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  * @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 #include "opt_manage.h"
  43
  44 /** Describes a pair of relative conditions lo < hi, lo rel_lo x, hi rel_hi x */
  45 typedef struct cond_pair {
  46         ir_node    *cmp_lo;  /**< The lo compare node. */
  47         ir_node    *cmp_hi;  /**< The hi compare node. */
  48         ir_relation rel_lo;  /**< The lo relation node. */
  49         ir_relation rel_hi;  /**< The hi relation node. */
  50         ir_tarval  *tv_lo;   /**< The tarval of cmp_lo node. */
  51         ir_tarval  *tv_hi;   /**< The tarval of cmp_hi node. */
  52         ir_mode    *lo_mode; /**< The mode of the cmp_lo operands. */
  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 bool find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  67 {
  68         if (is_Cmp(l) && is_Cmp(r)) {
  69                 ir_node    *const lol   = get_Cmp_left(l);
  70                 ir_node    *const lor   = get_Cmp_right(l);
  71                 ir_node    *const rol   = get_Cmp_left(r);
  72                 ir_node    *const ror   = get_Cmp_right(r);
  73                 ir_relation const pnc_l = get_Cmp_relation(l);
  74                 ir_relation const pnc_r = get_Cmp_relation(r);
  75
  76                 if (is_Const(lor) && is_Const_null(lor) &&
  77                         is_Const(ror) && is_Const_null(ror) &&
  78                         pnc_l == pnc_r &&
  79                         (pnc_l == ir_relation_less_greater || pnc_l == ir_relation_equal)) {
  80                         /* l == (lol !=|== NULL) && r == (rol !=|== NULL) */
  81                         res->cmp_lo  = l;
  82                         res->cmp_hi  = r;
  83                         res->rel_lo  = pnc_l;
  84                         res->rel_hi  = pnc_l;
  85                         res->tv_lo   = get_Const_tarval(lor);
  86                         res->tv_hi   = get_Const_tarval(ror);
  87                         res->lo_mode = get_irn_mode(lor);
  88
  89                         return true;
  90                 }
  91
  92                 if (lol == rol && lor != ror && is_Const(lor) && is_Const(ror)) {
  93                         /* l == (x CMP c_l), r == (x cmp c_r) */
  94                         ir_tarval  *const tv_l  = get_Const_tarval(lor);
  95                         ir_tarval  *const tv_r  = get_Const_tarval(ror);
  96                         ir_relation const rel   = tarval_cmp(tv_l, tv_r);
  97
  98                         res->lo_mode = get_irn_mode(lol);
  99
 100                         if (rel == ir_relation_less) {
 101                                 /* c_l < c_r */
 102                                 res->cmp_lo  = l;
 103                                 res->cmp_hi  = r;
 104                                 res->rel_lo  = pnc_l;
 105                                 res->rel_hi  = pnc_r;
 106                                 res->tv_lo   = tv_l;
 107                                 res->tv_hi   = tv_r;
 108                         } else if (rel == ir_relation_greater) {
 109                                 /* c_l > c_r */
 110                                 res->cmp_lo  = r;
 111                                 res->cmp_hi  = l;
 112                                 res->rel_lo  = pnc_r;
 113                                 res->rel_hi  = pnc_l;
 114                                 res->tv_lo   = tv_r;
 115                                 res->tv_hi   = tv_l;
 116                         } else {
 117                                 /* The constants shall be unequal but comparable.
