tcg/optimize.c

   1 /*
   2  * Optimizations for Tiny Code Generator for QEMU
   3  *
   4  * Copyright (c) 2010 Samsung Electronics.
   5  * Contributed by Kirill Batuzov <[email protected]>
   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 "qemu/osdep.h"
  27 #include "qemu-common.h"
  28 #include "exec/cpu-common.h"
  29 #include "tcg-op.h"
  30
  31 #define CASE_OP_32_64(x)                        \
  32         glue(glue(case INDEX_op_, x), _i32):    \
  33         glue(glue(case INDEX_op_, x), _i64)
  34
  35 #define CASE_OP_32_64_VEC(x)                    \
  36         glue(glue(case INDEX_op_, x), _i32):    \
  37         glue(glue(case INDEX_op_, x), _i64):    \
  38         glue(glue(case INDEX_op_, x), _vec)
  39
  40 struct tcg_temp_info {
  41     bool is_const;
  42     TCGTemp *prev_copy;
  43     TCGTemp *next_copy;
  44     tcg_target_ulong val;
  45     tcg_target_ulong mask;
  46 };
  47
  48 static inline struct tcg_temp_info *ts_info(TCGTemp *ts)
  49 {
  50     return ts->state_ptr;
  51 }
  52
  53 static inline struct tcg_temp_info *arg_info(TCGArg arg)
  54 {
  55     return ts_info(arg_temp(arg));
  56 }
  57
  58 static inline bool ts_is_const(TCGTemp *ts)
  59 {
  60     return ts_info(ts)->is_const;
  61 }
  62
  63 static inline bool arg_is_const(TCGArg arg)
  64 {
  65     return ts_is_const(arg_temp(arg));
  66 }
  67
  68 static inline bool ts_is_copy(TCGTemp *ts)
  69 {
  70     return ts_info(ts)->next_copy != ts;
  71 }
  72
  73 /* Reset TEMP's state, possibly removing the temp for the list of copies.  */
  74 static void reset_ts(TCGTemp *ts)
  75 {
  76     struct tcg_temp_info *ti = ts_info(ts);
  77     struct tcg_temp_info *pi = ts_info(ti->prev_copy);
  78     struct tcg_temp_info *ni = ts_info(ti->next_copy);
  79
  80     ni->prev_copy = ti->prev_copy;
  81     pi->next_copy = ti->next_copy;
  82     ti->next_copy = ts;
  83     ti->prev_copy = ts;
  84     ti->is_const = false;
  85     ti->mask = -1;
  86 }
  87
  88 static void reset_temp(TCGArg arg)
  89 {
  90     reset_ts(arg_temp(arg));
  91 }
  92
  93 /* Initialize and activate a temporary.  */
  94 static void init_ts_info(struct tcg_temp_info *infos,
  95                          TCGTempSet *temps_used, TCGTemp *ts)
  96 {
  97     size_t idx = temp_idx(ts);
  98     if (!test_bit(idx, temps_used->l)) {
  99         struct tcg_temp_info *ti = &infos[idx];
 100
 101         ts->state_ptr = ti;
 102         ti->next_copy = ts;
 103         ti->prev_copy = ts;
 104         ti->is_const = false;
 105         ti->mask = -1;
 106         set_bit(idx, temps_used->l);
 107     }
 108 }
 109
 110 static void init_arg_info(struct tcg_temp_info *infos,
 111                           TCGTempSet *temps_used, TCGArg arg)
 112 {
 113     init_ts_info(infos, temps_used, arg_temp(arg));
 114 }
 115
 116 static TCGTemp *find_better_copy(TCGContext *s, TCGTemp *ts)
 117 {
 118     TCGTemp *i;
 119
 120     /* If this is already a global, we can't do better. */
 121     if (ts->temp_global) {
 122         return ts;
 123     }
 124
 125     /* Search for a global first. */
 126     for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
 127         if (i->temp_global) {
 128             return i;
 129         }
 130     }
 131
 132     /* If it is a temp, search for a temp local. */
 133     if (!ts->temp_local) {
 134         for (i = ts_info(ts)->next_copy; i != ts; i = ts_info(i)->next_copy) {
 135             if (ts->temp_local) {
 136                 return i;
 137             }
 138         }
 139     }
 140
 141     /* Failure to find a better representation, return the same temp. */
 142     return ts;
 143 }
 144
 145 static bool ts_are_copies(TCGTemp *ts1, TCGTemp *ts2)
 146 {
 147     TCGTemp *i;
 148
 149     if (ts1 == ts2) {
 150         return true;
 151     }
 152
 153     if (!ts_is_copy(ts1) || !ts_is_copy(ts2)) {
 154         return false;
 155     }
 156
 157     for (i = ts_info(ts1)->next_copy; i != ts1; i = ts_info(i)->next_copy) {
 158         if (i == ts2) {
 159             return true;
 160         }
 161     }
 162
 163     return false;
 164 }
 165
 166 static bool args_are_copies(TCGArg arg1, TCGArg arg2)
 167 {
 168     return ts_are_copies(arg_temp(arg1), arg_temp(arg2));
 169 }
 170
 171 static void tcg_opt_gen_movi(TCGContext *s, TCGOp *op, TCGArg dst, TCGArg val)
 172 {
 173     const TCGOpDef *def;
 174     TCGOpcode new_op;
 175     tcg_target_ulong mask;
 176     struct tcg_temp_info *di = arg_info(dst);
 177
 178     def = &tcg_op_defs[op->opc];
 179     if (def->flags & TCG_OPF_VECTOR) {
 180         new_op = INDEX_op_dupi_vec;
 181     } else if (def->flags & TCG_OPF_64BIT) {
 182         new_op = INDEX_op_movi_i64;
 183     } else {
 184         new_op = INDEX_op_movi_i32;
 185     }
 186     op->opc = new_op;
 187     /* TCGOP_VECL and TCGOP_VECE remain unchanged.  */
 188     op->args[0] = dst;
 189     op->args[1] = val;
 190
 191     reset_temp(dst);
 192     di->is_const = true;
 193     di->val = val;
 194     mask = val;
 195     if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_movi_i32) {
 196         /* High bits of the destination are now garbage.  */
 197         mask |= ~0xffffffffull;
 198     }
 199     di->mask = mask;
 200 }
 201
 202 static void tcg_opt_gen_mov(TCGContext *s, TCGOp *op, TCGArg dst, TCGArg src)
 203 {
 204     TCGTemp *dst_ts = arg_temp(dst);
 205     TCGTemp *src_ts = arg_temp(src);
 206     const TCGOpDef *def;
 207     struct tcg_temp_info *di;
 208     struct tcg_temp_info *si;
 209     tcg_target_ulong mask;
 210     TCGOpcode new_op;
 211
 212     if (ts_are_copies(dst_ts, src_ts)) {
 213         tcg_op_remove(s, op);
 214         return;
 215     }
 216
