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

   1 /*
   2  * Copyright (C) 1995-2008 University of Karlsruhe.  All right reserved.
   3  *
   4  * This file is part of libFirm.
   5  *
   6  * This file may be distributed and/or modified under the terms of the
   7  * GNU General Public License version 2 as published by the Free Software
   8  * Foundation and appearing in the file LICENSE.GPL included in the
   9  * packaging of this file.
  10  *
  11  * Licensees holding valid libFirm Professional Edition licenses may use
  12  * this file in accordance with the libFirm Commercial License.
  13  * Agreement provided with the Software.
  14  *
  15  * This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
  16  * WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  17  * PURPOSE.
  18  */
  19
  20 /**
  21  * @file
  22  * @brief   boolean condition/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
  43 /** Describes a pair of relative conditions lo < hi, lo pnc_lo x, hi pnc_hi x */
  44 typedef struct cond_pair {
  45         ir_node   *cmp_lo;  /**< The lo compare node. */
  46         ir_node   *cmp_hi;  /**< The hi compare node. */
  47         pn_Cmp     pnc_lo;  /**< The lo relation node. */
  48         pn_Cmp     pnc_hi;  /**< The hi relation node. */
  49         ir_node   *proj_lo; /**< The mode_b result proj of cmp_lo. */
  50         ir_node   *proj_hi; /**< The mode_b result proj of cmp_hi. */
  51         ir_tarval *tv_lo;   /**< The tarval of cmp_lo node. */
  52         ir_tarval *tv_hi;   /**< The tarval of cmp_hi node. */
  53         ir_mode   *lo_mode; /**< The mode of the cmp_lo operands. */
  54 } cond_pair;
  55
  56 /** Environment for all walker in boolopt. */
  57 typedef struct {
  58         int changed;  /**< Set if the graph was changed. */
  59 } bool_opt_env_t;
  60
  61 DEBUG_ONLY(static firm_dbg_module_t *dbg);
  62
  63 /**
  64  * Check if tho given nodes, l and r, represent two compares with
  65  * ... . If yes, return non-zero and fill the res struct.
  66  */
  67 static int find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  68 {
  69         if (is_Proj(l) && is_Proj(r)) {
  70                 ir_node *const lo = get_Proj_pred(l);
  71                 ir_node *const ro = get_Proj_pred(r);
  72
  73                 if (is_Cmp(lo) && is_Cmp(ro)) {
  74                         ir_node *const lol   = get_Cmp_left(lo);
  75                         ir_node *const lor   = get_Cmp_right(lo);
  76                         ir_node *const rol   = get_Cmp_left(ro);
  77                         ir_node *const ror   = get_Cmp_right(ro);
  78                         pn_Cmp   const pnc_l = get_Proj_pn_cmp(l);
  79                         pn_Cmp   const pnc_r = get_Proj_pn_cmp(r);
  80
  81                         if (is_Const(lor) && is_Const_null(lor) &&
  82                             is_Const(ror) && is_Const_null(ror) &&
  83                             pnc_l == pnc_r &&
  84                             (pnc_l == pn_Cmp_Lg || pnc_l == pn_Cmp_Eq)) {
  85                                 /* lo == (lol !=|== NULL) && ro == (rol !=|== NULL) */
  86                                 res->cmp_lo  = lo;
  87                                 res->cmp_hi  = ro;
  88                                 res->pnc_lo  = pnc_l;
  89                                 res->pnc_hi  = pnc_l;
  90                                 res->proj_lo = l;
  91                                 res->proj_hi = r;
  92                                 res->tv_lo   = get_Const_tarval(lor);
  93                                 res->tv_hi   = get_Const_tarval(ror);
  94                                 res->lo_mode = get_irn_mode(lor);
  95
  96                                 return 1;
  97                         }
  98
  99                         if (lol == rol && lor != ror && is_Const(lor) && is_Const(ror)) {
 100                                 /* lo == (x CMP c_l), ro == (x cmp c_r) */
 101                                 ir_tarval *const tv_l  = get_Const_tarval(lor);
 102                                 ir_tarval *const tv_r  = get_Const_tarval(ror);
 103                                 pn_Cmp     const rel   = tarval_cmp(tv_l, tv_r);
 104
 105                                 res->lo_mode = get_irn_mode(lol);
 106
 107                                 if (rel == pn_Cmp_Lt) {
 108                                         /* c_l < c_r */
