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

   1 /*
   2  * This file is part of libFirm.
   3  * Copyright (C) 2012 University of Karlsruhe.
   4  */
   5
   6 /**
   7  * @file
   8  * @brief   boolean condition/control flow optimizations
   9  * @author  Matthias Braun, Christoph Mallon, Michael Beck
  10  */
  11 #include "config.h"
  12
  13 #include <assert.h>
  14 #include <string.h>
  15
  16 #include "adt/obst.h"
  17 #include "../adt/array_t.h"
  18 #include "iroptimize.h"
  19 #include "ircons.h"
  20 #include "irgmod.h"
  21 #include "irgwalk.h"
  22 #include "irprintf.h"
  23 #include "irnode_t.h"
  24 #include "tv.h"
  25 #include "irpass.h"
  26 #include "debug.h"
  27
  28 /** Describes a pair of relative conditions lo < hi, lo rel_lo x, hi rel_hi x */
  29 typedef struct cond_pair {
  30         ir_node    *cmp_lo;  /**< The lo compare node. */
  31         ir_node    *cmp_hi;  /**< The hi compare node. */
  32         ir_relation rel_lo;  /**< The lo relation node. */
  33         ir_relation rel_hi;  /**< The hi relation node. */
  34         ir_tarval  *tv_lo;   /**< The tarval of cmp_lo node. */
  35         ir_tarval  *tv_hi;   /**< The tarval of cmp_hi node. */
  36         ir_mode    *lo_mode; /**< The mode of the cmp_lo operands. */
  37 } cond_pair;
  38
  39 /** Environment for all walker in boolopt. */
  40 typedef struct {
  41         int changed;  /**< Set if the graph was changed. */
  42 } bool_opt_env_t;
  43
  44 DEBUG_ONLY(static firm_dbg_module_t *dbg;)
  45
  46 /**
  47  * Check if tho given nodes, l and r, represent two compares with
  48  * ... . If yes, return non-zero and fill the res struct.
  49  */
  50 static bool find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  51 {
  52         if (is_Cmp(l) && is_Cmp(r)) {
  53                 ir_node    *const lol   = get_Cmp_left(l);
  54                 ir_node    *const lor   = get_Cmp_right(l);
  55                 ir_node    *const rol   = get_Cmp_left(r);
  56                 ir_node    *const ror   = get_Cmp_right(r);
  57                 ir_relation const pnc_l = get_Cmp_relation(l);
  58                 ir_relation const pnc_r = get_Cmp_relation(r);
  59
  60                 if (is_Const(lor) && is_Const_null(lor) &&
  61                         is_Const(ror) && is_Const_null(ror) &&
  62                         pnc_l == pnc_r &&
  63                         (pnc_l == ir_relation_less_greater || pnc_l == ir_relation_equal)) {
  64                         /* l == (lol !=|== NULL) && r == (rol !=|== NULL) */
  65                         res->cmp_lo  = l;
  66                         res->cmp_hi  = r;
  67                         res->rel_lo  = pnc_l;
  68                         res->rel_hi  = pnc_l;
  69                         res->tv_lo   = get_Const_tarval(lor);
  70                         res->tv_hi   = get_Const_tarval(ror);
  71                         res->lo_mode = get_irn_mode(lor);
  72
  73                         return true;
  74                 }
  75
  76                 if (lol == rol && lor != ror && is_Const(lor) && is_Const(ror)) {
  77                         /* l == (x CMP c_l), r == (x cmp c_r) */
  78                         ir_tarval  *const tv_l  = get_Const_tarval(lor);
  79                         ir_tarval  *const tv_r  = get_Const_tarval(ror);
  80                         ir_relation const rel   = tarval_cmp(tv_l, tv_r);
  81
  82                         res->lo_mode = get_irn_mode(lol);
  83
  84                         if (rel == ir_relation_less) {
  85                                 /* c_l < c_r */
  86                                 res->cmp_lo  = l;
  87                                 res->cmp_hi  = r;
  88                                 res->rel_lo  = pnc_l;
  89                                 res->rel_hi  = pnc_r;
  90                                 res->tv_lo   = tv_l;
  91                                 res->tv_hi   = tv_r;
  92                         } else if (rel == ir_relation_greater) {
  93                                 /* c_l > c_r */
  94                                 res->cmp_lo  = r;
  95                                 res->cmp_hi  = l;
  96                                 res->rel_lo  = pnc_r;
  97                                 res->rel_hi  = pnc_l;
  98                                 res->tv_lo   = tv_r;
  99                                 res->tv_hi   = tv_l;
 100                         } else {
 101                                 /* The constants shall be unequal but comparable.