 217     reset_ts(dst_ts);
 218     di = ts_info(dst_ts);
 219     si = ts_info(src_ts);
 220     def = &tcg_op_defs[op->opc];
 221     if (def->flags & TCG_OPF_VECTOR) {
 222         new_op = INDEX_op_mov_vec;
 223     } else if (def->flags & TCG_OPF_64BIT) {
 224         new_op = INDEX_op_mov_i64;
 225     } else {
 226         new_op = INDEX_op_mov_i32;
 227     }
 228     op->opc = new_op;
 229     /* TCGOP_VECL and TCGOP_VECE remain unchanged.  */
 230     op->args[0] = dst;
 231     op->args[1] = src;
 232
 233     mask = si->mask;
 234     if (TCG_TARGET_REG_BITS > 32 && new_op == INDEX_op_mov_i32) {
 235         /* High bits of the destination are now garbage.  */
 236         mask |= ~0xffffffffull;
 237     }
 238     di->mask = mask;
 239
 240     if (src_ts->type == dst_ts->type) {
 241         struct tcg_temp_info *ni = ts_info(si->next_copy);
 242
 243         di->next_copy = si->next_copy;
 244         di->prev_copy = src_ts;
 245         ni->prev_copy = dst_ts;
 246         si->next_copy = dst_ts;
 247         di->is_const = si->is_const;
 248         di->val = si->val;
 249     }
 250 }
 251
 252 static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
 253 {
 254     uint64_t l64, h64;
 255
 256     switch (op) {
 257     CASE_OP_32_64(add):
 258         return x + y;
 259
 260     CASE_OP_32_64(sub):
 261         return x - y;
 262
 263     CASE_OP_32_64(mul):
 264         return x * y;
 265
 266     CASE_OP_32_64(and):
 267         return x & y;
 268
 269     CASE_OP_32_64(or):
 270         return x | y;
 271
 272     CASE_OP_32_64(xor):
 273         return x ^ y;
 274
 275     case INDEX_op_shl_i32:
 276         return (uint32_t)x << (y & 31);
 277
 278     case INDEX_op_shl_i64:
 279         return (uint64_t)x << (y & 63);
 280
 281     case INDEX_op_shr_i32:
 282         return (uint32_t)x >> (y & 31);
 283
 284     case INDEX_op_shr_i64:
 285         return (uint64_t)x >> (y & 63);
 286
 287     case INDEX_op_sar_i32:
 288         return (int32_t)x >> (y & 31);
 289
 290     case INDEX_op_sar_i64:
 291         return (int64_t)x >> (y & 63);
 292
 293     case INDEX_op_rotr_i32:
 294         return ror32(x, y & 31);
 295
 296     case INDEX_op_rotr_i64:
 297         return ror64(x, y & 63);
 298
 299     case INDEX_op_rotl_i32:
 300         return rol32(x, y & 31);
 301
 302     case INDEX_op_rotl_i64:
 303         return rol64(x, y & 63);
 304
 305     CASE_OP_32_64(not):
 306         return ~x;
 307
 308     CASE_OP_32_64(neg):
 309         return -x;
 310
 311     CASE_OP_32_64(andc):
 312         return x & ~y;
 313
 314     CASE_OP_32_64(orc):
 315         return x | ~y;
 316
 317     CASE_OP_32_64(eqv):
 318         return ~(x ^ y);
 319
 320     CASE_OP_32_64(nand):
 321         return ~(x & y);
 322
 323     CASE_OP_32_64(nor):
 324         return ~(x | y);
 325
 326     case INDEX_op_clz_i32:
 327         return (uint32_t)x ? clz32(x) : y;
 328
 329     case INDEX_op_clz_i64:
 330         return x ? clz64(x) : y;
 331
 332     case INDEX_op_ctz_i32:
 333         return (uint32_t)x ? ctz32(x) : y;
 334
 335     case INDEX_op_ctz_i64:
 336         return x ? ctz64(x) : y;
 337
 338     case INDEX_op_ctpop_i32:
 339         return ctpop32(x);
 340
 341     case INDEX_op_ctpop_i64:
 342         return ctpop64(x);
 343
 344     CASE_OP_32_64(ext8s):
 345         return (int8_t)x;
 346
 347     CASE_OP_32_64(ext16s):
 348         return (int16_t)x;
 349
 350     CASE_OP_32_64(ext8u):
 351         return (uint8_t)x;
 352
 353     CASE_OP_32_64(ext16u):
 354         return (uint16_t)x;
 355
 356     CASE_OP_32_64(bswap16):
 357         return bswap16(x);
 358
 359     CASE_OP_32_64(bswap32):
 360         return bswap32(x);
 361
 362     case INDEX_op_bswap64_i64:
 363         return bswap64(x);
 364
 365     case INDEX_op_ext_i32_i64:
 366     case INDEX_op_ext32s_i64:
 367         return (int32_t)x;
 368
 369     case INDEX_op_extu_i32_i64:
 370     case INDEX_op_extrl_i64_i32:
 371     case INDEX_op_ext32u_i64:
 372         return (uint32_t)x;
 373
 374     case INDEX_op_extrh_i64_i32:
 375         return (uint64_t)x >> 32;
 376
 377     case INDEX_op_muluh_i32:
 378         return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
 379     case INDEX_op_mulsh_i32:
 380         return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
 381
 382     case INDEX_op_muluh_i64:
 383         mulu64(&l64, &h64, x, y);
 384         return h64;
 385     case INDEX_op_mulsh_i64:
 386         muls64(&l64, &h64, x, y);
 387         return h64;
 388
 389     case INDEX_op_div_i32:
 390         /* Avoid crashing on divide by zero, otherwise undefined.  */
 391         return (int32_t)x / ((int32_t)y ? : 1);
 392     case INDEX_op_divu_i32:
 393         return (uint32_t)x / ((uint32_t)y ? : 1);
 394     case INDEX_op_div_i64:
 395         return (int64_t)x / ((int64_t)y ? : 1);
 396     case INDEX_op_divu_i64:
 397         return (uint64_t)x / ((uint64_t)y ? : 1);
 398
 399     case INDEX_op_rem_i32:
 400         return (int32_t)x % ((int32_t)y ? : 1);
 401     case INDEX_op_remu_i32:
 402         return (uint32_t)x % ((uint32_t)y ? : 1);
 403     case INDEX_op_rem_i64:
 404         return (int64_t)x % ((int64_t)y ? : 1);
 405     case INDEX_op_remu_i64:
 406         return (uint64_t)x % ((uint64_t)y ? : 1);
 407
 408     default:
 409         fprintf(stderr,
 410                 "Unrecognized operation %d in do_constant_folding.\n", op);
 411         tcg_abort();
 412     }
 413 }
 414
 415 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 416 {
 417     const TCGOpDef *def = &tcg_op_defs[op];
 418     TCGArg res = do_constant_folding_2(op, x, y);
 419     if (!(def->flags & TCG_OPF_64BIT)) {
 420         res = (int32_t)res;
