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/controlflow optimisations
  23  * @author  Matthias Braun, Christoph Mallon
  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 "ircons.h"
  33 #include "irgmod.h"
  34 #include "irgwalk.h"
  35 #include "irprintf.h"
  36 #include "irnode_t.h"
  37 #include "tv.h"
  38 #include "irpass.h"
  39
  40 typedef struct cond_pair {
  41         ir_node *cmp_lo;
  42         ir_node *cmp_hi;
  43         pn_Cmp   pnc_lo;
  44         pn_Cmp   pnc_hi;
  45         ir_node *proj_lo;
  46         ir_node *proj_hi;
  47         tarval  *tv_lo;
  48         tarval  *tv_hi;
  49 } cond_pair;
  50
  51 static int find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  52 {
  53         if (is_Proj(l) && is_Proj(r)) {
  54                 ir_node *const lo = get_Proj_pred(l);
  55                 ir_node *const ro = get_Proj_pred(r);
  56
  57                 if (is_Cmp(lo) && is_Cmp(ro)) {
  58                         ir_node *const lol = get_Cmp_left(lo);
  59                         ir_node *const lor = get_Cmp_right(lo);
  60                         ir_node *const rol = get_Cmp_left(ro);
  61                         ir_node *const ror = get_Cmp_right(ro);
  62
  63                         if(is_Const(lor) && is_Const_null(lor) && is_Const(ror) && is_Const_null(ror) && get_Proj_proj(l) == pn_Cmp_Lg && get_Proj_proj(r) == pn_Cmp_Lg) {
  64                                 ir_fprintf(stderr, "found zero zero\n");
  65                         }
  66
  67                         /* TODO float */
  68                         /* The constants shall be unequal.  Local optimisations handle the
  69                          * equal case */
  70                         if (lol == rol && mode_is_int(get_irn_mode(lol)) && lor != ror && is_Const(lor) && is_Const(ror)) {
  71                                 tarval *const tv_l  = get_Const_tarval(lor);
  72                                 tarval *const tv_r  = get_Const_tarval(ror);
  73                                 pn_Cmp  const pnc_l = get_Proj_proj(l);
  74                                 pn_Cmp  const pnc_r = get_Proj_proj(r);
  75                                 pn_Cmp  const rel   = tarval_cmp(tv_l, tv_r);
  76
  77                                 assert(rel != pn_Cmp_Eq);
  78
  79                                 if (rel == pn_Cmp_Lt) {
  80                                         res->cmp_lo  = lo;
  81                                         res->cmp_hi  = ro;
  82                                         res->pnc_lo  = pnc_l;
  83                                         res->pnc_hi  = pnc_r;
  84                                         res->proj_lo = l;
  85                                         res->proj_hi = r;
  86                                         res->tv_lo   = tv_l;
  87                                         res->tv_hi   = tv_r;
  88                                 } else {
  89                                         assert(rel == pn_Cmp_Gt);
  90                                         res->cmp_lo  = ro;
  91                                         res->cmp_hi  = lo;
  92                                         res->pnc_lo  = pnc_r;
  93                                         res->pnc_hi  = pnc_l;
  94                                         res->proj_lo = r;
  95                                         res->proj_hi = l;
  96                                         res->tv_lo   = tv_r;
  97                                         res->tv_hi   = tv_l;
  98                                 }
  99                                 return 1;
 100                         }
 101                 }
 102         }
 103         return 0;
 104 }
 105
 106 static ir_node *bool_and(cond_pair* const cpair)
 107 {
 108         ir_node *const cmp_lo  = cpair->cmp_lo;
 109         ir_node *const cmp_hi  = cpair->cmp_hi;
 110         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 111         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 112         ir_node *const proj_lo = cpair->proj_lo;
 113         ir_node *const proj_hi = cpair->proj_hi;
 114         tarval  *const tv_lo   = cpair->tv_lo;
 115         tarval  *const tv_hi   = cpair->tv_hi;
 116
 117         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 118         if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 119                         (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 120                 /* x <|<=|== lo | x ==|>=|> hi -> false */
 121                 ir_node *const t = new_Const(tarval_b_false);
 122                 return t;
 123         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 124                                                  (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 125                 /* x <|<=|== lo && x <|<=|!= hi -> x <|<=|== lo */
 126                 return proj_lo;
 127         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 128                                                  (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 129                 /* x >=|>|!= lo || x ==|>=|> hi -> x ==|>=|> hi */
 130                 return proj_hi;