 118                                  * Local optimizations handle the equal case. */
 119                                 return false;
 120                         }
 121                         return true;
 122                 }
 123         }
 124         return false;
 125 }
 126
 127 /**
 128  * Handle (lo rel_lo x) AND (hi rel_hi x)
 129  */
 130 static ir_node *bool_and(cond_pair* const cpair, ir_node *dst_block)
 131 {
 132         ir_node    *const cmp_lo  = cpair->cmp_lo;
 133         ir_node    *const cmp_hi  = cpair->cmp_hi;
 134         ir_relation       rel_lo  = cpair->rel_lo;
 135         ir_relation const rel_hi  = cpair->rel_hi;
 136         ir_tarval  *      tv_lo   = cpair->tv_lo;
 137         ir_tarval  *      tv_hi   = cpair->tv_hi;
 138         ir_mode    *      mode    = cpair->lo_mode;
 139         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 140
 141         if (rel_lo == ir_relation_equal && rel_hi == rel_lo &&
 142             tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 143             mode == get_tarval_mode(tv_hi)) {
 144                 /* p == NULL && q == NULL ==> (p&q) == NULL) */
 145                 ir_node *lol, *hil, *cmp, *c, *p;
 146
 147                 if (mode_is_reference(mode)) {
 148                         mode = find_unsigned_mode(mode);
 149                         if (! mode)
 150                                 return NULL;
 151                         tv_lo = tarval_convert_to(tv_lo, mode);
 152                         if (tv_lo == tarval_bad)
 153                                 return NULL;
 154                 }
 155                 if (mode_is_int(mode)) {
 156                         lol   = get_Cmp_left(cmp_lo);
 157                         lol   = new_r_Conv(dst_block, lol, mode);
 158                         hil   = get_Cmp_left(cmp_hi);
 159                         hil   = new_r_Conv(dst_block, hil, mode);
 160                         p     = new_r_And(dst_block, lol, hil, mode);
 161                         c     = new_r_Const(irg, tv_lo);
 162                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_equal);
 163                         return cmp;
 164                 }
 165         }
 166
 167         /* the following tests expect one common operand */
 168         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 169                 return 0;
 170
 171         /* TODO: for now reject float modes */
 172         if (! mode_is_int(mode))
 173                 return 0;
 174
 175         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 176         if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 177             (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 178                 /* x <|<=|== lo && x ==|>=|> hi ==> false */
 179                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 180                 return t;
 181         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 182                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 183                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 184                 return cmp_lo;
 185         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 186                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 187                 /* x >=|>|!= lo && x ==|>=|> hi ==> x ==|>=|> hi */
 188                 return cmp_hi;
 189         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 190                 if (rel_lo == ir_relation_greater_equal && rel_hi == ir_relation_less) {
 191                         /* x >= c && x < c + 1 ==> x == c */
 192                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_equal);
 193                         return p;
 194                 } else if (rel_lo == ir_relation_greater) {
 195                         if (rel_hi == ir_relation_less_greater) {
 196                                 /* x > c && x != c + 1 ==> x > c + 1 */
 197                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_greater);
 198                                 return p;
 199                         } else if (rel_hi == ir_relation_less) {
 200                                 /* x > c && x < c + 1 ==> false */
 201                                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 202                                 return t;
 203                         } else if (rel_hi == ir_relation_less_equal) {
 204                                 /* x > c && x <= c + 1 ==> x != c + 1 */
 205                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_equal);
 206                                 return p;
 207                         }
 208                 } else if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less) {
 209                         /* x != c && c < c + 1 ==> x < c */
 210                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_less);
 211                         return p;
 212                 }
 213         } else if ((rel_lo == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 214                    (rel_hi == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 215                    get_mode_arithmetic(mode) == irma_twos_complement) {
 216                 /* works for two-complements only */
 217                 /* x >|\= lo && x <|<= hi ==> (x - lo) <u|<=u (hi-lo) */
 218                 if (rel_lo == ir_relation_greater) {
 219                         /* must convert to >= */
 220                         ir_mode   *mode = get_tarval_mode(tv_lo);
 221                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 222                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 223                                 /* no overflow */
 224                                 tv_lo = n;
 225                                 rel_lo = ir_relation_greater_equal;
 226                         }
 227                 }
 228                 if (rel_lo == ir_relation_greater_equal) {
 229                         /* all fine */
 230                         ir_node *const block = get_nodes_block(cmp_hi);
 231                         ir_node *      x     = get_Cmp_left(cmp_hi);
 232                         ir_mode *      mode  = get_irn_mode(x);
 233                         ir_node *sub, *cmp, *c, *subc;
 234
 235                         if (mode_is_signed(mode)) {
 236                                 /* convert to unsigned */
 237                                 mode = find_unsigned_mode(mode);
 238                                 if (mode == NULL)
 239                                         return NULL;
 240                                 x     = new_r_Conv(block, x, mode);
 241                                 tv_lo = tarval_convert_to(tv_lo, mode);
 242                                 tv_hi = tarval_convert_to(tv_hi, mode);
 243                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 244                                         return NULL;
 245                         }
 246                         c    = new_r_Const(irg, tv_lo);
 247                         sub  = new_r_Sub(block, x, c, mode);
 248                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 249                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 250                         return cmp;
