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 #include "opt_manage.h"
  42
  43 /** Describes a pair of relative conditions lo < hi, lo rel_lo x, hi rel_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         ir_relation rel_lo;  /**< The lo relation node. */
  48         ir_relation rel_hi;  /**< The hi relation node. */
  49         ir_tarval  *tv_lo;   /**< The tarval of cmp_lo node. */
  50         ir_tarval  *tv_hi;   /**< The tarval of cmp_hi node. */
  51         ir_mode    *lo_mode; /**< The mode of the cmp_lo operands. */
  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 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  60
  61 /**
  62  * Check if tho given nodes, l and r, represent two compares with
  63  * ... . If yes, return non-zero and fill the res struct.
  64  */
  65 static bool find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  66 {
  67         if (is_Cmp(l) && is_Cmp(r)) {
  68                 ir_node    *const lol   = get_Cmp_left(l);
  69                 ir_node    *const lor   = get_Cmp_right(l);
  70                 ir_node    *const rol   = get_Cmp_left(r);
  71                 ir_node    *const ror   = get_Cmp_right(r);
  72                 ir_relation const pnc_l = get_Cmp_relation(l);
  73                 ir_relation const pnc_r = get_Cmp_relation(r);
  74
  75                 if (is_Const(lor) && is_Const_null(lor) &&
  76                         is_Const(ror) && is_Const_null(ror) &&
  77                         pnc_l == pnc_r &&
  78                         (pnc_l == ir_relation_less_greater || pnc_l == ir_relation_equal)) {
  79                         /* l == (lol !=|== NULL) && r == (rol !=|== NULL) */
  80                         res->cmp_lo  = l;
  81                         res->cmp_hi  = r;
  82                         res->rel_lo  = pnc_l;
  83                         res->rel_hi  = pnc_l;
  84                         res->tv_lo   = get_Const_tarval(lor);
  85                         res->tv_hi   = get_Const_tarval(ror);
  86                         res->lo_mode = get_irn_mode(lor);
  87
  88                         return true;
  89                 }
  90
  91                 if (lol == rol && lor != ror && is_Const(lor) && is_Const(ror)) {
  92                         /* l == (x CMP c_l), r == (x cmp c_r) */
  93                         ir_tarval  *const tv_l  = get_Const_tarval(lor);
  94                         ir_tarval  *const tv_r  = get_Const_tarval(ror);
  95                         ir_relation const rel   = tarval_cmp(tv_l, tv_r);
  96
  97                         res->lo_mode = get_irn_mode(lol);
  98
  99                         if (rel == ir_relation_less) {
 100                                 /* c_l < c_r */
 101                                 res->cmp_lo  = l;
 102                                 res->cmp_hi  = r;
 103                                 res->rel_lo  = pnc_l;
 104                                 res->rel_hi  = pnc_r;
 105                                 res->tv_lo   = tv_l;
 106                                 res->tv_hi   = tv_r;
 107                         } else if (rel == ir_relation_greater) {
 108                                 /* c_l > c_r */
 109                                 res->cmp_lo  = r;
 110                                 res->cmp_hi  = l;
 111                                 res->rel_lo  = pnc_r;
 112                                 res->rel_hi  = pnc_l;
 113                                 res->tv_lo   = tv_r;
 114                                 res->tv_hi   = tv_l;
 115                         } else {
 116                                 /* The constants shall be unequal but comparable.