 131         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 132                 if (pnc_lo == pn_Cmp_Ge && pnc_hi == pn_Cmp_Lt) {
 133                         /* x >= c || x < c + 1 -> x == c */
 134                         ir_node  *const block = get_nodes_block(cmp_lo);
 135                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Eq);
 136                         return p;
 137                 } else if (pnc_lo == pn_Cmp_Gt) {
 138                         if (pnc_hi == pn_Cmp_Lg) {
 139                                 /* x > c || x != c + 1 -> x > c + 1 */
 140                                 ir_node  *const block = get_nodes_block(cmp_hi);
 141                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Gt);
 142                                 return p;
 143                         } else if (pnc_hi == pn_Cmp_Lt) {
 144                                 /* x > c || x < c + 1 -> false */
 145                                 ir_node *const t = new_Const(tarval_b_false);
 146                                 return t;
 147                         } else if (pnc_hi == pn_Cmp_Le) {
 148                                 /* x > c || x <= c + 1 -> x != c + 1 */
 149                                 ir_node  *const block = get_nodes_block(cmp_hi);
 150                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Eq);
 151                                 return p;
 152                         }
 153                 } else if (pnc_lo == pn_Cmp_Lg && pnc_hi == pn_Cmp_Lt) {
 154                         /* x != c || c < c + 1 -> x < c */
 155                         ir_node  *const block = get_nodes_block(cmp_lo);
 156                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lt);
 157                         return p;
 158                 }
 159         }
 160         return NULL;
 161 }
 162
 163 static ir_node *bool_or(cond_pair *const cpair)
 164 {
 165         ir_node *const cmp_lo  = cpair->cmp_lo;
 166         ir_node *const cmp_hi  = cpair->cmp_hi;
 167         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 168         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 169         ir_node *const proj_lo = cpair->proj_lo;
 170         ir_node *const proj_hi = cpair->proj_hi;
 171         tarval  *const tv_lo   = cpair->tv_lo;
 172         tarval  *const tv_hi   = cpair->tv_hi;
 173
 174         /* Beware of NaN's, we can only check for (ordered) != here (which is Lg, not Ne) */
 175         if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 176                         (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 177                 /* x >=|>|!= lo | x <|<=|!= hi -> true */
 178                 ir_node *const t = new_Const(tarval_b_true);
 179                 return t;
 180         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 181                                                  (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Lg)) {
 182                 /* x <|<=|== lo || x <|<=|!= hi -> x <|<=|!= hi */
 183                 return proj_hi;
 184         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Lg) &&
 185                                                  (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 186                 /* x >=|>|!= lo || x ==|>=|> hi -> x >=|>|!= lo */
 187                 return proj_lo;
 188         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo, NULL))) { /* lo + 1 == hi */
 189                 if (pnc_lo == pn_Cmp_Lt && pnc_hi == pn_Cmp_Ge) {
 190                         /* x < c || x >= c + 1 -> x != c */
 191                         ir_node  *const block = get_nodes_block(cmp_lo);
 192                         ir_node  *const p = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Lg);
 193                         return p;
 194                 } else if (pnc_lo == pn_Cmp_Le) {
 195                         if (pnc_hi == pn_Cmp_Eq) {
 196                                 /* x <= c || x == c + 1 -> x <= c + 1 */
 197                                 ir_node  *const block = get_nodes_block(cmp_hi);
 198                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Le);
 199                                 return p;
 200                         } else if (pnc_hi == pn_Cmp_Ge) {
 201                                 /* x <= c || x >= c + 1 -> true */
 202                                 ir_node *const t = new_Const(tarval_b_true);
 203                                 return t;
 204                         } else if (pnc_hi == pn_Cmp_Gt) {
 205                                 /* x <= c || x > c + 1 -> x != c + 1 */
 206                                 ir_node  *const block = get_nodes_block(cmp_hi);
 207                                 ir_node  *const p = new_r_Proj(block, cmp_hi, mode_b, pn_Cmp_Lg);
 208                                 return p;
 209                         }
 210                 } else if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Ge) {
 211                         /* x == c || x >= c + 1 -> x >= c */
 212                         ir_node  *const block = get_nodes_block(cmp_lo);
