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     uint64_t l64, h64;
 202
 203     switch (op) {
 204     CASE_OP_32_64(add):
 205         return x + y;
 206
 207     CASE_OP_32_64(sub):
 208         return x - y;
 209
 210     CASE_OP_32_64(mul):
 211         return x * y;
 212
 213     CASE_OP_32_64(and):
 214         return x & y;
 215
 216     CASE_OP_32_64(or):
 217         return x | y;
 218
 219     CASE_OP_32_64(xor):
 220         return x ^ y;
 221
 222     case INDEX_op_shl_i32:
 223         return (uint32_t)x << (y & 31);
 224
 225     case INDEX_op_shl_i64:
 226         return (uint64_t)x << (y & 63);
 227
 228     case INDEX_op_shr_i32:
 229         return (uint32_t)x >> (y & 31);
 230
 231     case INDEX_op_trunc_shr_i32:
 232     case INDEX_op_shr_i64:
 233         return (uint64_t)x >> (y & 63);
 234
 235     case INDEX_op_sar_i32:
 236         return (int32_t)x >> (y & 31);
 237
 238     case INDEX_op_sar_i64:
 239         return (int64_t)x >> (y & 63);
 240
 241     case INDEX_op_rotr_i32:
 242         return ror32(x, y & 31);
 243
 244     case INDEX_op_rotr_i64:
 245         return ror64(x, y & 63);
 246
 247     case INDEX_op_rotl_i32:
 248         return rol32(x, y & 31);
 249
 250     case INDEX_op_rotl_i64:
 251         return rol64(x, y & 63);
 252
 253     CASE_OP_32_64(not):
 254         return ~x;
 255
 256     CASE_OP_32_64(neg):
 257         return -x;
 258
 259     CASE_OP_32_64(andc):
 260         return x & ~y;
 261
 262     CASE_OP_32_64(orc):
 263         return x | ~y;
 264
 265     CASE_OP_32_64(eqv):
 266         return ~(x ^ y);
 267
 268     CASE_OP_32_64(nand):
 269         return ~(x & y);
 270
 271     CASE_OP_32_64(nor):
 272         return ~(x | y);
 273
 274     CASE_OP_32_64(ext8s):
 275         return (int8_t)x;
 276
 277     CASE_OP_32_64(ext16s):
 278         return (int16_t)x;
 279
 280     CASE_OP_32_64(ext8u):
 281         return (uint8_t)x;
 282
 283     CASE_OP_32_64(ext16u):
 284         return (uint16_t)x;
 285
 286     case INDEX_op_ext32s_i64:
 287         return (int32_t)x;
 288
 289     case INDEX_op_ext32u_i64:
 290         return (uint32_t)x;
 291
 292     case INDEX_op_muluh_i32:
 293         return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
 294     case INDEX_op_mulsh_i32:
 295         return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
 296
 297     case INDEX_op_muluh_i64:
 298         mulu64(&l64, &h64, x, y);
 299         return h64;
 300     case INDEX_op_mulsh_i64:
 301         muls64(&l64, &h64, x, y);
 302         return h64;
 303
 304     case INDEX_op_div_i32:
 305         /* Avoid crashing on divide by zero, otherwise undefined.  */
 306         return (int32_t)x / ((int32_t)y ? : 1);
 307     case INDEX_op_divu_i32:
 308         return (uint32_t)x / ((uint32_t)y ? : 1);
 309     case INDEX_op_div_i64:
 310         return (int64_t)x / ((int64_t)y ? : 1);
 311     case INDEX_op_divu_i64:
 312         return (uint64_t)x / ((uint64_t)y ? : 1);
 313
 314     case INDEX_op_rem_i32:
 315         return (int32_t)x % ((int32_t)y ? : 1);
 316     case INDEX_op_remu_i32:
 317         return (uint32_t)x % ((uint32_t)y ? : 1);
 318     case INDEX_op_rem_i64:
 319         return (int64_t)x % ((int64_t)y ? : 1);
 320     case INDEX_op_remu_i64:
 321         return (uint64_t)x % ((uint64_t)y ? : 1);
 322
 323     default:
 324         fprintf(stderr,
 325                 "Unrecognized operation %d in do_constant_folding.\n", op);
 326         tcg_abort();
 327     }
 328 }
 329
 330 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 331 {
 332     TCGArg res = do_constant_folding_2(op, x, y);
 333     if (op_bits(op) == 32) {
 334         res &= 0xffffffff;
 335     }
 336     return res;
 337 }
 338
 339 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
 340 {
 341     switch (c) {
 342     case TCG_COND_EQ:
 343         return x == y;
 344     case TCG_COND_NE:
 345         return x != y;
 346     case TCG_COND_LT:
 347         return (int32_t)x < (int32_t)y;
 348     case TCG_COND_GE:
 349         return (int32_t)x >= (int32_t)y;
 350     case TCG_COND_LE:
 351         return (int32_t)x <= (int32_t)y;
 352     case TCG_COND_GT:
 353         return (int32_t)x > (int32_t)y;
 354     case TCG_COND_LTU:
 355         return x < y;
 356     case TCG_COND_GEU:
 357         return x >= y;
 358     case TCG_COND_LEU:
 359         return x <= y;
 360     case TCG_COND_GTU:
 361         return x > y;
 362     default:
 363         tcg_abort();
 364     }
 365 }
 366
 367 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
 368 {
 369     switch (c) {
 370     case TCG_COND_EQ:
 371         return x == y;