 117                                  * Local optimizations handle the equal case. */
 118                                 return false;
 119                         }
 120                         return true;
 121                 }
 122         }
 123         return false;
 124 }
 125
 126 /**
 127  * Handle (lo rel_lo x) AND (hi rel_hi x)
 128  */
 129 static ir_node *bool_and(cond_pair* const cpair, ir_node *dst_block)
 130 {
 131         ir_node    *const cmp_lo  = cpair->cmp_lo;
 132         ir_node    *const cmp_hi  = cpair->cmp_hi;
 133         ir_relation       rel_lo  = cpair->rel_lo;
 134         ir_relation const rel_hi  = cpair->rel_hi;
 135         ir_tarval  *      tv_lo   = cpair->tv_lo;
 136         ir_tarval  *      tv_hi   = cpair->tv_hi;
 137         ir_mode    *      mode    = cpair->lo_mode;
 138         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 139
 140         if (rel_lo == ir_relation_equal && rel_hi == rel_lo &&
 141             tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 142             mode == get_tarval_mode(tv_hi)) {
 143                 /* p == NULL && q == NULL ==> (p&q) == NULL) */
 144                 ir_node *lol, *hil, *cmp, *c, *p;
 145
 146                 if (mode_is_reference(mode)) {
 147                         mode = find_unsigned_mode(mode);
 148                         if (! mode)
 149                                 return NULL;
 150                         tv_lo = tarval_convert_to(tv_lo, mode);
 151                         if (tv_lo == tarval_bad)
 152                                 return NULL;
 153                 }
 154                 if (mode_is_int(mode)) {
 155                         lol   = get_Cmp_left(cmp_lo);
 156                         lol   = new_r_Conv(dst_block, lol, mode);
 157                         hil   = get_Cmp_left(cmp_hi);
 158                         hil   = new_r_Conv(dst_block, hil, mode);
 159                         p     = new_r_And(dst_block, lol, hil, mode);
 160                         c     = new_r_Const(irg, tv_lo);
 161                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_equal);
 162                         return cmp;
 163                 }
 164         }
 165
 166         /* the following tests expect one common operand */
 167         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 168                 return 0;
 169
 170         /* TODO: for now reject float modes */
 171         if (! mode_is_int(mode))
 172                 return 0;
 173
 174         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 175         if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 176             (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 177                 /* x <|<=|== lo && x ==|>=|> hi ==> false */
 178                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 179                 return t;
 180         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 181                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 182                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 183                 return cmp_lo;
 184         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 185                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 186                 /* x >=|>|!= lo && x ==|>=|> hi ==> x ==|>=|> hi */
 187                 return cmp_hi;
 188         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 189                 if (rel_lo == ir_relation_greater_equal && rel_hi == ir_relation_less) {
 190                         /* x >= c && x < c + 1 ==> x == c */
 191                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_equal);
 192                         return p;
 193                 } else if (rel_lo == ir_relation_greater) {
 194                         if (rel_hi == ir_relation_less_greater) {
 195                                 /* x > c && x != c + 1 ==> x > c + 1 */
 196                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_greater);
 197                                 return p;
 198                         } else if (rel_hi == ir_relation_less) {
 199                                 /* x > c && x < c + 1 ==> false */
 200                                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 201                                 return t;
 202                         } else if (rel_hi == ir_relation_less_equal) {
 203                                 /* x > c && x <= c + 1 ==> x != c + 1 */
 204                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_equal);
 205                                 return p;
 206                         }
 207                 } else if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less) {
 208                         /* x != c && c < c + 1 ==> x < c */
 209                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_less);
 210                         return p;
 211                 }
 212         } else if ((rel_lo == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 213                    (rel_hi == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 214                    get_mode_arithmetic(mode) == irma_twos_complement) {
 215                 /* works for two-complements only */
 216                 /* x >|\= lo && x <|<= hi ==> (x - lo) <u|<=u (hi-lo) */
 217                 if (rel_lo == ir_relation_greater) {
 218                         /* must convert to >= */
 219                         ir_mode   *mode = get_tarval_mode(tv_lo);
 220                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 221                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 222                                 /* no overflow */
 223                                 tv_lo = n;
 224                                 rel_lo = ir_relation_greater_equal;
 225                         }
 226                 }
 227                 if (rel_lo == ir_relation_greater_equal) {
 228                         /* all fine */
 229                         ir_node *const block = get_nodes_block(cmp_hi);
 230                         ir_node *      x     = get_Cmp_left(cmp_hi);
 231                         ir_mode *      mode  = get_irn_mode(x);
 232                         ir_node *sub, *cmp, *c, *subc;
 233
 234                         if (mode_is_signed(mode)) {
 235                                 /* convert to unsigned */
 236                                 mode = find_unsigned_mode(mode);
 237                                 if (mode == NULL)
 238                                         return NULL;
 239                                 x     = new_r_Conv(block, x, mode);
 240                                 tv_lo = tarval_convert_to(tv_lo, mode);
 241                                 tv_hi = tarval_convert_to(tv_hi, mode);
 242                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 243                                         return NULL;
 244                         }
 245                         c    = new_r_Const(irg, tv_lo);
 246                         sub  = new_r_Sub(block, x, c, mode);
 247                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 248                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 249                         return cmp;