 109                                         res->cmp_lo  = lo;
 110                                         res->cmp_hi  = ro;
 111                                         res->pnc_lo  = pnc_l;
 112                                         res->pnc_hi  = pnc_r;
 113                                         res->proj_lo = l;
 114                                         res->proj_hi = r;
 115                                         res->tv_lo   = tv_l;
 116                                         res->tv_hi   = tv_r;
 117                                 } else if (rel == pn_Cmp_Gt) {
 118                                         /* c_l > c_r */
 119                                         res->cmp_lo  = ro;
 120                                         res->cmp_hi  = lo;
 121                                         res->pnc_lo  = pnc_r;
 122                                         res->pnc_hi  = pnc_l;
 123                                         res->proj_lo = r;
 124                                         res->proj_hi = l;
 125                                         res->tv_lo   = tv_r;
 126                                         res->tv_hi   = tv_l;
 127                                 } else {
 128                                         /* The constants shall be unequal but comparable.
 129                                          * Local optimizations handle the equal case. */
 130                                         return 0;
 131                                 }
 132                                 return 1;
 133                         }
 134                 }
 135         }
 136         return 0;
 137 }
 138
 139 /**
 140  * Handle (lo pnc_lo x) AND (hi pnc_hi x)
 141  */
 142 static ir_node *bool_and(cond_pair* const cpair, ir_node *dst_block)
 143 {
 144         ir_node    *const cmp_lo  = cpair->cmp_lo;
 145         ir_node    *const cmp_hi  = cpair->cmp_hi;
 146         pn_Cmp            pnc_lo  = cpair->pnc_lo;
 147         pn_Cmp      const pnc_hi  = cpair->pnc_hi;
 148         ir_node    *const proj_lo = cpair->proj_lo;
 149         ir_node    *const proj_hi = cpair->proj_hi;
 150         ir_tarval  *      tv_lo   = cpair->tv_lo;
 151         ir_tarval  *      tv_hi   = cpair->tv_hi;
 152         ir_mode    *      mode    = cpair->lo_mode;
 153         ir_graph   *      irg     = get_irn_irg(cmp_lo);
 154
 155         if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Eq &&
 156             tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 157             mode == get_tarval_mode(tv_hi)) {
 158                 /* p == NULL && q == NULL ==> (p&q) == NULL) */
 159                 ir_node *lol, *hil, *cmp, *c, *p;
 160
 161                 if (mode_is_reference(mode)) {
 162                         mode = find_unsigned_mode(mode);
 163                         if (! mode)
 164                                 return NULL;
 165                         tv_lo = tarval_convert_to(tv_lo, mode);
 166                         if (tv_lo == tarval_bad)
 167                                 return NULL;
 168                 }
 169                 if (mode_is_int(mode)) {
 170                         lol   = get_Cmp_left(cmp_lo);
 171                         lol   = new_r_Conv(dst_block, lol, mode);
 172                         hil   = get_Cmp_left(cmp_hi);
 173                         hil   = new_r_Conv(dst_block, hil, mode);
 174                         p     = new_r_And(dst_block, lol, hil, mode);
 175                         c     = new_r_Const(irg, tv_lo);
 176                         cmp   = new_r_Cmp(dst_block, p, c);
 177                         p     = new_r_Proj(cmp, mode_b, pn_Cmp_Eq);
 178                         return p;
 179                 }
 180         }
 181
 182         /* the following tests expect one common operand */
 183         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 184                 return 0;
 185
 186         /* TODO: for now reject float modes */
 187         if (! mode_is_int(mode))
 188                 return 0;
 189
 190         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 191         if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 192             (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 193                 /* x <|<=|== lo && x ==|>=|> hi ==> false */
 194                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 195                 return t;
