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

   1 /*
   2  * Copyright (C) 1995-2011 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/control flow optimizations
  23  * @author  Matthias Braun, Christoph Mallon, Michael Beck
  24  */
  25 #include "config.h"
  26
  27 #include <assert.h>
  28 #include <string.h>
  29
  30 #include "adt/obst.h"
  31 #include "../adt/array_t.h"
  32 #include "iroptimize.h"
  33 #include "ircons.h"
  34 #include "irgmod.h"
  35 #include "irgwalk.h"
  36 #include "irprintf.h"
  37 #include "irnode_t.h"
  38 #include "tv.h"
  39 #include "irpass.h"
  40 #include "debug.h"
  41
  42 /** Describes a pair of relative conditions lo < hi, lo rel_lo x, hi rel_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         ir_relation rel_lo;  /**< The lo relation node. */
  47         ir_relation rel_hi;  /**< The hi relation node. */
  48         ir_tarval  *tv_lo;   /**< The tarval of cmp_lo node. */
  49         ir_tarval  *tv_hi;   /**< The tarval of cmp_hi node. */
  50         ir_mode    *lo_mode; /**< The mode of the cmp_lo operands. */
  51 } cond_pair;
  52
  53 /** Environment for all walker in boolopt. */
  54 typedef struct {
  55         int changed;  /**< Set if the graph was changed. */
  56 } bool_opt_env_t;
  57
  58 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  59
  60 /**
  61  * Check if tho given nodes, l and r, represent two compares with
  62  * ... . If yes, return non-zero and fill the res struct.
  63  */
  64 static bool find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  65 {
  66         if (is_Cmp(l) && is_Cmp(r)) {
  67                 ir_node    *const lol   = get_Cmp_left(l);
  68                 ir_node    *const lor   = get_Cmp_right(l);
  69                 ir_node    *const rol   = get_Cmp_left(r);
  70                 ir_node    *const ror   = get_Cmp_right(r);
  71                 ir_relation const pnc_l = get_Cmp_relation(l);
  72                 ir_relation const pnc_r = get_Cmp_relation(r);
  73
  74                 if (is_Const(lor) && is_Const_null(lor) &&
  75                         is_Const(ror) && is_Const_null(ror) &&
  76                         pnc_l == pnc_r &&
  77                         (pnc_l == ir_relation_less_greater || pnc_l == ir_relation_equal)) {
  78                         /* l == (lol !=|== NULL) && r == (rol !=|== NULL) */
  79                         res->cmp_lo  = l;
  80                         res->cmp_hi  = r;
  81                         res->rel_lo  = pnc_l;
  82                         res->rel_hi  = pnc_l;
  83                         res->tv_lo   = get_Const_tarval(lor);
  84                         res->tv_hi   = get_Const_tarval(ror);
  85                         res->lo_mode = get_irn_mode(lor);
  86
  87                         return true;
  88                 }
  89
  90                 if (lol == rol && lor != ror && is_Const(lor) && is_Const(ror)) {
  91                         /* l == (x CMP c_l), r == (x cmp c_r) */
  92                         ir_tarval  *const tv_l  = get_Const_tarval(lor);
  93                         ir_tarval  *const tv_r  = get_Const_tarval(ror);
  94                         ir_relation const rel   = tarval_cmp(tv_l, tv_r);
  95
  96                         res->lo_mode = get_irn_mode(lol);
  97
  98                         if (rel == ir_relation_less) {
  99                                 /* c_l < c_r */
 100                                 res->cmp_lo  = l;
 101                                 res->cmp_hi  = r;
 102                                 res->rel_lo  = pnc_l;
 103                                 res->rel_hi  = pnc_r;
 104                                 res->tv_lo   = tv_l;
 105                                 res->tv_hi   = tv_r;
 106                         } else if (rel == ir_relation_greater) {
 107                                 /* c_l > c_r */
 108                                 res->cmp_lo  = r;
 109                                 res->cmp_hi  = l;
 110                                 res->rel_lo  = pnc_r;
 111                                 res->rel_hi  = pnc_l;
 112                                 res->tv_lo   = tv_r;
 113                                 res->tv_hi   = tv_l;
 114                         } else {
 115                                 /* The constants shall be unequal but comparable.