 421     }
 422     return res;
 423 }
 424
 425 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
 426 {
 427     switch (c) {
 428     case TCG_COND_EQ:
 429         return x == y;
 430     case TCG_COND_NE:
 431         return x != y;
 432     case TCG_COND_LT:
 433         return (int32_t)x < (int32_t)y;
 434     case TCG_COND_GE:
 435         return (int32_t)x >= (int32_t)y;
 436     case TCG_COND_LE:
 437         return (int32_t)x <= (int32_t)y;
 438     case TCG_COND_GT:
 439         return (int32_t)x > (int32_t)y;
 440     case TCG_COND_LTU:
 441         return x < y;
 442     case TCG_COND_GEU:
 443         return x >= y;
 444     case TCG_COND_LEU:
 445         return x <= y;
 446     case TCG_COND_GTU:
 447         return x > y;
 448     default:
 449         tcg_abort();
 450     }
 451 }
 452
 453 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
 454 {
 455     switch (c) {
 456     case TCG_COND_EQ:
 457         return x == y;
 458     case TCG_COND_NE:
 459         return x != y;
 460     case TCG_COND_LT:
 461         return (int64_t)x < (int64_t)y;
 462     case TCG_COND_GE:
 463         return (int64_t)x >= (int64_t)y;
 464     case TCG_COND_LE:
 465         return (int64_t)x <= (int64_t)y;
 466     case TCG_COND_GT:
 467         return (int64_t)x > (int64_t)y;
 468     case TCG_COND_LTU:
 469         return x < y;
 470     case TCG_COND_GEU:
 471         return x >= y;
 472     case TCG_COND_LEU:
 473         return x <= y;
 474     case TCG_COND_GTU:
 475         return x > y;
 476     default:
 477         tcg_abort();
 478     }
 479 }
 480
 481 static bool do_constant_folding_cond_eq(TCGCond c)
 482 {
 483     switch (c) {
 484     case TCG_COND_GT:
 485     case TCG_COND_LTU:
 486     case TCG_COND_LT:
 487     case TCG_COND_GTU:
 488     case TCG_COND_NE:
 489         return 0;
 490     case TCG_COND_GE:
 491     case TCG_COND_GEU:
 492     case TCG_COND_LE:
 493     case TCG_COND_LEU:
 494     case TCG_COND_EQ:
 495         return 1;
 496     default:
 497         tcg_abort();
 498     }
 499 }
 500
 501 /* Return 2 if the condition can't be simplified, and the result
 502    of the condition (0 or 1) if it can */
 503 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 504                                        TCGArg y, TCGCond c)
 505 {
 506     tcg_target_ulong xv = arg_info(x)->val;
 507     tcg_target_ulong yv = arg_info(y)->val;
 508     if (arg_is_const(x) && arg_is_const(y)) {
 509         const TCGOpDef *def = &tcg_op_defs[op];
 510         tcg_debug_assert(!(def->flags & TCG_OPF_VECTOR));
 511         if (def->flags & TCG_OPF_64BIT) {
 512             return do_constant_folding_cond_64(xv, yv, c);
 513         } else {
 514             return do_constant_folding_cond_32(xv, yv, c);
 515         }
 516     } else if (args_are_copies(x, y)) {
 517         return do_constant_folding_cond_eq(c);
 518     } else if (arg_is_const(y) && yv == 0) {
 519         switch (c) {
 520         case TCG_COND_LTU:
 521             return 0;
 522         case TCG_COND_GEU:
 523             return 1;
 524         default:
 525             return 2;
 526         }
 527     }
 528     return 2;
 529 }
 530
 531 /* Return 2 if the condition can't be simplified, and the result
 532    of the condition (0 or 1) if it can */
 533 static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
 534 {
 535     TCGArg al = p1[0], ah = p1[1];
 536     TCGArg bl = p2[0], bh = p2[1];
 537
 538     if (arg_is_const(bl) && arg_is_const(bh)) {
 539         tcg_target_ulong blv = arg_info(bl)->val;
 540         tcg_target_ulong bhv = arg_info(bh)->val;
 541         uint64_t b = deposit64(blv, 32, 32, bhv);
 542
 543         if (arg_is_const(al) && arg_is_const(ah)) {
 544             tcg_target_ulong alv = arg_info(al)->val;
 545             tcg_target_ulong ahv = arg_info(ah)->val;
 546             uint64_t a = deposit64(alv, 32, 32, ahv);
 547             return do_constant_folding_cond_64(a, b, c);
 548         }
 549         if (b == 0) {
 550             switch (c) {
 551             case TCG_COND_LTU:
 552                 return 0;
 553             case TCG_COND_GEU:
 554                 return 1;
 555             default:
 556                 break;
 557             }
 558         }
 559     }
 560     if (args_are_copies(al, bl) && args_are_copies(ah, bh)) {
 561         return do_constant_folding_cond_eq(c);
 562     }
 563     return 2;
 564 }
 565
 566 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 567 {
 568     TCGArg a1 = *p1, a2 = *p2;
 569     int sum = 0;
 570     sum += arg_is_const(a1);
 571     sum -= arg_is_const(a2);
 572
 573     /* Prefer the constant in second argument, and then the form
 574        op a, a, b, which is better handled on non-RISC hosts. */
 575     if (sum > 0 || (sum == 0 && dest == a2)) {
 576         *p1 = a2;
 577         *p2 = a1;
 578         return true;
 579     }
 580     return false;
 581 }
 582
 583 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 584 {
 585     int sum = 0;
 586     sum += arg_is_const(p1[0]);
 587     sum += arg_is_const(p1[1]);
 588     sum -= arg_is_const(p2[0]);
 589     sum -= arg_is_const(p2[1]);
 590     if (sum > 0) {
 591         TCGArg t;
 592         t = p1[0], p1[0] = p2[0], p2[0] = t;
 593         t = p1[1], p1[1] = p2[1], p2[1] = t;
 594         return true;
 595     }
 596     return false;
 597 }
 598
 599 /* Propagate constants and copies, fold constant expressions. */
 600 void tcg_optimize(TCGContext *s)
 601 {
 602     int nb_temps, nb_globals;
 603     TCGOp *op, *op_next, *prev_mb = NULL;
 604     struct tcg_temp_info *infos;
 605     TCGTempSet temps_used;
 606
 607     /* Array VALS has an element for each temp.