 196         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 197                    (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 198                 /* x <|<=|== lo && x <|<=|!= hi ==> x <|<=|== lo */
 199                 return proj_lo;
 200         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 201                    (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 202                 /* x >=|>|!= lo && x ==|>=|> hi ==> x ==|>=|> hi */
 203                 return proj_hi;
 204         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 205                 if (pnc_lo == pn_Cmp_Ge && pnc_hi == pn_Cmp_Lt) {
 206                         /* x >= c && x < c + 1 ==> x == c */
 207                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, pn_Cmp_Eq);
 208                         return p;
 209                 } else if (pnc_lo == pn_Cmp_Gt) {
 210                         if (pnc_hi == pn_Cmp_Lg) {
 211                                 /* x > c && x != c + 1 ==> x > c + 1 */
 212                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, pn_Cmp_Gt);
 213                                 return p;
 214                         } else if (pnc_hi == pn_Cmp_Lt) {
 215                                 /* x > c && x < c + 1 ==> false */
 216                                 ir_node *const t = new_r_Const(irg, tarval_b_false);
 217                                 return t;
 218                         } else if (pnc_hi == pn_Cmp_Le) {
 219                                 /* x > c && x <= c + 1 ==> x != c + 1 */
 220                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, pn_Cmp_Eq);
 221                                 return p;
 222                         }
 223                 } else if (pnc_lo == pn_Cmp_Lg && pnc_hi == pn_Cmp_Lt) {
 224                         /* x != c && c < c + 1 ==> x < c */
 225                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, pn_Cmp_Lt);
 226                         return p;
 227                 }
 228         } else if ((pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ge) &&
 229                    (pnc_hi == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le) &&
 230                    get_mode_arithmetic(mode) == irma_twos_complement) {
 231                 /* works for two-complements only */
 232                 /* x >|\= lo && x <|<= hi ==> (x - lo) <u|<=u (hi-lo) */
 233                 if (pnc_lo == pn_Cmp_Gt) {
 234                         /* must convert to >= */
 235                         ir_mode   *mode = get_tarval_mode(tv_lo);
 236                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 237                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == pn_Cmp_Gt) {
 238                                 /* no overflow */
 239                                 tv_lo = n;
 240                                 pnc_lo = pn_Cmp_Ge;
 241                         }
 242                 }
 243                 if (pnc_lo == pn_Cmp_Ge) {
 244                         /* all fine */
 245                         ir_node *const block = get_nodes_block(cmp_hi);
 246                         ir_node *      x     = get_Cmp_left(cmp_hi);
 247                         ir_mode *      mode  = get_irn_mode(x);
 248                         ir_node *sub, *cmp, *c, *subc, *p;
 249
 250                         if (mode_is_signed(mode)) {
 251                                 /* convert to unsigned */
 252                                 mode = find_unsigned_mode(mode);
 253                                 if (mode == NULL)
 254                                         return NULL;
 255                                 x     = new_r_Conv(block, x, mode);
 256                                 tv_lo = tarval_convert_to(tv_lo, mode);
 257                                 tv_hi = tarval_convert_to(tv_hi, mode);
 258                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 259                                         return NULL;
 260                         }
 261                         c    = new_r_Const(irg, tv_lo);
 262                         sub  = new_r_Sub(block, x, c, mode);
 263                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 264                         cmp  = new_r_Cmp(block, sub, subc);
 265                         p    = new_r_Proj(cmp, mode_b, pnc_hi);
 266                         return p;
 267                 }