 372     case TCG_COND_NE:
 373         return x != y;
 374     case TCG_COND_LT:
 375         return (int64_t)x < (int64_t)y;
 376     case TCG_COND_GE:
 377         return (int64_t)x >= (int64_t)y;
 378     case TCG_COND_LE:
 379         return (int64_t)x <= (int64_t)y;
 380     case TCG_COND_GT:
 381         return (int64_t)x > (int64_t)y;
 382     case TCG_COND_LTU:
 383         return x < y;
 384     case TCG_COND_GEU:
 385         return x >= y;
 386     case TCG_COND_LEU:
 387         return x <= y;
 388     case TCG_COND_GTU:
 389         return x > y;
 390     default:
 391         tcg_abort();
 392     }
 393 }
 394
 395 static bool do_constant_folding_cond_eq(TCGCond c)
 396 {
 397     switch (c) {
 398     case TCG_COND_GT:
 399     case TCG_COND_LTU:
 400     case TCG_COND_LT:
 401     case TCG_COND_GTU:
 402     case TCG_COND_NE:
 403         return 0;
 404     case TCG_COND_GE:
 405     case TCG_COND_GEU:
 406     case TCG_COND_LE:
 407     case TCG_COND_LEU:
 408     case TCG_COND_EQ:
 409         return 1;
 410     default:
 411         tcg_abort();
 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_cond(TCGOpcode op, TCGArg x,
 418                                        TCGArg y, TCGCond c)
 419 {
 420     if (temps[x].state == TCG_TEMP_CONST && temps[y].state == TCG_TEMP_CONST) {
 421         switch (op_bits(op)) {
 422         case 32:
 423             return do_constant_folding_cond_32(temps[x].val, temps[y].val, c);
 424         case 64:
 425             return do_constant_folding_cond_64(temps[x].val, temps[y].val, c);
 426         default:
 427             tcg_abort();
 428         }
 429     } else if (temps_are_copies(x, y)) {
 430         return do_constant_folding_cond_eq(c);
 431     } else if (temps[y].state == TCG_TEMP_CONST && temps[y].val == 0) {
 432         switch (c) {
 433         case TCG_COND_LTU:
 434             return 0;
 435         case TCG_COND_GEU:
 436             return 1;
 437         default:
 438             return 2;
 439         }
 440     } else {
 441         return 2;
 442     }
 443 }
 444
 445 /* Return 2 if the condition can't be simplified, and the result
 446    of the condition (0 or 1) if it can */
 447 static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
 448 {
 449     TCGArg al = p1[0], ah = p1[1];
 450     TCGArg bl = p2[0], bh = p2[1];
 451
 452     if (temps[bl].state == TCG_TEMP_CONST
 453         && temps[bh].state == TCG_TEMP_CONST) {
 454         uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val;
 455
 456         if (temps[al].state == TCG_TEMP_CONST
 457             && temps[ah].state == TCG_TEMP_CONST) {
 458             uint64_t a;
 459             a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val;
 460             return do_constant_folding_cond_64(a, b, c);
 461         }
 462         if (b == 0) {
 463             switch (c) {
 464             case TCG_COND_LTU:
 465                 return 0;
 466             case TCG_COND_GEU:
 467                 return 1;
 468             default:
 469                 break;
 470             }
 471         }
 472     }
 473     if (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) {
 474         return do_constant_folding_cond_eq(c);
 475     }
 476     return 2;
 477 }
 478
 479 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 480 {
 481     TCGArg a1 = *p1, a2 = *p2;
 482     int sum = 0;
 483     sum += temps[a1].state == TCG_TEMP_CONST;
 484     sum -= temps[a2].state == TCG_TEMP_CONST;
 485
 486     /* Prefer the constant in second argument, and then the form
 487        op a, a, b, which is better handled on non-RISC hosts. */
 488     if (sum > 0 || (sum == 0 && dest == a2)) {
 489         *p1 = a2;
 490         *p2 = a1;
 491         return true;
 492     }
 493     return false;
 494 }
 495
 496 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 497 {
 498     int sum = 0;
 499     sum += temps[p1[0]].state == TCG_TEMP_CONST;
 500     sum += temps[p1[1]].state == TCG_TEMP_CONST;
 501     sum -= temps[p2[0]].state == TCG_TEMP_CONST;
 502     sum -= temps[p2[1]].state == TCG_TEMP_CONST;
 503     if (sum > 0) {
 504         TCGArg t;
 505         t = p1[0], p1[0] = p2[0], p2[0] = t;
 506         t = p1[1], p1[1] = p2[1], p2[1] = t;
 507         return true;
 508     }
 509     return false;
 510 }
 511
 512 /* Propagate constants and copies, fold constant expressions. */
 513 static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 514                                     TCGArg *args, TCGOpDef *tcg_op_defs)
 515 {
 516     int nb_ops, op_index, nb_temps, nb_globals;
 517     TCGArg *gen_args;
 518
 519     /* Array VALS has an element for each temp.
