tcg/optimize.c

   1 /*
   2  * Optimizations for Tiny Code Generator for QEMU
   3  *
   4  * Copyright (c) 2010 Samsung Electronics.
   5  * Contributed by Kirill Batuzov <batuzovk@ispras.ru>
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "config.h"
  27
  28 #include <stdlib.h>
  29 #include <stdio.h>
  30
  31 #include "qemu-common.h"
  32 #include "tcg-op.h"
  33
  34 #define CASE_OP_32_64(x)                        \
  35         glue(glue(case INDEX_op_, x), _i32):    \
  36         glue(glue(case INDEX_op_, x), _i64)
  37
  38 typedef enum {
  39     TCG_TEMP_UNDEF = 0,
  40     TCG_TEMP_CONST,
  41     TCG_TEMP_COPY,
  42 } tcg_temp_state;
  43
  44 struct tcg_temp_info {
  45     tcg_temp_state state;
  46     uint16_t prev_copy;
  47     uint16_t next_copy;
  48     tcg_target_ulong val;
  49     tcg_target_ulong mask;
  50 };
  51
  52 static struct tcg_temp_info temps[TCG_MAX_TEMPS];
  53
  54 /* Reset TEMP's state to TCG_TEMP_UNDEF.  If TEMP only had one copy, remove
  55    the copy flag from the left temp.  */
  56 static void reset_temp(TCGArg temp)
  57 {
  58     if (temps[temp].state == TCG_TEMP_COPY) {
  59         if (temps[temp].prev_copy == temps[temp].next_copy) {
  60             temps[temps[temp].next_copy].state = TCG_TEMP_UNDEF;
  61         } else {
  62             temps[temps[temp].next_copy].prev_copy = temps[temp].prev_copy;
  63             temps[temps[temp].prev_copy].next_copy = temps[temp].next_copy;
  64         }
  65     }
  66     temps[temp].state = TCG_TEMP_UNDEF;
  67     temps[temp].mask = -1;
  68 }
  69
  70 /* Reset all temporaries, given that there are NB_TEMPS of them.  */
  71 static void reset_all_temps(int nb_temps)
  72 {
  73     int i;
  74     for (i = 0; i < nb_temps; i++) {
  75         temps[i].state = TCG_TEMP_UNDEF;
  76         temps[i].mask = -1;
  77     }
  78 }
  79
  80 static int op_bits(TCGOpcode op)
  81 {
  82     const TCGOpDef *def = &tcg_op_defs[op];
  83     return def->flags & TCG_OPF_64BIT ? 64 : 32;
  84 }
  85
  86 static TCGOpcode op_to_movi(TCGOpcode op)
  87 {
  88     switch (op_bits(op)) {
  89     case 32:
  90         return INDEX_op_movi_i32;
  91     case 64:
  92         return INDEX_op_movi_i64;
  93     default:
  94         fprintf(stderr, "op_to_movi: unexpected return value of "
  95                 "function op_bits.\n");
  96         tcg_abort();
  97     }
  98 }
  99
 100 static TCGArg find_better_copy(TCGContext *s, TCGArg temp)
 101 {
 102     TCGArg i;
 103
 104     /* If this is already a global, we can't do better. */
 105     if (temp < s->nb_globals) {
 106         return temp;
 107     }
 108
 109     /* Search for a global first. */
 110     for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) {
 111         if (i < s->nb_globals) {
 112             return i;
 113         }
 114     }
 115
 116     /* If it is a temp, search for a temp local. */
 117     if (!s->temps[temp].temp_local) {
 118         for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) {
 119             if (s->temps[i].temp_local) {
 120                 return i;
 121             }
 122         }
 123     }
 124
 125     /* Failure to find a better representation, return the same temp. */
 126     return temp;
 127 }
 128
 129 static bool temps_are_copies(TCGArg arg1, TCGArg arg2)
 130 {
 131     TCGArg i;
 132
 133     if (arg1 == arg2) {
 134         return true;
 135     }
 136
 137     if (temps[arg1].state != TCG_TEMP_COPY
 138         || temps[arg2].state != TCG_TEMP_COPY) {
 139         return false;
 140     }
 141
 142     for (i = temps[arg1].next_copy ; i != arg1 ; i = temps[i].next_copy) {
 143         if (i == arg2) {
 144             return true;
 145         }
 146     }
 147
 148     return false;
 149 }
 150
 151 static void tcg_opt_gen_mov(TCGContext *s, TCGArg *gen_args,
 152                             TCGArg dst, TCGArg src)
 153 {
 154     reset_temp(dst);
 155     temps[dst].mask = temps[src].mask;
 156     assert(temps[src].state != TCG_TEMP_CONST);
 157
 158     if (s->temps[src].type == s->temps[dst].type) {
 159         if (temps[src].state != TCG_TEMP_COPY) {
 160             temps[src].state = TCG_TEMP_COPY;
 161             temps[src].next_copy = src;
 162             temps[src].prev_copy = src;
 163         }
 164         temps[dst].state = TCG_TEMP_COPY;
 165         temps[dst].next_copy = temps[src].next_copy;
 166         temps[dst].prev_copy = src;
 167         temps[temps[dst].next_copy].prev_copy = dst;
 168         temps[src].next_copy = dst;
 169     }
 170
 171     gen_args[0] = dst;
 172     gen_args[1] = src;
 173 }
