simplify.c

   1 /*
   2  * Simplify - do instruction simplification before CSE
   3  *
   4  * Copyright (C) 2004 Linus Torvalds
   5  */
   6
   7 #include <assert.h>
   8
   9 #include "parse.h"
  10 #include "expression.h"
  11 #include "linearize.h"
  12 #include "flow.h"
  13
  14 /* Find the trivial parent for a phi-source */
  15 static struct basic_block *phi_parent(struct basic_block *source, pseudo_t pseudo)
  16 {
  17         /* Can't go upwards if the pseudo is defined in the bb it came from.. */
  18         if (pseudo->type == PSEUDO_REG) {
  19                 struct instruction *def = pseudo->def;
  20                 if (def->bb == source)
  21                         return source;
  22         }
  23         if (bb_list_size(source->children) != 1 || bb_list_size(source->parents) != 1)
  24                 return source;
  25         return first_basic_block(source->parents);
  26 }
  27
  28 static void clear_phi(struct instruction *insn)
  29 {
  30         pseudo_t phi;
  31
  32         insn->bb = NULL;
  33         FOR_EACH_PTR(insn->phi_list, phi) {
  34                 *THIS_ADDRESS(phi) = VOID;
  35         } END_FOR_EACH_PTR(phi);
  36 }
  37
  38 static int if_convert_phi(struct instruction *insn)
  39 {
  40         pseudo_t array[3];
  41         struct basic_block *parents[3];
  42         struct basic_block *bb, *bb1, *bb2, *source;
  43         struct instruction *br;
  44         pseudo_t p1, p2;
  45
  46         bb = insn->bb;
  47         if (linearize_ptr_list((struct ptr_list *)insn->phi_list, (void **)array, 3) != 2)
  48                 return 0;
  49         if (linearize_ptr_list((struct ptr_list *)bb->parents, (void **)parents, 3) != 2)
  50                 return 0;
  51         p1 = array[0]->def->src1;
  52         bb1 = array[0]->def->bb;
  53         p2 = array[1]->def->src1;
  54         bb2 = array[1]->def->bb;
  55
  56         /* Only try the simple "direct parents" case */
  57         if ((bb1 != parents[0] || bb2 != parents[1]) &&
  58             (bb1 != parents[1] || bb2 != parents[0]))
  59                 return 0;
  60
  61         /*
  62          * See if we can find a common source for this..
  63          */
  64         source = phi_parent(bb1, p1);
  65         if (source != phi_parent(bb2, p2))
  66                 return 0;
  67
  68         /*
  69          * Cool. We now know that 'source' is the exclusive
  70          * parent of both phi-nodes, so the exit at the
  71          * end of it fully determines which one it is, and
  72          * we can turn it into a select.
  73          *
  74          * HOWEVER, right now we only handle regular
  75          * conditional branches. No multijumps or computed
  76          * stuff. Verify that here.
  77          */
  78         br = last_instruction(source->insns);
  79         if (!br || br->opcode != OP_BR)
  80                 return 0;
  81
  82         assert(br->cond);
  83         assert(br->bb_false);
  84
  85         /*
  86          * We're in business. Match up true/false with p1/p2.
  87          */
  88         if (br->bb_true == bb2 || br->bb_false == bb1) {
  89                 pseudo_t p = p1;
  90                 p1 = p2;
  91                 p2 = p;
  92         }
  93
  94         /*
  95          * Ok, we can now replace that last
  96          *
  97          *      br cond, a, b
  98          *
  99          * with the sequence
 100          *
 101          *      setcc cond
 102          *      select pseudo, p1, p2
 103          *      br cond, a, b
 104          *
 105          * and remove the phi-node. If it then
 106          * turns out that 'a' or 'b' is entirely
 107          * empty (common case), and now no longer
 108          * a phi-source, we'll be able to simplify
 109          * the conditional branch too.