 520        If this temp holds a constant then its value is kept in VALS' element.
 521        If this temp is a copy of other ones then the other copies are
 522        available through the doubly linked circular list. */
 523
 524     nb_temps = s->nb_temps;
 525     nb_globals = s->nb_globals;
 526     reset_all_temps(nb_temps);
 527
 528     nb_ops = tcg_opc_ptr - s->gen_opc_buf;
 529     gen_args = args;
 530     for (op_index = 0; op_index < nb_ops; op_index++) {
 531         TCGOpcode op = s->gen_opc_buf[op_index];
 532         const TCGOpDef *def = &tcg_op_defs[op];
 533         tcg_target_ulong mask, affected;
 534         int nb_oargs, nb_iargs, nb_args, i;
 535         TCGArg tmp;
 536
 537         if (op == INDEX_op_call) {
 538             *gen_args++ = tmp = *args++;
 539             nb_oargs = tmp >> 16;
 540             nb_iargs = tmp & 0xffff;
 541             nb_args = nb_oargs + nb_iargs + def->nb_cargs;
 542         } else {
 543             nb_oargs = def->nb_oargs;
 544             nb_iargs = def->nb_iargs;
 545             nb_args = def->nb_args;
 546         }
 547
 548         /* Do copy propagation */
 549         for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
 550             if (temps[args[i]].state == TCG_TEMP_COPY) {
 551                 args[i] = find_better_copy(s, args[i]);
 552             }
 553         }
 554
 555         /* For commutative operations make constant second argument */
 556         switch (op) {
 557         CASE_OP_32_64(add):
 558         CASE_OP_32_64(mul):
 559         CASE_OP_32_64(and):
 560         CASE_OP_32_64(or):
 561         CASE_OP_32_64(xor):
 562         CASE_OP_32_64(eqv):
 563         CASE_OP_32_64(nand):
 564         CASE_OP_32_64(nor):
 565         CASE_OP_32_64(muluh):
 566         CASE_OP_32_64(mulsh):
 567             swap_commutative(args[0], &args[1], &args[2]);
 568             break;
 569         CASE_OP_32_64(brcond):
 570             if (swap_commutative(-1, &args[0], &args[1])) {
 571                 args[2] = tcg_swap_cond(args[2]);
 572             }
 573             break;
 574         CASE_OP_32_64(setcond):
 575             if (swap_commutative(args[0], &args[1], &args[2])) {
 576                 args[3] = tcg_swap_cond(args[3]);
 577             }
 578             break;
 579         CASE_OP_32_64(movcond):
 580             if (swap_commutative(-1, &args[1], &args[2])) {
 581                 args[5] = tcg_swap_cond(args[5]);
 582             }
 583             /* For movcond, we canonicalize the "false" input reg to match
 584                the destination reg so that the tcg backend can implement
 585                a "move if true" operation.  */
 586             if (swap_commutative(args[0], &args[4], &args[3])) {
 587                 args[5] = tcg_invert_cond(args[5]);
 588             }
 589             break;
 590         CASE_OP_32_64(add2):
 591             swap_commutative(args[0], &args[2], &args[4]);
 592             swap_commutative(args[1], &args[3], &args[5]);
 593             break;
 594         CASE_OP_32_64(mulu2):
 595         CASE_OP_32_64(muls2):
 596             swap_commutative(args[0], &args[2], &args[3]);
 597             break;
 598         case INDEX_op_brcond2_i32:
 599             if (swap_commutative2(&args[0], &args[2])) {
 600                 args[4] = tcg_swap_cond(args[4]);
 601             }
 602             break;
 603         case INDEX_op_setcond2_i32:
 604             if (swap_commutative2(&args[1], &args[3])) {
 605                 args[5] = tcg_swap_cond(args[5]);
 606             }
 607             break;
 608         default:
 609             break;
 610         }
 611
 612         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
 613            and "sub r, 0, a => neg r, a" case.  */
 614         switch (op) {
 615         CASE_OP_32_64(shl):
 616         CASE_OP_32_64(shr):
 617         CASE_OP_32_64(sar):
 618         CASE_OP_32_64(rotl):
 619         CASE_OP_32_64(rotr):
 620             if (temps[args[1]].state == TCG_TEMP_CONST
 621                 && temps[args[1]].val == 0) {
 622                 s->gen_opc_buf[op_index] = op_to_movi(op);
 623                 tcg_opt_gen_movi(gen_args, args[0], 0);
 624                 args += 3;
 625                 gen_args += 2;
 626                 continue;
 627             }
 628             break;
 629         CASE_OP_32_64(sub):
 630             {
 631                 TCGOpcode neg_op;
 632                 bool have_neg;
 633
 634                 if (temps[args[2]].state == TCG_TEMP_CONST) {
 635                     /* Proceed with possible constant folding. */
 636                     break;
 637                 }
 638                 if (op == INDEX_op_sub_i32) {
 639                     neg_op = INDEX_op_neg_i32;
 640                     have_neg = TCG_TARGET_HAS_neg_i32;
 641                 } else {
 642                     neg_op = INDEX_op_neg_i64;
 643                     have_neg = TCG_TARGET_HAS_neg_i64;
 644                 }
 645                 if (!have_neg) {
 646                     break;
 647                 }
 648                 if (temps[args[1]].state == TCG_TEMP_CONST