 174
 175 static void tcg_opt_gen_movi(TCGArg *gen_args, TCGArg dst, TCGArg val)
 176 {
 177     reset_temp(dst);
 178     temps[dst].state = TCG_TEMP_CONST;
 179     temps[dst].val = val;
 180     temps[dst].mask = val;
 181     gen_args[0] = dst;
 182     gen_args[1] = val;
 183 }
 184
 185 static TCGOpcode op_to_mov(TCGOpcode op)
 186 {
 187     switch (op_bits(op)) {
 188     case 32:
 189         return INDEX_op_mov_i32;
 190     case 64:
 191         return INDEX_op_mov_i64;
 192     default:
 193         fprintf(stderr, "op_to_mov: unexpected return value of "
 194                 "function op_bits.\n");
 195         tcg_abort();
 196     }
 197 }
 198
 199 static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
 200 {
 201     switch (op) {
 202     CASE_OP_32_64(add):
 203         return x + y;
 204
 205     CASE_OP_32_64(sub):
 206         return x - y;
 207
 208     CASE_OP_32_64(mul):
 209         return x * y;
 210
 211     CASE_OP_32_64(and):
 212         return x & y;
 213
 214     CASE_OP_32_64(or):
 215         return x | y;
 216
 217     CASE_OP_32_64(xor):
 218         return x ^ y;
 219
 220     case INDEX_op_shl_i32:
 221         return (uint32_t)x << (uint32_t)y;
 222
 223     case INDEX_op_shl_i64:
 224         return (uint64_t)x << (uint64_t)y;
 225
 226     case INDEX_op_shr_i32:
 227         return (uint32_t)x >> (uint32_t)y;
 228
 229     case INDEX_op_shr_i64:
 230         return (uint64_t)x >> (uint64_t)y;
 231
 232     case INDEX_op_sar_i32:
 233         return (int32_t)x >> (int32_t)y;
 234
 235     case INDEX_op_sar_i64:
 236         return (int64_t)x >> (int64_t)y;
 237
 238     case INDEX_op_rotr_i32:
 239         x = ((uint32_t)x << (32 - y)) | ((uint32_t)x >> y);
 240         return x;
 241
 242     case INDEX_op_rotr_i64:
 243         x = ((uint64_t)x << (64 - y)) | ((uint64_t)x >> y);
 244         return x;
 245
 246     case INDEX_op_rotl_i32:
 247         x = ((uint32_t)x << y) | ((uint32_t)x >> (32 - y));
 248         return x;
 249
 250     case INDEX_op_rotl_i64:
 251         x = ((uint64_t)x << y) | ((uint64_t)x >> (64 - y));
 252         return x;
 253
 254     CASE_OP_32_64(not):
 255         return ~x;
 256
 257     CASE_OP_32_64(neg):
 258         return -x;
 259
 260     CASE_OP_32_64(andc):
 261         return x & ~y;
 262
 263     CASE_OP_32_64(orc):
 264         return x | ~y;
 265
 266     CASE_OP_32_64(eqv):
 267         return ~(x ^ y);
 268
 269     CASE_OP_32_64(nand):
 270         return ~(x & y);
 271
 272     CASE_OP_32_64(nor):
 273         return ~(x | y);
 274
 275     CASE_OP_32_64(ext8s):
 276         return (int8_t)x;
 277
 278     CASE_OP_32_64(ext16s):
 279         return (int16_t)x;
 280
 281     CASE_OP_32_64(ext8u):
 282         return (uint8_t)x;
 283
 284     CASE_OP_32_64(ext16u):
 285         return (uint16_t)x;
 286
 287     case INDEX_op_ext32s_i64:
 288         return (int32_t)x;
 289
 290     case INDEX_op_ext32u_i64:
 291         return (uint32_t)x;
 292
 293     default:
 294         fprintf(stderr,
 295                 "Unrecognized operation %d in do_constant_folding.\n", op);
 296         tcg_abort();
 297     }
 298 }
 299
 300 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 301 {
 302     TCGArg res = do_constant_folding_2(op, x, y);
 303     if (op_bits(op) == 32) {
 304         res &= 0xffffffff;
 305     }
 306     return res;
 307 }
 308
 309 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
 310 {
 311     switch (c) {
 312     case TCG_COND_EQ:
 313         return x == y;
 314     case TCG_COND_NE:
 315         return x != y;
 316     case TCG_COND_LT:
 317         return (int32_t)x < (int32_t)y;
 318     case TCG_COND_GE:
 319         return (int32_t)x >= (int32_t)y;
 320     case TCG_COND_LE:
 321         return (int32_t)x <= (int32_t)y;
 322     case TCG_COND_GT:
 323         return (int32_t)x > (int32_t)y;
 324     case TCG_COND_LTU:
 325         return x < y;
 326     case TCG_COND_GEU:
 327         return x >= y;
 328     case TCG_COND_LEU:
 329         return x <= y;
 330     case TCG_COND_GTU:
 331         return x > y;
 332     default:
 333         tcg_abort();
 334     }
 335 }
 336
 337 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
 338 {
 339     switch (c) {
 340     case TCG_COND_EQ:
 341         return x == y;
 342     case TCG_COND_NE:
 343         return x != y;
 344     case TCG_COND_LT:
 345         return (int64_t)x < (int64_t)y;
 346     case TCG_COND_GE:
 347         return (int64_t)x >= (int64_t)y;
 348     case TCG_COND_LE:
 349         return (int64_t)x <= (int64_t)y;
 350     case TCG_COND_GT:
 351         return (int64_t)x > (int64_t)y;
 352     case TCG_COND_LTU:
 353         return x < y;
 354     case TCG_COND_GEU:
 355         return x >= y;
 356     case TCG_COND_LEU:
 357         return x <= y;
 358     case TCG_COND_GTU:
 359         return x > y;
 360     default:
 361         tcg_abort();
 362     }
 363 }
 364
 365 static bool do_constant_folding_cond_eq(TCGCond c)
 366 {
 367     switch (c) {
 368     case TCG_COND_GT:
 369     case TCG_COND_LTU:
 370     case TCG_COND_LT:
 371     case TCG_COND_GTU:
 372     case TCG_COND_NE:
 373         return 0;
 374     case TCG_COND_GE:
 375     case TCG_COND_GEU:
 376     case TCG_COND_LE:
 377     case TCG_COND_LEU:
 378     case TCG_COND_EQ:
 379         return 1;
 380     default:
 381         tcg_abort();
 382     }
 383 }
 384
 385 /* Return 2 if the condition can't be simplified, and the result
 386    of the condition (0 or 1) if it can */
 387 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 388                                        TCGArg y, TCGCond c)
 389 {
 390     if (temps[x].state == TCG_TEMP_CONST && temps[y].state == TCG_TEMP_CONST) {
 391         switch (op_bits(op)) {
 392         case 32:
 393             return do_constant_folding_cond_32(temps[x].val, temps[y].val, c);
 394         case 64:
 395             return do_constant_folding_cond_64(temps[x].val, temps[y].val, c);
 396         default:
 397             tcg_abort();
 398         }
 399     } else if (temps_are_copies(x, y)) {
 400         return do_constant_folding_cond_eq(c);
 401     } else if (temps[y].state == TCG_TEMP_CONST && temps[y].val == 0) {
 402         switch (c) {
 403         case TCG_COND_LTU:
 404             return 0;
 405         case TCG_COND_GEU:
 406             return 1;
 407         default:
 408             return 2;
 409         }
 410     } else {
 411         return 2;
 412     }
 413 }
 414
 415 /* Return 2 if the condition can't be simplified, and the result
 416    of the condition (0 or 1) if it can */
 417 static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
 418 {
 419     TCGArg al = p1[0], ah = p1[1];
 420     TCGArg bl = p2[0], bh = p2[1];
 421
 422     if (temps[bl].state == TCG_TEMP_CONST
 423         && temps[bh].state == TCG_TEMP_CONST) {
 424         uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val;
 425
 426         if (temps[al].state == TCG_TEMP_CONST
 427             && temps[ah].state == TCG_TEMP_CONST) {
 428             uint64_t a;
 429             a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val;
 430             return do_constant_folding_cond_64(a, b, c);
 431         }
 432         if (b == 0) {
 433             switch (c) {
 434             case TCG_COND_LTU:
 435                 return 0;
 436             case TCG_COND_GEU:
 437                 return 1;
 438             default:
 439                 break;
 440             }
 441         }
 442     }
 443     if (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) {
 444         return do_constant_folding_cond_eq(c);
 445     }
 446     return 2;
 447 }
 448
 449 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 450 {
 451     TCGArg a1 = *p1, a2 = *p2;
 452     int sum = 0;
 453     sum += temps[a1].state == TCG_TEMP_CONST;
 454     sum -= temps[a2].state == TCG_TEMP_CONST;
 455
 456     /* Prefer the constant in second argument, and then the form
 457        op a, a, b, which is better handled on non-RISC hosts. */
 458     if (sum > 0 || (sum == 0 && dest == a2)) {
 459         *p1 = a2;
 460         *p2 = a1;
 461         return true;
 462     }
 463     return false;
 464 }
 465
 466 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 467 {
 468     int sum = 0;
 469     sum += temps[p1[0]].state == TCG_TEMP_CONST;
 470     sum += temps[p1[1]].state == TCG_TEMP_CONST;
 471     sum -= temps[p2[0]].state == TCG_TEMP_CONST;
 472     sum -= temps[p2[1]].state == TCG_TEMP_CONST;
 473     if (sum > 0) {
 474         TCGArg t;
 475         t = p1[0], p1[0] = p2[0], p2[0] = t;
 476         t = p1[1], p1[1] = p2[1], p2[1] = t;
 477         return true;
 478     }
 479     return false;
 480 }
 481
 482 /* Propagate constants and copies, fold constant expressions. */
 483 static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 484                                     TCGArg *args, TCGOpDef *tcg_op_defs)
 485 {
 486     int i, nb_ops, op_index, nb_temps, nb_globals, nb_call_args;
 487     tcg_target_ulong mask, affected;
 488     TCGOpcode op;
 489     const TCGOpDef *def;
 490     TCGArg *gen_args;
 491     TCGArg tmp;
 492
 493     /* Array VALS has an element for each temp.
