nsz Git - libfirm/blob - ir/opt/boolopt.c

   1 /*
   2  * Copyright (C) 1995-2008 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   boolean condition/controlflow optimisations
  23  * @author  Matthias Braun, Christoph Mallon, Michael Beck
  24  * @version $Id: cfopt.c 22579 2008-10-07 14:54:04Z beck $
  25  */
  26 #include "config.h"
  27
  28 #include <assert.h>
  29 #include <string.h>
  30
  31 #include "adt/obst.h"
  32 #include "../adt/array_t.h"
  33 #include "iroptimize.h"
  34 #include "ircons.h"
  35 #include "irgmod.h"
  36 #include "irgwalk.h"
  37 #include "irprintf.h"
  38 #include "irnode_t.h"
  39 #include "tv.h"
  40 #include "irpass.h"
  41
  42 /** Describes a pair of relative conditions lo < hi, lo pnc_lo x, hi pnc_hi x */
  43 typedef struct cond_pair {
  44         ir_node *cmp_lo;  /**< the lo compare node. */
  45         ir_node *cmp_hi;  /**< the hi compare node. */
  46         pn_Cmp   pnc_lo;  /**< the lo relation node. */
  47         pn_Cmp   pnc_hi;  /**< the hi relation node. */
  48         ir_node *proj_lo; /**< the mode_b result proj of cmp_lo */
  49         ir_node *proj_hi; /**< the mode_b result proj of cmp_hi */
  50         tarval  *tv_lo;   /**< the tarval of lo */
  51         tarval  *tv_hi;   /**< the tarval of hi */
  52 } cond_pair;
  53
  54 /** Environment for all walker in boolopt. */
  55 typedef struct {
  56         int changed;  /**< Set if the graph was changed. */
  57 } bool_opt_env_t;
  58
  59 /**
  60  * Check if tho given nodes, l and r, represent two compares with
  61  * ... . If yes, return non-zero and fill the res struct.
  62  */
  63 static int find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  64 {
  65         if (is_Proj(l) && is_Proj(r)) {
  66                 ir_node *const lo = get_Proj_pred(l);
  67                 ir_node *const ro = get_Proj_pred(r);
  68
  69                 if (is_Cmp(lo) && is_Cmp(ro)) {
  70                         ir_node *const lol = get_Cmp_left(lo);
  71                         ir_node *const lor = get_Cmp_right(lo);
  72                         ir_node *const rol = get_Cmp_left(ro);
  73                         ir_node *const ror = get_Cmp_right(ro);
  74
  75                         if (is_Const(lor) && is_Const_null(lor) &&
  76                                 is_Const(ror) && is_Const_null(ror) &&
  77                                 get_Proj_proj(l) == pn_Cmp_Lg &&
  78                                 get_Proj_proj(r) == pn_Cmp_Lg) {
  79                                 /* lo == (lol != NULL) && ro == (rol != NULL) */
  80
  81                                 /* TODO: found <null null> */
  82                         }
  83
  84                         /* TODO float */
  85                         /* The constants shall be unequal.  Local optimisations handle the
  86                          * equal case */
  87                         if (lol == rol && mode_is_int(get_irn_mode(lol)) && lor != ror && is_Const(lor) && is_Const(ror)) {
  88                                 /* lo == (x CMP c_l), ro == (x cmp c_r), c_l != c_r */
  89                                 tarval *const tv_l  = get_Const_tarval(lor);
  90                                 tarval *const tv_r  = get_Const_tarval(ror);
  91                                 pn_Cmp  const pnc_l = get_Proj_proj(l);
  92                                 pn_Cmp  const pnc_r = get_Proj_proj(r);
  93                                 pn_Cmp  const rel   = tarval_cmp(tv_l, tv_r);
  94
  95                                 assert(rel != pn_Cmp_Eq);
  96
  97                                 if (rel == pn_Cmp_Lt) {
  98                                         /* c_l < c_r */
  99                                         res->cmp_lo  = lo;
 100                                         res->cmp_hi  = ro;
 101                                         res->pnc_lo  = pnc_l;
 102                                         res->pnc_hi  = pnc_r;
 103                                         res->proj_lo = l;
 104                                         res->proj_hi = r;
 105                                         res->tv_lo   = tv_l;
 106                                         res->tv_hi   = tv_r;
 107                                 } else {
 108                                         assert(rel == pn_Cmp_Gt);
 109                                         /* c_l > c_r */
 110                                         res->cmp_lo  = ro;
 111                                         res->cmp_hi  = lo;
 112                                         res->pnc_lo  = pnc_r;
 113                                         res->pnc_hi  = pnc_l;
 114                                         res->proj_lo = r;
 115                                         res->proj_hi = l;
 116                                         res->tv_lo   = tv_r;