 268         }
 269         return NULL;
 270 }
 271
 272 /**
 273  * Handle (lo pnc_lo x) OR (hi pnc_hi x)
 274  */
 275 static ir_node *bool_or(cond_pair *const cpair, ir_node *dst_block)
 276 {
 277         ir_node   *const cmp_lo  = cpair->cmp_lo;
 278         ir_node   *const cmp_hi  = cpair->cmp_hi;
 279         pn_Cmp           pnc_lo  = cpair->pnc_lo;
 280         pn_Cmp     const pnc_hi  = cpair->pnc_hi;
 281         ir_node   *const proj_lo = cpair->proj_lo;
 282         ir_node   *const proj_hi = cpair->proj_hi;
 283         ir_tarval *      tv_lo   = cpair->tv_lo;
 284         ir_tarval *      tv_hi   = cpair->tv_hi;
 285         ir_mode   *      mode    = cpair->lo_mode;
 286         ir_graph  *      irg     = get_irn_irg(cmp_lo);
 287
 288         if (pnc_lo == pn_Cmp_Lg && pnc_hi == pn_Cmp_Lg &&
 289                 tarval_is_null(tv_lo) && tarval_is_null(tv_hi) &&
 290                 mode == get_tarval_mode(tv_hi)) {
 291                 /* p != NULL || q != NULL ==> (p|q) != NULL) */
 292                 ir_node *lol, *hil, *cmp, *c, *p;
 293
 294                 if (mode_is_reference(mode)) {
 295                         mode = find_unsigned_mode(mode);
 296                         if (! mode)
 297                                 return NULL;
 298                         tv_lo = tarval_convert_to(tv_lo, mode);
 299                         if (tv_lo == tarval_bad)
 300                                 return NULL;
 301                 }
 302                 if (mode_is_int(mode)) {
 303                         lol   = get_Cmp_left(cmp_lo);
 304                         lol   = new_r_Conv(dst_block, lol, mode);
 305                         hil   = get_Cmp_left(cmp_hi);
 306                         hil   = new_r_Conv(dst_block, hil, mode);
 307                         p     = new_r_Or(dst_block, lol, hil, mode);
 308                         c     = new_r_Const(irg, tv_lo);
 309                         cmp   = new_r_Cmp(dst_block, p, c);
 310                         p     = new_r_Proj(cmp, mode_b, pn_Cmp_Lg);
 311                         return p;
 312                 }
 313         }
 314
 315         /* the following tests expect one common operand */
 316         if (get_Cmp_left(cmp_lo) !=  get_Cmp_left(cmp_hi))
 317                 return 0;
 318
 319         /* TODO: for now reject float modes */
 320         if (! mode_is_int(mode))
 321                 return 0;
 322
 323         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 324         if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 325             (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 326                 /* x >=|>|!= lo | x <|<=|!= hi ==> true */
 327                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 328                 return t;
 329         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 330                    (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 331                 /* x <|<=|== lo || x <|<=|!= hi ==> x <|<=|!= hi */
 332                 return proj_hi;
 333         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 334                    (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 335                 /* x >=|>|!= lo || x ==|>=|> hi ==> x >=|>|!= lo */
 336                 return proj_lo;
 337         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 338                 if (pnc_lo == pn_Cmp_Lt && pnc_hi == pn_Cmp_Ge) {
 339                         /* x < c || x >= c + 1 ==> x != c */
 340                         ir_node  *const p = new_r_Proj(cmp_lo, mode_b, pn_Cmp_Lg);
 341                         return p;
 342                 } else if (pnc_lo == pn_Cmp_Le) {
 343                         if (pnc_hi == pn_Cmp_Eq) {
 344                                 /* x <= c || x == c + 1 ==> x <= c + 1 */
 345                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, pn_Cmp_Le);
 346                                 return p;
 347                         } else if (pnc_hi == pn_Cmp_Ge) {
 348                                 /* x <= c || x >= c + 1 ==> true */
 349                                 ir_node *const t = new_r_Const(irg, tarval_b_true);
 350                                 return t;
 351                         } else if (pnc_hi == pn_Cmp_Gt) {
 352                                 /* x <= c || x > c + 1 ==> x != c + 1 */