 494        If this temp holds a constant then its value is kept in VALS' element.
 495        If this temp is a copy of other ones then the other copies are
 496        available through the doubly linked circular list. */
 497
 498     nb_temps = s->nb_temps;
 499     nb_globals = s->nb_globals;
 500     reset_all_temps(nb_temps);
 501
 502     nb_ops = tcg_opc_ptr - s->gen_opc_buf;
 503     gen_args = args;
 504     for (op_index = 0; op_index < nb_ops; op_index++) {
 505         op = s->gen_opc_buf[op_index];
 506         def = &tcg_op_defs[op];
 507         /* Do copy propagation */
 508         if (op == INDEX_op_call) {
 509             int nb_oargs = args[0] >> 16;
 510             int nb_iargs = args[0] & 0xffff;
 511             for (i = nb_oargs + 1; i < nb_oargs + nb_iargs + 1; i++) {
 512                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 513                     args[i] = find_better_copy(s, args[i]);
 514                 }
 515             }
 516         } else {
 517             for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) {
 518                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 519                     args[i] = find_better_copy(s, args[i]);
 520                 }
 521             }
 522         }
 523
 524         /* For commutative operations make constant second argument */
 525         switch (op) {
 526         CASE_OP_32_64(add):
 527         CASE_OP_32_64(mul):
 528         CASE_OP_32_64(and):
 529         CASE_OP_32_64(or):
 530         CASE_OP_32_64(xor):
 531         CASE_OP_32_64(eqv):
 532         CASE_OP_32_64(nand):
 533         CASE_OP_32_64(nor):
 534             swap_commutative(args[0], &args[1], &args[2]);
 535             break;
 536         CASE_OP_32_64(brcond):
 537             if (swap_commutative(-1, &args[0], &args[1])) {
 538                 args[2] = tcg_swap_cond(args[2]);
 539             }
 540             break;
 541         CASE_OP_32_64(setcond):
 542             if (swap_commutative(args[0], &args[1], &args[2])) {
 543                 args[3] = tcg_swap_cond(args[3]);
 544             }
 545             break;
 546         CASE_OP_32_64(movcond):
 547             if (swap_commutative(-1, &args[1], &args[2])) {
 548                 args[5] = tcg_swap_cond(args[5]);
 549             }
 550             /* For movcond, we canonicalize the "false" input reg to match
 551                the destination reg so that the tcg backend can implement
 552                a "move if true" operation.  */
 553             if (swap_commutative(args[0], &args[4], &args[3])) {
 554                 args[5] = tcg_invert_cond(args[5]);
 555             }
 556             break;
 557         CASE_OP_32_64(add2):
 558             swap_commutative(args[0], &args[2], &args[4]);
 559             swap_commutative(args[1], &args[3], &args[5]);
 560             break;
 561         CASE_OP_32_64(mulu2):
 562         CASE_OP_32_64(muls2):
 563             swap_commutative(args[0], &args[2], &args[3]);
 564             break;
 565         case INDEX_op_brcond2_i32:
 566             if (swap_commutative2(&args[0], &args[2])) {
 567                 args[4] = tcg_swap_cond(args[4]);
 568             }
 569             break;
 570         case INDEX_op_setcond2_i32:
 571             if (swap_commutative2(&args[1], &args[3])) {
 572                 args[5] = tcg_swap_cond(args[5]);
 573             }
 574             break;
 575         default:
 576             break;
 577         }
 578
 579         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
 580            and "sub r, 0, a => neg r, a" case.  */
 581         switch (op) {
 582         CASE_OP_32_64(shl):
 583         CASE_OP_32_64(shr):
 584         CASE_OP_32_64(sar):
 585         CASE_OP_32_64(rotl):
 586         CASE_OP_32_64(rotr):
 587             if (temps[args[1]].state == TCG_TEMP_CONST
 588                 && temps[args[1]].val == 0) {
 589                 s->gen_opc_buf[op_index] = op_to_movi(op);
 590                 tcg_opt_gen_movi(gen_args, args[0], 0);
 591                 args += 3;
 592                 gen_args += 2;
 593                 continue;
 594             }
 595             break;
 596         CASE_OP_32_64(sub):
 597             {
 598                 TCGOpcode neg_op;
 599                 bool have_neg;
 600
 601                 if (temps[args[2]].state == TCG_TEMP_CONST) {
 602                     /* Proceed with possible constant folding. */
 603                     break;
 604                 }
 605                 if (op == INDEX_op_sub_i32) {
 606                     neg_op = INDEX_op_neg_i32;
 607                     have_neg = TCG_TARGET_HAS_neg_i32;
 608                 } else {
 609                     neg_op = INDEX_op_neg_i64;
 610                     have_neg = TCG_TARGET_HAS_neg_i64;
 611                 }
 612                 if (!have_neg) {
 613                     break;
 614                 }
 615                 if (temps[args[1]].state == TCG_TEMP_CONST
 616                     && temps[args[1]].val == 0) {
 617                     s->gen_opc_buf[op_index] = neg_op;