 110          */
 111         insert_select(source, br, insn, p1, p2);
 112         clear_phi(insn);
 113         return REPEAT_CSE;
 114 }
 115
 116 static int clean_up_phi(struct instruction *insn)
 117 {
 118         pseudo_t phi;
 119         struct instruction *last;
 120         int same;
 121
 122         last = NULL;
 123         same = 1;
 124         FOR_EACH_PTR(insn->phi_list, phi) {
 125                 struct instruction *def;
 126                 if (phi == VOID)
 127                         continue;
 128                 def = phi->def;
 129                 if (def->src1 == VOID || !def->bb)
 130                         continue;
 131                 if (last) {
 132                         if (last->src1 != def->src1)
 133                                 same = 0;
 134                         continue;
 135                 }
 136                 last = def;
 137         } END_FOR_EACH_PTR(phi);
 138
 139         if (same) {
 140                 pseudo_t pseudo = last ? last->src1 : VOID;
 141                 convert_instruction_target(insn, pseudo);
 142                 clear_phi(insn);
 143                 return REPEAT_CSE;
 144         }
 145
 146         return if_convert_phi(insn);
 147 }
 148
 149 static inline void remove_usage(pseudo_t p, pseudo_t *usep)
 150 {
 151         if (has_use_list(p)) {
 152                 delete_ptr_list_entry((struct ptr_list **)&p->users, usep, 1);
 153                 if (!p->users)
 154                         kill_instruction(p->def);
 155         }
 156 }
 157
 158 void kill_use(pseudo_t *usep)
 159 {
 160         if (usep) {
 161                 pseudo_t p = *usep;
 162                 *usep = VOID;
 163                 remove_usage(p, usep);
 164         }
 165 }
 166
 167 void kill_instruction(struct instruction *insn)
 168 {
 169         if (!insn || !insn->bb)
 170                 return;
 171
 172         switch (insn->opcode) {
 173         case OP_BINARY ... OP_BINCMP_END:
 174                 insn->bb = NULL;
 175                 kill_use(&insn->src1);
 176                 kill_use(&insn->src2);
 177                 repeat_phase |= REPEAT_CSE;
 178                 return;
 179
 180         case OP_NOT: case OP_NEG:
 181                 insn->bb = NULL;
 182                 kill_use(&insn->src1);
 183                 repeat_phase |= REPEAT_CSE;
 184                 return;
 185
 186         case OP_PHI:
 187                 insn->bb = NULL;
 188                 repeat_phase |= REPEAT_CSE;
 189                 return;
 190
 191         case OP_SYMADDR:
 192                 insn->bb = NULL;
 193                 repeat_phase |= REPEAT_CSE | REPEAT_SYMBOL_CLEANUP;
 194                 return;
 195
 196         case OP_RANGE:
 197                 insn->bb = NULL;
 198                 repeat_phase |= REPEAT_CSE;
 199                 kill_use(&insn->src1);
 200                 kill_use(&insn->src2);
 201                 kill_use(&insn->src3);
 202                 return;
 203         }
 204 }
 205
 206 /*
 207  * Kill trivially dead instructions
 208  */
 209 static int dead_insn(struct instruction *insn, pseudo_t *src1, pseudo_t *src2, pseudo_t *src3)
 210 {
 211         pseudo_t *usep;
 212         FOR_EACH_PTR(insn->target->users, usep) {
 213                 if (*usep != VOID)
 214                         return 0;
 215         } END_FOR_EACH_PTR(usep);
 216
 217         insn->bb = NULL;
 218         kill_use(src1);
 219         kill_use(src2);
 220         kill_use(src3);
 221         return REPEAT_CSE;
 222 }
 223
 224 static inline int constant(pseudo_t pseudo)
 225 {
 226         return pseudo->type == PSEUDO_VAL;
 227 }
 228
 229 static int replace_with_pseudo(struct instruction *insn, pseudo_t pseudo)
 230 {
 231         convert_instruction_target(insn, pseudo);
 232         insn->bb = NULL;
 233         return REPEAT_CSE;
 234 }
 235
 236 static int simplify_constant_rightside(struct instruction *insn)
 237 {
 238         long long value = insn->src2->value;
 239
 240         switch (insn->opcode) {
 241         case OP_SUB:
 242                 if (value) {
 243                         insn->opcode = OP_ADD;
 244                         insn->src2 = value_pseudo(-value);
 245                         return REPEAT_CSE;
 246                 }
 247         /* Fallthrough */
 248         case OP_ADD:
 249         case OP_OR: case OP_XOR:
 250         case OP_SHL:
 251         case OP_LSR: case OP_ASR:
 252                 if (!value)
 253                         return replace_with_pseudo(insn, insn->src1);
 254                 return 0;
 255
 256         case OP_AND:
 257         case OP_MULU: case OP_MULS:
 258                 if (!value)
 259                         return replace_with_pseudo(insn, insn->src2);