 353                                 ir_node  *const p = new_r_Proj(cmp_hi, mode_b, pn_Cmp_Lg);
 354                                 return p;
 355                         }
 356                 } else if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Ge) {
 357                         /* x == c || x >= c + 1 ==> x >= c */
 358                         ir_node  *const p     = new_r_Proj(cmp_lo, mode_b, pn_Cmp_Ge);
 359                         return p;
 360                 }
 361         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le) &&
 362                    (pnc_hi == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ge) &&
 363                    get_mode_arithmetic(mode) == irma_twos_complement) {
 364                 /* works for two-complements only */
 365                 /* x <|<= lo  || x >|>= hi ==> (x - lo) >u|>=u (hi-lo) */
 366                 if (pnc_lo == pn_Cmp_Le) {
 367                         /* must convert to < */
 368                         ir_mode   *mode = get_tarval_mode(tv_lo);
 369                         ir_tarval *n    = tarval_add(tv_lo, get_mode_one(mode));
 370                         if (n != tarval_bad && tarval_cmp(n, tv_lo) == pn_Cmp_Gt) {
 371                                 /* no overflow */
 372                                 tv_lo = n;
 373                                 pnc_lo = pn_Cmp_Lt;
 374                         }
 375                 }
 376                 if (pnc_lo == pn_Cmp_Lt) {
 377                         /* all fine */
 378                         ir_node *const block = get_nodes_block(cmp_hi);
 379                         ir_node *      x     = get_Cmp_left(cmp_hi);
 380                         ir_mode *      mode  = get_irn_mode(x);
 381                         ir_node *sub, *cmp, *c, *subc, *p;
 382
 383                         if (mode_is_signed(mode)) {
 384                                 /* convert to unsigned */
 385                                 mode = find_unsigned_mode(mode);
 386                                 if (mode == NULL)
 387                                         return NULL;
 388                                 x     = new_r_Conv(block, x, mode);
 389                                 tv_lo = tarval_convert_to(tv_lo, mode);
 390                                 tv_hi = tarval_convert_to(tv_hi, mode);
 391                                 if (tv_lo == tarval_bad || tv_hi == tarval_bad)
 392                                         return NULL;
 393                         }
 394                         c    = new_r_Const(irg, tv_lo);
 395                         sub  = new_r_Sub(block, x, c, mode);
 396                         subc = new_r_Sub(block, new_r_Const(irg, tv_hi), c, mode);
 397                         cmp  = new_r_Cmp(block, sub, subc);
 398                         p    = new_r_Proj(cmp, mode_b, pnc_hi);
 399                         return p;
 400                 }
 401         }
 402         return NULL;
 403 }
 404
 405 /**
 406  * Walker, tries to optimize Andb and Orb nodes.
 407  */
 408 static void bool_walk(ir_node *n, void *ctx)
 409 {
 410         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 411
 412         if (get_irn_mode(n) != mode_b)
 413                 return;
 414
 415         if (is_And(n)) {
 416                 ir_node *const l = get_And_left(n);
 417                 ir_node *const r = get_And_right(n);
 418                 ir_node *      replacement;
 419                 cond_pair      cpair;
 420                 if (!find_cond_pair(l, r, &cpair))
 421                         return;
 422                 replacement = bool_and(&cpair, get_nodes_block(n));
 423                 if (replacement) {
 424                         exchange(n, replacement);
 425                         env->changed = 1;
 426                 }
 427         } else if (is_Or(n)) {
 428                 ir_node *const l = get_Or_left(n);
 429                 ir_node *const r = get_Or_right(n);
 430                 ir_node *      replacement;
 431                 cond_pair      cpair;
 432                 if (!find_cond_pair(l, r, &cpair))
 433                         return;
 434                 replacement = bool_or(&cpair, get_nodes_block(n));
 435                 if (replacement) {
 436                         exchange(n, replacement);
 437                         env->changed = 1;
 438                 }
 439         }
 440 }
 441
 442 /**
 443  * Walker, clear Block marker and Phi lists.