 649                     && temps[args[1]].val == 0) {
 650                     s->gen_opc_buf[op_index] = neg_op;
 651                     reset_temp(args[0]);
 652                     gen_args[0] = args[0];
 653                     gen_args[1] = args[2];
 654                     args += 3;
 655                     gen_args += 2;
 656                     continue;
 657                 }
 658             }
 659             break;
 660         CASE_OP_32_64(xor):
 661         CASE_OP_32_64(nand):
 662             if (temps[args[1]].state != TCG_TEMP_CONST
 663                 && temps[args[2]].state == TCG_TEMP_CONST
 664                 && temps[args[2]].val == -1) {
 665                 i = 1;
 666                 goto try_not;
 667             }
 668             break;
 669         CASE_OP_32_64(nor):
 670             if (temps[args[1]].state != TCG_TEMP_CONST
 671                 && temps[args[2]].state == TCG_TEMP_CONST
 672                 && temps[args[2]].val == 0) {
 673                 i = 1;
 674                 goto try_not;
 675             }
 676             break;
 677         CASE_OP_32_64(andc):
 678             if (temps[args[2]].state != TCG_TEMP_CONST
 679                 && temps[args[1]].state == TCG_TEMP_CONST
 680                 && temps[args[1]].val == -1) {
 681                 i = 2;
 682                 goto try_not;
 683             }
 684             break;
 685         CASE_OP_32_64(orc):
 686         CASE_OP_32_64(eqv):
 687             if (temps[args[2]].state != TCG_TEMP_CONST
 688                 && temps[args[1]].state == TCG_TEMP_CONST
 689                 && temps[args[1]].val == 0) {
 690                 i = 2;
 691                 goto try_not;
 692             }
 693             break;
 694         try_not:
 695             {
 696                 TCGOpcode not_op;
 697                 bool have_not;
 698
 699                 if (def->flags & TCG_OPF_64BIT) {
 700                     not_op = INDEX_op_not_i64;
 701                     have_not = TCG_TARGET_HAS_not_i64;
 702                 } else {
 703                     not_op = INDEX_op_not_i32;
 704                     have_not = TCG_TARGET_HAS_not_i32;
 705                 }
 706                 if (!have_not) {
 707                     break;
 708                 }
 709                 s->gen_opc_buf[op_index] = not_op;
 710                 reset_temp(args[0]);
 711                 gen_args[0] = args[0];
 712                 gen_args[1] = args[i];
 713                 args += 3;
 714                 gen_args += 2;
 715                 continue;
 716             }
 717         default:
 718             break;
 719         }
 720
 721         /* Simplify expression for "op r, a, const => mov r, a" cases */
 722         switch (op) {
 723         CASE_OP_32_64(add):
 724         CASE_OP_32_64(sub):
 725         CASE_OP_32_64(shl):
 726         CASE_OP_32_64(shr):
 727         CASE_OP_32_64(sar):
 728         CASE_OP_32_64(rotl):
 729         CASE_OP_32_64(rotr):
 730         CASE_OP_32_64(or):
 731         CASE_OP_32_64(xor):
 732         CASE_OP_32_64(andc):
 733             if (temps[args[1]].state != TCG_TEMP_CONST
 734                 && temps[args[2]].state == TCG_TEMP_CONST
 735                 && temps[args[2]].val == 0) {
 736                 goto do_mov3;
 737             }
 738             break;
 739         CASE_OP_32_64(and):
 740         CASE_OP_32_64(orc):
 741         CASE_OP_32_64(eqv):
 742             if (temps[args[1]].state != TCG_TEMP_CONST
 743                 && temps[args[2]].state == TCG_TEMP_CONST
 744                 && temps[args[2]].val == -1) {
 745                 goto do_mov3;
 746             }
 747             break;
 748         do_mov3:
 749             if (temps_are_copies(args[0], args[1])) {
 750                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 751             } else {
 752                 s->gen_opc_buf[op_index] = op_to_mov(op);
 753                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 754                 gen_args += 2;
 755             }
 756             args += 3;
 757             continue;
 758         default:
 759             break;
 760         }
 761
 762         /* Simplify using known-zero bits. Currently only ops with a single
 763            output argument is supported. */
 764         mask = -1;
 765         affected = -1;
 766         switch (op) {
 767         CASE_OP_32_64(ext8s):
 768             if ((temps[args[1]].mask & 0x80) != 0) {
 769                 break;
 770             }
 771         CASE_OP_32_64(ext8u):
 772             mask = 0xff;
 773             goto and_const;
 774         CASE_OP_32_64(ext16s):
 775             if ((temps[args[1]].mask & 0x8000) != 0) {
 776                 break;
 777             }
 778         CASE_OP_32_64(ext16u):
 779             mask = 0xffff;
 780             goto and_const;
 781         case INDEX_op_ext32s_i64:
 782             if ((temps[args[1]].mask & 0x80000000) != 0) {
 783                 break;
 784             }
 785         case INDEX_op_ext32u_i64:
 786             mask = 0xffffffffU;
 787             goto and_const;
 788