 260                 return 0;
 261         }
 262         return 0;
 263 }
 264
 265 static int simplify_constant_leftside(struct instruction *insn)
 266 {
 267         long long value = insn->src1->value;
 268
 269         switch (insn->opcode) {
 270         case OP_ADD: case OP_OR: case OP_XOR:
 271                 if (!value)
 272                         return replace_with_pseudo(insn, insn->src2);
 273                 return 0;
 274
 275         case OP_SHL:
 276         case OP_LSR: case OP_ASR:
 277         case OP_AND:
 278         case OP_MULU: case OP_MULS:
 279                 if (!value)
 280                         return replace_with_pseudo(insn, insn->src1);
 281                 return 0;
 282         }
 283         return 0;
 284 }
 285
 286 static int simplify_constant_binop(struct instruction *insn)
 287 {
 288         /* FIXME! Verify signs and sizes!! */
 289         long long left = insn->src1->value;
 290         long long right = insn->src2->value;
 291         unsigned long long ul, ur;
 292         long long res, mask, bits;
 293
 294         mask = 1ULL << (insn->size-1);
 295         bits = mask | (mask-1);
 296
 297         if (left & mask)
 298                 left |= ~bits;
 299         if (right & mask)
 300                 right |= ~bits;
 301         ul = left & bits;
 302         ur = right & bits;
 303
 304         switch (insn->opcode) {
 305         case OP_ADD:
 306                 res = left + right;
 307                 break;
 308         case OP_SUB:
 309                 res = left - right;
 310                 break;
 311         case OP_MULU:
 312                 res = ul * ur;
 313                 break;
 314         case OP_MULS:
 315                 res = left * right;
 316                 break;
 317         case OP_DIVU:
 318                 if (!ur)
 319                         return 0;
 320                 res = ul / ur;
 321                 break;
 322         case OP_DIVS:
 323                 if (!right)
 324                         return 0;
 325                 res = left / right;
 326                 break;
 327         case OP_MODU:
 328                 if (!ur)
 329                         return 0;
 330                 res = ul % ur;
 331                 break;
 332         case OP_MODS:
 333                 if (!right)
 334                         return 0;
 335                 res = left % right;
 336                 break;
 337         case OP_SHL:
 338                 res = left << right;
 339                 break;
 340         case OP_LSR:
 341                 res = ul >> ur;
 342                 break;
 343         case OP_ASR:
 344                 res = left >> right;
 345                 break;
 346        /* Logical */
 347         case OP_AND:
 348                 res = left & right;
 349                 break;
 350         case OP_OR:
 351                 res = left | right;
 352                 break;
 353         case OP_XOR:
 354                 res = left ^ right;
 355                 break;
 356         case OP_AND_BOOL:
 357                 res = left && right;
 358                 break;
 359         case OP_OR_BOOL:
 360                 res = left || right;
 361                 break;
 362
 363         /* Binary comparison */
 364         case OP_SET_EQ:
 365                 res = left == right;
 366                 break;
 367         case OP_SET_NE:
 368                 res = left != right;
 369                 break;
 370         case OP_SET_LE:
 371                 res = left <= right;
 372                 break;
 373         case OP_SET_GE:
 374                 res = left >= right;
 375                 break;
 376         case OP_SET_LT:
 377                 res = left < right;
 378                 break;
 379         case OP_SET_GT:
 380                 res = left > right;
 381                 break;
 382         case OP_SET_B:
 383                 res = ul < ur;
 384                 break;
 385         case OP_SET_A:
 386                 res = ul > ur;
 387                 break;
 388         case OP_SET_BE:
 389                 res = ul <= ur;
 390                 break;
 391         case OP_SET_AE:
 392                 res = ul >= ur;
 393                 break;
 394         default:
 395                 return 0;
 396         }
 397         res &= bits;
 398
 399         replace_with_pseudo(insn, value_pseudo(res));
 400         return REPEAT_CSE;
 401 }
 402
 403 static int simplify_binop(struct instruction *insn)
 404 {
 405         if (dead_insn(insn, &insn->src1, &insn->src2, NULL))
 406                 return REPEAT_CSE;
 407         if (constant(insn->src1)) {
 408                 if (constant(insn->src2))