 608        If this temp holds a constant then its value is kept in VALS' element.
 609        If this temp is a copy of other ones then the other copies are
 610        available through the doubly linked circular list. */
 611
 612     nb_temps = s->nb_temps;
 613     nb_globals = s->nb_globals;
 614     bitmap_zero(temps_used.l, nb_temps);
 615     infos = tcg_malloc(sizeof(struct tcg_temp_info) * nb_temps);
 616
 617     QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
 618         tcg_target_ulong mask, partmask, affected;
 619         int nb_oargs, nb_iargs, i;
 620         TCGArg tmp;
 621         TCGOpcode opc = op->opc;
 622         const TCGOpDef *def = &tcg_op_defs[opc];
 623
 624         /* Count the arguments, and initialize the temps that are
 625            going to be used */
 626         if (opc == INDEX_op_call) {
 627             nb_oargs = TCGOP_CALLO(op);
 628             nb_iargs = TCGOP_CALLI(op);
 629             for (i = 0; i < nb_oargs + nb_iargs; i++) {
 630                 TCGTemp *ts = arg_temp(op->args[i]);
 631                 if (ts) {
 632                     init_ts_info(infos, &temps_used, ts);
 633                 }
 634             }
 635         } else {
 636             nb_oargs = def->nb_oargs;
 637             nb_iargs = def->nb_iargs;
 638             for (i = 0; i < nb_oargs + nb_iargs; i++) {
 639                 init_arg_info(infos, &temps_used, op->args[i]);
 640             }
 641         }
 642
 643         /* Do copy propagation */
 644         for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
 645             TCGTemp *ts = arg_temp(op->args[i]);
 646             if (ts && ts_is_copy(ts)) {
 647                 op->args[i] = temp_arg(find_better_copy(s, ts));
 648             }
 649         }
 650
 651         /* For commutative operations make constant second argument */
 652         switch (opc) {
 653         CASE_OP_32_64_VEC(add):
 654         CASE_OP_32_64_VEC(mul):
 655         CASE_OP_32_64_VEC(and):
 656         CASE_OP_32_64_VEC(or):
 657         CASE_OP_32_64_VEC(xor):
 658         CASE_OP_32_64(eqv):
 659         CASE_OP_32_64(nand):
 660         CASE_OP_32_64(nor):
 661         CASE_OP_32_64(muluh):
 662         CASE_OP_32_64(mulsh):
 663             swap_commutative(op->args[0], &op->args[1], &op->args[2]);
 664             break;
 665         CASE_OP_32_64(brcond):
 666             if (swap_commutative(-1, &op->args[0], &op->args[1])) {
 667                 op->args[2] = tcg_swap_cond(op->args[2]);
 668             }
 669             break;
 670         CASE_OP_32_64(setcond):
 671             if (swap_commutative(op->args[0], &op->args[1], &op->args[2])) {
 672                 op->args[3] = tcg_swap_cond(op->args[3]);
 673             }
 674             break;
 675         CASE_OP_32_64(movcond):
 676             if (swap_commutative(-1, &op->args[1], &op->args[2])) {
 677                 op->args[5] = tcg_swap_cond(op->args[5]);
 678             }
 679             /* For movcond, we canonicalize the "false" input reg to match
 680                the destination reg so that the tcg backend can implement
 681                a "move if true" operation.  */
 682             if (swap_commutative(op->args[0], &op->args[4], &op->args[3])) {
 683                 op->args[5] = tcg_invert_cond(op->args[5]);
 684             }
 685             break;
 686         CASE_OP_32_64(add2):
 687             swap_commutative(op->args[0], &op->args[2], &op->args[4]);
 688             swap_commutative(op->args[1], &op->args[3], &op->args[5]);
 689             break;
 690         CASE_OP_32_64(mulu2):
 691         CASE_OP_32_64(muls2):
 692             swap_commutative(op->args[0], &op->args[2], &op->args[3]);
 693             break;
 694         case INDEX_op_brcond2_i32:
 695             if (swap_commutative2(&op->args[0], &op->args[2])) {
 696                 op->args[4] = tcg_swap_cond(op->args[4]);
 697             }
 698             break;
 699         case INDEX_op_setcond2_i32:
 700             if (swap_commutative2(&op->args[1], &op->args[3])) {
 701                 op->args[5] = tcg_swap_cond(op->args[5]);
 702             }
 703             break;
 704         default:
 705             break;
 706         }
 707
 708         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
 709            and "sub r, 0, a => neg r, a" case.  */
 710         switch (opc) {
 711         CASE_OP_32_64(shl):
 712         CASE_OP_32_64(shr):
 713         CASE_OP_32_64(sar):
 714         CASE_OP_32_64(rotl):
 715         CASE_OP_32_64(rotr):
 716             if (arg_is_const(op->args[1])
 717                 && arg_info(op->args[1])->val == 0) {
 718                 tcg_opt_gen_movi(s, op, op->args[0], 0);
 719                 continue;
 720             }
 721             break;
 722         CASE_OP_32_64_VEC(sub):
 723             {
 724                 TCGOpcode neg_op;
 725                 bool have_neg;
 726
 727                 if (arg_is_const(op->args[2])) {
 728                     /* Proceed with possible constant folding. */
 729                     break;
 730                 }
 731                 if (opc == INDEX_op_sub_i32) {
 732                     neg_op = INDEX_op_neg_i32;
 733                     have_neg = TCG_TARGET_HAS_neg_i32;
 734                 } else if (opc == INDEX_op_sub_i64) {
 735                     neg_op = INDEX_op_neg_i64;
 736                     have_neg = TCG_TARGET_HAS_neg_i64;
 737                 } else if (TCG_TARGET_HAS_neg_vec) {
 738                     TCGType type = TCGOP_VECL(op) + TCG_TYPE_V64;
 739                     unsigned vece = TCGOP_VECE(op);
 740                     neg_op = INDEX_op_neg_vec;
 741                     have_neg = tcg_can_emit_vec_op(neg_op, type, vece) > 0;
 742                 } else {
 743                     break;
 744                 }
 745                 if (!have_neg) {
 746                     break;
 747                 }
 748                 if (arg_is_const(op->args[1])
 749                     && arg_info(op->args[1])->val == 0) {
 750                     op->opc = neg_op;
 751                     reset_temp(op->args[0]);
 752                     op->args[1] = op->args[2];
 753                     continue;
 754                 }
 755             }
 756             break;
 757         CASE_OP_32_64_VEC(xor):
 758         CASE_OP_32_64(nand):
 759             if (!arg_is_const(op->args[1])
 760                 && arg_is_const(op->args[2])
 761                 && arg_info(op->args[2])->val == -1) {
 762                 i = 1;
 763                 goto try_not;
 764             }
 765             break;
 766         CASE_OP_32_64(nor):
 767             if (!arg_is_const(op->args[1])
 768                 && arg_is_const(op->args[2])
 769                 && arg_info(op->args[2])->val == 0) {
 770                 i = 1;
 771                 goto try_not;
 772             }
 773             break;
 774         CASE_OP_32_64_VEC(andc):
 775             if (!arg_is_const(op->args[2])
 776                 && arg_is_const(op->args[1])
 777                 && arg_info(op->args[1])->val == -1) {
 778                 i = 2;
 779                 goto try_not;
 780             }
 781             break;
 782         CASE_OP_32_64_VEC(orc):
 783         CASE_OP_32_64(eqv):
 784             if (!arg_is_const(op->args[2])
 785                 && arg_is_const(op->args[1])
 786                 && arg_info(op->args[1])->val == 0) {
 787                 i = 2;
 788                 goto try_not;
 789             }
 790             break;
 791         try_not:
 792             {
 793                 TCGOpcode not_op;
 794                 bool have_not;
 795
 796                 if (def->flags & TCG_OPF_VECTOR) {