 618                     reset_temp(args[0]);
 619                     gen_args[0] = args[0];
 620                     gen_args[1] = args[2];
 621                     args += 3;
 622                     gen_args += 2;
 623                     continue;
 624                 }
 625             }
 626             break;
 627         default:
 628             break;
 629         }
 630
 631         /* Simplify expression for "op r, a, 0 => mov r, a" cases */
 632         switch (op) {
 633         CASE_OP_32_64(add):
 634         CASE_OP_32_64(sub):
 635         CASE_OP_32_64(shl):
 636         CASE_OP_32_64(shr):
 637         CASE_OP_32_64(sar):
 638         CASE_OP_32_64(rotl):
 639         CASE_OP_32_64(rotr):
 640         CASE_OP_32_64(or):
 641         CASE_OP_32_64(xor):
 642             if (temps[args[1]].state == TCG_TEMP_CONST) {
 643                 /* Proceed with possible constant folding. */
 644                 break;
 645             }
 646             if (temps[args[2]].state == TCG_TEMP_CONST
 647                 && temps[args[2]].val == 0) {
 648                 if (temps_are_copies(args[0], args[1])) {
 649                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 650                 } else {
 651                     s->gen_opc_buf[op_index] = op_to_mov(op);
 652                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 653                     gen_args += 2;
 654                 }
 655                 args += 3;
 656                 continue;
 657             }
 658             break;
 659         default:
 660             break;
 661         }
 662
 663         /* Simplify using known-zero bits */
 664         mask = -1;
 665         affected = -1;
 666         switch (op) {
 667         CASE_OP_32_64(ext8s):
 668             if ((temps[args[1]].mask & 0x80) != 0) {
 669                 break;
 670             }
 671         CASE_OP_32_64(ext8u):
 672             mask = 0xff;
 673             goto and_const;
 674         CASE_OP_32_64(ext16s):
 675             if ((temps[args[1]].mask & 0x8000) != 0) {
 676                 break;
 677             }
 678         CASE_OP_32_64(ext16u):
 679             mask = 0xffff;
 680             goto and_const;
 681         case INDEX_op_ext32s_i64:
 682             if ((temps[args[1]].mask & 0x80000000) != 0) {
 683                 break;
 684             }
 685         case INDEX_op_ext32u_i64:
 686             mask = 0xffffffffU;
 687             goto and_const;
 688
 689         CASE_OP_32_64(and):
 690             mask = temps[args[2]].mask;
 691             if (temps[args[2]].state == TCG_TEMP_CONST) {
 692         and_const:
 693                 affected = temps[args[1]].mask & ~mask;
 694             }
 695             mask = temps[args[1]].mask & mask;
 696             break;
 697
 698         CASE_OP_32_64(sar):
 699             if (temps[args[2]].state == TCG_TEMP_CONST) {
 700                 mask = ((tcg_target_long)temps[args[1]].mask
 701                         >> temps[args[2]].val);
 702             }
 703             break;
 704
 705         CASE_OP_32_64(shr):
 706             if (temps[args[2]].state == TCG_TEMP_CONST) {
 707                 mask = temps[args[1]].mask >> temps[args[2]].val;
 708             }
 709             break;
 710
 711         CASE_OP_32_64(shl):
 712             if (temps[args[2]].state == TCG_TEMP_CONST) {
 713                 mask = temps[args[1]].mask << temps[args[2]].val;
 714             }
 715             break;
 716
 717         CASE_OP_32_64(neg):
 718             /* Set to 1 all bits to the left of the rightmost.  */
 719             mask = -(temps[args[1]].mask & -temps[args[1]].mask);
 720             break;
 721
 722         CASE_OP_32_64(deposit):
 723             tmp = ((1ull << args[4]) - 1);
 724             mask = ((temps[args[1]].mask & ~(tmp << args[3]))
 725                     | ((temps[args[2]].mask & tmp) << args[3]));
 726             break;
 727
 728         CASE_OP_32_64(or):
 729         CASE_OP_32_64(xor):
 730             mask = temps[args[1]].mask | temps[args[2]].mask;
 731             break;
 732
 733         CASE_OP_32_64(setcond):
 734             mask = 1;
 735             break;
 736
 737         CASE_OP_32_64(movcond):
 738             mask = temps[args[3]].mask | temps[args[4]].mask;
 739             break;
 740
 741         default:
 742             break;
 743         }
 744
 745         if (mask == 0) {
 746             assert(def->nb_oargs == 1);
 747             s->gen_opc_buf[op_index] = op_to_movi(op);
 748             tcg_opt_gen_movi(gen_args, args[0], 0);
 749             args += def->nb_oargs + def->nb_iargs + def->nb_cargs;
 750             gen_args += 2;
 751             continue;
 752         }
 753         if (affected == 0) {
 754             assert(def->nb_oargs == 1);
 755             if (temps_are_copies(args[0], args[1])) {
 756                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 757             } else if (temps[args[1]].state != TCG_TEMP_CONST) {
 758                 s->gen_opc_buf[op_index] = op_to_mov(op);