 116                                  * Local optimizations handle the equal case. */
 117                                 return false;
 118                         }
 119                         return true;
 120                 }
 121         }
 122         return false;
 123 }
 124
 125 /**
 126  * Handle (lo rel_lo x) AND (hi rel_hi x)
 127  */
 128 static ir_node *bool_and(cond_pair* const cpair, ir_node *dst_block)
 129 {
 130         ir_node    *const cmp_lo  = cpair->cmp_lo;
 131         ir_node    *const cmp_hi  = cpair->cmp_hi;
 132         ir_relation       rel_lo  = cpair->rel_lo;
 133         ir_relation const rel_hi  = cpair->rel_hi;
 134         ir_tarval  *      tv_lo   = cpair->tv_lo;
 135         ir_tarval  *      tv_hi   = cpair->tv_hi;
 136         ir_mode    *      mode    = cpair->lo_mode;
 137         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 138
 139         if (rel_lo == ir_relation_equal && rel_hi == rel_lo &&
 140             tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 141             mode == get_tarval_mode(tv_hi)) {
 142                 /* p == NULL && q == NULL ==> (p&q) == NULL) */
 143                 ir_node *lol, *hil, *cmp, *c, *p;
 144
 145                 if (mode_is_reference(mode)) {
 146                         mode = find_unsigned_mode(mode);
 147                         if (! mode)
 148                                 return NULL;
 149                         tv_lo = tarval_convert_to(tv_lo, mode);
 150                         if (tv_lo == tarval_bad)
 151                                 return NULL;
 152                 }
 153                 if (mode_is_int(mode)) {
 154                         lol   = get_Cmp_left(cmp_lo);
 155                         lol   = new_r_Conv(dst_block, lol, mode);
 156                         hil   = get_Cmp_left(cmp_hi);
 157                         hil   = new_r_Conv(dst_block, hil, mode);
 158                         p     = new_r_And(dst_block, lol, hil, mode);
 159                         c     = new_r_Const(irg, tv_lo);
 160                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_equal);
 161                         return cmp;
 162                 }
 163         }
 164
 165         /* the following tests expect one common operand */
 166         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 167                 return 0;
 168
 169         /* TODO: for now reject float modes */
 170         if (! mode_is_int(mode))
 171                 return 0;
 172
 173         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 174         if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 175             (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 176                 /* x <|<=|== lo && x ==|>=|> hi ==> false */
 177                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 178                 return t;
 179         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 180                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 181                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 182                 return cmp_lo;
 183         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 184                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 185                 /* x >=|>|!= lo && x ==|>=|> hi ==> x ==|>=|> hi */
 186                 return cmp_hi;
 187         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 188                 if (rel_lo == ir_relation_greater_equal && rel_hi == ir_relation_less) {
 189                         /* x >= c && x < c + 1 ==> x == c */
 190                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_equal);
 191                         return p;
 192                 } else if (rel_lo == ir_relation_greater) {
 193                         if (rel_hi == ir_relation_less_greater) {
 194                                 /* x > c && x != c + 1 ==> x > c + 1 */
 195                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_greater);
 196                                 return p;
 197                         } else if (rel_hi == ir_relation_less) {
 198                                 /* x > c && x < c + 1 ==> false */
 199                                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 200                                 return t;
 201                         } else if (rel_hi == ir_relation_less_equal) {
 202                                 /* x > c && x <= c + 1 ==> x != c + 1 */
 203                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_equal);
 204                                 return p;
 205                         }
 206                 } else if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less) {
 207                         /* x != c && c < c + 1 ==> x < c */
 208                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_less);
 209                         return p;
 210                 }
 211         } else if ((rel_lo == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 212                    (rel_hi == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 213                    get_mode_arithmetic(mode) == irma_twos_complement) {
 214                 /* works for two-complements only */
 215                 /* x >|\= lo && x <|<= hi ==> (x - lo) <u|<=u (hi-lo) */
 216                 if (rel_lo == ir_relation_greater) {
 217                         /* must convert to >= */
 218                         ir_mode   *mode = get_tarval_mode(tv_lo);
 219                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 220                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 221                                 /* no overflow */
 222                                 tv_lo = n;
