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 #include "debug.h"
  42
  43 /** Describes a pair of relative conditions lo < hi, lo pnc_lo x, hi pnc_hi x */
  44 typedef struct cond_pair {
  45         ir_node *cmp_lo;  /**< the lo compare node. */
  46         ir_node *cmp_hi;  /**< the hi compare node. */
  47         pn_Cmp   pnc_lo;  /**< the lo relation node. */
  48         pn_Cmp   pnc_hi;  /**< the hi relation node. */
  49         ir_node *proj_lo; /**< the mode_b result proj of cmp_lo */
  50         ir_node *proj_hi; /**< the mode_b result proj of cmp_hi */
  51         tarval  *tv_lo;   /**< the tarval of lo */
  52         tarval  *tv_hi;   /**< the tarval of hi */
  53 } cond_pair;
  54
  55 /** Environment for all walker in boolopt. */
  56 typedef struct {
  57         int changed;  /**< Set if the graph was changed. */
  58 } bool_opt_env_t;
  59
  60 DEBUG_ONLY(static firm_dbg_module_t *dbg);
  61
  62 /**
  63  * Check if tho given nodes, l and r, represent two compares with
  64  * ... . If yes, return non-zero and fill the res struct.
  65  */
  66 static int find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  67 {
  68         if (is_Proj(l) && is_Proj(r)) {
  69                 ir_node *const lo = get_Proj_pred(l);
  70                 ir_node *const ro = get_Proj_pred(r);
  71
  72                 if (is_Cmp(lo) && is_Cmp(ro)) {
  73                         ir_node *const lol = get_Cmp_left(lo);
  74                         ir_node *const lor = get_Cmp_right(lo);
  75                         ir_node *const rol = get_Cmp_left(ro);
  76                         ir_node *const ror = get_Cmp_right(ro);
  77
  78                         if (is_Const(lor) && is_Const_null(lor) &&
  79                                 is_Const(ror) && is_Const_null(ror) &&
  80                                 get_Proj_proj(l) == pn_Cmp_Lg &&
  81                                 get_Proj_proj(r) == pn_Cmp_Lg) {
  82                                 /* lo == (lol != NULL) && ro == (rol != NULL) */
  83
  84                                 DB((dbg, LEVEL_1, "found <null null>\n"));
  85                         }
  86
  87                         /* TODO float */
  88                         /* The constants shall be unequal.  Local optimisations handle the
  89                          * equal case */
  90                         if (lol == rol && mode_is_int(get_irn_mode(lol)) && lor != ror && is_Const(lor) && is_Const(ror)) {
  91                                 /* lo == (x CMP c_l), ro == (x cmp c_r), c_l != c_r */
  92                                 tarval *const tv_l  = get_Const_tarval(lor);
  93                                 tarval *const tv_r  = get_Const_tarval(ror);
  94                                 pn_Cmp  const pnc_l = get_Proj_proj(l);
  95                                 pn_Cmp  const pnc_r = get_Proj_proj(r);
  96                                 pn_Cmp  const rel   = tarval_cmp(tv_l, tv_r);
  97
  98                                 assert(rel != pn_Cmp_Eq);
  99
 100                                 if (rel == pn_Cmp_Lt) {
 101                                         /* c_l < c_r */
 102                                         res->cmp_lo  = lo;
 103                                         res->cmp_hi  = ro;
 104                                         res->pnc_lo  = pnc_l;
 105                                         res->pnc_hi  = pnc_r;
 106                                         res->proj_lo = l;
 107                                         res->proj_hi = r;
 108                                         res->tv_lo   = tv_l;
 109                                         res->tv_hi   = tv_r;
 110                                 } else {
 111                                         assert(rel == pn_Cmp_Gt);
 112                                         /* c_l > c_r */
 113                                         res->cmp_lo  = ro;
 114                                         res->cmp_hi  = lo;
 115                                         res->pnc_lo  = pnc_r;
 116                                         res->pnc_hi  = pnc_l;
 117                                         res->proj_lo = r;
 118                                         res->proj_hi = l;
 119                                         res->tv_lo   = tv_r;
 120                                         res->tv_hi   = tv_l;
 121                                 }
 122                                 return 1;
 123                         }
 124                 }
 125         }
 126         return 0;
 127 }
 128
 129 /**
 130  * Handle (lo pnc_lo x) AND (hi pnc_hi x)
 131  */
 132 static ir_node *bool_and(cond_pair* const cpair)
 133 {
 134         ir_node *const cmp_lo  = cpair->cmp_lo;
 135         ir_node *const cmp_hi  = cpair->cmp_hi;
 136         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 137         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 138         ir_node *const proj_lo = cpair->proj_lo;
 139         ir_node *const proj_hi = cpair->proj_hi;
 140         tarval  *const tv_lo   = cpair->tv_lo;
 141         tarval  *const tv_hi   = cpair->tv_hi;
 142
 143         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 144         if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 145             (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 146                 /* x <|<=|== lo | x ==|>=|> hi ==> false */