 444  */
 445 static void clear_block_infos(ir_node *node, void *env)
 446 {
 447         (void) env;
 448
 449         /* we visit blocks before any other nodes (from the block) */
 450         if (!is_Block(node))
 451                 return;
 452
 453         /* clear the PHI list */
 454         set_Block_phis(node, NULL);
 455         set_Block_mark(node, 0);
 456 }
 457
 458 /**
 459  * Walker: collect Phi nodes and mark
 460  */
 461 static void collect_phis(ir_node *node, void *env)
 462 {
 463         (void) env;
 464
 465         if (is_Phi(node)) {
 466                 ir_node *block = get_nodes_block(node);
 467                 add_Block_phi(block, node);
 468                 return;
 469         }
 470
 471         /* Ignore control flow nodes, these will be removed. */
 472         if (get_irn_pinned(node) == op_pin_state_pinned &&
 473                         !is_Block(node) && !is_cfop(node)) {
 474                                 /* found a pinned non-cf node, mark its block */
 475                 ir_node *block = get_nodes_block(node);
 476                 set_Block_mark(block, 1);
 477         }
 478 }
 479
 480 /**
 481  * If node is a Jmp in a block containing no pinned instruction
 482  * and having only one predecessor, skip the block and return its
 483  * cf predecessor, else the node itself.
 484  */
 485 static ir_node *skip_empty_blocks(ir_node *node)
 486 {
 487         while (is_Jmp(node)) {
 488                 ir_node *block = get_nodes_block(node);
 489
 490                 if (get_Block_n_cfgpreds(block) != 1)
 491                         break;
 492
 493                 if (get_Block_mark(block))
 494                         break;
 495
 496                 node = get_Block_cfgpred(block, 0);
 497         }
 498         return node;
 499 }
 500
 501 /**
 502  * Check if two block inputs can be fused.
 503  * This can be done, if block contains no Phi node that depends on
 504  * different inputs idx_i and idx_j.
 505  */
 506 static int can_fuse_block_inputs(const ir_node *block, int idx_i, int idx_j)
 507 {
 508         const ir_node *phi;
 509
 510         for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 511                 if (get_Phi_pred(phi, idx_i) != get_Phi_pred(phi, idx_j))
 512                         return 0;
 513         }
 514         return 1;
 515 }
 516
 517 /**
 518  * Remove block input with given index.
 519  */
 520 static void remove_block_input(ir_node *block, int idx)
 521 {
 522         int i, j, n = get_Block_n_cfgpreds(block) - 1;
 523         ir_node *phi, **ins;
 524
 525         NEW_ARR_A(ir_node *, ins, n);
 526
 527         if (n == 1) {
 528                 /* all Phis will be deleted */
 529                 ir_node *next_phi;
 530
 531                 for (phi = get_Block_phis(block); phi != NULL; phi = next_phi) {
 532                         next_phi = get_Phi_next(phi);
 533                         exchange(phi, get_Phi_pred(phi, idx ^ 1));
 534                 }
 535                 set_Block_phis(block, NULL);
 536         } else {
 537                 for (phi = get_Block_phis(block); phi != NULL; phi = get_Phi_next(phi)) {
 538                         for (i = j = 0; i <= n; ++i) {
 539                                 if (i != idx)
 540                                         ins[j++] = get_Phi_pred(phi, i);
 541                         }
 542                         set_irn_in(phi, n, ins);
 543                 }
 544         }
 545         for (i = j = 0; i <= n; ++i) {
 546                 if (i != idx)
 547                         ins[j++] = get_Block_cfgpred(block, i);
 548         }
 549         set_irn_in(block, n, ins);
 550 }
 551
 552 /**
 553  * Under the preposition that we have a chain of blocks from
 554  * from_block to to_block, collapse them all into to_block.
 555  */
 556 static void move_nodes_to_block(ir_node *jmp, ir_node *to_block)
 557 {
 558         ir_node *new_jmp = NULL;
 559         ir_node *block, *next_block;
 560
 561         for (block = get_nodes_block(jmp); block != to_block; block = next_block) {
 562                 new_jmp = get_Block_cfgpred(block, 0);
 563                 next_block = get_nodes_block(new_jmp);
 564                 exchange(block, to_block);
 565         }
 566         if (new_jmp)
 567                 exchange(jmp, new_jmp);
 568 }
 569
 570 /**
 571  * Block walker:
 572  *
 573  * if we can find the following structure,
 574  *
 575  *        upper_block
 576  *         /       |
 577  *        /        |
 578  *   lower_block   |
 579  *     /  \        |
 580  *   ... low_idx up_idx
 581  *          \      |
 582  *            block
 583  *
 584  * try to convert it into a (x pnc_lo c_lo) || (x pnc_hi c_hi)
 585  * and optimize.