 797                     not_op = INDEX_op_not_vec;
 798                     have_not = TCG_TARGET_HAS_not_vec;
 799                 } else if (def->flags & TCG_OPF_64BIT) {
 800                     not_op = INDEX_op_not_i64;
 801                     have_not = TCG_TARGET_HAS_not_i64;
 802                 } else {
 803                     not_op = INDEX_op_not_i32;
 804                     have_not = TCG_TARGET_HAS_not_i32;
 805                 }
 806                 if (!have_not) {
 807                     break;
 808                 }
 809                 op->opc = not_op;
 810                 reset_temp(op->args[0]);
 811                 op->args[1] = op->args[i];
 812                 continue;
 813             }
 814         default:
 815             break;
 816         }
 817
 818         /* Simplify expression for "op r, a, const => mov r, a" cases */
 819         switch (opc) {
 820         CASE_OP_32_64_VEC(add):
 821         CASE_OP_32_64_VEC(sub):
 822         CASE_OP_32_64_VEC(or):
 823         CASE_OP_32_64_VEC(xor):
 824         CASE_OP_32_64_VEC(andc):
 825         CASE_OP_32_64(shl):
 826         CASE_OP_32_64(shr):
 827         CASE_OP_32_64(sar):
 828         CASE_OP_32_64(rotl):
 829         CASE_OP_32_64(rotr):
 830             if (!arg_is_const(op->args[1])
 831                 && arg_is_const(op->args[2])
 832                 && arg_info(op->args[2])->val == 0) {
 833                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
 834                 continue;
 835             }
 836             break;
 837         CASE_OP_32_64_VEC(and):
 838         CASE_OP_32_64_VEC(orc):
 839         CASE_OP_32_64(eqv):
 840             if (!arg_is_const(op->args[1])
 841                 && arg_is_const(op->args[2])
 842                 && arg_info(op->args[2])->val == -1) {
 843                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
 844                 continue;
 845             }
 846             break;
 847         default:
 848             break;
 849         }
 850
 851         /* Simplify using known-zero bits. Currently only ops with a single
 852            output argument is supported. */
 853         mask = -1;
 854         affected = -1;
 855         switch (opc) {
 856         CASE_OP_32_64(ext8s):
 857             if ((arg_info(op->args[1])->mask & 0x80) != 0) {
 858                 break;
 859             }
 860         CASE_OP_32_64(ext8u):
 861             mask = 0xff;
 862             goto and_const;
 863         CASE_OP_32_64(ext16s):
 864             if ((arg_info(op->args[1])->mask & 0x8000) != 0) {
 865                 break;
 866             }
 867         CASE_OP_32_64(ext16u):
 868             mask = 0xffff;
 869             goto and_const;
 870         case INDEX_op_ext32s_i64:
 871             if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
 872                 break;
 873             }
 874         case INDEX_op_ext32u_i64:
 875             mask = 0xffffffffU;
 876             goto and_const;
 877
 878         CASE_OP_32_64(and):
 879             mask = arg_info(op->args[2])->mask;
 880             if (arg_is_const(op->args[2])) {
 881         and_const:
 882                 affected = arg_info(op->args[1])->mask & ~mask;
 883             }
 884             mask = arg_info(op->args[1])->mask & mask;
 885             break;
 886
 887         case INDEX_op_ext_i32_i64:
 888             if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
 889                 break;
 890             }
 891         case INDEX_op_extu_i32_i64:
 892             /* We do not compute affected as it is a size changing op.  */
 893             mask = (uint32_t)arg_info(op->args[1])->mask;
 894             break;
 895
 896         CASE_OP_32_64(andc):
 897             /* Known-zeros does not imply known-ones.  Therefore unless
 898                op->args[2] is constant, we can't infer anything from it.  */
 899             if (arg_is_const(op->args[2])) {
 900                 mask = ~arg_info(op->args[2])->mask;
 901                 goto and_const;
 902             }
 903             /* But we certainly know nothing outside args[1] may be set. */
 904             mask = arg_info(op->args[1])->mask;
 905             break;
 906
 907         case INDEX_op_sar_i32:
 908             if (arg_is_const(op->args[2])) {
 909                 tmp = arg_info(op->args[2])->val & 31;
 910                 mask = (int32_t)arg_info(op->args[1])->mask >> tmp;
 911             }
 912             break;
 913         case INDEX_op_sar_i64:
 914             if (arg_is_const(op->args[2])) {
 915                 tmp = arg_info(op->args[2])->val & 63;
 916                 mask = (int64_t)arg_info(op->args[1])->mask >> tmp;
 917             }
 918             break;
 919
 920         case INDEX_op_shr_i32:
 921             if (arg_is_const(op->args[2])) {
 922                 tmp = arg_info(op->args[2])->val & 31;
 923                 mask = (uint32_t)arg_info(op->args[1])->mask >> tmp;
 924             }
 925             break;
 926         case INDEX_op_shr_i64:
 927             if (arg_is_const(op->args[2])) {
 928                 tmp = arg_info(op->args[2])->val & 63;
 929                 mask = (uint64_t)arg_info(op->args[1])->mask >> tmp;
 930             }
 931             break;
 932
 933         case INDEX_op_extrl_i64_i32:
 934             mask = (uint32_t)arg_info(op->args[1])->mask;
 935             break;
 936         case INDEX_op_extrh_i64_i32:
 937             mask = (uint64_t)arg_info(op->args[1])->mask >> 32;
 938             break;
 939
 940         CASE_OP_32_64(shl):
 941             if (arg_is_const(op->args[2])) {
 942                 tmp = arg_info(op->args[2])->val & (TCG_TARGET_REG_BITS - 1);
 943                 mask = arg_info(op->args[1])->mask << tmp;
 944             }
 945             break;
 946
 947         CASE_OP_32_64(neg):
 948             /* Set to 1 all bits to the left of the rightmost.  */
 949             mask = -(arg_info(op->args[1])->mask
 950                      & -arg_info(op->args[1])->mask);
 951             break;
 952
 953         CASE_OP_32_64(deposit):
 954             mask = deposit64(arg_info(op->args[1])->mask,
 955                              op->args[3], op->args[4],
 956                              arg_info(op->args[2])->mask);
 957             break;
 958
 959         CASE_OP_32_64(extract):
 960             mask = extract64(arg_info(op->args[1])->mask,
 961                              op->args[2], op->args[3]);
 962             if (op->args[2] == 0) {
 963                 affected = arg_info(op->args[1])->mask & ~mask;
 964             }
 965             break;
 966         CASE_OP_32_64(sextract):
 967             mask = sextract64(arg_info(op->args[1])->mask,
 968                               op->args[2], op->args[3]);
 969             if (op->args[2] == 0 && (tcg_target_long)mask >= 0) {
 970                 affected = arg_info(op->args[1])->mask & ~mask;
 971             }
 972             break;
 973
 974         CASE_OP_32_64(or):
 975         CASE_OP_32_64(xor):
 976             mask = arg_info(op->args[1])->mask | arg_info(op->args[2])->mask;
 977             break;
 978
 979         case INDEX_op_clz_i32:
 980         case INDEX_op_ctz_i32:
 981             mask = arg_info(op->args[2])->mask | 31;
 982             break;
 983
 984         case INDEX_op_clz_i64:
 985         case INDEX_op_ctz_i64:
 986             mask = arg_info(op->args[2])->mask | 63;
 987             break;
 988
 989         case INDEX_op_ctpop_i32:
 990             mask = 32 | 31;
 991             break;
 992         case INDEX_op_ctpop_i64:
 993             mask = 64 | 63;
 994             break;
 995
 996         CASE_OP_32_64(setcond):