 251                 }
 252         }
 253         return NULL;
 254 }
 255
 256 /**
 257  * Handle (lo rel_lo x) OR (hi rel_hi x)
 258  */
 259 static ir_node *bool_or(cond_pair *const cpair, ir_node *dst_block)
 260 {
 261         ir_node    *const cmp_lo  = cpair->cmp_lo;
 262         ir_node    *const cmp_hi  = cpair->cmp_hi;
 263         ir_relation       rel_lo  = cpair->rel_lo;
 264         ir_relation const rel_hi  = cpair->rel_hi;
 265         ir_tarval  *      tv_lo   = cpair->tv_lo;
 266         ir_tarval  *      tv_hi   = cpair->tv_hi;
 267         ir_mode    *      mode    = cpair->lo_mode;
 268         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 269
 270         if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less_greater &&
 271                 tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 272                 mode == get_tarval_mode(tv_hi)) {
 273                 /* p != NULL || q != NULL ==> (p|q) != NULL) */
 274                 ir_node *lol, *hil, *cmp, *c, *p;
 275
 276                 if (mode_is_reference(mode)) {
 277                         mode = find_unsigned_mode(mode);
 278                         if (! mode)
 279                                 return NULL;
 280                         tv_lo = tarval_convert_to(tv_lo, mode);
 281                         if (tv_lo == tarval_bad)
 282                                 return NULL;
 283                 }
 284                 if (mode_is_int(mode)) {
 285                         lol   = get_Cmp_left(cmp_lo);
 286                         lol   = new_r_Conv(dst_block, lol, mode);
 287                         hil   = get_Cmp_left(cmp_hi);
 288                         hil   = new_r_Conv(dst_block, hil, mode);
 289                         p     = new_r_Or(dst_block, lol, hil, mode);
 290                         c     = new_r_Const(irg, tv_lo);
 291                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_less_greater);
 292                         return cmp;
 293                 }
 294         }
 295
 296         /* the following tests expect one common operand */
 297         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 298                 return 0;
 299
 300         /* TODO: for now reject float modes */
 301         if (! mode_is_int(mode))
 302                 return 0;
 303
 304         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 305         if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 306             (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 307                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 308                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 309                 return t;
 310         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 311                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 312                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 313                 return cmp_hi;
 314         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 315                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 316                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 317                 return cmp_lo;
 318         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 319                 if (rel_lo == ir_relation_less && rel_hi == ir_relation_greater_equal) {
 320                         /* x < c || x >= c + 1 ==> x != c */
 321                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_less_greater);
 322                         return p;
 323                 } else if (rel_lo == ir_relation_less_equal) {
 324                         if (rel_hi == ir_relation_equal) {
 325                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 326                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_equal);
 327                                 return p;
 328                         } else if (rel_hi == ir_relation_greater_equal) {
 329                                 /* x <= c || x >= c + 1 ==> true */
 330                                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 331                                 return t;
 332                         } else if (rel_hi == ir_relation_greater) {
 333                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 334                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_greater);
 335                                 return p;
 336                         }
 337                 } else if (rel_lo == ir_relation_equal && rel_hi == ir_relation_greater_equal) {
 338                         /* x == c || x >= c + 1 ==> x >= c */
 339                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_greater_equal);
 340                         return p;
 341                 }
 342         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 343                    (rel_hi == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 344                    get_mode_arithmetic(mode) == irma_twos_complement) {
 345                 /* works for two-complements only */
 346                 /* x <|<= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 347                 if (rel_lo == ir_relation_less_equal) {
 348                         /* must convert to < */
 349                         ir_mode   *mode = get_tarval_mode(tv_lo);
 350                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 351                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 352                                 /* no overflow */
 353                                 tv_lo = n;
 354                                 rel_lo = ir_relation_less;
 355                         }
 356                 }
 357                 if (rel_lo == ir_relation_less) {
 358                         /* all fine */
 359                         ir_node *const block = get_nodes_block(cmp_hi);
 360                         ir_node *      x     = get_Cmp_left(cmp_hi);
 361                         ir_mode *      mode  = get_irn_mode(x);
 362                         ir_node *sub, *cmp, *c, *subc;
 363
 364                         if (mode_is_signed(mode)) {
 365                                 /* convert to unsigned */
 366                                 mode = find_unsigned_mode(mode);
 367                                 if (mode == NULL)
 368                                         return NULL;
 369                                 x     = new_r_Conv(block, x, mode);
 370                                 tv_lo = tarval_convert_to(tv_lo, mode);
 371                                 tv_hi = tarval_convert_to(tv_hi, mode);
 372                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 373                                         return NULL;
 374                         }
 375                         c    = new_r_Const(irg, tv_lo);
 376                         sub  = new_r_Sub(block, x, c, mode);
 377                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 378                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 379                         return cmp;
 380                 }
 381         }
 382         return NULL;
 383 }
 384
 385 /**
 386  * Walker, tries to optimize Andb and Orb nodes.