 147                 ir_node *const t = new_Const(tarval_b_false);
 148                 return t;
 149         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 150                    (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 151                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 152                 return proj_lo;
 153         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 154                    (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 155                 /* x >=|>|!= lo || x ==|>=|> hi ==> x ==|>=|> hi */
 156                 return proj_hi;
 157         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 158                 if (pnc_lo == pn_Cmp_Ge && pnc_hi == pn_Cmp_Lt) {
 159                         /* x >= c || x < c + 1 ==> x == c */
 160                         ir_node  *const block = get_nodes_block(cmp_lo);
 161                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Eq);
 162                         return p;
 163                 } else if (pnc_lo == pn_Cmp_Gt) {
 164                         if (pnc_hi == pn_Cmp_Lg) {
 165                                 /* x > c || x != c + 1 ==> x > c + 1 */
 166                                 ir_node  *const block = get_nodes_block(cmp_hi);
 167                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Gt);
 168                                 return p;
 169                         } else if (pnc_hi == pn_Cmp_Lt) {
 170                                 /* x > c || x < c + 1 ==> false */
 171                                 ir_node *const t = new_Const(tarval_b_false);
 172                                 return t;
 173                         } else if (pnc_hi == pn_Cmp_Le) {
 174                                 /* x > c || x <= c + 1 ==> x != c + 1 */
 175                                 ir_node  *const block = get_nodes_block(cmp_hi);
 176                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Eq);
 177                                 return p;
 178                         }
 179                 } else if (pnc_lo == pn_Cmp_Lg && pnc_hi == pn_Cmp_Lt) {
 180                         /* x != c || c < c + 1 ==> x < c */
 181                         ir_node  *const block = get_nodes_block(cmp_lo);
 182                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lt);
 183                         return p;
 184                 }
 185         }
 186         return NULL;
 187 }
 188
 189 /**
 190  * Handle (lo pnc_lo x) OR (hi pnc_hi x)
 191  */
 192 static ir_node *bool_or(cond_pair *const cpair)
 193 {
 194         ir_node *const cmp_lo  = cpair->cmp_lo;
 195         ir_node *const cmp_hi  = cpair->cmp_hi;
 196         pn_Cmp         pnc_lo  = cpair->pnc_lo;
 197         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 198         ir_node *const proj_lo = cpair->proj_lo;
 199         ir_node *const proj_hi = cpair->proj_hi;
 200         tarval  *      tv_lo   = cpair->tv_lo;
 201         tarval  *      tv_hi   = cpair->tv_hi;
 202
 203         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 204         if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 205             (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 206                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 207                 ir_node *const t = new_Const(tarval_b_true);
 208                 return t;
 209         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 210                    (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 211                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 212                 return proj_hi;
 213         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 214                    (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 215                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 216                 return proj_lo;
 217         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 218                 if (pnc_lo == pn_Cmp_Lt && pnc_hi == pn_Cmp_Ge) {
 219                         /* x < c || x >= c + 1 ==> x != c */
 220                         ir_node  *const block = get_nodes_block(cmp_lo);
 221                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lg);
 222                         return p;
 223                 } else if (pnc_lo == pn_Cmp_Le) {
 224                         if (pnc_hi == pn_Cmp_Eq) {
 225                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 226                                 ir_node  *const block = get_nodes_block(cmp_hi);
 227                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Le);
 228                                 return p;
 229                         } else if (pnc_hi == pn_Cmp_Ge) {
 230                                 /* x <= c || x >= c + 1 ==> true */
 231                                 ir_node *const t = new_Const(tarval_b_true);
 232                                 return t;
 233                         } else if (pnc_hi == pn_Cmp_Gt) {
 234                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 235                                 ir_node  *const block = get_nodes_block(cmp_hi);
 236                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Lg);
 237                                 return p;
 238                         }
 239                 } else if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Ge) {