 250                 }
 251         }
 252         return NULL;
 253 }
 254
 255 /**
 256  * Handle (lo rel_lo x) OR (hi rel_hi x)
 257  */
 258 static ir_node *bool_or(cond_pair *const cpair, ir_node *dst_block)
 259 {
 260         ir_node    *const cmp_lo  = cpair->cmp_lo;
 261         ir_node    *const cmp_hi  = cpair->cmp_hi;
 262         ir_relation       rel_lo  = cpair->rel_lo;
 263         ir_relation const rel_hi  = cpair->rel_hi;
 264         ir_tarval  *      tv_lo   = cpair->tv_lo;
 265         ir_tarval  *      tv_hi   = cpair->tv_hi;
 266         ir_mode    *      mode    = cpair->lo_mode;
 267         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 268
 269         if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less_greater &&
 270                 tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 271                 mode == get_tarval_mode(tv_hi)) {
 272                 /* p != NULL || q != NULL ==> (p|q) != NULL) */
 273                 ir_node *lol, *hil, *cmp, *c, *p;
 274
 275                 if (mode_is_reference(mode)) {
 276                         mode = find_unsigned_mode(mode);
 277                         if (! mode)
 278                                 return NULL;
 279                         tv_lo = tarval_convert_to(tv_lo, mode);
 280                         if (tv_lo == tarval_bad)
 281                                 return NULL;
 282                 }
 283                 if (mode_is_int(mode)) {
 284                         lol   = get_Cmp_left(cmp_lo);
 285                         lol   = new_r_Conv(dst_block, lol, mode);
 286                         hil   = get_Cmp_left(cmp_hi);
 287                         hil   = new_r_Conv(dst_block, hil, mode);
 288                         p     = new_r_Or(dst_block, lol, hil, mode);
 289                         c     = new_r_Const(irg, tv_lo);
 290                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_less_greater);
 291                         return cmp;
 292                 }
 293         }
 294
 295         /* the following tests expect one common operand */
 296         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 297                 return 0;
 298
 299         /* TODO: for now reject float modes */
 300         if (! mode_is_int(mode))
 301                 return 0;
 302
 303         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 304         if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 305             (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 306                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 307                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 308                 return t;
 309         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 310                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 311                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 312                 return cmp_hi;
 313         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 314                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 315                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 316                 return cmp_lo;
 317         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 318                 if (rel_lo == ir_relation_less && rel_hi == ir_relation_greater_equal) {
 319                         /* x < c || x >= c + 1 ==> x != c */
 320                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_less_greater);
 321                         return p;
 322                 } else if (rel_lo == ir_relation_less_equal) {
 323                         if (rel_hi == ir_relation_equal) {
 324                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 325                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_equal);
 326                                 return p;
 327                         } else if (rel_hi == ir_relation_greater_equal) {
 328                                 /* x <= c || x >= c + 1 ==> true */
 329                                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 330                                 return t;
 331                         } else if (rel_hi == ir_relation_greater) {
 332                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 333                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_greater);
 334                                 return p;
 335                         }
 336                 } else if (rel_lo == ir_relation_equal && rel_hi == ir_relation_greater_equal) {
 337                         /* x == c || x >= c + 1 ==> x >= c */
 338                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_greater_equal);
 339                         return p;
 340                 }
 341         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 342                    (rel_hi == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 343                    get_mode_arithmetic(mode) == irma_twos_complement) {
 344                 /* works for two-complements only */
 345                 /* x <|<= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 346                 if (rel_lo == ir_relation_less_equal) {
 347                         /* must convert to < */
 348                         ir_mode   *mode = get_tarval_mode(tv_lo);
 349                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 350                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 351                                 /* no overflow */
 352                                 tv_lo = n;
 353                                 rel_lo = ir_relation_less;
 354                         }
 355                 }
 356                 if (rel_lo == ir_relation_less) {
 357                         /* all fine */
 358                         ir_node *const block = get_nodes_block(cmp_hi);
 359                         ir_node *      x     = get_Cmp_left(cmp_hi);
 360                         ir_mode *      mode  = get_irn_mode(x);
 361                         ir_node *sub, *cmp, *c, *subc;
 362
 363                         if (mode_is_signed(mode)) {
 364                                 /* convert to unsigned */
 365                                 mode = find_unsigned_mode(mode);
 366                                 if (mode == NULL)
 367                                         return NULL;
 368                                 x     = new_r_Conv(block, x, mode);
 369                                 tv_lo = tarval_convert_to(tv_lo, mode);
 370                                 tv_hi = tarval_convert_to(tv_hi, mode);
 371                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 372                                         return NULL;
 373                         }
 374                         c    = new_r_Const(irg, tv_lo);
 375                         sub  = new_r_Sub(block, x, c, mode);
 376                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 377                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 378                         return cmp;
 379                 }
 380         }
 381         return NULL;
 382 }
 383
 384 /**
 385  * Walker, tries to optimize Andb and Orb nodes.