 387  */
 388 static void bool_walk(ir_node *n, void *ctx)
 389 {
 390         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 391
 392         if (get_irn_mode(n) != mode_b)
 393                 return;
 394
 395         if (is_And(n)) {
 396                 ir_node *const l = get_And_left(n);
 397                 ir_node *const r = get_And_right(n);
 398                 ir_node *      replacement;
 399                 cond_pair      cpair;
 400                 if (!find_cond_pair(l, r, &cpair))
 401                         return;
 402                 replacement = bool_and(&cpair, get_nodes_block(n));
 403                 if (replacement) {
 404                         exchange(n, replacement);
 405                         env->changed = 1;
 406                 }
 407         } else if (is_Or(n)) {
 408                 ir_node *const l = get_Or_left(n);
 409                 ir_node *const r = get_Or_right(n);
 410                 ir_node *      replacement;
 411                 cond_pair      cpair;
 412                 if (!find_cond_pair(l, r, &cpair))
 413                         return;
 414                 replacement = bool_or(&cpair, get_nodes_block(n));
 415                 if (replacement) {
 416                         exchange(n, replacement);
 417                         env->changed = 1;
 418                 }
 419         }
 420 }
 421
 422 /**
 423  * Walker, clear Block marker and Phi lists.
 424  */
 425 static void clear_block_infos(ir_node *node, void *env)
 426 {
 427         (void) env;
 428
 429         /* we visit blocks before any other nodes (from the block) */
 430         if (!is_Block(node))
 431                 return;
 432
 433         /* clear the PHI list */
 434         set_Block_phis(node, NULL);
 435         set_Block_mark(node, 0);
 436 }
 437
 438 /**
 439  * Walker: collect Phi nodes and mark
 440  */
 441 static void collect_phis(ir_node *node, void *env)
 442 {
 443         (void) env;
 444
 445         if (is_Phi(node)) {
 446                 ir_node *block = get_nodes_block(node);
 447                 add_Block_phi(block, node);
 448                 return;
 449         }
 450
 451         /* Ignore control flow nodes, these will be removed. */
 452         if (get_irn_pinned(node) == op_pin_state_pinned &&
 453                         !is_Block(node) && !is_cfop(node)) {
 454                                 /* found a pinned non-cf node, mark its block */
 455                 ir_node *block = get_nodes_block(node);
 456                 set_Block_mark(block, 1);
 457         }
 458 }
 459
 460 /**
 461  * If node is a Jmp in a block containing no pinned instruction
 462  * and having only one predecessor, skip the block and return its
 463  * cf predecessor, else the node itself.
 464  */
 465 static ir_node *skip_empty_blocks(ir_node *node)
 466 {
 467         while (is_Jmp(node)) {
 468                 ir_node *block = get_nodes_block(node);
 469
 470                 if (get_Block_n_cfgpreds(block) != 1)
 471                         break;
 472
 473                 if (get_Block_mark(block))
 474                         break;
 475
 476                 node = get_Block_cfgpred(block, 0);
 477         }
 478         return node;
 479 }
 480
 481 /**
 482  * Check if two block inputs can be fused.
 483  * This can be done, if block contains no Phi node that depends on
 484  * different inputs idx_i and idx_j.
 485  */
 486 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j)
 487 {
 488         const ir_node *phi;
 489
 490         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 491                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 492                         return 0;
 493         }
 494         return 1;
 495 }
 496
 497 /**
 498  * Remove block input with given index.
