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

   1 #include <assert.h>
   2 #include <string.h>
   3
   4 #include "adt/obst.h"
   5 #include "ircons.h"
   6 #include "irgmod.h"
   7 #include "irgwalk.h"
   8 #include "irnode.h"
   9 #include "tv.h"
  10
  11 typedef struct cond_pair {
  12         ir_node *cmp_lo;
  13         ir_node *cmp_hi;
  14         pn_Cmp   pnc_lo;
  15         pn_Cmp   pnc_hi;
  16         ir_node *proj_lo;
  17         ir_node *proj_hi;
  18         tarval  *tv_lo;
  19         tarval  *tv_hi;
  20 } cond_pair;
  21
  22 static int find_cond_pair(ir_node *const l, ir_node *const r, cond_pair *const res)
  23 {
  24         if (is_Proj(l) && is_Proj(r)) {
  25                 ir_node *const lo = get_Proj_pred(l);
  26                 ir_node *const ro = get_Proj_pred(r);
  27
  28                 if (is_Cmp(lo) && is_Cmp(ro)) {
  29                         ir_node *const lol = get_Cmp_left(lo);
  30                         ir_node *const lor = get_Cmp_right(lo);
  31                         ir_node *const rol = get_Cmp_left(ro);
  32                         ir_node *const ror = get_Cmp_right(ro);
  33
  34                         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) {
  35                                 ir_fprintf(stderr, "found zero zero\n");
  36                         }
  37
  38                         /* TODO float */
  39                         /* The constants shall be unequal.  Local optimisations handle the
  40                          * equal case */
  41                         if (lol == rol && mode_is_int(get_irn_mode(lol)) && lor != ror && is_Const(lor) && is_Const(ror)) {
  42                                 tarval *const tv_l  = get_Const_tarval(lor);
  43                                 tarval *const tv_r  = get_Const_tarval(ror);
  44                                 pn_Cmp  const pnc_l = get_Proj_proj(l);
  45                                 pn_Cmp  const pnc_r = get_Proj_proj(r);
  46                                 pn_Cmp  const rel   = tarval_cmp(tv_l, tv_r);
  47
  48                                 assert(rel != pn_Cmp_Eq);
  49
  50                                 if (rel == pn_Cmp_Lt) {
  51                                         res->cmp_lo  = lo;
  52                                         res->cmp_hi  = ro;
  53                                         res->pnc_lo  = pnc_l;
  54                                         res->pnc_hi  = pnc_r;
  55                                         res->proj_lo = l;
  56                                         res->proj_hi = r;
  57                                         res->tv_lo   = tv_l;
  58                                         res->tv_hi   = tv_r;
  59                                 } else {
  60                                         assert(rel == pn_Cmp_Gt);
  61                                         res->cmp_lo  = ro;
  62                                         res->cmp_hi  = lo;
  63                                         res->pnc_lo  = pnc_r;
  64                                         res->pnc_hi  = pnc_l;
  65                                         res->proj_lo = r;
  66                                         res->proj_hi = l;
  67                                         res->tv_lo   = tv_r;
  68                                         res->tv_hi   = tv_l;
  69                                 }
  70                                 return 1;
  71                         }
  72                 }
  73         }
  74         return 0;
  75 }
  76
  77 static ir_node *bool_and(cond_pair* const cpair)
  78 {
  79         ir_node *const cmp_lo  = cpair->cmp_lo;
  80         ir_node *const cmp_hi  = cpair->cmp_hi;
  81         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
  82         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
  83         ir_node *const proj_lo = cpair->proj_lo;
  84         ir_node *const proj_hi = cpair->proj_hi;
  85         tarval  *const tv_lo   = cpair->tv_lo;
  86         tarval  *const tv_hi   = cpair->tv_hi;
  87
  88         if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
  89                         (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
  90                 /* x <|<=|== lo | x ==|>=|> hi -> false */
  91                 ir_node *const t = new_Const(mode_b, tarval_b_false);
  92                 return t;