 997         case INDEX_op_setcond2_i32:
 998             mask = 1;
 999             break;
1000
1001         CASE_OP_32_64(movcond):
1002             mask = arg_info(op->args[3])->mask | arg_info(op->args[4])->mask;
1003             break;
1004
1005         CASE_OP_32_64(ld8u):
1006             mask = 0xff;
1007             break;
1008         CASE_OP_32_64(ld16u):
1009             mask = 0xffff;
1010             break;
1011         case INDEX_op_ld32u_i64:
1012             mask = 0xffffffffu;
1013             break;
1014
1015         CASE_OP_32_64(qemu_ld):
1016             {
1017                 TCGMemOpIdx oi = op->args[nb_oargs + nb_iargs];
1018                 TCGMemOp mop = get_memop(oi);
1019                 if (!(mop & MO_SIGN)) {
1020                     mask = (2ULL << ((8 << (mop & MO_SIZE)) - 1)) - 1;
1021                 }
1022             }
1023             break;
1024
1025         default:
1026             break;
1027         }
1028
1029         /* 32-bit ops generate 32-bit results.  For the result is zero test
1030            below, we can ignore high bits, but for further optimizations we
1031            need to record that the high bits contain garbage.  */
1032         partmask = mask;
1033         if (!(def->flags & TCG_OPF_64BIT)) {
1034             mask |= ~(tcg_target_ulong)0xffffffffu;
1035             partmask &= 0xffffffffu;
1036             affected &= 0xffffffffu;
1037         }
1038
1039         if (partmask == 0) {
1040             tcg_debug_assert(nb_oargs == 1);
1041             tcg_opt_gen_movi(s, op, op->args[0], 0);
1042             continue;
1043         }
1044         if (affected == 0) {
1045             tcg_debug_assert(nb_oargs == 1);
1046             tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1047             continue;
1048         }
1049
1050         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
1051         switch (opc) {
1052         CASE_OP_32_64_VEC(and):
1053         CASE_OP_32_64_VEC(mul):
1054         CASE_OP_32_64(muluh):
1055         CASE_OP_32_64(mulsh):
1056             if (arg_is_const(op->args[2])
1057                 && arg_info(op->args[2])->val == 0) {
1058                 tcg_opt_gen_movi(s, op, op->args[0], 0);
1059                 continue;
1060             }
1061             break;
1062         default:
1063             break;
1064         }
1065
1066         /* Simplify expression for "op r, a, a => mov r, a" cases */
1067         switch (opc) {
1068         CASE_OP_32_64_VEC(or):
1069         CASE_OP_32_64_VEC(and):
1070             if (args_are_copies(op->args[1], op->args[2])) {
1071                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1072                 continue;
1073             }
1074             break;
1075         default:
1076             break;
1077         }
1078
1079         /* Simplify expression for "op r, a, a => movi r, 0" cases */
1080         switch (opc) {
1081         CASE_OP_32_64_VEC(andc):
1082         CASE_OP_32_64_VEC(sub):
1083         CASE_OP_32_64_VEC(xor):
1084             if (args_are_copies(op->args[1], op->args[2])) {
1085                 tcg_opt_gen_movi(s, op, op->args[0], 0);
1086                 continue;
1087             }
1088             break;
1089         default:
1090             break;
1091         }
1092
1093         /* Propagate constants through copy operations and do constant
1094            folding.  Constants will be substituted to arguments by register
1095            allocator where needed and possible.  Also detect copies. */
1096         switch (opc) {
1097         CASE_OP_32_64_VEC(mov):
1098             tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1099             break;
1100         CASE_OP_32_64(movi):
1101         case INDEX_op_dupi_vec:
1102             tcg_opt_gen_movi(s, op, op->args[0], op->args[1]);
1103             break;
1104
1105         case INDEX_op_dup_vec:
1106             if (arg_is_const(op->args[1])) {
1107                 tmp = arg_info(op->args[1])->val;
1108                 tmp = dup_const(TCGOP_VECE(op), tmp);
1109                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1110                 break;
1111             }
1112             goto do_default;
1113
1114         CASE_OP_32_64(not):
1115         CASE_OP_32_64(neg):
1116         CASE_OP_32_64(ext8s):
1117         CASE_OP_32_64(ext8u):
1118         CASE_OP_32_64(ext16s):
1119         CASE_OP_32_64(ext16u):
1120         CASE_OP_32_64(ctpop):
1121         CASE_OP_32_64(bswap16):
1122         CASE_OP_32_64(bswap32):
1123         case INDEX_op_bswap64_i64:
1124         case INDEX_op_ext32s_i64:
1125         case INDEX_op_ext32u_i64:
1126         case INDEX_op_ext_i32_i64:
1127         case INDEX_op_extu_i32_i64:
1128         case INDEX_op_extrl_i64_i32:
1129         case INDEX_op_extrh_i64_i32:
1130             if (arg_is_const(op->args[1])) {
1131                 tmp = do_constant_folding(opc, arg_info(op->args[1])->val, 0);
1132                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1133                 break;
1134             }
1135             goto do_default;
1136
1137         CASE_OP_32_64(add):
1138         CASE_OP_32_64(sub):
1139         CASE_OP_32_64(mul):
1140         CASE_OP_32_64(or):
1141         CASE_OP_32_64(and):
1142         CASE_OP_32_64(xor):
1143         CASE_OP_32_64(shl):
1144         CASE_OP_32_64(shr):
1145         CASE_OP_32_64(sar):
1146         CASE_OP_32_64(rotl):
1147         CASE_OP_32_64(rotr):
1148         CASE_OP_32_64(andc):
1149         CASE_OP_32_64(orc):
1150         CASE_OP_32_64(eqv):
1151         CASE_OP_32_64(nand):
1152         CASE_OP_32_64(nor):
1153         CASE_OP_32_64(muluh):
1154         CASE_OP_32_64(mulsh):
1155         CASE_OP_32_64(div):
1156         CASE_OP_32_64(divu):
1157         CASE_OP_32_64(rem):
1158         CASE_OP_32_64(remu):
1159             if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1160                 tmp = do_constant_folding(opc, arg_info(op->args[1])->val,
1161                                           arg_info(op->args[2])->val);
1162                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1163                 break;
1164             }
1165             goto do_default;
1166
1167         CASE_OP_32_64(clz):
1168         CASE_OP_32_64(ctz):
1169             if (arg_is_const(op->args[1])) {
1170                 TCGArg v = arg_info(op->args[1])->val;
1171                 if (v != 0) {
1172                     tmp = do_constant_folding(opc, v, 0);
1173                     tcg_opt_gen_movi(s, op, op->args[0], tmp);
1174                 } else {
1175                     tcg_opt_gen_mov(s, op, op->args[0], op->args[2]);
1176                 }
1177                 break;
1178             }
1179             goto do_default;
1180
1181         CASE_OP_32_64(deposit):
1182             if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1183                 tmp = deposit64(arg_info(op->args[1])->val,
1184                                 op->args[3], op->args[4],
1185                                 arg_info(op->args[2])->val);
1186                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1187                 break;
1188             }
1189             goto do_default;
1190
1191         CASE_OP_32_64(extract):
1192             if (arg_is_const(op->args[1])) {
1193                 tmp = extract64(arg_info(op->args[1])->val,
1194                                 op->args[2], op->args[3]);
1195                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1196                 break;
1197             }
1198             goto do_default;
1199
1200         CASE_OP_32_64(sextract):
1201             if (arg_is_const(op->args[1])) {
