Mulh(node) is_Mux(node) is_NoMem(node)
 431         is_Pin(node) is_Proj(node) is_Quot(node)
 432         is_Raise(node) is_Return(node) is_Sel(node) is_Start(node) is_Store(node)
 433         is_SymConst(node) is_Sync(node) is_Tuple(node)
 434         */
 435
 436         /* Merge the newly calculated values with those that might already exist*/
 437         if (new_bits_set != tarval_bad) {
 438                 new_bits_set = tarval_or(new_bits_set, vrp->bits_set);
 439                 if (tarval_cmp(new_bits_set, vrp->bits_set) != pn_Cmp_Eq) {
 440                         something_changed = 1;
 441                         vrp->bits_set = new_bits_set;
 442                 }
 443         }
 444
 445         if (new_bits_not_set != tarval_bad) {
 446                 new_bits_not_set = tarval_or(new_bits_not_set, vrp->bits_not_set);
 447
 448                 if (tarval_cmp(new_bits_not_set, vrp->bits_not_set) != pn_Cmp_Eq) {
 449                         something_changed = 1;
 450                         vrp->bits_not_set = new_bits_not_set;
 451                 }
 452         }
 453
 454         if (vrp->range_type == VRP_UNDEFINED &&
 455                         new_range_type != VRP_UNDEFINED) {
 456                 something_changed = 1;
 457                 vrp->range_type = new_range_type;
 458                 vrp->range_bottom = new_range_bottom;
 459                 vrp->range_top = new_range_top;
 460
 461         } else if (vrp->range_type == VRP_RANGE) {
 462                 if (new_range_type == VRP_RANGE) {
 463                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Lt) {
 464                                 something_changed = 1;
 465                                 vrp->range_bottom = new_range_bottom;
 466                         }
 467                         if (tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Gt) {
 468                                 something_changed = 1;
 469                                 vrp->range_top = new_range_top;
 470                         }
 471                 }
 472
 473                 if (new_range_type == VRP_ANTIRANGE) {
 474                         /* if they are overlapping, cut the range.*/
 475                         /* TODO: Maybe we can preserve more information here*/
 476                         if (tarval_cmp(vrp->range_bottom, new_range_top) == pn_Cmp_Gt &&
 477                                         tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 478                                 something_changed = 1;
 479                                 vrp->range_bottom = new_range_top;
 480
 481                         } else if (tarval_cmp(vrp->range_top, new_range_bottom) == pn_Cmp_Gt &&
 482                                         tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Lt) {
 483                                 something_changed = 1;
 484                                 vrp->range_top = new_range_bottom;
 485                         }
 486
 487                         /* We can not handle the case where the anti range is in the*/
 488                         /* range*/
 489
 490                 }
 491         } else if (vrp->range_type == VRP_ANTIRANGE) {
 492                 if (new_range_type == VRP_ANTIRANGE) {
 493                         if (tarval_cmp(vrp->range_bottom, new_range_bottom) == pn_Cmp_Gt) {
 494                                 something_changed = 1;
 495                                 vrp->range_bottom = new_range_bottom;
 496                         }
 497                         if (tarval_cmp(vrp->range_top, new_range_top) == pn_Cmp_Lt) {
 498                                 something_changed = 1;
 499                                 vrp->range_top = new_range_top;
 500                         }
 501                 }
 502
 503                 if (new_range_type == VRP_RANGE) {
 504                         if (tarval_cmp(vrp->range_bottom, new_range_top) == pn_Cmp_Gt) {
 505                                 something_changed = 1;
 506                                 vrp->range_bottom = new_range_top;
 507                         }
 508                         if (tarval_cmp(vrp->range_top, new_range_bottom) == pn_Cmp_Lt) {
 509                                 something_changed = 1;
 510                                 vrp->range_top = new_range_bottom;
 511                         }
 512                 }
 513         }
 514
 515         assert(tarval_is_null(
 516                                 tarval_and(vrp->bits_set, vrp->bits_not_set)));
 517         return something_changed;
 518 }
 519
 520 static void vrp_first_pass(ir_node *n, void *e)
 521 {
 522         ir_node *succ;
 523         int i;
 524         struct vrp_env_t *env = e;
 525
 526         if (is_Block(n))
 527                 return;
 528
 529         set_irn_link(n, VISITED);
 530
 531         vrp_update_node(n);
 532
 533         for (i = get_irn_n_outs(n) - 1; i >=0; --i) {
 534                 succ =  get_irn_out(n, i);
 535                 if (get_irn_link(succ) == VISITED) {