 409                         return simplify_constant_binop(insn);
 410                 return simplify_constant_leftside(insn);
 411         }
 412         if (constant(insn->src2))
 413                 return simplify_constant_rightside(insn);
 414         return 0;
 415 }
 416
 417 static void switch_pseudo(pseudo_t *pp1, pseudo_t *pp2)
 418 {
 419         pseudo_t p1 = *pp1, p2 = *pp2;
 420
 421         use_pseudo(p2, pp1);
 422         use_pseudo(p1, pp2);
 423         remove_usage(p1, pp1);
 424         remove_usage(p2, pp2);
 425 }
 426
 427 static int canonical_order(pseudo_t p1, pseudo_t p2)
 428 {
 429         /* symbol/constants on the right */
 430         if (p1->type == PSEUDO_VAL)
 431                 return p2->type == PSEUDO_VAL;
 432
 433         if (p1->type == PSEUDO_SYM)
 434                 return p2->type == PSEUDO_SYM || p2->type == PSEUDO_VAL;
 435
 436         return 1;
 437 }
 438
 439 static int simplify_commutative_binop(struct instruction *insn)
 440 {
 441         if (!canonical_order(insn->src1, insn->src2)) {
 442                 switch_pseudo(&insn->src1, &insn->src2);
 443                 return REPEAT_CSE;
 444         }
 445         return 0;
 446 }
 447
 448 static inline int simple_pseudo(pseudo_t pseudo)
 449 {
 450         return pseudo->type == PSEUDO_VAL || pseudo->type == PSEUDO_SYM;
 451 }
 452
 453 static int simplify_associative_binop(struct instruction *insn)
 454 {
 455         struct instruction *def;
 456         pseudo_t pseudo = insn->src1;
 457
 458         if (!simple_pseudo(insn->src2))
 459                 return 0;
 460         if (pseudo->type != PSEUDO_REG)
 461                 return 0;
 462         def = pseudo->def;
 463         if (def == insn)
 464                 return 0;
 465         if (def->opcode != insn->opcode)
 466                 return 0;
 467         if (!simple_pseudo(def->src2))
 468                 return 0;
 469         if (ptr_list_size((struct ptr_list *)def->target->users) != 1)
 470                 return 0;
 471         switch_pseudo(&def->src1, &insn->src2);
 472         return REPEAT_CSE;
 473 }
 474
 475 static int simplify_constant_unop(struct instruction *insn)
 476 {
 477         long long val = insn->src1->value;
 478         long long res, mask;
 479
 480         switch (insn->opcode) {
 481         case OP_NOT:
 482                 res = ~val;
 483                 break;
 484         case OP_NEG:
 485                 res = -val;
 486                 break;
 487         default:
 488                 return 0;
 489         }
 490         mask = 1ULL << (insn->size-1);
 491         res &= mask | (mask-1);
 492
 493         replace_with_pseudo(insn, value_pseudo(res));
 494         return REPEAT_CSE;
 495 }
 496
 497 static int simplify_unop(struct instruction *insn)
 498 {
 499         if (dead_insn(insn, &insn->src1, NULL, NULL))
 500                 return REPEAT_CSE;
 501         if (constant(insn->src1))
 502                 return simplify_constant_unop(insn);
 503         return 0;
 504 }
 505
 506 static int simplify_one_memop(struct instruction *insn, pseudo_t orig)
 507 {
 508         pseudo_t addr = insn->src;
 509         pseudo_t new, off;
 510
 511         if (addr->type == PSEUDO_REG) {
 512                 struct instruction *def = addr->def;
 513                 if (def->opcode == OP_SYMADDR && def->src) {
 514                         kill_use(&insn->src);
 515                         use_pseudo(def->src, &insn->src);
 516                         return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP;
 517                 }
 518                 if (def->opcode == OP_ADD) {
 519                         new = def->src1;
 520                         off = def->src2;
 521                         if (constant(off))
 522                                 goto offset;
 523                         new = off;
 524                         off = def->src1;
 525                         if (constant(off))
 526                                 goto offset;
 527                         return 0;
 528                 }
 529         }
 530         return 0;
 531
 532 offset:
 533         /* Invalid code */
 534         if (new == orig) {
 535                 if (new == VOID)
 536                         return 0;
 537                 new = VOID;
 538                 warning(insn->pos, "crazy programmer");
 539         }
 540         insn->offset += off->value;
 541         use_pseudo(new, &insn->src);
 542         remove_usage(addr, &insn->src);
 543         return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP;
 544 }
 545
 546 /*
 547  * We walk the whole chain of adds/subs backwards. That's not
 548  * only more efficient, but it allows us to find looops.