1202                 tmp = sextract64(arg_info(op->args[1])->val,
1203                                  op->args[2], op->args[3]);
1204                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1205                 break;
1206             }
1207             goto do_default;
1208
1209         CASE_OP_32_64(extract2):
1210             if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1211                 TCGArg v1 = arg_info(op->args[1])->val;
1212                 TCGArg v2 = arg_info(op->args[2])->val;
1213
1214                 if (opc == INDEX_op_extract2_i64) {
1215                     tmp = (v1 >> op->args[3]) | (v2 << (64 - op->args[3]));
1216                 } else {
1217                     tmp = (v1 >> op->args[3]) | (v2 << (32 - op->args[3]));
1218                     tmp = (int32_t)tmp;
1219                 }
1220                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1221                 break;
1222             }
1223             goto do_default;
1224
1225         CASE_OP_32_64(setcond):
1226             tmp = do_constant_folding_cond(opc, op->args[1],
1227                                            op->args[2], op->args[3]);
1228             if (tmp != 2) {
1229                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1230                 break;
1231             }
1232             goto do_default;
1233
1234         CASE_OP_32_64(brcond):
1235             tmp = do_constant_folding_cond(opc, op->args[0],
1236                                            op->args[1], op->args[2]);
1237             if (tmp != 2) {
1238                 if (tmp) {
1239                     bitmap_zero(temps_used.l, nb_temps);
1240                     op->opc = INDEX_op_br;
1241                     op->args[0] = op->args[3];
1242                 } else {
1243                     tcg_op_remove(s, op);
1244                 }
1245                 break;
1246             }
1247             goto do_default;
1248
1249         CASE_OP_32_64(movcond):
1250             tmp = do_constant_folding_cond(opc, op->args[1],
1251                                            op->args[2], op->args[5]);
1252             if (tmp != 2) {
1253                 tcg_opt_gen_mov(s, op, op->args[0], op->args[4-tmp]);
1254                 break;
1255             }
1256             if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
1257                 tcg_target_ulong tv = arg_info(op->args[3])->val;
1258                 tcg_target_ulong fv = arg_info(op->args[4])->val;
1259                 TCGCond cond = op->args[5];
1260                 if (fv == 1 && tv == 0) {
1261                     cond = tcg_invert_cond(cond);
1262                 } else if (!(tv == 1 && fv == 0)) {
1263                     goto do_default;
1264                 }
1265                 op->args[3] = cond;
1266                 op->opc = opc = (opc == INDEX_op_movcond_i32
1267                                  ? INDEX_op_setcond_i32
1268                                  : INDEX_op_setcond_i64);
1269                 nb_iargs = 2;
1270             }
1271             goto do_default;
1272
1273         case INDEX_op_add2_i32:
1274         case INDEX_op_sub2_i32:
1275             if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])
1276                 && arg_is_const(op->args[4]) && arg_is_const(op->args[5])) {
1277                 uint32_t al = arg_info(op->args[2])->val;
1278                 uint32_t ah = arg_info(op->args[3])->val;
1279                 uint32_t bl = arg_info(op->args[4])->val;
1280                 uint32_t bh = arg_info(op->args[5])->val;
1281                 uint64_t a = ((uint64_t)ah << 32) | al;
1282                 uint64_t b = ((uint64_t)bh << 32) | bl;
1283                 TCGArg rl, rh;
1284                 TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32);
1285
1286                 if (opc == INDEX_op_add2_i32) {
1287                     a += b;
1288                 } else {
1289                     a -= b;
1290                 }
1291
1292                 rl = op->args[0];
1293                 rh = op->args[1];
1294                 tcg_opt_gen_movi(s, op, rl, (int32_t)a);
1295                 tcg_opt_gen_movi(s, op2, rh, (int32_t)(a >> 32));
1296                 break;
1297             }
1298             goto do_default;
1299
1300         case INDEX_op_mulu2_i32:
1301             if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
1302                 uint32_t a = arg_info(op->args[2])->val;
1303                 uint32_t b = arg_info(op->args[3])->val;
1304                 uint64_t r = (uint64_t)a * b;
1305                 TCGArg rl, rh;
1306                 TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32);
1307
1308                 rl = op->args[0];
1309                 rh = op->args[1];
1310                 tcg_opt_gen_movi(s, op, rl, (int32_t)r);
1311                 tcg_opt_gen_movi(s, op2, rh, (int32_t)(r >> 32));
1312                 break;
1313             }
1314             goto do_default;
1315
1316         case INDEX_op_brcond2_i32:
1317             tmp = do_constant_folding_cond2(&op->args[0], &op->args[2],
1318                                             op->args[4]);
1319             if (tmp != 2) {
1320                 if (tmp) {
1321             do_brcond_true:
1322                     bitmap_zero(temps_used.l, nb_temps);
1323                     op->opc = INDEX_op_br;
1324                     op->args[0] = op->args[5];
1325                 } else {
1326             do_brcond_false:
1327                     tcg_op_remove(s, op);
1328                 }
1329             } else if ((op->args[4] == TCG_COND_LT
1330                         || op->args[4] == TCG_COND_GE)
1331                        && arg_is_const(op->args[2])
1332                        && arg_info(op->args[2])->val == 0
1333                        && arg_is_const(op->args[3])
1334                        && arg_info(op->args[3])->val == 0) {
1335                 /* Simplify LT/GE comparisons vs zero to a single compare
1336                    vs the high word of the input.  */
1337             do_brcond_high:
1338                 bitmap_zero(temps_used.l, nb_temps);
1339                 op->opc = INDEX_op_brcond_i32;
1340                 op->args[0] = op->args[1];
1341                 op->args[1] = op->args[3];
1342                 op->args[2] = op->args[4];
1343                 op->args[3] = op->args[5];
1344             } else if (op->args[4] == TCG_COND_EQ) {
1345                 /* Simplify EQ comparisons where one of the pairs
1346                    can be simplified.  */
1347                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1348                                                op->args[0], op->args[2],
1349                                                TCG_COND_EQ);
1350                 if (tmp == 0) {
1351                     goto do_brcond_false;
1352                 } else if (tmp == 1) {
1353                     goto do_brcond_high;
1354                 }
1355                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1356                                                op->args[1], op->args[3],
1357                                                TCG_COND_EQ);
1358                 if (tmp == 0) {
1359                     goto do_brcond_false;
1360                 } else if (tmp != 1) {
1361                     goto do_default;
1362                 }
1363             do_brcond_low:
1364                 bitmap_zero(temps_used.l, nb_temps);
1365                 op->opc = INDEX_op_brcond_i32;
1366                 op->args[1] = op->args[2];
1367                 op->args[2] = op->args[4];
1368                 op->args[3] = op->args[5];
1369             } else if (op->args[4] == TCG_COND_NE) {