 536                         /* we found a loop*/
 537                         waitq_put(env->workqueue, n);
 538                 }
 539         }
 540 }
 541
 542 static void *vrp_init_node(ir_phase *phase, const ir_node *n, void *old)
 543 {
 544         ir_mode *mode;
 545         vrp_attr *vrp;
 546
 547         ir_printf("initialized node nr: %d\n", get_irn_node_nr(n));
 548         if (old) {
 549                 assert(1==0 && "init called for node already initialized");
 550         }
 551         vrp = phase_alloc(phase, sizeof(vrp_attr));
 552
 553         memset(vrp, 0, sizeof(vrp_attr));
 554         /* Initialize the vrp information to default */
 555
 556         mode = get_irn_mode(n);
 557
 558         vrp->range_type = VRP_UNDEFINED;
 559
 560         /* TODO: We might be able to optimize space usage if we do not allocate
 561          * vrp space for non-int nodes. (currently caught by vrp_update_node)
 562          */
 563         if (mode_is_int(mode)) {
 564                 /* We are assuming that 0 is always represented as this modes null */
 565                 vrp->valid = 1;
 566                 vrp->bits_set =
 567                 vrp->bits_not_set = get_mode_null(mode);
 568                 vrp->range_bottom =
 569                 vrp->range_top = get_tarval_top();
 570         } else {
 571                 vrp->valid = 0;
 572                 vrp->bits_set =
 573                 vrp->bits_not_set =
 574                 vrp->range_bottom =
 575                 vrp->range_top = get_tarval_bad();
 576         }
 577
 578         /* TODO: We might be able to set better vrp info at this time, if this is
 579          * a node which is newly created in an already initialized irg
 580          *
 581          * maybe just call vrp_update_node and if it returns one, iterate over
 582          * successors
 583          */
 584         return vrp;
 585 }
 586
 587 void set_vrp_data(ir_graph *irg)
 588 {
 589
 590         ir_node *succ, *node;
 591         int i;
 592         struct vrp_env_t *env;
 593         ir_phase *phase;
 594
 595         if (!irg) {
 596                 /* no graph, skip */
 597                 return;
 598         }
 599
 600         assure_irg_outs(irg); /* ensure that out edges are consistent*/
 601         if (!(phase = get_irg_phase(irg, PHASE_VRP))) {
 602                                 /* this is our first run */
 603                 phase = init_irg_phase(irg, PHASE_VRP, 0, vrp_init_node);
 604                 env = phase_alloc(phase, sizeof(struct vrp_env_t));
 605                 phase->priv = env;
 606         } else {
 607                 env = phase->priv;
 608         }
 609
 610         env->workqueue = new_waitq();
 611
 612
 613         irg_walk_graph(irg, NULL, vrp_first_pass, env);
 614
 615         /* while there are entries in the worklist, continue*/
 616         while (!waitq_empty(env->workqueue)) {
 617                 node = waitq_get(env->workqueue);
 618
 619                 if (vrp_update_node(node)) {
 620                         /* if something changed, add successors to worklist*/
 621                         for (i = get_irn_n_outs(node) - 1; i >=0; --i) {
 622                                 succ =  get_irn_out(node, i);
 623                                 waitq_put(env->workqueue, node);
 624                         }
 625                 }
 626         }
 627         del_waitq(env->workqueue);
 628 }
 629
 630
 631 ir_graph_pass_t *set_vrp_pass(const char *name)
 632 {
 633         return def_graph_pass(name ? name : "set_vrp", set_vrp_data);
 634 }
 635
 636 pn_Cmp vrp_cmp(const ir_node *left, const ir_node *right)
 637 {
 638         vrp_attr *vrp_left, *vrp_right;
 639
 640         vrp_left = vrp_get_info(left);
 641         vrp_right = vrp_get_info(right);
 642
 643         if (!vrp_left || !vrp_right) {
 644                 return pn_Cmp_False;
 645         }
 646
 647         if (vrp_left->range_type == VRP_RANGE && vrp_right->range_type == VRP_RANGE) {
 648                 if (tarval_cmp(vrp_left->range_top, vrp_right->range_bottom) == pn_Cmp_Lt) {
 649                         return pn_Cmp_Lt;
 650                 }
 651                 if (tarval_cmp(vrp_left->range_bottom, vrp_right->range_top) == pn_Cmp_Gt) {
 652                         return pn_Cmp_Gt;
 653                 }
 654         }
 655
 656         if (!tarval_is_null(tarval_and(vrp_left->bits_set, vrp_right->bits_not_set)) ||
 657                         !tarval_is_null(tarval_and(vrp_left->bits_not_set, vrp_right->bits_set))) {
 658                 return pn_Cmp_Lg;
 659         }
 660         /* TODO: We can get way more information here*/
 661
 662         return pn_Cmp_False;
 663 }
 664
 665 vrp_attr *vrp_get_info(const ir_node *n) {
 666         ir_graph *irg = get_irn_irg(n);
 667         ir_phase *phase = get_irg_phase(irg, PHASE_VRP);
 668
 669
 670         if (!phase) {
 671                 /* phase has not yet been initialized */
 672                 return NULL;
 673         }
 674
 675         return phase_get_irn_data(phase, n);
 676 }