 223                                 rel_lo = ir_relation_greater_equal;
 224                         }
 225                 }
 226                 if (rel_lo == ir_relation_greater_equal) {
 227                         /* all fine */
 228                         ir_node *const block = get_nodes_block(cmp_hi);
 229                         ir_node *      x     = get_Cmp_left(cmp_hi);
 230                         ir_mode *      mode  = get_irn_mode(x);
 231                         ir_node *sub, *cmp, *c, *subc;
 232
 233                         if (mode_is_signed(mode)) {
 234                                 /* convert to unsigned */
 235                                 mode = find_unsigned_mode(mode);
 236                                 if (mode == NULL)
 237                                         return NULL;
 238                                 x     = new_r_Conv(block, x, mode);
 239                                 tv_lo = tarval_convert_to(tv_lo, mode);
 240                                 tv_hi = tarval_convert_to(tv_hi, mode);
 241                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 242                                         return NULL;
 243                         }
 244                         c    = new_r_Const(irg, tv_lo);
 245                         sub  = new_r_Sub(block, x, c, mode);
 246                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 247                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 248                         return cmp;
 249                 }
 250         }
 251         return NULL;
 252 }
 253
 254 /**
 255  * Handle (lo rel_lo x) OR (hi rel_hi x)
 256  */
 257 static ir_node *bool_or(cond_pair *const cpair, ir_node *dst_block)
 258 {
 259         ir_node    *const cmp_lo  = cpair->cmp_lo;
 260         ir_node    *const cmp_hi  = cpair->cmp_hi;
 261         ir_relation       rel_lo  = cpair->rel_lo;
 262         ir_relation const rel_hi  = cpair->rel_hi;
 263         ir_tarval  *      tv_lo   = cpair->tv_lo;
 264         ir_tarval  *      tv_hi   = cpair->tv_hi;
 265         ir_mode    *      mode    = cpair->lo_mode;
 266         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 267
 268         if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less_greater &&
 269                 tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 270                 mode == get_tarval_mode(tv_hi)) {
 271                 /* p != NULL || q != NULL ==> (p|q) != NULL) */
 272                 ir_node *lol, *hil, *cmp, *c, *p;
 273
 274                 if (mode_is_reference(mode)) {
 275                         mode = find_unsigned_mode(mode);
 276                         if (! mode)
 277                                 return NULL;
 278                         tv_lo = tarval_convert_to(tv_lo, mode);
 279                         if (tv_lo == tarval_bad)
 280                                 return NULL;
 281                 }
 282                 if (mode_is_int(mode)) {
 283                         lol   = get_Cmp_left(cmp_lo);
 284                         lol   = new_r_Conv(dst_block, lol, mode);
 285                         hil   = get_Cmp_left(cmp_hi);
 286                         hil   = new_r_Conv(dst_block, hil, mode);
 287                         p     = new_r_Or(dst_block, lol, hil, mode);
 288                         c     = new_r_Const(irg, tv_lo);
 289                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_less_greater);
 290                         return cmp;
 291                 }
 292         }
 293
 294         /* the following tests expect one common operand */
 295         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 296                 return 0;
 297
 298         /* TODO: for now reject float modes */
 299         if (! mode_is_int(mode))
 300                 return 0;
 301
 302         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 303         if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 304             (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 305                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 306                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 307                 return t;
 308         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 309                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 310                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 311                 return cmp_hi;
 312         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 313                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 314                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 315                 return cmp_lo;
 316         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 317                 if (rel_lo == ir_relation_less && rel_hi == ir_relation_greater_equal) {
 318                         /* x < c || x >= c + 1 ==> x != c */
 319                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_less_greater);
 320                         return p;
 321                 } else if (rel_lo == ir_relation_less_equal) {
 322                         if (rel_hi == ir_relation_equal) {
 323                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 324                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_equal);
 325                                 return p;
 326                         } else if (rel_hi == ir_relation_greater_equal) {
 327                                 /* x <= c || x >= c + 1 ==> true */
 328                                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 329                                 return t;
 330                         } else if (rel_hi == ir_relation_greater) {