 789         CASE_OP_32_64(and):
 790             mask = temps[args[2]].mask;
 791             if (temps[args[2]].state == TCG_TEMP_CONST) {
 792         and_const:
 793                 affected = temps[args[1]].mask & ~mask;
 794             }
 795             mask = temps[args[1]].mask & mask;
 796             break;
 797
 798         CASE_OP_32_64(andc):
 799             /* Known-zeros does not imply known-ones.  Therefore unless
 800                args[2] is constant, we can't infer anything from it.  */
 801             if (temps[args[2]].state == TCG_TEMP_CONST) {
 802                 mask = ~temps[args[2]].mask;
 803                 goto and_const;
 804             }
 805             /* But we certainly know nothing outside args[1] may be set. */
 806             mask = temps[args[1]].mask;
 807             break;
 808
 809         case INDEX_op_sar_i32:
 810             if (temps[args[2]].state == TCG_TEMP_CONST) {
 811                 tmp = temps[args[2]].val & 31;
 812                 mask = (int32_t)temps[args[1]].mask >> tmp;
 813             }
 814             break;
 815         case INDEX_op_sar_i64:
 816             if (temps[args[2]].state == TCG_TEMP_CONST) {
 817                 tmp = temps[args[2]].val & 63;
 818                 mask = (int64_t)temps[args[1]].mask >> tmp;
 819             }
 820             break;
 821
 822         case INDEX_op_shr_i32:
 823             if (temps[args[2]].state == TCG_TEMP_CONST) {
 824                 tmp = temps[args[2]].val & 31;
 825                 mask = (uint32_t)temps[args[1]].mask >> tmp;
 826             }
 827             break;
 828         case INDEX_op_shr_i64:
 829             if (temps[args[2]].state == TCG_TEMP_CONST) {
 830                 tmp = temps[args[2]].val & 63;
 831                 mask = (uint64_t)temps[args[1]].mask >> tmp;
 832             }
 833             break;
 834
 835         case INDEX_op_trunc_shr_i32:
 836             mask = (uint64_t)temps[args[1]].mask >> args[2];
 837             break;
 838
 839         CASE_OP_32_64(shl):
 840             if (temps[args[2]].state == TCG_TEMP_CONST) {
 841                 tmp = temps[args[2]].val & (TCG_TARGET_REG_BITS - 1);
 842                 mask = temps[args[1]].mask << tmp;
 843             }
 844             break;
 845
 846         CASE_OP_32_64(neg):
 847             /* Set to 1 all bits to the left of the rightmost.  */
 848             mask = -(temps[args[1]].mask & -temps[args[1]].mask);
 849             break;
 850
 851         CASE_OP_32_64(deposit):
 852             mask = deposit64(temps[args[1]].mask, args[3], args[4],
 853                              temps[args[2]].mask);
 854             break;
 855
 856         CASE_OP_32_64(or):
 857         CASE_OP_32_64(xor):
 858             mask = temps[args[1]].mask | temps[args[2]].mask;
 859             break;
 860
 861         CASE_OP_32_64(setcond):
 862             mask = 1;
 863             break;
 864
 865         CASE_OP_32_64(movcond):
 866             mask = temps[args[3]].mask | temps[args[4]].mask;
 867             break;
 868
 869         CASE_OP_32_64(ld8u):
 870         case INDEX_op_qemu_ld8u:
 871             mask = 0xff;
 872             break;
 873         CASE_OP_32_64(ld16u):
 874         case INDEX_op_qemu_ld16u:
 875             mask = 0xffff;
 876             break;
 877         case INDEX_op_ld32u_i64:
 878 #if TCG_TARGET_REG_BITS == 64
 879         case INDEX_op_qemu_ld32u:
 880 #endif
 881             mask = 0xffffffffu;
 882             break;
 883
 884         CASE_OP_32_64(qemu_ld):
 885             {
 886                 TCGMemOp mop = args[nb_oargs + nb_iargs];
 887                 if (!(mop & MO_SIGN)) {
 888                     mask = (2ULL << ((8 << (mop & MO_SIZE)) - 1)) - 1;
 889                 }
 890             }
 891             break;
 892
 893         default:
 894             break;
 895         }
 896
 897         /* 32-bit ops (non 64-bit ops and non load/store ops) generate 32-bit
 898            results */
 899         if (!(def->flags & (TCG_OPF_CALL_CLOBBER | TCG_OPF_64BIT))) {
 900             mask &= 0xffffffffu;
 901         }
 902
 903         if (mask == 0) {
 904             assert(nb_oargs == 1);
 905             s->gen_opc_buf[op_index] = op_to_movi(op);
 906             tcg_opt_gen_movi(gen_args, args[0], 0);
 907             args += nb_args;
 908             gen_args += 2;
 909             continue;
 910         }
 911         if (affected == 0) {
 912             assert(nb_oargs == 1);
 913             if (temps_are_copies(args[0], args[1])) {
 914                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 915             } else if (temps[args[1]].state != TCG_TEMP_CONST) {
 916                 s->gen_opc_buf[op_index] = op_to_mov(op);
 917                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 918                 gen_args += 2;
 919             } else {
 920                 s->gen_opc_buf[op_index] = op_to_movi(op);
 921                 tcg_opt_gen_movi(gen_args, args[0], temps[args[1]].val);
 922                 gen_args += 2;
 923             }
 924             args += nb_args;
 925             continue;
 926         }