 117                                         res->tv_hi   = tv_l;
 118                                 }
 119                                 return 1;
 120                         }
 121                 }
 122         }
 123         return 0;
 124 }
 125
 126 /**
 127  * Handle (lo pnc_lo x) AND (hi pnc_hi x)
 128  */
 129 static ir_node *bool_and(cond_pair* const cpair)
 130 {
 131         ir_node *const cmp_lo  = cpair->cmp_lo;
 132         ir_node *const cmp_hi  = cpair->cmp_hi;
 133         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 134         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 135         ir_node *const proj_lo = cpair->proj_lo;
 136         ir_node *const proj_hi = cpair->proj_hi;
 137         tarval  *const tv_lo   = cpair->tv_lo;
 138         tarval  *const tv_hi   = cpair->tv_hi;
 139
 140         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 141         if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 142             (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 143                 /* x <|<=|== lo | x ==|>=|> hi -> false */
 144                 ir_node *const t = new_Const(tarval_b_false);
 145                 return t;
 146         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 147                    (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 148                 /* x <|<=|== lo && x <|<=|!= hi -> x <|<=|== lo */
 149                 return proj_lo;
 150         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 151                    (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 152                 /* x >=|>|!= lo || x ==|>=|> hi -> x ==|>=|> hi */
 153                 return proj_hi;
 154         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 155                 if (pnc_lo == pn_Cmp_Ge && pnc_hi == pn_Cmp_Lt) {
 156                         /* x >= c || x < c + 1 -> x == c */
 157                         ir_node  *const block = get_nodes_block(cmp_lo);
 158                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Eq);
 159                         return p;
 160                 } else if (pnc_lo == pn_Cmp_Gt) {
 161                         if (pnc_hi == pn_Cmp_Lg) {
 162                                 /* x > c || x != c + 1 -> x > c + 1 */
 163                                 ir_node  *const block = get_nodes_block(cmp_hi);
 164                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Gt);
 165                                 return p;
 166                         } else if (pnc_hi == pn_Cmp_Lt) {
 167                                 /* x > c || x < c + 1 -> false */
 168                                 ir_node *const t = new_Const(tarval_b_false);
 169                                 return t;
 170                         } else if (pnc_hi == pn_Cmp_Le) {
 171                                 /* x > c || x <= c + 1 -> x != c + 1 */
 172                                 ir_node  *const block = get_nodes_block(cmp_hi);
 173                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Eq);
 174                                 return p;
 175                         }
 176                 } else if (pnc_lo == pn_Cmp_Lg && pnc_hi == pn_Cmp_Lt) {
 177                         /* x != c || c < c + 1 -> x < c */
 178                         ir_node  *const block = get_nodes_block(cmp_lo);
 179                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lt);
 180                         return p;
 181                 }
 182         }
 183         return NULL;
 184 }
 185
 186 /**
 187  * Handle (lo pnc_lo x) OR (hi pnc_hi x)
 188  */
 189 static ir_node *bool_or(cond_pair *const cpair)
 190 {
 191         ir_node *const cmp_lo  = cpair->cmp_lo;
 192         ir_node *const cmp_hi  = cpair->cmp_hi;
 193         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 194         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 195         ir_node *const proj_lo = cpair->proj_lo;
 196         ir_node *const proj_hi = cpair->proj_hi;
 197         tarval  *const tv_lo   = cpair->tv_lo;
 198         tarval  *const tv_hi   = cpair->tv_hi;
 199
 200         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 201         if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 202                         (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 203                 /* x >=|>|!= lo | x <|<=|!= hi -> true */
 204                 ir_node *const t = new_Const(tarval_b_true);
 205                 return t;
 206         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 207                                                  (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 208                 /* x <|<=|== lo || x <|<=|!= hi -> x <|<=|!= hi */
 209                 return proj_hi;