 331                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 332                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_greater);
 333                                 return p;
 334                         }
 335                 } else if (rel_lo == ir_relation_equal && rel_hi == ir_relation_greater_equal) {
 336                         /* x == c || x >= c + 1 ==> x >= c */
 337                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_greater_equal);
 338                         return p;
 339                 }
 340         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 341                    (rel_hi == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 342                    get_mode_arithmetic(mode) == irma_twos_complement) {
 343                 /* works for two-complements only */
 344                 /* x <|<= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 345                 if (rel_lo == ir_relation_less_equal) {
 346                         /* must convert to < */
 347                         ir_mode   *mode = get_tarval_mode(tv_lo);
 348                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 349                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 350                                 /* no overflow */
 351                                 tv_lo = n;
 352                                 rel_lo = ir_relation_less;
 353                         }
 354                 }
 355                 if (rel_lo == ir_relation_less) {
 356                         /* all fine */
 357                         ir_node *const block = get_nodes_block(cmp_hi);
 358                         ir_node *      x     = get_Cmp_left(cmp_hi);
 359                         ir_mode *      mode  = get_irn_mode(x);
 360                         ir_node *sub, *cmp, *c, *subc;
 361
 362                         if (mode_is_signed(mode)) {
 363                                 /* convert to unsigned */
 364                                 mode = find_unsigned_mode(mode);
 365                                 if (mode == NULL)
 366                                         return NULL;
 367                                 x     = new_r_Conv(block, x, mode);
 368                                 tv_lo = tarval_convert_to(tv_lo, mode);
 369                                 tv_hi = tarval_convert_to(tv_hi, mode);
 370                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 371                                         return NULL;
 372                         }
 373                         c    = new_r_Const(irg, tv_lo);
 374                         sub  = new_r_Sub(block, x, c, mode);
 375                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 376                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 377                         return cmp;
 378                 }
 379         }
 380         return NULL;
 381 }
 382
 383 /**
 384  * Walker, tries to optimize Andb and Orb nodes.
 385  */
 386 static void bool_walk(ir_node *n, void *ctx)
 387 {
 388         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 389
 390         if (get_irn_mode(n) != mode_b)
 391                 return;
 392
 393         if (is_And(n)) {
 394                 ir_node *const l = get_And_left(n);
 395                 ir_node *const r = get_And_right(n);
 396                 ir_node *      replacement;
 397                 cond_pair      cpair;
 398                 if (!find_cond_pair(l, r, &cpair))
 399                         return;
 400                 replacement = bool_and(&cpair, get_nodes_block(n));
 401                 if (replacement) {
 402                         exchange(n, replacement);
 403                         env->changed = 1;
 404                 }
 405         } else if (is_Or(n)) {
 406                 ir_node *const l = get_Or_left(n);
 407                 ir_node *const r = get_Or_right(n);
 408                 ir_node *      replacement;
 409                 cond_pair      cpair;
 410                 if (!find_cond_pair(l, r, &cpair))
 411                         return;
 412                 replacement = bool_or(&cpair, get_nodes_block(n));
 413                 if (replacement) {
 414                         exchange(n, replacement);
 415                         env->changed = 1;
 416                 }
 417         }
 418 }
 419
 420 /**
 421  * Walker, clear Block marker and Phi lists.
 422  */
 423 static void clear_block_infos(ir_node *node, void *env)
 424 {
 425         (void) env;
 426
 427         /* we visit blocks before any other nodes (from the block) */
 428         if (!is_Block(node))
 429                 return;
 430
 431         /* clear the PHI list */
 432         set_Block_phis(node, NULL);
 433         set_Block_mark(node, 0);
 434 }
 435
 436 /**
 437  * Walker: collect Phi nodes and mark
 438  */
 439 static void collect_phis(ir_node *node, void *env)
 440 {
 441         (void) env;
 442
 443         if (is_Phi(node)) {
 444                 ir_node *block = get_nodes_block(node);
 445                 add_Block_phi(block, node);
 446                 return;
 447         }
 448
 449         /* Ignore control flow nodes, these will be removed. */
 450         if (get_irn_pinned(node) == op_pin_state_pinned &&
 451                         !is_Block(node) && !is_cfop(node)) {
 452                                 /* found a pinned non-cf node, mark its block */
 453                 ir_node *block = get_nodes_block(node);
 454                 set_Block_mark(block, 1);
 455         }
 456 }
 457
 458 /**
 459  * If node is a Jmp in a block containing no pinned instruction
 460  * and having only one predecessor, skip the block and return its
 461  * cf predecessor, else the node itself.