 549  */
 550 static int simplify_memop(struct instruction *insn)
 551 {
 552         int one, ret = 0;
 553         pseudo_t orig = insn->src;
 554
 555         do {
 556                 one = simplify_one_memop(insn, orig);
 557                 ret |= one;
 558         } while (one);
 559         return ret;
 560 }
 561
 562 static int simplify_cast(struct instruction *insn)
 563 {
 564         struct symbol *orig_type;
 565         int orig_size, size;
 566         pseudo_t src;
 567
 568         if (dead_insn(insn, &insn->src, NULL, NULL))
 569                 return REPEAT_CSE;
 570
 571         orig_type = insn->orig_type;
 572         if (!orig_type)
 573                 return 0;
 574         orig_size = orig_type->bit_size;
 575         size = insn->size;
 576         src = insn->src;
 577
 578         /* A cast of a "and" might be a no-op.. */
 579         if (src->type == PSEUDO_REG) {
 580                 struct instruction *def = src->def;
 581                 if (def->opcode == OP_AND && def->size >= size) {
 582                         pseudo_t val = def->src2;
 583                         if (val->type == PSEUDO_VAL) {
 584                                 unsigned long long value = val->value;
 585                                 if (!(value >> (size-1)))
 586                                         goto simplify;
 587                         }
 588                 }
 589         }
 590
 591         if (size == orig_size) {
 592                 int op = (orig_type->ctype.modifiers & MOD_SIGNED) ? OP_SCAST : OP_CAST;
 593                 if (insn->opcode == op)
 594                         goto simplify;
 595         }
 596
 597         return 0;
 598
 599 simplify:
 600         return replace_with_pseudo(insn, insn->src);
 601 }
 602
 603 static int simplify_select(struct instruction *insn)
 604 {
 605         pseudo_t cond, src1, src2;
 606
 607         if (dead_insn(insn, &insn->src1, &insn->src2, &insn->src3))
 608                 return REPEAT_CSE;
 609
 610         cond = insn->src1;
 611         src1 = insn->src2;
 612         src2 = insn->src3;
 613         if (constant(cond) || src1 == src2) {
 614                 pseudo_t *kill, take;
 615                 kill_use(&insn->src1);
 616                 take = cond->value ? src1 : src2;
 617                 kill = cond->value ? &insn->src3 : &insn->src2;
 618                 kill_use(kill);
 619                 replace_with_pseudo(insn, take);
 620                 return REPEAT_CSE;
 621         }
 622         if (constant(src1) && constant(src2)) {
 623                 long long val1 = src1->value;
 624                 long long val2 = src2->value;
 625
 626                 /* The pair 0/1 is special - replace with SETNE/SETEQ */
 627                 if ((val1 | val2) == 1) {
 628                         int opcode = OP_SET_EQ;
 629                         if (val1) {
 630                                 src1 = src2;
 631                                 opcode = OP_SET_NE;
 632                         }
 633                         insn->opcode = opcode;
 634                         /* insn->src1 is already cond */
 635                         insn->src2 = src1; /* Zero */
 636                         return REPEAT_CSE;
 637                 }
 638         }
 639         return 0;
 640 }
 641
 642 static int is_in_range(pseudo_t src, long long low, long long high)
 643 {
 644         long long value;
 645
 646         switch (src->type) {
 647         case PSEUDO_VAL:
 648                 value = src->value;
 649                 return value >= low && value <= high;
 650         default:
 651                 return 0;
 652         }
 653 }
 654
 655 static int simplify_range(struct instruction *insn)
 656 {
 657         pseudo_t src1, src2, src3;
 658
 659         src1 = insn->src1;
 660         src2 = insn->src2;
 661         src3 = insn->src3;