 586  */
 587 static void find_cf_and_or_walker(ir_node *block, void *ctx)
 588 {
 589         bool_opt_env_t *env = (bool_opt_env_t*)ctx;
 590         int low_idx, up_idx;
 591         int n_cfgpreds;
 592
 593         /* because we modify the graph in regions we might not visited yet,
 594          * Id nodes might arise here. Ignore them.
 595          */
 596         if (is_Id(block))
 597                 return;
 598
 599         n_cfgpreds = get_Block_n_cfgpreds(block);
 600 restart:
 601         if (n_cfgpreds < 2)
 602                 return;
 603
 604         for (low_idx = 0; low_idx < n_cfgpreds; ++low_idx) {
 605                 ir_node      *lower_block;
 606                 ir_node      *lower_cf;
 607                 ir_node      *cond;
 608                 ir_node      *cond_selector;
 609                 ir_node      *lower_pred;
 610
 611                 lower_cf = get_Block_cfgpred(block, low_idx);
 612                 lower_cf = skip_empty_blocks(lower_cf);
 613                 if (!is_Proj(lower_cf))
 614                         continue;
 615
 616                 cond = get_Proj_pred(lower_cf);
 617                 if (!is_Cond(cond))
 618                         continue;
 619
 620                 lower_block = get_nodes_block(cond);
 621                 if (get_Block_n_cfgpreds(lower_block) != 1)
 622                         continue;
 623
 624                 /* the block must not produce any side-effects */
 625                 if (get_Block_mark(lower_block))
 626                         continue;
 627
 628                 cond_selector = get_Cond_selector(cond);
 629                 if (get_irn_mode(cond_selector) != mode_b)
 630                         continue;
 631
 632                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 633
 634                 for (up_idx = 0; up_idx < n_cfgpreds; ++up_idx) {
 635                         ir_node   *upper_block;
 636                         ir_node   *upper_cf;
 637                         ir_node   *upper_cond;
 638                         ir_node   *upper_cond_selector;
 639                         ir_node   *replacement;
 640                         cond_pair  cpair;
 641
 642                         upper_cf    = get_Block_cfgpred(block, up_idx);
 643                         upper_cf    = skip_empty_blocks(upper_cf);
 644                         if (is_Bad(upper_cf))
 645                                 continue;
 646                         upper_block = get_nodes_block(upper_cf);
 647                         if (upper_block != lower_pred)
 648                                 continue;
 649                         if (!block_dominates(upper_block, block))
 650                                 continue;
 651
 652                         assert(is_Proj(upper_cf));
 653                         upper_cond = get_Proj_pred(upper_cf);
 654                         assert(is_Cond(upper_cond));
 655                         upper_cond_selector = get_Cond_selector(upper_cond);
 656                         if (get_irn_mode(upper_cond_selector) != mode_b)
 657                                 continue;
 658
 659                         /* we have found the structure */
 660                         /* check Phis: There must be NO Phi in block that
 661                            depends on the existence of low block */
 662                         if (!can_fuse_block_inputs(block, low_idx, up_idx))
 663                                 continue;
 664
 665                         /* all fine, try it */
 666                         if (!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 667                                 continue;
 668
 669                         /* normalize pncs: we need the true case to jump into the
 670                          * common block (ie. conjunctive normal form) */
 671                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 672                                 if (cpair.proj_lo == cond_selector) {
 673                                         ir_mode *mode  = get_tarval_mode(cpair.tv_lo);
 674                                         ir_node *cmp   = get_Proj_pred(cpair.proj_lo);
 675                                         cpair.pnc_lo   = get_negated_pnc(cpair.pnc_lo, mode);
 676                                         cpair.proj_lo  = new_r_Proj(cmp, mode_b, cpair.pnc_lo);
 677                                 } else {
 678                                         ir_mode *mode  = get_tarval_mode(cpair.tv_hi);
