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