 240                         /* x == c || x >= c + 1 ==> x >= c */
 241                         ir_node  *const block = get_nodes_block(cmp_lo);
 242                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Ge);
 243                         return p;
 244                 }
 245         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le) &&
 246                 (pnc_hi == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ge)) {
 247                 /* works for two-complements only */
 248                 /* x <|\= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 249                 if (pnc_lo == pn_Cmp_Lt) {
 250                         /* must convert to <= */
 251                         ir_mode *mode = get_tarval_mode(tv_lo);
 252                         tarval *n = tarval_sub(tv_lo, get_mode_one(mode), NULL);
 253                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == pn_Cmp_Lt) {
 254                                 /* no overflow */
 255                                 tv_lo = n;
 256                                 pnc_lo = pn_Cmp_Le;
 257                         }
 258                 }
 259                 if (pnc_lo == pn_Cmp_Le) {
 260                         /* all fine */
 261                         ir_node *const block = get_nodes_block(cmp_hi);
 262                         ir_node *      x     = get_Cmp_left(cmp_hi);
 263                         ir_mode *      mode  = get_irn_mode(x);
 264                         ir_node *sub, *cmp, *c, *subc, *p;
 265
 266                         if (mode_is_signed(mode)) {
 267                                 /* convert to unsigned */
 268                                 mode = find_unsigned_mode(mode);
 269                                 if (mode == NULL)
 270                                         return NULL;
 271                                 x     = new_r_Conv(block, x, mode);
 272                                 tv_lo = tarval_convert_to(tv_lo, mode);
 273                                 tv_hi = tarval_convert_to(tv_hi, mode);
 274                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 275                                         return NULL;
 276                         }
 277                         c    = new_Const(tv_lo);
 278                         sub  = new_r_Sub(block, x, c, mode);
 279                         subc = new_r_Sub(block, new_Const(tv_hi), c, mode);
 280                         cmp  = new_r_Cmp(block, sub, subc);
 281                         p    = new_r_Proj(block, cmp, mode_b, pnc_hi);
 282                         return p;
 283                 }
 284         }
 285         return NULL;
 286 }
 287
 288 /**
 289  * Walker, tries to optimize Andb and Orb nodes.
 290  */
 291 static void bool_walk(ir_node *n, void *ctx)
 292 {
 293         bool_opt_env_t *env = ctx;
 294
 295         if (get_irn_mode(n) != mode_b)
 296                 return;
 297
 298         if (is_And(n)) {
 299                 ir_node *const l = get_And_left(n);
 300                 ir_node *const r = get_And_right(n);
 301                 ir_node *      replacement;
 302                 cond_pair      cpair;
 303                 if (!find_cond_pair(l, r, &cpair))
 304                         return;
 305                 replacement = bool_and(&cpair);
 306                 if (replacement) {
 307                         exchange(n, replacement);
 308                         env->changed = 1;
 309                 }
 310         } else if (is_Or(n)) {
 311                 ir_node *const l = get_Or_left(n);
 312                 ir_node *const r = get_Or_right(n);
 313                 ir_node *      replacement;
 314                 cond_pair      cpair;
 315                 if (!find_cond_pair(l, r, &cpair))
 316                         return;
 317                 replacement = bool_or(&cpair);
 318                 if (replacement) {
 319                         exchange(n, replacement);
 320                         env->changed = 1;
 321                 }
 322         }
 323 }
 324
 325 /**
 326  * Walker, clear Block marker and Phi lists.
 327  */
 328 static void clear_block_infos(ir_node *node, void *env)
 329 {
 330         (void) env;
 331
 332         /* we visit blocks before any other nodes (from the block) */
 333         if (!is_Block(node))
 334                 return;
 335
 336         /* clear the PHI list */
 337         set_Block_phis(node, NULL);
 338         set_Block_mark(node, 0);
 339 }
 340
 341 /**
 342  * Walker: collect Phi nodes and mark
 343  */
 344 static void collect_phis(ir_node *node, void *env)
 345 {
 346         (void) env;
 347
 348         if (is_Phi(node)) {
 349                 ir_node *block = get_nodes_block(node);
 350                 add_Block_phi(block, node);
 351                 return;
 352         }
 353
 354         /* Ignore control flow nodes, these will be removed. */
 355         if (get_irn_pinned(node) == op_pin_state_pinned &&
 356                         !is_Block(node) && !is_cfop(node)) {
 357                                 /* found a pinned non-cf node, mark its block */
 358                 ir_node *block = get_nodes_block(node);
 359                 set_Block_mark(block, 1);
 360         }
 361 }
 362
 363 /**
 364  * If node is a Jmp in a block containing no pinned instruction
 365  * and having only one predecessor, skip the block and return its
 366  * cf predecessor, else the node itself.