 759                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 760                 gen_args += 2;
 761             } else {
 762                 s->gen_opc_buf[op_index] = op_to_movi(op);
 763                 tcg_opt_gen_movi(gen_args, args[0], temps[args[1]].val);
 764                 gen_args += 2;
 765             }
 766             args += def->nb_iargs + 1;
 767             continue;
 768         }
 769
 770         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
 771         switch (op) {
 772         CASE_OP_32_64(and):
 773         CASE_OP_32_64(mul):
 774             if ((temps[args[2]].state == TCG_TEMP_CONST
 775                 && temps[args[2]].val == 0)) {
 776                 s->gen_opc_buf[op_index] = op_to_movi(op);
 777                 tcg_opt_gen_movi(gen_args, args[0], 0);
 778                 args += 3;
 779                 gen_args += 2;
 780                 continue;
 781             }
 782             break;
 783         default:
 784             break;
 785         }
 786
 787         /* Simplify expression for "op r, a, a => mov r, a" cases */
 788         switch (op) {
 789         CASE_OP_32_64(or):
 790         CASE_OP_32_64(and):
 791             if (temps_are_copies(args[1], args[2])) {
 792                 if (temps_are_copies(args[0], args[1])) {
 793                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 794                 } else {
 795                     s->gen_opc_buf[op_index] = op_to_mov(op);
 796                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 797                     gen_args += 2;
 798                 }
 799                 args += 3;
 800                 continue;
 801             }
 802             break;
 803         default:
 804             break;
 805         }
 806
 807         /* Simplify expression for "op r, a, a => movi r, 0" cases */
 808         switch (op) {
 809         CASE_OP_32_64(sub):
 810         CASE_OP_32_64(xor):
 811             if (temps_are_copies(args[1], args[2])) {
 812                 s->gen_opc_buf[op_index] = op_to_movi(op);
 813                 tcg_opt_gen_movi(gen_args, args[0], 0);
 814                 gen_args += 2;
 815                 args += 3;
 816                 continue;
 817             }
 818             break;
 819         default:
 820             break;
 821         }
 822
 823         /* Propagate constants through copy operations and do constant
 824            folding.  Constants will be substituted to arguments by register
 825            allocator where needed and possible.  Also detect copies. */
 826         switch (op) {
 827         CASE_OP_32_64(mov):
 828             if (temps_are_copies(args[0], args[1])) {
 829                 args += 2;
 830                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 831                 break;
 832             }
 833             if (temps[args[1]].state != TCG_TEMP_CONST) {
 834                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 835                 gen_args += 2;
 836                 args += 2;
 837                 break;
 838             }
 839             /* Source argument is constant.  Rewrite the operation and
 840                let movi case handle it. */
 841             op = op_to_movi(op);
 842             s->gen_opc_buf[op_index] = op;
 843             args[1] = temps[args[1]].val;
 844             /* fallthrough */
 845         CASE_OP_32_64(movi):
 846             tcg_opt_gen_movi(gen_args, args[0], args[1]);
 847             gen_args += 2;
 848             args += 2;
 849             break;
 850
 851         CASE_OP_32_64(not):
 852         CASE_OP_32_64(neg):
 853         CASE_OP_32_64(ext8s):
 854         CASE_OP_32_64(ext8u):
 855         CASE_OP_32_64(ext16s):
 856         CASE_OP_32_64(ext16u):
 857         case INDEX_op_ext32s_i64:
 858         case INDEX_op_ext32u_i64:
 859             if (temps[args[1]].state == TCG_TEMP_CONST) {
 860                 s->gen_opc_buf[op_index] = op_to_movi(op);
 861                 tmp = do_constant_folding(op, temps[args[1]].val, 0);
 862                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 863                 gen_args += 2;
 864                 args += 2;
 865                 break;
 866             }
 867             goto do_default;
 868
 869         CASE_OP_32_64(add):
 870         CASE_OP_32_64(sub):
 871         CASE_OP_32_64(mul):
 872         CASE_OP_32_64(or):
 873         CASE_OP_32_64(and):
 874         CASE_OP_32_64(xor):
 875         CASE_OP_32_64(shl):
 876         CASE_OP_32_64(shr):
 877         CASE_OP_32_64(sar):
 878         CASE_OP_32_64(rotl):
 879         CASE_OP_32_64(rotr):
 880         CASE_OP_32_64(andc):
 881         CASE_OP_32_64(orc):
 882         CASE_OP_32_64(eqv):
 883         CASE_OP_32_64(nand):
 884         CASE_OP_32_64(nor):
 885             if (temps[args[1]].state == TCG_TEMP_CONST
 886                 && temps[args[2]].state == TCG_TEMP_CONST) {
 887                 s->gen_opc_buf[op_index] = op_to_movi(op);
 888                 tmp = do_constant_folding(op, temps[args[1]].val,