 210         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 211                                                  (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 212                 /* x >=|>|!= lo || x ==|>=|> hi -> x >=|>|!= lo */
 213                 return proj_lo;
 214         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 215                 if (pnc_lo == pn_Cmp_Lt && pnc_hi == pn_Cmp_Ge) {
 216                         /* x < c || x >= c + 1 -> x != c */
 217                         ir_node  *const block = get_nodes_block(cmp_lo);
 218                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lg);
 219                         return p;
 220                 } else if (pnc_lo == pn_Cmp_Le) {
 221                         if (pnc_hi == pn_Cmp_Eq) {
 222                                 /* x <= c || x == c + 1 -> x <= c + 1 */
 223                                 ir_node  *const block = get_nodes_block(cmp_hi);
 224                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Le);
 225                                 return p;
 226                         } else if (pnc_hi == pn_Cmp_Ge) {
 227                                 /* x <= c || x >= c + 1 -> true */
 228                                 ir_node *const t = new_Const(tarval_b_true);
 229                                 return t;
 230                         } else if (pnc_hi == pn_Cmp_Gt) {
 231                                 /* x <= c || x > c + 1 -> x != c + 1 */
 232                                 ir_node  *const block = get_nodes_block(cmp_hi);
 233                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Lg);
 234                                 return p;
 235                         }
 236                 } else if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Ge) {
 237                         /* x == c || x >= c + 1 -> x >= c */
 238                         ir_node  *const block = get_nodes_block(cmp_lo);
 239                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Ge);
 240                         return p;
 241                 }
 242         }
 243         return NULL;
 244 }
 245
 246 /**
 247  * Walker, tries to optimize Andb and Orb nodes.
 248  */
 249 static void bool_walk(ir_node *n, void *ctx)
 250 {
 251         bool_opt_env_t *env = ctx;
 252
 253         if (get_irn_mode(n) != mode_b)
 254                 return;
 255
 256         if (is_And(n)) {
 257                 ir_node *const l = get_And_left(n);
 258                 ir_node *const r = get_And_right(n);
 259                 ir_node *      replacement;
 260                 cond_pair      cpair;
 261                 if (!find_cond_pair(l, r, &cpair))
 262                         return;
 263                 replacement = bool_and(&cpair);
 264                 if (replacement) {
 265                         exchange(n, replacement);
 266                         env->changed = 1;
 267                 }
 268         } else if (is_Or(n)) {
 269                 ir_node *const l = get_Or_left(n);
 270                 ir_node *const r = get_Or_right(n);
 271                 ir_node *      replacement;
 272                 cond_pair      cpair;
 273                 if (!find_cond_pair(l, r, &cpair))
 274                         return;
 275                 replacement = bool_or(&cpair);
 276                 if (replacement) {
 277                         exchange(n, replacement);
 278                         env->changed = 1;
 279                 }
 280         }
 281 }
 282
 283 /**
 284  * Walker, clear Block marker and Phi lists.
 285  */
 286 static void clear_block_infos(ir_node *node, void *env)
 287 {
 288         (void) env;
 289
 290         /* we visit blocks before any other nodes (from the block) */
 291         if (!is_Block(node))
 292                 return;
 293
 294         /* clear the PHI list */
 295         set_Block_phis(node, NULL);
 296         set_Block_mark(node, 0);
 297 }
 298
 299 /**
 300  * Walker: collect Phi nodes and mark
 301  */
 302 static void collect_phis(ir_node *node, void *env)
 303 {
 304         (void) env;
 305
 306         if (is_Phi(node)) {
 307                 ir_node *block = get_nodes_block(node);
 308                 add_Block_phi(block, node);
 309                 return;
 310         }
 311
 312         /* Ignore control flow nodes, these will be removed. */
 313         if (get_irn_pinned(node) == op_pin_state_pinned &&
 314                         !is_Block(node) && !is_cfop(node)) {
 315                                 /* found a pinned non-cf node, mark its block */
 316                 ir_node *block = get_nodes_block(node);
 317                 set_Block_mark(block, 1);
 318         }
 319 }
 320
 321 /**
 322  * If node is a Jmp in a block containing no pinned instruction
 323  * and having only one predecessor, skip the block and return its
 324  * cf predecessor, else the node itself.