 367  */
 368 static ir_node *skip_empty_blocks(ir_node *node)
 369 {
 370         while (is_Jmp(node)) {
 371                 ir_node *block = get_nodes_block(node);
 372
 373                 if (get_Block_n_cfgpreds(block) != 1)
 374                         break;
 375
 376                 if (get_Block_mark(block))
 377                         break;
 378
 379                 node = get_Block_cfgpred(block, 0);
 380         }
 381         return node;
 382 }
 383
 384 /**
 385  * Check if two block inputs can be fused.
 386  * This can be done, if block contains no Phi node that depends on
 387  * different inputs idx_i and idx_j.
 388  */
 389 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j) {
 390         const ir_node *phi;
 391
 392         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 393                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 394                         return 0;
 395         }
 396         return 1;
 397 }
 398
 399 /**
 400  * Remove block input with given index.
 401  */
 402 static void remove_block_input(ir_node *block, int idx)
 403 {
 404         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 405         ir_node *phi, **ins;
 406
 407         NEW_ARR_A(ir_node *, ins, n);
 408
 409         if (n == 1) {
 410                 /* all Phis will be deleted */
 411                 ir_node *next_phi;
 412
 413                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 414                         next_phi = get_Phi_next(phi);
 415                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 416                 }
 417                 set_Block_phis(block, NULL);
 418         } else {
 419                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 420                         for (i = j = 0; i <= n; ++i) {
 421                                 if (i != idx)
 422                                         ins[j++] = get_Phi_pred(phi, i);
 423                         }
 424                         set_irn_in(phi, n, ins);
 425                 }
 426         }
 427         for (i = j = 0; i <= n; ++i) {
 428                 if (i != idx)
 429                         ins[j++] = get_Block_cfgpred(block, i);
 430         }
 431         set_irn_in(block, n, ins);
 432 }
 433
 434 /**
 435  * Under the preposition that we have a chain of blocks from
 436  * from_block to to_block, collapse them all into to_block.
 437  */
 438 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block) {
 439         ir_node *new_jmp = NULL;
 440         ir_node *block, *next_block;
 441
 442         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 443                 new_jmp = get_Block_cfgpred(block, 0);
 444                 next_block = get_nodes_block(new_jmp);
 445                 exchange(block, to_block);
 446         }
 447         if (new_jmp)
 448                 exchange(jmp, new_jmp);
 449 }
 450
 451 /**
 452  * Block walker:
 453  *
 454  * if we can find the following structure,
 455  *
 456  *        upper_block
 457  *         /       |
 458  *        /        |
 459  *   lower_block   |
 460  *     /  \        |
 461  *   ... low_idx up_idx
 462  *          \      |
 463  *            block
 464  *
 465  * try to convert it into a (x pnc_lo c_lo) || (x pnc_hi c_hi)
 466  * and optimize.