 927
 928         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
 929         switch (op) {
 930         CASE_OP_32_64(and):
 931         CASE_OP_32_64(mul):
 932         CASE_OP_32_64(muluh):
 933         CASE_OP_32_64(mulsh):
 934             if ((temps[args[2]].state == TCG_TEMP_CONST
 935                 && temps[args[2]].val == 0)) {
 936                 s->gen_opc_buf[op_index] = op_to_movi(op);
 937                 tcg_opt_gen_movi(gen_args, args[0], 0);
 938                 args += 3;
 939                 gen_args += 2;
 940                 continue;
 941             }
 942             break;
 943         default:
 944             break;
 945         }
 946
 947         /* Simplify expression for "op r, a, a => mov r, a" cases */
 948         switch (op) {
 949         CASE_OP_32_64(or):
 950         CASE_OP_32_64(and):
 951             if (temps_are_copies(args[1], args[2])) {
 952                 if (temps_are_copies(args[0], args[1])) {
 953                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 954                 } else {
 955                     s->gen_opc_buf[op_index] = op_to_mov(op);
 956                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 957                     gen_args += 2;
 958                 }
 959                 args += 3;
 960                 continue;
 961             }
 962             break;
 963         default:
 964             break;
 965         }
 966
 967         /* Simplify expression for "op r, a, a => movi r, 0" cases */
 968         switch (op) {
 969         CASE_OP_32_64(andc):
 970         CASE_OP_32_64(sub):
 971         CASE_OP_32_64(xor):
 972             if (temps_are_copies(args[1], args[2])) {
 973                 s->gen_opc_buf[op_index] = op_to_movi(op);
 974                 tcg_opt_gen_movi(gen_args, args[0], 0);
 975                 gen_args += 2;
 976                 args += 3;
 977                 continue;
 978             }
 979             break;
 980         default:
 981             break;
 982         }
 983
 984         /* Propagate constants through copy operations and do constant
 985            folding.  Constants will be substituted to arguments by register
 986            allocator where needed and possible.  Also detect copies. */
 987         switch (op) {
 988         CASE_OP_32_64(mov):
 989             if (temps_are_copies(args[0], args[1])) {
 990                 args += 2;
 991                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 992                 break;
 993             }
 994             if (temps[args[1]].state != TCG_TEMP_CONST) {
 995                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 996                 gen_args += 2;
 997                 args += 2;
 998                 break;
 999             }
1000             /* Source argument is constant.  Rewrite the operation and
1001                let movi case handle it. */
1002             op = op_to_movi(op);
1003             s->gen_opc_buf[op_index] = op;
1004             args[1] = temps[args[1]].val;
1005             /* fallthrough */
1006         CASE_OP_32_64(movi):
1007             tcg_opt_gen_movi(gen_args, args[0], args[1]);
1008             gen_args += 2;
1009             args += 2;
1010             break;
1011
1012         CASE_OP_32_64(not):
1013         CASE_OP_32_64(neg):
1014         CASE_OP_32_64(ext8s):
1015         CASE_OP_32_64(ext8u):
1016         CASE_OP_32_64(ext16s):
1017         CASE_OP_32_64(ext16u):
1018         case INDEX_op_ext32s_i64:
1019         case INDEX_op_ext32u_i64:
1020             if (temps[args[1]].state == TCG_TEMP_CONST) {
1021                 s->gen_opc_buf[op_index] = op_to_movi(op);
1022                 tmp = do_constant_folding(op, temps[args[1]].val, 0);
1023                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1024                 gen_args += 2;
1025                 args += 2;
1026                 break;
1027             }
1028             goto do_default;
1029
1030         case INDEX_op_trunc_shr_i32:
1031             if (temps[args[1]].state == TCG_TEMP_CONST) {
1032                 s->gen_opc_buf[op_index] = op_to_movi(op);
1033                 tmp = do_constant_folding(op, temps[args[1]].val, args[2]);
1034                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1035                 gen_args += 2;
1036                 args += 3;
1037                 break;
1038             }
1039             goto do_default;
1040
1041         CASE_OP_32_64(add):
1042         CASE_OP_32_64(sub):
1043         CASE_OP_32_64(mul):
1044         CASE_OP_32_64(or):
1045         CASE_OP_32_64(and):
1046         CASE_OP_32_64(xor):
1047         CASE_OP_32_64(shl):
1048         CASE_OP_32_64(shr):
1049         CASE_OP_32_64(sar):
1050         CASE_OP_32_64(rotl):
1051         CASE_OP_32_64(rotr):
1052         CASE_OP_32_64(andc):
1053         CASE_OP_32_64(orc):
1054         CASE_OP_32_64(eqv):
1055         CASE_OP_32_64(nand):
1056         CASE_OP_32_64(nor):
1057         CASE_OP_32_64(muluh):
1058         CASE_OP_32_64(mulsh):
1059         CASE_OP_32_64(div):
1060         CASE_OP_32_64(divu):
1061         CASE_OP_32_64(rem):