  93         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
  94                                                  (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Ne)) {
  95                 /* x <|<=|== lo && x <|<=|!= hi -> x <|<=|== lo */
  96                 return proj_lo;
  97         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ne) &&
  98                                                  (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
  99                 /* x >=|>|!= lo || x ==|>=|> hi -> x ==|>=|> hi */
 100                 return proj_hi;
 101         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo))) { /* lo + 1 == hi */
 102                 if (pnc_lo == pn_Cmp_Ge && pnc_hi == pn_Cmp_Lt) {
 103                         /* x >= c || x < c + 1 -> x == c */
 104                         ir_graph *const irg   = current_ir_graph;
 105                         ir_node  *const block = get_nodes_block(cmp_lo);
 106                         ir_node  *const p = new_r_Proj(irg, block, cmp_lo, mode_b, pn_Cmp_Eq);
 107                         return p;
 108                 } else if (pnc_lo == pn_Cmp_Gt) {
 109                         if (pnc_hi == pn_Cmp_Ne) {
 110                                 /* x > c || x != c + 1 -> x > c + 1 */
 111                                 ir_graph *const irg   = current_ir_graph;
 112                                 ir_node  *const block = get_nodes_block(cmp_hi);
 113                                 ir_node  *const p = new_r_Proj(irg, block, cmp_hi, mode_b, pn_Cmp_Gt);
 114                                 return p;
 115                         } else if (pnc_hi == pn_Cmp_Lt) {
 116                                 /* x > c || x < c + 1 -> false */
 117                                 ir_node *const t = new_Const(mode_b, tarval_b_false);
 118                                 return t;
 119                         } else if (pnc_hi == pn_Cmp_Le) {
 120                                 /* x > c || x <= c + 1 -> x != c + 1 */
 121                                 ir_graph *const irg   = current_ir_graph;
 122                                 ir_node  *const block = get_nodes_block(cmp_hi);
 123                                 ir_node  *const p = new_r_Proj(irg, block, cmp_hi, mode_b, pn_Cmp_Eq);
 124                                 return p;
 125                         }
 126                 } else if (pnc_lo == pn_Cmp_Ne && pnc_hi == pn_Cmp_Lt) {
 127                         /* x != c || c < c + 1 -> x < c */
 128                         ir_graph *const irg   = current_ir_graph;
 129                         ir_node  *const block = get_nodes_block(cmp_lo);
 130                         ir_node  *const p     = new_r_Proj(irg, block, cmp_lo, mode_b, pn_Cmp_Lt);
 131                         return p;
 132                 }
 133         }
 134         return NULL;
 135 }
 136
 137 static ir_node *bool_or(cond_pair *const cpair)
 138 {
 139         ir_node *const cmp_lo  = cpair->cmp_lo;
 140         ir_node *const cmp_hi  = cpair->cmp_hi;
 141         pn_Cmp   const pnc_lo  = cpair->pnc_lo;
 142         pn_Cmp   const pnc_hi  = cpair->pnc_hi;
 143         ir_node *const proj_lo = cpair->proj_lo;
 144         ir_node *const proj_hi = cpair->proj_hi;
 145         tarval  *const tv_lo   = cpair->tv_lo;
 146         tarval  *const tv_hi   = cpair->tv_hi;
 147
 148         if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ne) &&
 149                         (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Ne)) {
 150                 /* x >=|>|!= lo | x <|<=|!= hi -> true */
 151                 ir_node *const t = new_Const(mode_b, tarval_b_true);
 152                 return t;
 153         } else if ((pnc_lo == pn_Cmp_Lt || pnc_lo == pn_Cmp_Le || pnc_lo == pn_Cmp_Eq) &&
 154                                                  (pnc_hi == pn_Cmp_Lt || pnc_hi == pn_Cmp_Le || pnc_hi == pn_Cmp_Ne)) {
 155                 /* x <|<=|== lo || x <|<=|!= hi -> x <|<=|!= hi */
 156                 return proj_hi;
 157         } else if ((pnc_lo == pn_Cmp_Ge || pnc_lo == pn_Cmp_Gt || pnc_lo == pn_Cmp_Ne) &&
 158                                                  (pnc_hi == pn_Cmp_Eq || pnc_hi == pn_Cmp_Ge || pnc_hi == pn_Cmp_Gt)) {
 159                 /* x >=|>|!= lo || x ==|>=|> hi -> x >=|>|!= lo */
 160                 return proj_lo;