 462  */
 463 static ir_node *skip_empty_blocks(ir_node *node)
 464 {
 465         while (is_Jmp(node)) {
 466                 ir_node *block = get_nodes_block(node);
 467
 468                 if (get_Block_n_cfgpreds(block) != 1)
 469                         break;
 470
 471                 if (get_Block_mark(block))
 472                         break;
 473
 474                 node = get_Block_cfgpred(block, 0);
 475         }
 476         return node;
 477 }
 478
 479 /**
 480  * Check if two block inputs can be fused.
 481  * This can be done, if block contains no Phi node that depends on
 482  * different inputs idx_i and idx_j.
 483  */
 484 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j)
 485 {
 486         const ir_node *phi;
 487
 488         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 489                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 490                         return 0;
 491         }
 492         return 1;
 493 }
 494
 495 /**
 496  * Remove block input with given index.
 497  */
 498 static void remove_block_input(ir_node *block, int idx)
 499 {
 500         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 501         ir_node *phi, **ins;
 502
 503         NEW_ARR_A(ir_node *, ins, n);
 504
 505         if (n == 1) {
 506                 /* all Phis will be deleted */
 507                 ir_node *next_phi;
 508
 509                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 510                         next_phi = get_Phi_next(phi);
 511                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 512                 }
 513                 set_Block_phis(block, NULL);
 514         } else {
 515                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 516                         for (i = j = 0; i <= n; ++i) {
 517                                 if (i != idx)
 518                                         ins[j++] = get_Phi_pred(phi, i);
 519                         }
 520                         set_irn_in(phi, n, ins);
 521                 }
 522         }
 523         for (i = j = 0; i <= n; ++i) {
 524                 if (i != idx)
 525                         ins[j++] = get_Block_cfgpred(block, i);
 526         }
 527         set_irn_in(block, n, ins);
 528 }
 529
 530 /**
 531  * Under the preposition that we have a chain of blocks from
 532  * from_block to to_block, collapse them all into to_block.
 533  */
 534 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block)
 535 {
 536         ir_node *new_jmp = NULL;
 537         ir_node *block, *next_block;
 538
 539         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 540                 new_jmp = get_Block_cfgpred(block, 0);
 541                 next_block = get_nodes_block(new_jmp);
 542                 exchange(block, to_block);
 543         }
 544         if (new_jmp)
 545                 exchange(jmp, new_jmp);
 546 }
 547
 548 /**
 549  * Block walker:
 550  *
 551  * if we can find the following structure,
 552  *
 553  *        upper_block
 554  *         /       |
 555  *        /        |
 556  *   lower_block   |
 557  *     /  \        |
 558  *   ... low_idx up_idx
 559  *          \      |
 560  *            block
 561  *
 562  * try to convert it into a (x rel_lo c_lo) || (x rel_hi c_hi)
 563  * and optimize.
 564  */
 565 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 566 {
 567         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 568         int low_idx, up_idx;
 569         int n_cfgpreds;
 570
 571         /* because we modify the graph in regions we might not visited yet,
 572          * Id nodes might arise here. Ignore them.
 573          */
 574         if (is_Id(block))
 575                 return;
 576
 577         n_cfgpreds = get_Block_n_cfgpreds(block);
 578 restart:
 579         if (n_cfgpreds < 2)
 580                 return;
 581
 582         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 583                 ir_node      *lower_block;
 584                 ir_node      *lower_cf;
 585                 ir_node      *cond;
 586                 ir_node      *cond_selector;
 587                 ir_node      *lower_pred;
 588
 589                 lower_cf = get_Block_cfgpred(block, low_idx);
 590                 lower_cf = skip_empty_blocks(lower_cf);
 591                 if (!is_Proj(lower_cf))
 592                         continue;
 593
 594                 cond = get_Proj_pred(lower_cf);
 595                 if (!is_Cond(cond))
 596                         continue;
 597
 598                 lower_block = get_nodes_block(cond);
 599                 if (get_Block_n_cfgpreds(lower_block) != 1)
 600                         continue;
 601
 602                 /* the block must not produce any side-effects */
 603                 if (get_Block_mark(lower_block))
 604                         continue;
 605
 606                 cond_selector = get_Cond_selector(cond);
 607                 if (get_irn_mode(cond_selector) != mode_b)
 608                         continue;
 609
 610                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 611
 612                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 613                         ir_node   *upper_block;
 614                         ir_node   *upper_cf;
 615                         ir_node   *upper_cond;
 616                         ir_node   *upper_cond_selector;
 617                         ir_node   *replacement;
 618                         cond_pair  cpair;
 619
 620                         upper_cf = get_Block_cfgpred(block, up_idx);
 621                         upper_cf = skip_empty_blocks(upper_cf);
 622                         if (is_Bad(upper_cf))
 623                                 continue;
 624                         upper_block = get_nodes_block(upper_cf);
 625                         if (upper_block != lower_pred)
 626                                 continue;
 627                         if (!block_dominates(upper_block, block))
 628                                 continue;
 629
 630                         assert(is_Proj(upper_cf));