 662         if (src2->type != PSEUDO_VAL || src3->type != PSEUDO_VAL)
 663                 return 0;
 664         if (is_in_range(src1, src2->value, src3->value)) {
 665                 kill_instruction(insn);
 666                 return REPEAT_CSE;
 667         }
 668         return 0;
 669 }
 670
 671 /*
 672  * Simplify "set_ne/eq $0 + br"
 673  */
 674 static int simplify_cond_branch(struct instruction *br, pseudo_t cond, struct instruction *def, pseudo_t *pp)
 675 {
 676         use_pseudo(*pp, &br->cond);
 677         remove_usage(cond, &br->cond);
 678         if (def->opcode == OP_SET_EQ) {
 679                 struct basic_block *true = br->bb_true;
 680                 struct basic_block *false = br->bb_false;
 681                 br->bb_false = true;
 682                 br->bb_true = false;
 683         }
 684         return REPEAT_CSE;
 685 }
 686
 687 static int simplify_branch(struct instruction *insn)
 688 {
 689         pseudo_t cond = insn->cond;
 690
 691         if (!cond)
 692                 return 0;
 693
 694         /* Constant conditional */
 695         if (constant(cond)) {
 696                 insert_branch(insn->bb, insn, cond->value ? insn->bb_true : insn->bb_false);
 697                 return REPEAT_CSE;
 698         }
 699
 700         /* Same target? */
 701         if (insn->bb_true == insn->bb_false) {
 702                 struct basic_block *bb = insn->bb;
 703                 struct basic_block *target = insn->bb_false;
 704                 remove_bb_from_list(&target->parents, bb, 1);
 705                 remove_bb_from_list(&bb->children, target, 1);
 706                 insn->bb_false = NULL;
 707                 kill_use(&insn->cond);
 708                 insn->cond = NULL;
 709                 return REPEAT_CSE;
 710         }
 711
 712         /* Conditional on a SETNE $0 or SETEQ $0 */
 713         if (cond->type == PSEUDO_REG) {
 714                 struct instruction *def = cond->def;
 715
 716                 if (def->opcode == OP_SET_NE || def->opcode == OP_SET_EQ) {
 717                         if (constant(def->src1) && !def->src1->value)
 718                                 return simplify_cond_branch(insn, cond, def, &def->src2);
 719                         if (constant(def->src2) && !def->src2->value)
 720                                 return simplify_cond_branch(insn, cond, def, &def->src1);
 721                 }
 722                 if (def->opcode == OP_SEL) {
 723                         if (constant(def->src2) && constant(def->src3)) {
 724                                 long long val1 = def->src2->value;
 725                                 long long val2 = def->src3->value;
 726                                 if (!val1 && !val2) {
 727                                         insert_branch(insn->bb, insn, insn->bb_false);
 728                                         return REPEAT_CSE;
 729                                 }
 730                                 if (val1 && val2) {
 731                                         insert_branch(insn->bb, insn, insn->bb_true);
 732                                         return REPEAT_CSE;
 733                                 }
 734                                 if (val2) {
 735                                         struct basic_block *true = insn->bb_true;
 736                                         struct basic_block *false = insn->bb_false;
 737                                         insn->bb_false = true;
 738                                         insn->bb_true = false;
 739                                 }
 740                                 use_pseudo(def->src1, &insn->cond);
 741                                 remove_usage(cond, &insn->cond);
 742                                 return REPEAT_CSE;
 743                         }
 744                 }