 386  */
 387 static void bool_walk(ir_node *n, void *ctx)
 388 {
 389         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 390
 391         if (get_irn_mode(n) != mode_b)
 392                 return;
 393
 394         if (is_And(n)) {
 395                 ir_node *const l = get_And_left(n);
 396                 ir_node *const r = get_And_right(n);
 397                 ir_node *      replacement;
 398                 cond_pair      cpair;
 399                 if (!find_cond_pair(l, r, &cpair))
 400                         return;
 401                 replacement = bool_and(&cpair, get_nodes_block(n));
 402                 if (replacement) {
 403                         exchange(n, replacement);
 404                         env->changed = 1;
 405                 }
 406         } else if (is_Or(n)) {
 407                 ir_node *const l = get_Or_left(n);
 408                 ir_node *const r = get_Or_right(n);
 409                 ir_node *      replacement;
 410                 cond_pair      cpair;
 411                 if (!find_cond_pair(l, r, &cpair))
 412                         return;
 413                 replacement = bool_or(&cpair, get_nodes_block(n));
 414                 if (replacement) {
 415                         exchange(n, replacement);
 416                         env->changed = 1;
 417                 }
 418         }
 419 }
 420
 421 /**
 422  * Walker, clear Block marker and Phi lists.
 423  */
 424 static void clear_block_infos(ir_node *node, void *env)
 425 {
 426         (void) env;
 427
 428         /* we visit blocks before any other nodes (from the block) */
 429         if (!is_Block(node))
 430                 return;
 431
 432         /* clear the PHI list */
 433         set_Block_phis(node, NULL);
 434         set_Block_mark(node, 0);
 435 }
 436
 437 /**
 438  * Walker: collect Phi nodes and mark
 439  */
 440 static void collect_phis(ir_node *node, void *env)
 441 {
 442         (void) env;
 443
 444         if (is_Phi(node)) {
 445                 ir_node *block = get_nodes_block(node);
 446                 add_Block_phi(block, node);
 447                 return;
 448         }
 449
 450         /* Ignore control flow nodes, these will be removed. */
 451         if (get_irn_pinned(node) == op_pin_state_pinned &&
 452                         !is_Block(node) && !is_cfop(node)) {
 453                                 /* found a pinned non-cf node, mark its block */
 454                 ir_node *block = get_nodes_block(node);
 455                 set_Block_mark(block, 1);
 456         }
 457 }
 458
 459 /**
 460  * If node is a Jmp in a block containing no pinned instruction
 461  * and having only one predecessor, skip the block and return its
 462  * cf predecessor, else the node itself.
 463  */
 464 static ir_node *skip_empty_blocks(ir_node *node)
 465 {
 466         while (is_Jmp(node)) {
 467                 ir_node *block = get_nodes_block(node);
 468
 469                 if (get_Block_n_cfgpreds(block) != 1)
 470                         break;
 471
 472                 if (get_Block_mark(block))
 473                         break;
 474
 475                 node = get_Block_cfgpred(block, 0);
 476         }
 477         return node;
 478 }
 479
 480 /**
 481  * Check if two block inputs can be fused.
 482  * This can be done, if block contains no Phi node that depends on
 483  * different inputs idx_i and idx_j.
 484  */
 485 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j)
 486 {
 487         const ir_node *phi;
 488
 489         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 490                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 491                         return 0;
 492         }
 493         return 1;
 494 }
 495
 496 /**
 497  * Remove block input with given index.