 102                                  * Local optimizations handle the equal case. */
 103                                 return false;
 104                         }
 105                         return true;
 106                 }
 107         }
 108         return false;
 109 }
 110
 111 /**
 112  * Handle (lo rel_lo x) AND (hi rel_hi x)
 113  */
 114 static ir_node *bool_and(cond_pair* const cpair, ir_node *dst_block)
 115 {
 116         ir_node    *const cmp_lo  = cpair->cmp_lo;
 117         ir_node    *const cmp_hi  = cpair->cmp_hi;
 118         ir_relation       rel_lo  = cpair->rel_lo;
 119         ir_relation const rel_hi  = cpair->rel_hi;
 120         ir_tarval  *      tv_lo   = cpair->tv_lo;
 121         ir_tarval  *      tv_hi   = cpair->tv_hi;
 122         ir_mode    *      mode    = cpair->lo_mode;
 123         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 124
 125         if (rel_lo == ir_relation_equal && rel_hi == rel_lo &&
 126             tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 127             mode == get_tarval_mode(tv_hi)) {
 128                 /* p == NULL && q == NULL ==> (p&q) == NULL) */
 129                 ir_node *lol, *hil, *cmp, *c, *p;
 130
 131                 if (mode_is_reference(mode)) {
 132                         mode = find_unsigned_mode(mode);
 133                         if (! mode)
 134                                 return NULL;
 135                         tv_lo = tarval_convert_to(tv_lo, mode);
 136                         if (tv_lo == tarval_bad)
 137                                 return NULL;
 138                 }
 139                 if (mode_is_int(mode)) {
 140                         lol   = get_Cmp_left(cmp_lo);
 141                         lol   = new_r_Conv(dst_block, lol, mode);
 142                         hil   = get_Cmp_left(cmp_hi);
 143                         hil   = new_r_Conv(dst_block, hil, mode);
 144                         p     = new_r_And(dst_block, lol, hil, mode);
 145                         c     = new_r_Const(irg, tv_lo);
 146                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_equal);
 147                         return cmp;
 148                 }
 149         }
 150
 151         /* the following tests expect one common operand */
 152         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 153                 return 0;
 154
 155         /* TODO: for now reject float modes */
 156         if (! mode_is_int(mode))
 157                 return 0;
 158
 159         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 160         if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 161             (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 162                 /* x <|<=|== lo && x ==|>=|> hi ==> false */
 163                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 164                 return t;
 165         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 166                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 167                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 168                 return cmp_lo;
 169         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 170                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 171                 /* x >=|>|!= lo && x ==|>=|> hi ==> x ==|>=|> hi */
 172                 return cmp_hi;
 173         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 174                 if (rel_lo == ir_relation_greater_equal && rel_hi == ir_relation_less) {
 175                         /* x >= c && x < c + 1 ==> x == c */
 176                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_equal);
 177                         return p;
 178                 } else if (rel_lo == ir_relation_greater) {
 179                         if (rel_hi == ir_relation_less_greater) {
 180                                 /* x > c && x != c + 1 ==> x > c + 1 */
 181                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_greater);
 182                                 return p;
 183                         } else if (rel_hi == ir_relation_less) {
 184                                 /* x > c && x < c + 1 ==> false */
 185                                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 186                                 return t;
 187                         } else if (rel_hi == ir_relation_less_equal) {
 188                                 /* x > c && x <= c + 1 ==> x != c + 1 */
 189                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_equal);
 190                                 return p;
 191                         }
 192                 } else if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less) {
 193                         /* x != c && c < c + 1 ==> x < c */
 194                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_less);
 195                         return p;
 196                 }