 745                 if (def->opcode == OP_CAST || def->opcode == OP_SCAST) {
 746                         int orig_size = def->orig_type ? def->orig_type->bit_size : 0;
 747                         if (def->size > orig_size) {
 748                                 use_pseudo(def->src, &insn->cond);
 749                                 remove_usage(cond, &insn->cond);
 750                                 return REPEAT_CSE;
 751                         }
 752                 }
 753         }
 754         return 0;
 755 }
 756
 757 static int simplify_switch(struct instruction *insn)
 758 {
 759         pseudo_t cond = insn->cond;
 760         long long val;
 761         struct multijmp *jmp;
 762
 763         if (!constant(cond))
 764                 return 0;
 765         val = insn->cond->value;
 766
 767         FOR_EACH_PTR(insn->multijmp_list, jmp) {
 768                 /* Default case */
 769                 if (jmp->begin > jmp->end)
 770                         goto found;
 771                 if (val >= jmp->begin && val <= jmp->end)
 772                         goto found;
 773         } END_FOR_EACH_PTR(jmp);
 774         warning(insn->pos, "Impossible case statement");
 775         return 0;
 776
 777 found:
 778         insert_branch(insn->bb, insn, jmp->target);
 779         return REPEAT_CSE;
 780 }
 781
 782 int simplify_instruction(struct instruction *insn)
 783 {
 784         if (!insn->bb)
 785                 return 0;
 786         switch (insn->opcode) {
 787         case OP_ADD: case OP_MULS:
 788         case OP_AND: case OP_OR: case OP_XOR:
 789         case OP_AND_BOOL: case OP_OR_BOOL:
 790                 if (simplify_binop(insn))
 791                         return REPEAT_CSE;
 792                 if (simplify_commutative_binop(insn))
 793                         return REPEAT_CSE;
 794                 return simplify_associative_binop(insn);
 795
 796         case OP_MULU:
 797         case OP_SET_EQ: case OP_SET_NE:
 798                 if (simplify_binop(insn))
 799                         return REPEAT_CSE;
 800                 return simplify_commutative_binop(insn);
 801
 802         case OP_SUB:
 803         case OP_DIVU: case OP_DIVS:
 804         case OP_MODU: case OP_MODS:
 805         case OP_SHL:
 806         case OP_LSR: case OP_ASR:
 807         case OP_SET_LE: case OP_SET_GE:
 808         case OP_SET_LT: case OP_SET_GT:
 809         case OP_SET_B:  case OP_SET_A:
 810         case OP_SET_BE: case OP_SET_AE:
 811                 return simplify_binop(insn);
 812
 813         case OP_NOT: case OP_NEG:
 814                 return simplify_unop(insn);
 815         case OP_LOAD: case OP_STORE:
 816                 return simplify_memop(insn);
 817         case OP_SYMADDR:
 818                 if (dead_insn(insn, NULL, NULL, NULL))
 819                         return REPEAT_CSE | REPEAT_SYMBOL_CLEANUP;
 820                 return replace_with_pseudo(insn, insn->symbol);
 821         case OP_CAST:
 822         case OP_SCAST:
 823         case OP_FPCAST:
 824         case OP_PTRCAST:
 825                 return simplify_cast(insn);
 826         case OP_PHI:
 827                 if (dead_insn(insn, NULL, NULL, NULL)) {
 828                         clear_phi(insn);
 829                         return REPEAT_CSE;
 830                 }
 831                 return clean_up_phi(insn);
 832         case OP_PHISOURCE:
 833                 if (dead_insn(insn, &insn->phi_src, NULL, NULL))
 834                         return REPEAT_CSE;
 835                 break;
 836         case OP_SEL:
 837                 return simplify_select(insn);
 838         case OP_BR:
 839                 return simplify_branch(insn);
 840         case OP_SWITCH:
 841                 return simplify_switch(insn);
 842         case OP_RANGE:
 843                 return simplify_range(insn);
 844         }
 845         return 0;
 846 }