 889                                           temps[args[2]].val);
 890                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 891                 gen_args += 2;
 892                 args += 3;
 893                 break;
 894             }
 895             goto do_default;
 896
 897         CASE_OP_32_64(deposit):
 898             if (temps[args[1]].state == TCG_TEMP_CONST
 899                 && temps[args[2]].state == TCG_TEMP_CONST) {
 900                 s->gen_opc_buf[op_index] = op_to_movi(op);
 901                 tmp = ((1ull << args[4]) - 1);
 902                 tmp = (temps[args[1]].val & ~(tmp << args[3]))
 903                       | ((temps[args[2]].val & tmp) << args[3]);
 904                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 905                 gen_args += 2;
 906                 args += 5;
 907                 break;
 908             }
 909             goto do_default;
 910
 911         CASE_OP_32_64(setcond):
 912             tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
 913             if (tmp != 2) {
 914                 s->gen_opc_buf[op_index] = op_to_movi(op);
 915                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 916                 gen_args += 2;
 917                 args += 4;
 918                 break;
 919             }
 920             goto do_default;
 921
 922         CASE_OP_32_64(brcond):
 923             tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
 924             if (tmp != 2) {
 925                 if (tmp) {
 926                     reset_all_temps(nb_temps);
 927                     s->gen_opc_buf[op_index] = INDEX_op_br;
 928                     gen_args[0] = args[3];
 929                     gen_args += 1;
 930                 } else {
 931                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 932                 }
 933                 args += 4;
 934                 break;
 935             }
 936             goto do_default;
 937
 938         CASE_OP_32_64(movcond):
 939             tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
 940             if (tmp != 2) {
 941                 if (temps_are_copies(args[0], args[4-tmp])) {
 942                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 943                 } else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
 944                     s->gen_opc_buf[op_index] = op_to_movi(op);
 945                     tcg_opt_gen_movi(gen_args, args[0], temps[args[4-tmp]].val);
 946                     gen_args += 2;
 947                 } else {
 948                     s->gen_opc_buf[op_index] = op_to_mov(op);
 949                     tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
 950                     gen_args += 2;
 951                 }
 952                 args += 6;
 953                 break;
 954             }
 955             goto do_default;
 956
 957         case INDEX_op_add2_i32:
 958         case INDEX_op_sub2_i32:
 959             if (temps[args[2]].state == TCG_TEMP_CONST
 960                 && temps[args[3]].state == TCG_TEMP_CONST
 961                 && temps[args[4]].state == TCG_TEMP_CONST
 962                 && temps[args[5]].state == TCG_TEMP_CONST) {
 963                 uint32_t al = temps[args[2]].val;
 964                 uint32_t ah = temps[args[3]].val;
 965                 uint32_t bl = temps[args[4]].val;
 966                 uint32_t bh = temps[args[5]].val;
 967                 uint64_t a = ((uint64_t)ah << 32) | al;
 968                 uint64_t b = ((uint64_t)bh << 32) | bl;
 969                 TCGArg rl, rh;
 970
 971                 if (op == INDEX_op_add2_i32) {
 972                     a += b;
 973                 } else {
 974                     a -= b;
 975                 }
 976
 977                 /* We emit the extra nop when we emit the add2/sub2.  */
 978                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
 979
 980                 rl = args[0];
 981                 rh = args[1];
 982                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
 983                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
 984                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)a);
 985                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(a >> 32));
 986                 gen_args += 4;
 987                 args += 6;
 988                 break;
 989             }
 990             goto do_default;
 991
 992         case INDEX_op_mulu2_i32:
 993             if (temps[args[2]].state == TCG_TEMP_CONST
 994                 && temps[args[3]].state == TCG_TEMP_CONST) {
 995                 uint32_t a = temps[args[2]].val;
 996                 uint32_t b = temps[args[3]].val;
 997                 uint64_t r = (uint64_t)a * b;
 998                 TCGArg rl, rh;
 999
1000                 /* We emit the extra nop when we emit the mulu2.  */
1001                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
1002
1003                 rl = args[0];
1004                 rh = args[1];