 631                         upper_cond = get_Proj_pred(upper_cf);
 632                         assert(is_Cond(upper_cond));
 633                         upper_cond_selector = get_Cond_selector(upper_cond);
 634                         if (get_irn_mode(upper_cond_selector) != mode_b)
 635                                 continue;
 636
 637                         /* we have found the structure */
 638                         /* check Phis: There must be NO Phi in block that
 639                            depends on the existence of low block */
 640                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 641                                 continue;
 642
 643                         /* all fine, try it */
 644                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 645                                 continue;
 646
 647                         /* normalize pncs: we need the true case to jump into the
 648                          * common block (i.e. conjunctive normal form) */
 649                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 650                                 if (cpair.cmp_lo == cond_selector) {
 651                                         ir_node  *cmp   = cpair.cmp_lo;
 652                                         ir_node  *block = get_nodes_block(cmp);
 653                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 654                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 655                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 656                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 657                                 } else {
 658                                         ir_node  *cmp   = cpair.cmp_hi;
 659                                         ir_node  *block = get_nodes_block(cmp);
 660                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 661                                         assert(cmp == cond_selector);
 662                                         cpair.rel_hi = get_negated_relation(cpair.rel_hi);
 663                                         cpair.cmp_hi = new_rd_Cmp(dbgi, block,
 664                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 665                                 }
 666                         }
 667                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 668                                 if (cpair.cmp_lo == upper_cond_selector) {
 669                                         ir_node  *cmp   = cpair.cmp_lo;
 670                                         ir_node  *block = get_nodes_block(cmp);
 671                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 672                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 673                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 674                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 675                                 } else {
 676                                         ir_node  *cmp   = cpair.cmp_hi;
 677                                         ir_node  *block = get_nodes_block(cmp);
 678                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 679                                         assert(cmp == upper_cond_selector);
 680                                         cpair.rel_hi   = get_negated_relation(cpair.rel_hi);
 681                                         cpair.cmp_hi   = new_rd_Cmp(dbgi, block,
 682                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 683                                 }
 684                         }
 685
 686                         /* can we optimize the case? */
 687                         replacement = bool_or(&cpair, upper_block);
 688                         if (replacement == NULL)
 689                                 continue;
 690
 691                         env->changed = 1;
 692
 693                         DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
 694                                 get_irn_irg(upper_block), upper_block, lower_block));
 695
 696                         /* move all expressions on the path to lower/upper block */
 697                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 698                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 699
 700                         /* move all nodes from lower block to upper block */
 701                         exchange(lower_block, upper_block);
 702
 703                         remove_block_input(block, up_idx);
 704                         --n_cfgpreds;
 705
 706                         /* the optimizations expected the true case to jump */
 707                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 708                                 ir_node *block = get_nodes_block(replacement);
 709                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 710                         }
 711                         set_Cond_selector(cond, replacement);
 712
 713                         goto restart;
 714                 }
 715         }
 716 }
 717
 718 void opt_bool(ir_graph *const irg)
 719 {
 720         bool_opt_env_t env;
 721
 722         /* register a debug mask */
 723         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 724
 725         env.changed = 0;
 726
 727         /* optimize simple Andb and Orb cases */
 728         irg_walk_graph(irg, NULL, bool_walk, &env);
 729
 730         /* now more complicated cases: find control flow And/Or and optimize. */
 731         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 732         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 733         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 734         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 735
 736         confirm_irg_properties(irg,
 737                 env.changed ? IR_GRAPH_PROPERTIES_NONE : IR_GRAPH_PROPERTIES_ALL);
 738 }
 739
 740 /* Creates an ir_graph pass for opt_bool. */
 741 ir_graph_pass_t *opt_bool_pass(const char *name)
 742 {
 743         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 744 }