 213                         ir_node  *const p     = new_r_Proj(block, cmp_lo, mode_b, pn_Cmp_Ge);
 214                         return p;
 215                 }
 216         }
 217         return NULL;
 218 }
 219
 220 static void bool_walk(ir_node *n, void *env)
 221 {
 222         (void)env;
 223
 224         if (get_irn_mode(n) != mode_b)
 225                 return;
 226
 227         if (is_And(n)) {
 228                 ir_node *const l = get_And_left(n);
 229                 ir_node *const r = get_And_right(n);
 230                 ir_node *      replacement;
 231                 cond_pair      cpair;
 232                 if (!find_cond_pair(l, r, &cpair))
 233                         return;
 234                 replacement = bool_and(&cpair);
 235                 if (replacement)
 236                         exchange(n, replacement);
 237         } else if (is_Or(n)) {
 238                 ir_node *const l = get_Or_left(n);
 239                 ir_node *const r = get_Or_right(n);
 240                 ir_node *      replacement;
 241                 cond_pair      cpair;
 242                 if (!find_cond_pair(l, r, &cpair))
 243                         return;
 244                 replacement = bool_or(&cpair);
 245                 if (replacement)
 246                         exchange(n, replacement);
 247         }
 248 }
 249
 250 /**
 251  * Walker, clear Block mark and Phi list
 252  */
 253 static void clear_block_infos(ir_node *node, void *env)
 254 {
 255         (void) env;
 256
 257         /* we visit blocks before any other nodes (from the block) */
 258         if (!is_Block(node))
 259                 return;
 260
 261         /* clear the PHI list */
 262         set_Block_phis(node, NULL);
 263         set_Block_mark(node, 0);
 264 }
 265
 266 /**
 267  * Walker: collect Phi nodes and update the
 268  */
 269 static void collect_phis(ir_node *node, void *env)
 270 {
 271         (void) env;
 272
 273         if (is_Phi(node)) {
 274                 ir_node *block = get_nodes_block(node);
 275                 add_Block_phi(block, node);
 276                 return;
 277         }
 278
 279         /* Ignore control flow nodes, these will be removed. */
 280         if (get_irn_pinned(node) == op_pin_state_pinned &&
 281                         !is_Block(node) && !is_cfop(node)) {
 282                 ir_node *block = get_nodes_block(node);
 283                 set_Block_mark(block, 1);
 284         }
 285 }
 286
 287 /**
 288  * If node is a Jmp in a block containing no pinned instruction
 289  * and having only one predecessor, skip the block and return its
 290  * cf predecessor, else the node itself.
 291  */
 292 static ir_node *skip_empty_block(ir_node *node)
 293 {
 294         ir_node      *block;
 295
 296         if(!is_Jmp(node))
 297                 return node;
 298
 299         block = get_nodes_block(node);
 300         if(get_Block_n_cfgpreds(block) != 1)
 301                 return node;
 302
 303         if(get_Block_mark(block))
 304                 return node;
 305
 306         return get_Block_cfgpred(block, 0);
 307 }
 308
 309 static void find_cf_and_or_walker(ir_node *block, void *env)
 310 {
 311         int i, i2;
 312         int n_cfgpreds = get_Block_n_cfgpreds(block);
 313         (void) env;
 314
 315         if(n_cfgpreds < 2)
 316                 return;
 317
 318         /* Find the following structure:
 319          *
 320          *        upper_block
 321          *         /       |
 322          *        /        |
 323          *   lower_block   |
 324          *     /  \        |
 325          *   ...   \       |
 326          *           block
 327          */
 328
 329 restart:
 330         for(i = 0; i < n_cfgpreds; ++i) {
 331                 ir_node      *lower_block;
 332                 ir_node      *lower_cf;
 333                 ir_node      *cond;
 334                 ir_node      *cond_selector;
 335                 ir_node      *lower_pred;
 336
 337                 lower_cf = get_Block_cfgpred(block, i);
 338                 lower_cf = skip_empty_block(lower_cf);
 339                 if(!is_Proj(lower_cf))
 340                         continue;
 341
 342                 cond = get_Proj_pred(lower_cf);
 343                 if(!is_Cond(cond))
 344                         continue;
 345
 346                 lower_block = get_nodes_block(cond);
 347                 if(get_Block_n_cfgpreds(lower_block) != 1)
 348                         continue;
 349
 350                 /* the block must not produce any side-effects */
 351                 if(get_Block_mark(lower_block))
 352                         continue;
 353
 354                 cond_selector = get_Cond_selector(cond);
 355                 if(get_irn_mode(cond_selector) != mode_b)
 356                         continue;
 357
 358                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 359
 360                 for(i2 = 0; i2 < n_cfgpreds; ++i2) {
 361                         ir_node   *upper_block;
 362                         ir_node   *upper_cf;
 363                         ir_node   *upper_cond;
 364                         ir_node   *upper_cond_selector;