 197         } else if ((rel_lo == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 198                    (rel_hi == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 199                    get_mode_arithmetic(mode) == irma_twos_complement) {
 200                 /* works for two-complements only */
 201                 /* x >|\= lo && x <|<= hi ==> (x - lo) <u|<=u (hi-lo) */
 202                 if (rel_lo == ir_relation_greater) {
 203                         /* must convert to >= */
 204                         ir_mode   *mode = get_tarval_mode(tv_lo);
 205                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 206                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 207                                 /* no overflow */
 208                                 tv_lo = n;
 209                                 rel_lo = ir_relation_greater_equal;
 210                         }
 211                 }
 212                 if (rel_lo == ir_relation_greater_equal) {
 213                         /* all fine */
 214                         ir_node *const block = get_nodes_block(cmp_hi);
 215                         ir_node *      x     = get_Cmp_left(cmp_hi);
 216                         ir_mode *      mode  = get_irn_mode(x);
 217                         ir_node *sub, *cmp, *c, *subc;
 218
 219                         if (mode_is_signed(mode)) {
 220                                 /* convert to unsigned */
 221                                 mode = find_unsigned_mode(mode);
 222                                 if (mode == NULL)
 223                                         return NULL;
 224                                 x     = new_r_Conv(block, x, mode);
 225                                 tv_lo = tarval_convert_to(tv_lo, mode);
 226                                 tv_hi = tarval_convert_to(tv_hi, mode);
 227                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 228                                         return NULL;
 229                         }
 230                         c    = new_r_Const(irg, tv_lo);
 231                         sub  = new_r_Sub(block, x, c, mode);
 232                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 233                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 234                         return cmp;
 235                 }
 236         }
 237         return NULL;
 238 }
 239
 240 /**
 241  * Handle (lo rel_lo x) OR (hi rel_hi x)
 242  */
 243 static ir_node *bool_or(cond_pair *const cpair, ir_node *dst_block)
 244 {
 245         ir_node    *const cmp_lo  = cpair->cmp_lo;
 246         ir_node    *const cmp_hi  = cpair->cmp_hi;
 247         ir_relation       rel_lo  = cpair->rel_lo;
 248         ir_relation const rel_hi  = cpair->rel_hi;
 249         ir_tarval  *      tv_lo   = cpair->tv_lo;
 250         ir_tarval  *      tv_hi   = cpair->tv_hi;
 251         ir_mode    *      mode    = cpair->lo_mode;
 252         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 253
 254         if (rel_lo == ir_relation_less_greater && rel_hi == ir_relation_less_greater &&
 255                 tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 256                 mode == get_tarval_mode(tv_hi)) {
 257                 /* p != NULL || q != NULL ==> (p|q) != NULL) */
 258                 ir_node *lol, *hil, *cmp, *c, *p;
 259
 260                 if (mode_is_reference(mode)) {
 261                         mode = find_unsigned_mode(mode);
 262                         if (! mode)
 263                                 return NULL;
 264                         tv_lo = tarval_convert_to(tv_lo, mode);
 265                         if (tv_lo == tarval_bad)
 266                                 return NULL;
 267                 }
 268                 if (mode_is_int(mode)) {
 269                         lol   = get_Cmp_left(cmp_lo);
 270                         lol   = new_r_Conv(dst_block, lol, mode);
 271                         hil   = get_Cmp_left(cmp_hi);
 272                         hil   = new_r_Conv(dst_block, hil, mode);
 273                         p     = new_r_Or(dst_block, lol, hil, mode);
 274                         c     = new_r_Const(irg, tv_lo);
 275                         cmp   = new_r_Cmp(dst_block, p, c, ir_relation_less_greater);
 276                         return cmp;
 277                 }
 278         }
 279
 280         /* the following tests expect one common operand */
 281         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 282                 return 0;
 283
 284         /* TODO: for now reject float modes */
 285         if (! mode_is_int(mode))
 286                 return 0;
 287
 288         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 289         if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 290             (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 291                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 292                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 293                 return t;