 467  */
 468 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 469 {
 470         int low_idx, up_idx;
 471         int n_cfgpreds = get_Block_n_cfgpreds(block);
 472         bool_opt_env_t *env = ctx;
 473
 474 restart:
 475         if (n_cfgpreds < 2)
 476                 return;
 477
 478         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 479                 ir_node      *lower_block;
 480                 ir_node      *lower_cf;
 481                 ir_node      *cond;
 482                 ir_node      *cond_selector;
 483                 ir_node      *lower_pred;
 484
 485                 lower_cf = get_Block_cfgpred(block, low_idx);
 486                 lower_cf = skip_empty_blocks(lower_cf);
 487                 if (!is_Proj(lower_cf))
 488                         continue;
 489
 490                 cond = get_Proj_pred(lower_cf);
 491                 if (!is_Cond(cond))
 492                         continue;
 493
 494                 lower_block = get_nodes_block(cond);
 495                 if (get_Block_n_cfgpreds(lower_block) != 1)
 496                         continue;
 497
 498                 /* the block must not produce any side-effects */
 499                 if (get_Block_mark(lower_block))
 500                         continue;
 501
 502                 cond_selector = get_Cond_selector(cond);
 503                 if (get_irn_mode(cond_selector) != mode_b)
 504                         continue;
 505
 506                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 507
 508                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 509                         ir_node   *upper_block;
 510                         ir_node   *upper_cf;
 511                         ir_node   *upper_cond;
 512                         ir_node   *upper_cond_selector;
 513                         ir_node   *replacement;
 514                         cond_pair  cpair;
 515
 516                         upper_cf    = get_Block_cfgpred(block, up_idx);
 517                         upper_cf    = skip_empty_blocks(upper_cf);
 518                         if (is_Bad(upper_cf))
 519                                 continue;
 520                         upper_block = get_nodes_block(upper_cf);
 521                         if (upper_block != lower_pred)
 522                                 continue;
 523
 524                         assert(is_Proj(upper_cf));
 525                         upper_cond = get_Proj_pred(upper_cf);
 526                         assert(is_Cond(upper_cond));
 527                         upper_cond_selector = get_Cond_selector(upper_cond);
 528                         if (get_irn_mode(upper_cond_selector) != mode_b)
 529                                 continue;
 530
 531                         /* we have found the structure */
 532                         /* check Phis: There must be NO Phi in block that
 533                            depends on the existence of low block */
 534                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 535                                 continue;
 536
 537                         /* all fine, try it */
 538                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 539                                 continue;
 540
 541                         /* normalize pncs: we need the true case to jump into the
 542                          * common block (ie. conjunctive normal form) */
 543                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 544                                 if (cpair.proj_lo == cond_selector) {
 545                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 546                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 547                                         cpair.proj_lo = new_r_Proj(lower_block,
 548                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 549                                 } else {
 550                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 551                                         assert(cpair.proj_hi == cond_selector);
 552                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 553                                         cpair.proj_hi = new_r_Proj(lower_block,
 554                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 555                                 }
 556                         }
 557                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 558                                 if (cpair.proj_lo == upper_cond_selector) {
 559                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 560                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 561                                         cpair.proj_lo = new_r_Proj(upper_block,
 562                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 563                                 } else {
 564                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 565                                         assert(cpair.proj_hi == upper_cond_selector);
 566                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 567                                         cpair.proj_hi = new_r_Proj(upper_block,
 568                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 569                                 }
 570                         }
 571
 572                         /* can we optimize the case? */
 573                         replacement = bool_or(&cpair);
 574                         if (replacement == NULL)
 575                                 continue;
 576
 577                         env->changed = 1;
 578
 579                         /* move all expressions on the path to lower/upper block */
 580                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 581                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 582
 583                         /* move all nodes from lower block to upper block */
 584                         exchange(lower_block, upper_block);
 585
 586                         remove_block_input(block, up_idx);
 587                         --n_cfgpreds;
 588
 589                         /* the optimisations expected the true case to jump */
 590                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 591                                 ir_node *block = get_nodes_block(replacement);
 592                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 593                         }
 594                         set_Cond_selector(cond, replacement);
 595
 596                         DB((dbg, LEVEL_1, "%+F: replaced (ub %+F)\n", current_ir_graph, upper_block));
 597                         goto restart;
 598                 }
 599         }
 600 }
 601
 602 void opt_bool(ir_graph *const irg)
 603 {
 604         bool_opt_env_t env;
 605
 606         /* register a debug mask */
 607         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 608
 609         /* works better with one return block only */
 610         normalize_one_return(irg);
 611
 612         env.changed = 0;
 613
 614         /* optimize simple Andb and Orb cases */
 615         irg_walk_graph(irg, NULL, bool_walk, &env);
 616
 617         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 618
 619         /* now more complicated cases: find control flow And/Or and optimize. */
 620         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 621         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 622
 623         if (env.changed) {
 624                 set_irg_outs_inconsistent(irg);
 625                 set_irg_doms_inconsistent(irg);
 626                 set_irg_extblk_inconsistent(irg);
 627                 set_irg_loopinfo_inconsistent(irg);
 628         }
 629
 630         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 631 }
 632
 633 /* Creates an ir_graph pass for opt_bool. */
 634 ir_graph_pass_t *opt_bool_pass(const char *name)
 635 {
 636         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 637 }  /* opt_bool_pass */