 365                         ir_node   *replacement;
 366                         cond_pair  cpair;
 367
 368                         upper_cf    = get_Block_cfgpred(block, i2);
 369                         upper_cf    = skip_empty_block(upper_cf);
 370                         if(is_Bad(upper_cf))
 371                                 continue;
 372                         upper_block = get_nodes_block(upper_cf);
 373                         if(upper_block != lower_pred)
 374                                 continue;
 375
 376                         assert(is_Proj(upper_cf));
 377                         upper_cond = get_Proj_pred(upper_cf);
 378                         assert(is_Cond(upper_cond));
 379                         upper_cond_selector = get_Cond_selector(upper_cond);
 380                         if(get_irn_mode(upper_cond_selector) != mode_b)
 381                                 continue;
 382
 383                         /* we have found the structure */
 384                         /* TODO: check phis */
 385                         if(!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 386                                 continue;
 387
 388                         /* normalize pncs: we need the true case to jump into the
 389                          * common block (ie. conjunctive normal form) */
 390                         if(get_Proj_proj(lower_cf) == pn_Cond_false) {
 391                                 if(cpair.proj_lo == cond_selector) {
 392                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 393                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 394                                         cpair.proj_lo = new_r_Proj(lower_block,
 395                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 396                                 } else {
 397                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 398                                         assert(cpair.proj_hi == cond_selector);
 399                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 400                                         cpair.proj_hi = new_r_Proj(lower_block,
 401                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 402                                 }
 403                         }
 404                         if(get_Proj_proj(upper_cf) == pn_Cond_false) {
 405                                 if(cpair.proj_lo == upper_cond_selector) {
 406                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 407                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 408                                         cpair.proj_lo = new_r_Proj(upper_block,
 409                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 410                                 } else {
 411                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 412                                         assert(cpair.proj_hi == upper_cond_selector);
 413                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 414                                         cpair.proj_hi = new_r_Proj(upper_block,
 415                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 416                                 }
 417                         }
 418
 419                         /* can we optimize the case? */
 420                         replacement = bool_or(&cpair);
 421                         if(replacement == NULL)
 422                                 continue;
 423
 424                         /* move all nodes from lower block to upper block */
 425                         exchange(lower_block, upper_block);
 426
 427                         set_Block_cfgpred(block, i2, new_Bad());
 428
 429                         /* the optimisations expected the true case to jump */
 430                         if(get_Proj_proj(lower_cf) == pn_Cond_false) {
 431                                 ir_node *block = get_nodes_block(replacement);
 432                                 replacement    = new_rd_Not(NULL, block, replacement, mode_b);
 433                         }
 434                         set_Cond_selector(cond, replacement);
 435
 436                         ir_fprintf(stderr, "replaced (ub %+F)\n", upper_block);
 437                         goto restart;
 438                 }
 439         }
 440 }
 441
 442 void opt_bool(ir_graph *const irg)
 443 {
 444         irg_walk_graph(irg, NULL, bool_walk, NULL);
 445
 446         ir_reserve_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 447
 448         irg_walk_graph(irg, clear_block_infos, collect_phis, NULL);
 449
 450         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, NULL);
 451
 452         set_irg_outs_inconsistent(irg);
 453         set_irg_doms_inconsistent(irg);
 454         set_irg_extblk_inconsistent(irg);
 455         set_irg_loopinfo_inconsistent(irg);
 456
 457         ir_free_resources(irg, IR_RESOURCE_BLOCK_MARK | IR_RESOURCE_PHI_LIST);
 458 }
 459
 460 /* Creates an ir_graph pass for opt_bool. */
 461 ir_graph_pass_t *opt_bool_pass(const char *name)
 462 {
 463         return def_graph_pass(name ? name : "opt_bool", opt_bool);
 464 }  /* opt_bool_pass */