 499  */
 500 static void remove_block_input(ir_node *block, int idx)
 501 {
 502         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 503         ir_node *phi, **ins;
 504
 505         NEW_ARR_A(ir_node *, ins, n);
 506
 507         if (n == 1) {
 508                 /* all Phis will be deleted */
 509                 ir_node *next_phi;
 510
 511                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 512                         next_phi = get_Phi_next(phi);
 513                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 514                 }
 515                 set_Block_phis(block, NULL);
 516         } else {
 517                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 518                         for (i = j = 0; i <= n; ++i) {
 519                                 if (i != idx)
 520                                         ins[j++] = get_Phi_pred(phi, i);
 521                         }
 522                         set_irn_in(phi, n, ins);
 523                 }
 524         }
 525         for (i = j = 0; i <= n; ++i) {
 526                 if (i != idx)
 527                         ins[j++] = get_Block_cfgpred(block, i);
 528         }
 529         set_irn_in(block, n, ins);
 530 }
 531
 532 /**
 533  * Under the preposition that we have a chain of blocks from
 534  * from_block to to_block, collapse them all into to_block.
 535  */
 536 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block)
 537 {
 538         ir_node *new_jmp = NULL;
 539         ir_node *block, *next_block;
 540
 541         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 542                 new_jmp = get_Block_cfgpred(block, 0);
 543                 next_block = get_nodes_block(new_jmp);
 544                 exchange(block, to_block);
 545         }
 546         if (new_jmp)
 547                 exchange(jmp, new_jmp);
 548 }
 549
 550 /**
 551  * Block walker:
 552  *
 553  * if we can find the following structure,
 554  *
 555  *        upper_block
 556  *         /       |
 557  *        /        |
 558  *   lower_block   |
 559  *     /  \        |
 560  *   ... low_idx up_idx
 561  *          \      |
 562  *            block
 563  *
 564  * try to convert it into a (x rel_lo c_lo) || (x rel_hi c_hi)
 565  * and optimize.
 566  */
 567 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 568 {
 569         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 570         int low_idx, up_idx;
 571         int n_cfgpreds;
 572
 573         /* because we modify the graph in regions we might not visited yet,
 574          * Id nodes might arise here. Ignore them.
 575          */
 576         if (is_Id(block))
 577                 return;
 578
 579         n_cfgpreds = get_Block_n_cfgpreds(block);
 580 restart:
 581         if (n_cfgpreds < 2)
 582                 return;
 583
 584         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 585                 ir_node      *lower_block;
 586                 ir_node      *lower_cf;
 587                 ir_node      *cond;
 588                 ir_node      *cond_selector;
 589                 ir_node      *lower_pred;
 590
 591                 lower_cf = get_Block_cfgpred(block, low_idx);
 592                 lower_cf = skip_empty_blocks(lower_cf);
 593                 if (!is_Proj(lower_cf))
 594                         continue;
 595
 596                 cond = get_Proj_pred(lower_cf);
 597                 if (!is_Cond(cond))
 598                         continue;
 599
 600                 lower_block = get_nodes_block(cond);
 601                 if (get_Block_n_cfgpreds(lower_block) != 1)
 602                         continue;
 603
 604                 /* the block must not produce any side-effects */
 605                 if (get_Block_mark(lower_block))
 606                         continue;
 607
 608                 cond_selector = get_Cond_selector(cond);
 609                 if (get_irn_mode(cond_selector) != mode_b)
 610                         continue;
 611
 612                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 613
 614                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 615                         ir_node   *upper_block;
 616                         ir_node   *upper_cf;
 617                         ir_node   *upper_cond;
 618                         ir_node   *upper_cond_selector;
 619                         ir_node   *replacement;
 620                         cond_pair  cpair;
 621
 622                         upper_cf = get_Block_cfgpred(block, up_idx);
 623                         upper_cf = skip_empty_blocks(upper_cf);
 624                         if (is_Bad(upper_cf))
 625                                 continue;
 626                         upper_block = get_nodes_block(upper_cf);
 627                         if (upper_block != lower_pred)
 628                                 continue;
 629                         if (!block_dominates(upper_block, block))
 630                                 continue;
 631
 632                         assert(is_Proj(upper_cf));
 633                         upper_cond = get_Proj_pred(upper_cf);
 634                         assert(is_Cond(upper_cond));
 635                         upper_cond_selector = get_Cond_selector(upper_cond);
 636                         if (get_irn_mode(upper_cond_selector) != mode_b)
 637                                 continue;
 638
 639                         /* we have found the structure */
 640                         /* check Phis: There must be NO Phi in block that
 641                            depends on the existence of low block */
 642                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 643                                 continue;
 644
 645                         /* all fine, try it */