 498  */
 499 static void remove_block_input(ir_node *block, int idx)
 500 {
 501         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 502         ir_node *phi, **ins;
 503
 504         NEW_ARR_A(ir_node *, ins, n);
 505
 506         if (n == 1) {
 507                 /* all Phis will be deleted */
 508                 ir_node *next_phi;
 509
 510                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 511                         next_phi = get_Phi_next(phi);
 512                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 513                 }
 514                 set_Block_phis(block, NULL);
 515         } else {
 516                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 517                         for (i = j = 0; i <= n; ++i) {
 518                                 if (i != idx)
 519                                         ins[j++] = get_Phi_pred(phi, i);
 520                         }
 521                         set_irn_in(phi, n, ins);
 522                 }
 523         }
 524         for (i = j = 0; i <= n; ++i) {
 525                 if (i != idx)
 526                         ins[j++] = get_Block_cfgpred(block, i);
 527         }
 528         set_irn_in(block, n, ins);
 529 }
 530
 531 /**
 532  * Under the preposition that we have a chain of blocks from
 533  * from_block to to_block, collapse them all into to_block.
 534  */
 535 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block)
 536 {
 537         ir_node *new_jmp = NULL;
 538         ir_node *block, *next_block;
 539
 540         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 541                 new_jmp = get_Block_cfgpred(block, 0);
 542                 next_block = get_nodes_block(new_jmp);
 543                 exchange(block, to_block);
 544         }
 545         if (new_jmp)
 546                 exchange(jmp, new_jmp);
 547 }
 548
 549 /**
 550  * Block walker:
 551  *
 552  * if we can find the following structure,
 553  *
 554  *        upper_block
 555  *         /       |
 556  *        /        |
 557  *   lower_block   |
 558  *     /  \        |
 559  *   ... low_idx up_idx
 560  *          \      |
 561  *            block
 562  *
 563  * try to convert it into a (x rel_lo c_lo) || (x rel_hi c_hi)
 564  * and optimize.
 565  */
 566 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 567 {
 568         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 569         int low_idx, up_idx;
 570         int n_cfgpreds;
 571
 572         /* because we modify the graph in regions we might not visited yet,
 573          * Id nodes might arise here. Ignore them.
 574          */
 575         if (is_Id(block))
 576                 return;
 577
 578         n_cfgpreds = get_Block_n_cfgpreds(block);
 579 restart:
 580         if (n_cfgpreds < 2)
 581                 return;
 582
 583         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 584                 ir_node      *lower_block;
 585                 ir_node      *lower_cf;
 586                 ir_node      *cond;
 587                 ir_node      *cond_selector;
 588                 ir_node      *lower_pred;
 589
 590                 lower_cf = get_Block_cfgpred(block, low_idx);
 591                 lower_cf = skip_empty_blocks(lower_cf);
 592                 if (!is_Proj(lower_cf))
 593                         continue;
 594
 595                 cond = get_Proj_pred(lower_cf);
 596                 if (!is_Cond(cond))
 597                         continue;
 598
 599                 lower_block = get_nodes_block(cond);
 600                 if (get_Block_n_cfgpreds(lower_block) != 1)
 601                         continue;
 602
 603                 /* the block must not produce any side-effects */
 604                 if (get_Block_mark(lower_block))
 605                         continue;
 606
 607                 cond_selector = get_Cond_selector(cond);
 608                 if (get_irn_mode(cond_selector) != mode_b)
 609                         continue;
 610
 611                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 612
 613                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 614                         ir_node   *upper_block;
 615                         ir_node   *upper_cf;
 616                         ir_node   *upper_cond;
 617                         ir_node   *upper_cond_selector;
 618                         ir_node   *replacement;
 619                         cond_pair  cpair;
 620
 621                         upper_cf = get_Block_cfgpred(block, up_idx);
 622                         upper_cf = skip_empty_blocks(upper_cf);
 623                         if (is_Bad(upper_cf))
 624                                 continue;
 625                         upper_block = get_nodes_block(upper_cf);
 626                         if (upper_block != lower_pred)
 627                                 continue;
 628                         if (!block_dominates(upper_block, block))
 629                                 continue;
 630
 631                         assert(is_Proj(upper_cf));
 632                         upper_cond = get_Proj_pred(upper_cf);
 633                         assert(is_Cond(upper_cond));
 634                         upper_cond_selector = get_Cond_selector(upper_cond);
 635                         if (get_irn_mode(upper_cond_selector) != mode_b)
 636                                 continue;
 637
 638                         /* we have found the structure */
 639                         /* check Phis: There must be NO Phi in block that
 640                            depends on the existence of low block */
 641                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 642                                 continue;
 643
 644                         /* all fine, try it */