 325  */
 326 static ir_node *skip_empty_blocks(ir_node *node)
 327 {
 328         while (is_Jmp(node)) {
 329                 ir_node *block = get_nodes_block(node);
 330
 331                 if (get_Block_n_cfgpreds(block) != 1)
 332                         break;
 333
 334                 if (get_Block_mark(block))
 335                         break;
 336
 337                 node = get_Block_cfgpred(block, 0);
 338         }
 339         return node;
 340 }
 341
 342 /**
 343  * Check if two block inputs can be fused.
 344  * This can be done, if block contains no Phi node that depends on
 345  * different inputs idx_i and idx_j.
 346  */
 347 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j) {
 348         const ir_node *phi;
 349
 350         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 351                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 352                         return 0;
 353         }
 354         return 1;
 355 }
 356
 357 /**
 358  * Remove block input with given index.
 359  */
 360 static void remove_block_input(ir_node *block, int idx)
 361 {
 362         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 363         ir_node *phi, **ins;
 364
 365         NEW_ARR_A(ir_node *, ins, n);
 366
 367         if (n == 1) {
 368                 /* all Phis will be deleted */
 369                 ir_node *next_phi;
 370
 371                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 372                         next_phi = get_Phi_next(phi);
 373                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 374                 }
 375                 set_Block_phis(block, NULL);
 376         } else {
 377                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 378                         for (i = j = 0; i <= n; ++i) {
 379                                 if (i != idx)
 380                                         ins[j++] = get_Phi_pred(phi, i);
 381                         }
 382                         set_irn_in(phi, n, ins);
 383                 }
 384         }
 385         for (i = j = 0; i <= n; ++i) {
 386                 if (i != idx)
 387                         ins[j++] = get_Block_cfgpred(block, i);
 388         }
 389         set_irn_in(block, n, ins);
 390 }
 391
 392 /**
 393  * Under the preposition that we have a chain of blocks from
 394  * from_block to to_block, collapse them all into to_block.
 395  */
 396 static void move_nodes_to_block(ir_node *from_block, ir_node *to_block) {
 397         ir_node *block, *next_block;
 398
 399         for (block = from_block; block != to_block; block = next_block) {
 400                 next_block = get_Block_cfgpred(block, 0);
 401                 exchange(block, to_block);
 402         }
 403 }
 404
 405 /**
 406  * Block walker:
 407  *
 408  * if we can find the following structure,
 409  *
 410  *        upper_block
 411  *         /       |
 412  *        /        |
 413  *   lower_block   |
 414  *     /  \        |
 415  *   ... low_idx up_idx
 416  *          \      |
 417  *            block
 418  *
 419  * try to convert it into a (x pnc_lo c_lo) || (x pnc_hi c_hi)
 420  * and optimize.