 294         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal || rel_lo == ir_relation_equal) &&
 295                    (rel_hi == ir_relation_less || rel_hi == ir_relation_less_equal || rel_hi == ir_relation_less_greater)) {
 296                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 297                 return cmp_hi;
 298         } else if ((rel_lo == ir_relation_greater_equal || rel_lo == ir_relation_greater || rel_lo == ir_relation_less_greater) &&
 299                    (rel_hi == ir_relation_equal || rel_hi == ir_relation_greater_equal || rel_hi == ir_relation_greater)) {
 300                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 301                 return cmp_lo;
 302         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 303                 if (rel_lo == ir_relation_less && rel_hi == ir_relation_greater_equal) {
 304                         /* x < c || x >= c + 1 ==> x != c */
 305                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, ir_relation_less_greater);
 306                         return p;
 307                 } else if (rel_lo == ir_relation_less_equal) {
 308                         if (rel_hi == ir_relation_equal) {
 309                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 310                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_equal);
 311                                 return p;
 312                         } else if (rel_hi == ir_relation_greater_equal) {
 313                                 /* x <= c || x >= c + 1 ==> true */
 314                                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 315                                 return t;
 316                         } else if (rel_hi == ir_relation_greater) {
 317                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 318                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, ir_relation_less_greater);
 319                                 return p;
 320                         }
 321                 } else if (rel_lo == ir_relation_equal && rel_hi == ir_relation_greater_equal) {
 322                         /* x == c || x >= c + 1 ==> x >= c */
 323                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, ir_relation_greater_equal);
 324                         return p;
 325                 }
 326         } else if ((rel_lo == ir_relation_less || rel_lo == ir_relation_less_equal) &&
 327                    (rel_hi == ir_relation_greater || rel_lo == ir_relation_greater_equal) &&
 328                    get_mode_arithmetic(mode) == irma_twos_complement) {
 329                 /* works for two-complements only */
 330                 /* x <|<= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 331                 if (rel_lo == ir_relation_less_equal) {
 332                         /* must convert to < */
 333                         ir_mode   *mode = get_tarval_mode(tv_lo);
 334                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 335                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == ir_relation_greater) {
 336                                 /* no overflow */
 337                                 tv_lo = n;
 338                                 rel_lo = ir_relation_less;
 339                         }
 340                 }
 341                 if (rel_lo == ir_relation_less) {
 342                         /* all fine */
 343                         ir_node *const block = get_nodes_block(cmp_hi);
 344                         ir_node *      x     = get_Cmp_left(cmp_hi);
 345                         ir_mode *      mode  = get_irn_mode(x);
 346                         ir_node *sub, *cmp, *c, *subc;
 347
 348                         if (mode_is_signed(mode)) {
 349                                 /* convert to unsigned */
 350                                 mode = find_unsigned_mode(mode);
 351                                 if (mode == NULL)
 352                                         return NULL;
 353                                 x     = new_r_Conv(block, x, mode);
 354                                 tv_lo = tarval_convert_to(tv_lo, mode);
 355                                 tv_hi = tarval_convert_to(tv_hi, mode);
 356                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 357                                         return NULL;
 358                         }
 359                         c    = new_r_Const(irg, tv_lo);
 360                         sub  = new_r_Sub(block, x, c, mode);
 361                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 362                         cmp  = new_r_Cmp(block, sub, subc, rel_hi);
 363                         return cmp;
 364                 }
 365         }
 366         return NULL;
 367 }
 368
 369 /**
 370  * Walker, tries to optimize Andb and Orb nodes.