 679                                         ir_node *cmp   = get_Proj_pred(cpair.proj_hi);
 680                                         assert(cpair.proj_hi == cond_selector);
 681                                         cpair.pnc_hi   = get_negated_pnc(cpair.pnc_hi, mode);
 682                                         cpair.proj_hi  = new_r_Proj(cmp, mode_b, cpair.pnc_hi);
 683                                 }
 684                         }
 685                         if (get_Proj_proj(upper_cf) == pn_Cond_false) {
 686                                 if (cpair.proj_lo == upper_cond_selector) {
 687                                         ir_mode *mode  = get_tarval_mode(cpair.tv_lo);
 688                                         ir_node *cmp   = get_Proj_pred(cpair.proj_lo);
 689                                         cpair.pnc_lo   = get_negated_pnc(cpair.pnc_lo, mode);
 690                                         cpair.proj_lo  = new_r_Proj(cmp, mode_b, cpair.pnc_lo);
 691                                 } else {
 692                                         ir_mode *mode  = get_tarval_mode(cpair.tv_hi);
 693                                         ir_node *cmp   = get_Proj_pred(cpair.proj_hi);
 694                                         assert(cpair.proj_hi == upper_cond_selector);
 695                                         cpair.pnc_hi   = get_negated_pnc(cpair.pnc_hi, mode);
 696                                         cpair.proj_hi  = new_r_Proj(cmp, mode_b, cpair.pnc_hi);
 697                                 }
 698                         }
 699
 700                         /* can we optimize the case? */
 701                         replacement = bool_or(&cpair, upper_block);
 702                         if (replacement == NULL)
 703                                 continue;
 704
 705                         env->changed = 1;
 706
 707                         DB((dbg, LEVEL_1, "boolopt: %+F: fusing (ub %+F lb %+F)\n",
 708                                 get_irn_irg(upper_block), upper_block, lower_block));
 709
 710                         /* move all expressions on the path to lower/upper block */
 711                         move_nodes_to_block(get_Block_cfgpred(block, up_idx), upper_block);
 712                         move_nodes_to_block(get_Block_cfgpred(block, low_idx), lower_block);
 713
 714                         /* move all nodes from lower block to upper block */
 715                         exchange(lower_block, upper_block);
 716
 717                         remove_block_input(block, up_idx);
 718                         --n_cfgpreds;
 719
 720                         /* the optimizations expected the true case to jump */
 721                         if (get_Proj_proj(lower_cf) == pn_Cond_false) {
 722                                 ir_node *block = get_nodes_block(replacement);
 723                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 724                         }
 725                         set_Cond_selector(cond, replacement);
 726
 727                         goto restart;
 728                 }
 729         }
 730 }
 731
 732 void opt_bool(ir_graph *const irg)
 733 {
 734         bool_opt_env_t env;
 735
 736         /* register a debug mask */
 737         FIRM_DBG_REGISTER(dbg, "firm.opt.bool");
 738
 739         /* works better with one return block only */
 740         normalize_one_return(irg);
 741
 742         env.changed = 0;
 743
 744         /* optimize simple Andb and Orb cases */
 745         irg_walk_graph(irg, NULL, bool_walk, &env);
 746
 747         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 748
 749         /* now more complicated cases: find control flow And/Or and optimize. */
 750         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 751         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, &env);
 752
 753         if (env.changed) {
 754                 set_irg_outs_inconsistent(irg);
 755                 set_irg_doms_inconsistent(irg);
 756                 set_irg_extblk_inconsistent(irg);
 757                 set_irg_loopinfo_inconsistent(irg);
 758         }
 759
 760         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 761 }
 762
 763 /* Creates an ir_graph pass for opt_bool. */
 764 ir_graph_pass_t *opt_bool_pass(const char *name)
 765 {
 766         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 767 }  /* opt_bool_pass */