 421  */
 422 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 423 {
 424         int low_idx, up_idx;
 425         int n_cfgpreds = get_Block_n_cfgpreds(block);
 426         bool_opt_env_t *env = ctx;
 427
 428         if (n_cfgpreds < 2)
 429                 return;
 430
 431 restart:
 432         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 433                 ir_node      *lower_block;
 434                 ir_node      *lower_cf;
 435                 ir_node      *cond;
 436                 ir_node      *cond_selector;
 437                 ir_node      *lower_pred;
 438
 439                 lower_cf = get_Block_cfgpred(block, low_idx);
 440                 lower_cf = skip_empty_blocks(lower_cf);
 441                 if (!is_Proj(lower_cf))
 442                         continue;
 443
 444                 cond = get_Proj_pred(lower_cf);
 445                 if (!is_Cond(cond))
 446                         continue;
 447
 448                 lower_block = get_nodes_block(cond);
 449                 if (get_Block_n_cfgpreds(lower_block) != 1)
 450                         continue;
 451
 452                 /* the block must not produce any side-effects */
 453                 if (get_Block_mark(lower_block))
 454                         continue;
 455
 456                 cond_selector = get_Cond_selector(cond);
 457                 if (get_irn_mode(cond_selector) != mode_b)
 458                         continue;
 459
 460                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 461
 462                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 463                         ir_node   *upper_block;
 464                         ir_node   *upper_cf;
 465                         ir_node   *upper_cond;
 466                         ir_node   *upper_cond_selector;
 467                         ir_node   *replacement;
 468                         cond_pair  cpair;
 469
 470                         upper_cf    = get_Block_cfgpred(block, up_idx);
 471                         upper_cf    = skip_empty_blocks(upper_cf);
 472                         if (is_Bad(upper_cf))
 473                                 continue;
 474                         upper_block = get_nodes_block(upper_cf);
 475                         if (upper_block != lower_pred)
 476                                 continue;
 477
 478                         assert(is_Proj(upper_cf));
 479                         upper_cond = get_Proj_pred(upper_cf);
 480                         assert(is_Cond(upper_cond));
 481                         upper_cond_selector = get_Cond_selector(upper_cond);
 482                         if (get_irn_mode(upper_cond_selector) != mode_b)
 483                                 continue;
 484
 485                         /* we have found the structure */
 486                         /* check Phis: There must be NO Phi in block that
 487                            depends on the existence of low block */
 488                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 489                                 continue;
 490
 491                         /* all fine, try it */
 492                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 493                                 continue;
 494
 495                         /* normalize pncs: we need the true case to jump into the
 496                          * common block (ie. conjunctive normal form) */
 497                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 498                                 if (cpair.proj_lo == cond_selector) {
 499                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 500                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 501                                         cpair.proj_lo = new_r_Proj(lower_block,
 502                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 503                                 } else {
 504                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 505                                         assert(cpair.proj_hi == cond_selector);
 506                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 507                                         cpair.proj_hi = new_r_Proj(lower_block,
 508                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 509                                 }
 510                         }
 511                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 512                                 if (cpair.proj_lo == upper_cond_selector) {
 513                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 514                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 515                                         cpair.proj_lo = new_r_Proj(upper_block,
 516                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 517                                 } else {
 518                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 519                                         assert(cpair.proj_hi == upper_cond_selector);
 520                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 521                                         cpair.proj_hi = new_r_Proj(upper_block,
 522                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 523                                 }
 524                         }
 525
 526                         /* can we optimize the case? */
 527                         replacement = bool_or(&cpair);
 528                         if (replacement == NULL)
 529                                 continue;
 530
 531                         env->changed = 1;
 532
 533                         /* move all expressions on the path to lower/upper block */
 534                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 535                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 536
 537                         /* move all nodes from lower block to upper block */
 538                         exchange(lower_block, upper_block);
 539
 540                         remove_block_input(block, up_idx);
 541
 542                         /* the optimisations expected the true case to jump */
 543                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 544                                 ir_node *block = get_nodes_block(replacement);
 545                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 546                         }
 547                         set_Cond_selector(cond, replacement);
 548
 549                         ir_fprintf(stderr, "replaced (ub %+F)\n", upper_block);
 550                         goto restart;
 551                 }
 552         }
 553 }
 554
 555 void opt_bool(ir_graph *const irg)
 556 {
 557         bool_opt_env_t env;
 558
 559         /* works better with one return block only */
 560         normalize_one_return(irg);
 561
 562         env.changed = 0;
 563
 564         /* optimize simple Andb and Orb cases */
 565         irg_walk_graph(irg, NULL, bool_walk, &env);
 566
 567         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 568
 569         /* now more complicated cases: find control flow And/Or and optimize. */
 570         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 571         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 572
 573         if (env.changed) {
 574                 set_irg_outs_inconsistent(irg);
 575                 set_irg_doms_inconsistent(irg);
 576                 set_irg_extblk_inconsistent(irg);
 577                 set_irg_loopinfo_inconsistent(irg);
 578         }
 579
 580         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 581 }
 582
 583 /* Creates an ir_graph pass for opt_bool. */
 584 ir_graph_pass_t *opt_bool_pass(const char *name)
 585 {
 586         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 587 }  /* opt_bool_pass */