 371  */
 372 static void bool_walk(ir_node *n, void *ctx)
 373 {
 374         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 375
 376         if (get_irn_mode(n) != mode_b)
 377                 return;
 378
 379         if (is_And(n)) {
 380                 ir_node *const l = get_And_left(n);
 381                 ir_node *const r = get_And_right(n);
 382                 ir_node *      replacement;
 383                 cond_pair      cpair;
 384                 if (!find_cond_pair(l, r, &cpair))
 385                         return;
 386                 replacement = bool_and(&cpair, get_nodes_block(n));
 387                 if (replacement) {
 388                         exchange(n, replacement);
 389                         env->changed = 1;
 390                 }
 391         } else if (is_Or(n)) {
 392                 ir_node *const l = get_Or_left(n);
 393                 ir_node *const r = get_Or_right(n);
 394                 ir_node *      replacement;
 395                 cond_pair      cpair;
 396                 if (!find_cond_pair(l, r, &cpair))
 397                         return;
 398                 replacement = bool_or(&cpair, get_nodes_block(n));
 399                 if (replacement) {
 400                         exchange(n, replacement);
 401                         env->changed = 1;
 402                 }
 403         }
 404 }
 405
 406 /**
 407  * Walker, clear Block marker and Phi lists.
 408  */
 409 static void clear_block_infos(ir_node *node, void *env)
 410 {
 411         (void) env;
 412
 413         /* we visit blocks before any other nodes (from the block) */
 414         if (!is_Block(node))
 415                 return;
 416
 417         /* clear the PHI list */
 418         set_Block_phis(node, NULL);
 419         set_Block_mark(node, 0);
 420 }
 421
 422 /**
 423  * Walker: collect Phi nodes and mark
 424  */
 425 static void collect_phis(ir_node *node, void *env)
 426 {
 427         (void) env;
 428
 429         if (is_Phi(node)) {
 430                 ir_node *block = get_nodes_block(node);
 431                 add_Block_phi(block, node);
 432                 return;
 433         }
 434
 435         /* Ignore control flow nodes, these will be removed. */
 436         if (get_irn_pinned(node) == op_pin_state_pinned &&
 437                         !is_Block(node) && !is_cfop(node)) {
 438                                 /* found a pinned non-cf node, mark its block */
 439                 ir_node *block = get_nodes_block(node);
 440                 set_Block_mark(block, 1);
 441         }
 442 }
 443
 444 /**
 445  * If node is a Jmp in a block containing no pinned instruction
 446  * and having only one predecessor, skip the block and return its
 447  * cf predecessor, else the node itself.
 448  */
 449 static ir_node *skip_empty_blocks(ir_node *node)
 450 {
 451         while (is_Jmp(node)) {
 452                 ir_node *block = get_nodes_block(node);
 453
 454                 if (get_Block_n_cfgpreds(block) != 1)
 455                         break;
 456
 457                 if (get_Block_mark(block))
 458                         break;
 459
 460                 node = get_Block_cfgpred(block, 0);
 461         }
 462         return node;
 463 }
 464
 465 /**
 466  * Check if two block inputs can be fused.
 467  * This can be done, if block contains no Phi node that depends on
 468  * different inputs idx_i and idx_j.
 469  */
 470 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j)
 471 {
 472         const ir_node *phi;
 473
 474         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 475                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 476                         return 0;
 477         }
 478         return 1;
 479 }
 480
 481 /**
 482  * Remove block input with given index.