 161         } else if (tarval_is_one(tarval_sub(tv_hi, tv_lo))) { /* lo + 1 == hi */
 162                 if (pnc_lo == pn_Cmp_Lt && pnc_hi == pn_Cmp_Ge) {
 163                         /* x < c || x >= c + 1 -> x != c */
 164                         ir_graph *const irg   = current_ir_graph;
 165                         ir_node  *const block = get_nodes_block(cmp_lo);
 166                         ir_node  *const p = new_r_Proj(irg, block, cmp_lo, mode_b, pn_Cmp_Ne);
 167                         return p;
 168                 } else if (pnc_lo == pn_Cmp_Le) {
 169                         if (pnc_hi == pn_Cmp_Eq) {
 170                                 /* x <= c || x == c + 1 -> x <= c + 1 */
 171                                 ir_graph *const irg   = current_ir_graph;
 172                                 ir_node  *const block = get_nodes_block(cmp_hi);
 173                                 ir_node  *const p = new_r_Proj(irg, block, cmp_hi, mode_b, pn_Cmp_Le);
 174                                 return p;
 175                         } else if (pnc_hi == pn_Cmp_Ge) {
 176                                 /* x <= c || x >= c + 1 -> true */
 177                                 ir_node *const t = new_Const(mode_b, tarval_b_true);
 178                                 return t;
 179                         } else if (pnc_hi == pn_Cmp_Gt) {
 180                                 /* x <= c || x > c + 1 -> x != c + 1 */
 181                                 ir_graph *const irg   = current_ir_graph;
 182                                 ir_node  *const block = get_nodes_block(cmp_hi);
 183                                 ir_node  *const p = new_r_Proj(irg, block, cmp_hi, mode_b, pn_Cmp_Ne);
 184                                 return p;
 185                         }
 186                 } else if (pnc_lo == pn_Cmp_Eq && pnc_hi == pn_Cmp_Ge) {
 187                         /* x == c || c >= c + 1 -> x >= c */
 188                         ir_graph *const irg   = current_ir_graph;
 189                         ir_node  *const block = get_nodes_block(cmp_lo);
 190                         ir_node  *const p     = new_r_Proj(irg, block, cmp_lo, mode_b, pn_Cmp_Ge);
 191                         return p;
 192                 }
 193         }
 194         return NULL;
 195 }
 196
 197 static void bool_walk(ir_node *n, void *env)
 198 {
 199         (void)env;
 200
 201         if (get_irn_mode(n) != mode_b)
 202                 return;
 203
 204         if (is_And(n)) {
 205                 ir_node *const l = get_And_left(n);
 206                 ir_node *const r = get_And_right(n);
 207                 ir_node *      replacement;
 208                 cond_pair      cpair;
 209                 if (!find_cond_pair(l, r, &cpair))
 210                         return;
 211                 replacement = bool_and(&cpair);
 212                 if (replacement)
 213                         exchange(n, replacement);
 214         } else if (is_Or(n)) {
 215                 ir_node *const l = get_Or_left(n);
 216                 ir_node *const r = get_Or_right(n);
 217                 ir_node *      replacement;
 218                 cond_pair      cpair;
 219                 if (!find_cond_pair(l, r, &cpair))
 220                         return;
 221                 replacement = bool_or(&cpair);
 222                 if (replacement)
 223                         exchange(n, replacement);
 224         }
 225 }
 226
 227 static struct obstack obst;
 228
 229 typedef struct block_info_t {
 230         ir_node *phi;   /**< head of the Phi list */
 231         int has_pinned; /**< set if the block contains instructions that cannot be
 232                              moved */
 233 } block_info_t;
 234
 235 static block_info_t* get_block_blockinfo(ir_node* block)
 236 {
 237         return get_irn_link(block);
 238 }
 239
 240 static void create_blockinfos(ir_node *node, void *env)
 241 {
 242         block_info_t *block_info;
 243         (void) env;
 244
 245         /* we visit blocks before any other nodes (from the block) */
 246         if (!is_Block(node))
 247                 return;
 248
 249         block_info = obstack_alloc(&obst, sizeof(block_info[0]));
 250         memset(block_info, 0, sizeof(block_info[0]));
 251         set_irn_link(node, block_info);
 252 }
 253
 254 static void collect_phis(ir_node *node, void *env)
 255 {
 256         (void) env;