1005                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1006                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
1007                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)r);
1008                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(r >> 32));
1009                 gen_args += 4;
1010                 args += 4;
1011                 break;
1012             }
1013             goto do_default;
1014
1015         case INDEX_op_brcond2_i32:
1016             tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
1017             if (tmp != 2) {
1018                 if (tmp) {
1019                     reset_all_temps(nb_temps);
1020                     s->gen_opc_buf[op_index] = INDEX_op_br;
1021                     gen_args[0] = args[5];
1022                     gen_args += 1;
1023                 } else {
1024                     s->gen_opc_buf[op_index] = INDEX_op_nop;
1025                 }
1026             } else if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
1027                        && temps[args[2]].state == TCG_TEMP_CONST
1028                        && temps[args[3]].state == TCG_TEMP_CONST
1029                        && temps[args[2]].val == 0
1030                        && temps[args[3]].val == 0) {
1031                 /* Simplify LT/GE comparisons vs zero to a single compare
1032                    vs the high word of the input.  */
1033                 reset_all_temps(nb_temps);
1034                 s->gen_opc_buf[op_index] = INDEX_op_brcond_i32;
1035                 gen_args[0] = args[1];
1036                 gen_args[1] = args[3];
1037                 gen_args[2] = args[4];
1038                 gen_args[3] = args[5];
1039                 gen_args += 4;
1040             } else {
1041                 goto do_default;
1042             }
1043             args += 6;
1044             break;
1045
1046         case INDEX_op_setcond2_i32:
1047             tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]);
1048             if (tmp != 2) {
1049                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1050                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1051                 gen_args += 2;
1052             } else if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
1053                        && temps[args[3]].state == TCG_TEMP_CONST
1054                        && temps[args[4]].state == TCG_TEMP_CONST
1055                        && temps[args[3]].val == 0
1056                        && temps[args[4]].val == 0) {
1057                 /* Simplify LT/GE comparisons vs zero to a single compare
1058                    vs the high word of the input.  */
1059                 s->gen_opc_buf[op_index] = INDEX_op_setcond_i32;
1060                 reset_temp(args[0]);
1061                 gen_args[0] = args[0];
1062                 gen_args[1] = args[2];
1063                 gen_args[2] = args[4];
1064                 gen_args[3] = args[5];
1065                 gen_args += 4;
1066             } else {
1067                 goto do_default;
1068             }
1069             args += 6;
1070             break;
1071
1072         case INDEX_op_call:
1073             nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);
1074             if (!(args[nb_call_args + 1] & (TCG_CALL_NO_READ_GLOBALS |
1075                                             TCG_CALL_NO_WRITE_GLOBALS))) {
1076                 for (i = 0; i < nb_globals; i++) {
1077                     reset_temp(i);
1078                 }
1079             }
1080             for (i = 0; i < (args[0] >> 16); i++) {
1081                 reset_temp(args[i + 1]);
1082             }
1083             i = nb_call_args + 3;
1084             while (i) {
1085                 *gen_args = *args;
1086                 args++;
1087                 gen_args++;
1088                 i--;
1089             }
1090             break;
1091
1092         default:
1093         do_default:
1094             /* Default case: we know nothing about operation (or were unable
1095                to compute the operation result) so no propagation is done.
1096                We trash everything if the operation is the end of a basic
1097                block, otherwise we only trash the output args.  "mask" is
1098                the non-zero bits mask for the first output arg.  */
1099             if (def->flags & TCG_OPF_BB_END) {
1100                 reset_all_temps(nb_temps);
1101             } else {
1102                 for (i = 0; i < def->nb_oargs; i++) {
1103                     reset_temp(args[i]);
1104                 }
1105             }
1106             for (i = 0; i < def->nb_args; i++) {
1107                 gen_args[i] = args[i];
1108             }
1109             args += def->nb_args;
1110             gen_args += def->nb_args;
1111             break;
1112         }
1113     }
1114
1115     return gen_args;
1116 }
1117
1118 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr,
1119         TCGArg *args, TCGOpDef *tcg_op_defs)
1120 {
1121     TCGArg *res;
1122     res = tcg_constant_folding(s, tcg_opc_ptr, args, tcg_op_defs);
1123     return res;
1124 }