 483  */
 484 static void remove_block_input(ir_node *block, int idx)
 485 {
 486         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 487         ir_node *phi, **ins;
 488
 489         NEW_ARR_A(ir_node *, ins, n);
 490
 491         if (n == 1) {
 492                 /* all Phis will be deleted */
 493                 ir_node *next_phi;
 494
 495                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 496                         next_phi = get_Phi_next(phi);
 497                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 498                 }
 499                 set_Block_phis(block, NULL);
 500         } else {
 501                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 502                         for (i = j = 0; i <= n; ++i) {
 503                                 if (i != idx)
 504                                         ins[j++] = get_Phi_pred(phi, i);
 505                         }
 506                         set_irn_in(phi, n, ins);
 507                 }
 508         }
 509         for (i = j = 0; i <= n; ++i) {
 510                 if (i != idx)
 511                         ins[j++] = get_Block_cfgpred(block, i);
 512         }
 513         set_irn_in(block, n, ins);
 514 }
 515
 516 /**
 517  * Under the preposition that we have a chain of blocks from
 518  * from_block to to_block, collapse them all into to_block.
 519  */
 520 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block)
 521 {
 522         ir_node *new_jmp = NULL;
 523         ir_node *block, *next_block;
 524
 525         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 526                 new_jmp = get_Block_cfgpred(block, 0);
 527                 next_block = get_nodes_block(new_jmp);
 528                 exchange(block, to_block);
 529         }
 530         if (new_jmp)
 531                 exchange(jmp, new_jmp);
 532 }
 533
 534 /**
 535  * Block walker:
 536  *
 537  * if we can find the following structure,
 538  *
 539  *        upper_block
 540  *         /       |
 541  *        /        |
 542  *   lower_block   |
 543  *     /  \        |
 544  *   ... low_idx up_idx
 545  *          \      |
 546  *            block
 547  *
 548  * try to convert it into a (x rel_lo c_lo) || (x rel_hi c_hi)
 549  * and optimize.
 550  */
 551 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 552 {
 553         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 554         int low_idx, up_idx;
 555         int n_cfgpreds;
 556
 557         /* because we modify the graph in regions we might not visited yet,
 558          * Id nodes might arise here. Ignore them.
 559          */
 560         if (is_Id(block))
 561                 return;
 562
 563         n_cfgpreds = get_Block_n_cfgpreds(block);
 564 restart:
 565         if (n_cfgpreds < 2)
 566                 return;
 567
 568         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 569                 ir_node      *lower_block;
 570                 ir_node      *lower_cf;
 571                 ir_node      *cond;
 572
 573                 lower_cf = get_Block_cfgpred(block, low_idx);
 574                 lower_cf = skip_empty_blocks(lower_cf);
 575                 if (!is_Proj(lower_cf))
 576                         continue;
 577
 578                 cond = get_Proj_pred(lower_cf);
 579                 if (!is_Cond(cond))
 580                         continue;
 581
 582                 lower_block = get_nodes_block(cond);
 583                 if (get_Block_n_cfgpreds(lower_block) != 1)
 584                         continue;
 585
 586                 /* the block must not produce any side-effects */
 587                 if (get_Block_mark(lower_block))
 588                         continue;
 589
 590                 ir_node *const cond_selector = get_Cond_selector(cond);
 591                 ir_node *const lower_pred    = get_Block_cfgpred_block(lower_block, 0);
 592                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 593                         ir_node   *upper_block;
 594                         ir_node   *upper_cf;
 595                         ir_node   *replacement;
 596                         cond_pair  cpair;
 597
 598                         upper_cf = get_Block_cfgpred(block, up_idx);
 599                         upper_cf = skip_empty_blocks(upper_cf);
 600                         if (is_Bad(upper_cf))
 601                                 continue;
 602                         upper_block = get_nodes_block(upper_cf);
 603                         if (upper_block != lower_pred)
 604                                 continue;
 605                         if (!block_dominates(upper_block, block))
 606                                 continue;
 607
 608                         /* we have found the structure */
 609                         /* check Phis: There must be NO Phi in block that
 610                            depends on the existence of low block */
 611                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 612                                 continue;
 613
 614                         /* all fine, try it */
 615                         ir_node *const upper_cond          = get_Proj_pred(upper_cf);
 616                         ir_node *const upper_cond_selector = get_Cond_selector(upper_cond);
 617                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 618                                 continue;