 257
 258         if (is_Phi(node)) {
 259                 ir_node      *block = get_nodes_block(node);
 260                 block_info_t *bi    = get_block_blockinfo(block);
 261
 262                 set_irn_link(node, bi->phi);
 263                 bi->phi = node;
 264                 return;
 265         }
 266
 267         /* Ignore control flow nodes, these will be removed. */
 268         if (get_irn_pinned(node) == op_pin_state_pinned &&
 269                         !is_Block(node) && !is_cfop(node)) {
 270                 ir_node      *block = get_nodes_block(node);
 271                 block_info_t *bi    = get_block_blockinfo(block);
 272
 273                 bi->has_pinned = 1;
 274         }
 275 }
 276
 277 ir_node *skip_empty_block(ir_node *node)
 278 {
 279         ir_node      *block;
 280         block_info_t *block_info;
 281
 282         if(!is_Jmp(node))
 283                 return node;
 284
 285         block = get_nodes_block(node);
 286         if(get_Block_n_cfgpreds(block) != 1)
 287                 return node;
 288
 289         block_info = get_block_blockinfo(block);
 290         if(block_info->has_pinned)
 291                 return node;
 292
 293         return get_Block_cfgpred(block, 0);
 294 }
 295
 296 static void find_cf_and_or_walker(ir_node *block, void *env)
 297 {
 298         int i, i2;
 299         int n_cfgpreds = get_Block_n_cfgpreds(block);
 300         (void) env;
 301
 302         if(n_cfgpreds < 2)
 303                 return;
 304
 305         /* Find the following structure:
 306          *
 307          *        upper_block
 308          *         /       |
 309          *        /        |
 310          *   lower_block   |
 311          *     /  \        |
 312          *   ...   \       |
 313          *           block
 314          */
 315
 316 restart:
 317         for(i = 0; i < n_cfgpreds; ++i) {
 318                 ir_node      *lower_block;
 319                 ir_node      *lower_cf;
 320                 ir_node      *cond;
 321                 ir_node      *cond_selector;
 322                 block_info_t *block_info;
 323                 ir_node      *lower_pred;
 324
 325                 lower_cf = get_Block_cfgpred(block, i);
 326                 lower_cf = skip_empty_block(lower_cf);
 327                 if(!is_Proj(lower_cf))
 328                         continue;
 329
 330                 lower_block = get_nodes_block(lower_cf);
 331                 if(get_Block_n_cfgpreds(lower_block) != 1)
 332                         continue;
 333
 334                 cond = get_Proj_pred(lower_cf);
 335                 if(!is_Cond(cond))
 336                         continue;
 337
 338                 cond_selector = get_Cond_selector(cond);
 339                 if(get_irn_mode(cond_selector) != mode_b)
 340                         continue;
 341
 342                 /* the block must not produce any side-effects */
 343                 block_info = get_block_blockinfo(lower_block);
 344                 if(block_info->has_pinned)
 345                         continue;
 346
 347                 lower_pred = get_Block_cfgpred_block(lower_block, 0);
 348
 349                 for(i2 = 0; i2 < n_cfgpreds; ++i2) {
 350                         ir_node   *upper_block;
 351                         ir_node   *upper_cf;
 352                         ir_node   *upper_cond;
 353                         ir_node   *upper_cond_selector;
 354                         ir_node   *replacement;
 355                         ir_graph  *irg;
 356                         cond_pair  cpair;
 357
 358                         upper_cf    = get_Block_cfgpred(block, i2);
 359                         upper_cf    = skip_empty_block(upper_cf);
 360                         if(is_Bad(upper_cf))
 361                                 continue;
 362                         upper_block = get_nodes_block(upper_cf);
 363                         if(upper_block != lower_pred)
 364                                 continue;
 365
 366                         assert(is_Proj(upper_cf));
 367                         upper_cond = get_Proj_pred(upper_cf);
 368                         assert(is_Cond(upper_cond));
 369                         upper_cond_selector = get_Cond_selector(upper_cond);
 370                         if(get_irn_mode(upper_cond_selector) != mode_b)
 371                                 continue;