 646                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 647                                 continue;
 648
 649                         /* normalize pncs: we need the true case to jump into the
 650                          * common block (ie. conjunctive normal form) */
 651                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 652                                 if (cpair.cmp_lo == cond_selector) {
 653                                         ir_node  *cmp   = cpair.cmp_lo;
 654                                         ir_node  *block = get_nodes_block(cmp);
 655                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 656                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 657                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 658                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 659                                 } else {
 660                                         ir_node  *cmp   = cpair.cmp_hi;
 661                                         ir_node  *block = get_nodes_block(cmp);
 662                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 663                                         assert(cmp == cond_selector);
 664                                         cpair.rel_hi = get_negated_relation(cpair.rel_hi);
 665                                         cpair.cmp_hi = new_rd_Cmp(dbgi, block,
 666                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 667                                 }
 668                         }
 669                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 670                                 if (cpair.cmp_lo == upper_cond_selector) {
 671                                         ir_node  *cmp   = cpair.cmp_lo;
 672                                         ir_node  *block = get_nodes_block(cmp);
 673                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 674                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 675                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 676                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 677                                 } else {
 678                                         ir_node  *cmp   = cpair.cmp_hi;
 679                                         ir_node  *block = get_nodes_block(cmp);
 680                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 681                                         assert(cmp == upper_cond_selector);
 682                                         cpair.rel_hi   = get_negated_relation(cpair.rel_hi);
 683                                         cpair.cmp_hi   = new_rd_Cmp(dbgi, block,
 684                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 685                                 }
 686                         }
 687
 688                         /* can we optimize the case? */
 689                         replacement = bool_or(&cpair, upper_block);
 690                         if (replacement == NULL)
 691                                 continue;
 692
 693                         env->changed = 1;
 694
 695                         DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
 696                                 get_irn_irg(upper_block), upper_block, lower_block));
 697
 698                         /* move all expressions on the path to lower/upper block */
 699                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 700                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 701
 702                         /* move all nodes from lower block to upper block */
 703                         exchange(lower_block, upper_block);
 704
 705                         remove_block_input(block, up_idx);
 706                         --n_cfgpreds;
 707
 708                         /* the optimizations expected the true case to jump */
 709                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 710                                 ir_node *block = get_nodes_block(replacement);
 711                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 712                         }
 713                         set_Cond_selector(cond, replacement);
 714
 715                         goto restart;
 716                 }
 717         }
 718 }
 719
 720 static ir_graph_state_t do_simplify_bool(ir_graph *const irg)
 721 {
 722         bool_opt_env_t env;
 723         ir_graph_state_t res = 0;
 724
 725         /* register a debug mask */
 726         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 727
 728         env.changed = 0;
 729
 730         /* optimize simple Andb and Orb cases */
 731         irg_walk_graph(irg, NULL, bool_walk, &env);
 732
 733         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 734
 735         /* now more complicated cases: find control flow And/Or and optimize. */
 736         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 737         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 738
 739         if (! env.changed) {
 740                 res |= IR_GRAPH_STATE_CONSISTENT_DOMINANCE;
 741         }
 742
 743         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 744
 745         return res;
 746 }
 747
 748 static optdesc_t opt_simplify_bool = {
 749         "bool-simplification",
 750         IR_GRAPH_STATE_ONE_RETURN, /* works better with one return block only */
 751         do_simplify_bool,
 752 };
 753
 754 void opt_bool(ir_graph *irg)
 755 {
 756         perform_irg_optimization(irg, &opt_simplify_bool);
 757 }
 758
 759 /* Creates an ir_graph pass for opt_bool. */
 760 ir_graph_pass_t *opt_bool_pass(const char *name)
 761 {
 762         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 763 }