 619
 620                         /* normalize pncs: we need the true case to jump into the
 621                          * common block (i.e. conjunctive normal form) */
 622                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 623                                 if (cpair.cmp_lo == cond_selector) {
 624                                         ir_node  *cmp   = cpair.cmp_lo;
 625                                         ir_node  *block = get_nodes_block(cmp);
 626                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 627                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 628                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 629                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 630                                 } else {
 631                                         ir_node  *cmp   = cpair.cmp_hi;
 632                                         ir_node  *block = get_nodes_block(cmp);
 633                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 634                                         assert(cmp == cond_selector);
 635                                         cpair.rel_hi = get_negated_relation(cpair.rel_hi);
 636                                         cpair.cmp_hi = new_rd_Cmp(dbgi, block,
 637                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 638                                 }
 639                         }
 640                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 641                                 if (cpair.cmp_lo == upper_cond_selector) {
 642                                         ir_node  *cmp   = cpair.cmp_lo;
 643                                         ir_node  *block = get_nodes_block(cmp);
 644                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 645                                         cpair.rel_lo    = get_negated_relation(cpair.rel_lo);
 646                                         cpair.cmp_lo    = new_rd_Cmp(dbgi, block,
 647                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_lo);
 648                                 } else {
 649                                         ir_node  *cmp   = cpair.cmp_hi;
 650                                         ir_node  *block = get_nodes_block(cmp);
 651                                         dbg_info *dbgi  = get_irn_dbg_info(cmp);
 652                                         assert(cmp == upper_cond_selector);
 653                                         cpair.rel_hi   = get_negated_relation(cpair.rel_hi);
 654                                         cpair.cmp_hi   = new_rd_Cmp(dbgi, block,
 655                                                         get_Cmp_left(cmp), get_Cmp_right(cmp), cpair.rel_hi);
 656                                 }
 657                         }
 658
 659                         /* can we optimize the case? */
 660                         replacement = bool_or(&cpair, upper_block);
 661                         if (replacement == NULL)
 662                                 continue;
 663
 664                         env->changed = 1;
 665
 666                         DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
 667                                 get_irn_irg(upper_block), upper_block, lower_block));
 668
 669                         /* move all expressions on the path to lower/upper block */
 670                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 671                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 672
 673                         /* move all nodes from lower block to upper block */
 674                         exchange(lower_block, upper_block);
 675
 676                         remove_block_input(block, up_idx);
 677                         --n_cfgpreds;
 678
 679                         /* the optimizations expected the true case to jump */
 680                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 681                                 ir_node *block = get_nodes_block(replacement);
 682                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 683                         }
 684                         set_Cond_selector(cond, replacement);
 685
 686                         goto restart;
 687                 }
 688         }
 689 }
 690
 691 void opt_bool(ir_graph *const irg)
 692 {
 693         bool_opt_env_t env;
 694
 695         /* register a debug mask */
 696         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 697
 698         env.changed = 0;
 699
 700         /* optimize simple Andb and Orb cases */
 701         irg_walk_graph(irg, NULL, bool_walk, &env);
 702
 703         /* now more complicated cases: find control flow And/Or and optimize. */
 704         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 705         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 706         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 707         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 708
 709         confirm_irg_properties(irg,
 710                 env.changed ? IR_GRAPH_PROPERTIES_NONE : IR_GRAPH_PROPERTIES_ALL);
 711 }
 712
 713 /* Creates an ir_graph pass for opt_bool. */
 714 ir_graph_pass_t *opt_bool_pass(const char *name)
 715 {
 716         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 717 }