 372
 373                         /* we have found the structure */
 374                         /* TODO: check phis */
 375                         if(!find_cond_pair(cond_selector, upper_cond_selector, &cpair))
 376                                 continue;
 377
 378                         /* normalize pncs: we need the true case to jump into the
 379                          * common block */
 380                         irg = current_ir_graph;
 381                         if(get_Proj_proj(lower_cf) == pn_Cond_false) {
 382                                 if(cpair.proj_lo == cond_selector) {
 383                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 384                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 385                                         cpair.proj_lo = new_r_Proj(irg, lower_block,
 386                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 387                                 } else {
 388                                         assert(cpair.proj_hi == cond_selector);
 389                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 390                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 391                                         cpair.proj_hi = new_r_Proj(irg, lower_block,
 392                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 393                                 }
 394                         }
 395                         if(get_Proj_proj(upper_cf) == pn_Cond_false) {
 396                                 if(cpair.proj_lo == upper_cond_selector) {
 397                                         ir_mode *mode = get_tarval_mode(cpair.tv_lo);
 398                                         cpair.pnc_lo  = get_negated_pnc(cpair.pnc_lo, mode);
 399                                         cpair.proj_lo = new_r_Proj(irg, upper_block,
 400                                                         get_Proj_pred(cpair.proj_lo), mode_b, cpair.pnc_lo);
 401                                 } else {
 402                                         assert(cpair.proj_hi == upper_cond_selector);
 403                                         ir_mode *mode = get_tarval_mode(cpair.tv_hi);
 404                                         cpair.pnc_hi  = get_negated_pnc(cpair.pnc_hi, mode);
 405                                         cpair.proj_hi = new_r_Proj(irg, upper_block,
 406                                                         get_Proj_pred(cpair.proj_hi), mode_b, cpair.pnc_hi);
 407                                 }
 408                         }
 409
 410                         /* can we optimize the case? */
 411                         replacement = bool_or(&cpair);
 412                         if(replacement == NULL)
 413                                 continue;
 414
 415                         /* move all nodes from lower block to upper block */
 416                         exchange(lower_block, upper_block);
 417
 418                         set_Block_cfgpred(block, i2, new_Bad());
 419
 420                         /* the optimisations expected the true case to jump */
 421                         if(get_Proj_proj(lower_cf) == pn_Cond_false) {
 422                                 ir_node *block = get_nodes_block(replacement);
 423                                 replacement    = new_rd_Not(NULL, current_ir_graph, block,
 424                                                             replacement, mode_b);
 425                         }
 426                         set_Cond_selector(cond, replacement);
 427
 428                         ir_fprintf(stderr, "replaced (ub %+F)\n", upper_block);
 429                         goto restart;
 430                 }
 431         }
 432 }
 433
 434 void opt_bool(ir_graph *const irg)
 435 {
 436         irg_walk_graph(irg, NULL, bool_walk, NULL);
 437
 438         set_using_irn_link(irg);
 439
 440         obstack_init(&obst);
 441
 442         irg_walk_graph(irg, create_blockinfos, collect_phis, NULL);
 443
 444         irg_block_walk_graph(irg, NULL, find_cf_and_or_walker, NULL);
 445
 446         obstack_free(&obst, NULL);
 447
 448         set_irg_outs_inconsistent(irg);
 449         set_irg_doms_inconsistent(irg);
 450         set_irg_extblk_inconsistent(irg);
 451         set_irg_loopinfo_inconsistent(irg);
 452
 453         clear_using_irn_link(irg);
 454 }