 645                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 646                                 continue;
 647
 648                         /* normalize pncs: we need the true case to jump into the
 649                          * common block (ie. conjunctive normal form) */
 650                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 651                                 if (cpair.cmp_lo == cond_selector) {
 652                                         ir_node  *cmp   = cpair.cmp_lo;
 653                                         ir_node  *block = get_nodes_block(cmp);
 654                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 655                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 656                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 657                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 658                                 } else {
 659                                         ir_node  *cmp   = cpair.cmp_hi;
 660                                         ir_node  *block = get_nodes_block(cmp);
 661                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 662                                         assert(cmp == cond_selector);
 663                                         cpair.rel_hi = get_negated_relation(cpair.rel_hi);
 664                                         cpair.cmp_hi = new_rd_Cmp(dbgi, block,
 665                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 666                                 }
 667                         }
 668                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 669                                 if (cpair.cmp_lo == upper_cond_selector) {
 670                                         ir_node  *cmp   = cpair.cmp_lo;
 671                                         ir_node  *block = get_nodes_block(cmp);
 672                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 673                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 674                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 675                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 676                                 } else {
 677                                         ir_node  *cmp   = cpair.cmp_hi;
 678                                         ir_node  *block = get_nodes_block(cmp);
 679                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 680                                         assert(cmp == upper_cond_selector);
 681                                         cpair.rel_hi   = get_negated_relation(cpair.rel_hi);
 682                                         cpair.cmp_hi   = new_rd_Cmp(dbgi, block,
 683                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 684                                 }
 685                         }
 686
 687                         /* can we optimize the case? */
 688                         replacement = bool_or(&cpair, upper_block);
 689                         if (replacement == NULL)
 690                                 continue;
 691
 692                         env->changed = 1;
 693
 694                         DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
 695                                 get_irn_irg(upper_block), upper_block, lower_block));
 696
 697                         /* move all expressions on the path to lower/upper block */
 698                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 699                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 700
 701                         /* move all nodes from lower block to upper block */
 702                         exchange(lower_block, upper_block);
 703
 704                         remove_block_input(block, up_idx);
 705                         --n_cfgpreds;
 706
 707                         /* the optimizations expected the true case to jump */
 708                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 709                                 ir_node *block = get_nodes_block(replacement);
 710                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 711                         }
 712                         set_Cond_selector(cond, replacement);
 713
 714                         goto restart;
 715                 }
 716         }
 717 }
 718
 719 static ir_graph_state_t do_simplify_bool(ir_graph *const irg)
 720 {
 721         bool_opt_env_t env;
 722         ir_graph_state_t res = 0;
 723
 724         /* register a debug mask */
 725         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 726
 727         env.changed = 0;
 728
 729         /* optimize simple Andb and Orb cases */
 730         irg_walk_graph(irg, NULL, bool_walk, &env);
 731
 732         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 733
 734         /* now more complicated cases: find control flow And/Or and optimize. */
 735         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 736         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 737
 738         if (! env.changed) {
 739                 res |= IR_GRAPH_STATE_CONSISTENT_DOMINANCE;
 740         }
 741
 742         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 743
 744         return res;
 745 }
 746
 747 static optdesc_t opt_simplify_bool = {
 748         "bool-simplification",
 749         IR_GRAPH_STATE_ONE_RETURN, /* works better with one return block only */
 750         do_simplify_bool,
 751 };
 752
 753 void opt_bool(ir_graph *irg)
 754 {
 755         perform_irg_optimization(irg, &opt_simplify_bool);
 756 }
 757
 758 /* Creates an ir_graph pass for opt_bool. */
 759 ir_graph_pass_t *opt_bool_pass(const char *name)
 760 {
 761         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 762 }