1062         CASE_OP_32_64(remu):
1063             if (temps[args[1]].state == TCG_TEMP_CONST
1064                 && temps[args[2]].state == TCG_TEMP_CONST) {
1065                 s->gen_opc_buf[op_index] = op_to_movi(op);
1066                 tmp = do_constant_folding(op, temps[args[1]].val,
1067                                           temps[args[2]].val);
1068                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1069                 gen_args += 2;
1070                 args += 3;
1071                 break;
1072             }
1073             goto do_default;
1074
1075         CASE_OP_32_64(deposit):
1076             if (temps[args[1]].state == TCG_TEMP_CONST
1077                 && temps[args[2]].state == TCG_TEMP_CONST) {
1078                 s->gen_opc_buf[op_index] = op_to_movi(op);
1079                 tmp = deposit64(temps[args[1]].val, args[3], args[4],
1080                                 temps[args[2]].val);
1081                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1082                 gen_args += 2;
1083                 args += 5;
1084                 break;
1085             }
1086             goto do_default;
1087
1088         CASE_OP_32_64(setcond):
1089             tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
1090             if (tmp != 2) {
1091                 s->gen_opc_buf[op_index] = op_to_movi(op);
1092                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1093                 gen_args += 2;
1094                 args += 4;
1095                 break;
1096             }
1097             goto do_default;
1098
1099         CASE_OP_32_64(brcond):
1100             tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
1101             if (tmp != 2) {
1102                 if (tmp) {
1103                     reset_all_temps(nb_temps);
1104                     s->gen_opc_buf[op_index] = INDEX_op_br;
1105                     gen_args[0] = args[3];
1106                     gen_args += 1;
1107                 } else {
1108                     s->gen_opc_buf[op_index] = INDEX_op_nop;
1109                 }
1110                 args += 4;
1111                 break;
1112             }
1113             goto do_default;
1114
1115         CASE_OP_32_64(movcond):
1116             tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
1117             if (tmp != 2) {
1118                 if (temps_are_copies(args[0], args[4-tmp])) {
1119                     s->gen_opc_buf[op_index] = INDEX_op_nop;
1120                 } else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
1121                     s->gen_opc_buf[op_index] = op_to_movi(op);
1122                     tcg_opt_gen_movi(gen_args, args[0], temps[args[4-tmp]].val);
1123                     gen_args += 2;
1124                 } else {
1125                     s->gen_opc_buf[op_index] = op_to_mov(op);
1126                     tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
1127                     gen_args += 2;
1128                 }
1129                 args += 6;
1130                 break;
1131             }
1132             goto do_default;
1133
1134         case INDEX_op_add2_i32:
1135         case INDEX_op_sub2_i32:
1136             if (temps[args[2]].state == TCG_TEMP_CONST
1137                 && temps[args[3]].state == TCG_TEMP_CONST
1138                 && temps[args[4]].state == TCG_TEMP_CONST
1139                 && temps[args[5]].state == TCG_TEMP_CONST) {
1140                 uint32_t al = temps[args[2]].val;
1141                 uint32_t ah = temps[args[3]].val;
1142                 uint32_t bl = temps[args[4]].val;
1143                 uint32_t bh = temps[args[5]].val;
1144                 uint64_t a = ((uint64_t)ah << 32) | al;
1145                 uint64_t b = ((uint64_t)bh << 32) | bl;
1146                 TCGArg rl, rh;
1147
1148                 if (op == INDEX_op_add2_i32) {
1149                     a += b;
1150                 } else {
1151                     a -= b;
1152                 }
1153
1154                 /* We emit the extra nop when we emit the add2/sub2.  */
1155                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
1156
1157                 rl = args[0];
1158                 rh = args[1];
1159                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1160                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
1161                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)a);
1162                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(a >> 32));
1163                 gen_args += 4;
1164                 args += 6;
1165                 break;
1166             }
1167             goto do_default;
1168
1169         case INDEX_op_mulu2_i32:
1170             if (temps[args[2]].state == TCG_TEMP_CONST
1171                 && temps[args[3]].state == TCG_TEMP_CONST) {
1172                 uint32_t a = temps[args[2]].val;
1173                 uint32_t b = temps[args[3]].val;
1174                 uint64_t r = (uint64_t)a * b;
1175                 TCGArg rl, rh;
1176
1177                 /* We emit the extra nop when we emit the mulu2.  */
1178                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
1179
1180                 rl = args[0];
1181                 rh = args[1];
1182                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1183                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
1184                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)r);
1185                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(r >> 32));
1186                 gen_args += 4;
1187                 args += 4;
1188                 break;
1189             }
1190             goto do_default;
1191
1192         case INDEX_op_brcond2_i32:
1193             tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
1194             if (tmp != 2) {
1195                 if (tmp) {
1196                     reset_all_temps(nb_temps);
1197                     s->gen_opc_buf[op_index] = INDEX_op_br;
1198                     gen_args[0] = args[5];
1199                     gen_args += 1;
1200                 } else {
1201                     s->gen_opc_buf[op_index] = INDEX_op_nop;
1202                 }
1203             } else if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
1204                        && temps[args[2]].state == TCG_TEMP_CONST
1205                        && temps[args[3]].state == TCG_TEMP_CONST
1206                        && temps[args[2]].val == 0
1207                        && temps[args[3]].val == 0) {
1208                 /* Simplify LT/GE comparisons vs zero to a single compare
1209                    vs the high word of the input.  */
1210                 reset_all_temps(nb_temps);
1211                 s->gen_opc_buf[op_index] = INDEX_op_brcond_i32;
1212                 gen_args[0] = args[1];
1213                 gen_args[1] = args[3];
1214                 gen_args[2] = args[4];
1215                 gen_args[3] = args[5];
1216                 gen_args += 4;
1217             } else {
1218                 goto do_default;
1219             }
1220             args += 6;
1221             break;
1222
1223         case INDEX_op_setcond2_i32:
1224             tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]);
1225             if (tmp != 2) {
1226                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1227                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1228                 gen_args += 2;
1229             } else if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
1230                        && temps[args[3]].state == TCG_TEMP_CONST
1231                        && temps[args[4]].state == TCG_TEMP_CONST
1232                        && temps[args[3]].val == 0
1233                        && temps[args[4]].val == 0) {
1234                 /* Simplify LT/GE comparisons vs zero to a single compare
1235                    vs the high word of the input.  */
1236                 s->gen_opc_buf[op_index] = INDEX_op_setcond_i32;
1237                 reset_temp(args[0]);
1238                 gen_args[0] = args[0];
1239                 gen_args[1] = args[2];
1240                 gen_args[2] = args[4];
1241                 gen_args[3] = args[5];
1242                 gen_args += 4;
1243             } else {
1244                 goto do_default;
1245             }
1246             args += 6;
1247             break;
1248
1249         case INDEX_op_call:
1250             if (!(args[nb_oargs + nb_iargs + 1]
1251                   & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
1252                 for (i = 0; i < nb_globals; i++) {
1253                     reset_temp(i);
1254                 }
1255             }
1256             goto do_reset_output;
1257
1258         default:
1259         do_default:
1260             /* Default case: we know nothing about operation (or were unable
1261                to compute the operation result) so no propagation is done.
1262                We trash everything if the operation is the end of a basic
1263                block, otherwise we only trash the output args.  "mask" is
1264                the non-zero bits mask for the first output arg.  */
1265             if (def->flags & TCG_OPF_BB_END) {
1266                 reset_all_temps(nb_temps);
1267             } else {
1268         do_reset_output:
1269                 for (i = 0; i < nb_oargs; i++) {
1270                     reset_temp(args[i]);
1271                     /* Save the corresponding known-zero bits mask for the
1272                        first output argument (only one supported so far). */
1273                     if (i == 0) {
1274                         temps[args[i]].mask = mask;
1275                     }
1276                 }
1277             }
1278             for (i = 0; i < nb_args; i++) {
1279                 gen_args[i] = args[i];
1280             }
1281             args += nb_args;
1282             gen_args += nb_args;
1283             break;
1284         }
1285     }
1286
1287     return gen_args;
1288 }
1289
1290 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr,
1291         TCGArg *args, TCGOpDef *tcg_op_defs)
1292 {
1293     TCGArg *res;
1294     res = tcg_constant_folding(s, tcg_opc_ptr, args, tcg_op_defs);
1295     return res;
1296 }