1370                 /* Simplify NE comparisons where one of the pairs
1371                    can be simplified.  */
1372                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1373                                                op->args[0], op->args[2],
1374                                                TCG_COND_NE);
1375                 if (tmp == 0) {
1376                     goto do_brcond_high;
1377                 } else if (tmp == 1) {
1378                     goto do_brcond_true;
1379                 }
1380                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1381                                                op->args[1], op->args[3],
1382                                                TCG_COND_NE);
1383                 if (tmp == 0) {
1384                     goto do_brcond_low;
1385                 } else if (tmp == 1) {
1386                     goto do_brcond_true;
1387                 }
1388                 goto do_default;
1389             } else {
1390                 goto do_default;
1391             }
1392             break;
1393
1394         case INDEX_op_setcond2_i32:
1395             tmp = do_constant_folding_cond2(&op->args[1], &op->args[3],
1396                                             op->args[5]);
1397             if (tmp != 2) {
1398             do_setcond_const:
1399                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1400             } else if ((op->args[5] == TCG_COND_LT
1401                         || op->args[5] == TCG_COND_GE)
1402                        && arg_is_const(op->args[3])
1403                        && arg_info(op->args[3])->val == 0
1404                        && arg_is_const(op->args[4])
1405                        && arg_info(op->args[4])->val == 0) {
1406                 /* Simplify LT/GE comparisons vs zero to a single compare
1407                    vs the high word of the input.  */
1408             do_setcond_high:
1409                 reset_temp(op->args[0]);
1410                 arg_info(op->args[0])->mask = 1;
1411                 op->opc = INDEX_op_setcond_i32;
1412                 op->args[1] = op->args[2];
1413                 op->args[2] = op->args[4];
1414                 op->args[3] = op->args[5];
1415             } else if (op->args[5] == TCG_COND_EQ) {
1416                 /* Simplify EQ comparisons where one of the pairs
1417                    can be simplified.  */
1418                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1419                                                op->args[1], op->args[3],
1420                                                TCG_COND_EQ);
1421                 if (tmp == 0) {
1422                     goto do_setcond_const;
1423                 } else if (tmp == 1) {
1424                     goto do_setcond_high;
1425                 }
1426                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1427                                                op->args[2], op->args[4],
1428                                                TCG_COND_EQ);
1429                 if (tmp == 0) {
1430                     goto do_setcond_high;
1431                 } else if (tmp != 1) {
1432                     goto do_default;
1433                 }
1434             do_setcond_low:
1435                 reset_temp(op->args[0]);
1436                 arg_info(op->args[0])->mask = 1;
1437                 op->opc = INDEX_op_setcond_i32;
1438                 op->args[2] = op->args[3];
1439                 op->args[3] = op->args[5];
1440             } else if (op->args[5] == TCG_COND_NE) {
1441                 /* Simplify NE comparisons where one of the pairs
1442                    can be simplified.  */
1443                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1444                                                op->args[1], op->args[3],
1445                                                TCG_COND_NE);
1446                 if (tmp == 0) {
1447                     goto do_setcond_high;
1448                 } else if (tmp == 1) {
1449                     goto do_setcond_const;
1450                 }
1451                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1452                                                op->args[2], op->args[4],
1453                                                TCG_COND_NE);
1454                 if (tmp == 0) {
1455                     goto do_setcond_low;
1456                 } else if (tmp == 1) {
1457                     goto do_setcond_const;
1458                 }
1459                 goto do_default;
1460             } else {
1461                 goto do_default;
1462             }
1463             break;
1464
1465         case INDEX_op_call:
1466             if (!(op->args[nb_oargs + nb_iargs + 1]
1467                   & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
1468                 for (i = 0; i < nb_globals; i++) {
1469                     if (test_bit(i, temps_used.l)) {
1470                         reset_ts(&s->temps[i]);
1471                     }
1472                 }
1473             }
1474             goto do_reset_output;
1475
1476         default:
1477         do_default:
1478             /* Default case: we know nothing about operation (or were unable
1479                to compute the operation result) so no propagation is done.
1480                We trash everything if the operation is the end of a basic
1481                block, otherwise we only trash the output args.  "mask" is
1482                the non-zero bits mask for the first output arg.  */
1483             if (def->flags & TCG_OPF_BB_END) {
1484                 bitmap_zero(temps_used.l, nb_temps);
1485             } else {
1486         do_reset_output:
1487                 for (i = 0; i < nb_oargs; i++) {
1488                     reset_temp(op->args[i]);
1489                     /* Save the corresponding known-zero bits mask for the
1490                        first output argument (only one supported so far). */
1491                     if (i == 0) {
1492                         arg_info(op->args[i])->mask = mask;
1493                     }
1494                 }
1495             }
1496             break;
1497         }
1498
1499         /* Eliminate duplicate and redundant fence instructions.  */
1500         if (prev_mb) {
1501             switch (opc) {
1502             case INDEX_op_mb:
1503                 /* Merge two barriers of the same type into one,
1504                  * or a weaker barrier into a stronger one,
1505                  * or two weaker barriers into a stronger one.
1506                  *   mb X; mb Y => mb X|Y
1507                  *   mb; strl => mb; st
1508                  *   ldaq; mb => ld; mb
1509                  *   ldaq; strl => ld; mb; st
1510                  * Other combinations are also merged into a strong
1511                  * barrier.  This is stricter than specified but for
1512                  * the purposes of TCG is better than not optimizing.
1513                  */
1514                 prev_mb->args[0] |= op->args[0];
1515                 tcg_op_remove(s, op);
1516                 break;
1517
1518             default:
1519                 /* Opcodes that end the block stop the optimization.  */
1520                 if ((def->flags & TCG_OPF_BB_END) == 0) {
1521                     break;
1522                 }
1523                 /* fallthru */
1524             case INDEX_op_qemu_ld_i32:
1525             case INDEX_op_qemu_ld_i64:
1526             case INDEX_op_qemu_st_i32:
1527             case INDEX_op_qemu_st_i64:
1528             case INDEX_op_call:
1529                 /* Opcodes that touch guest memory stop the optimization.  */
1530                 prev_mb = NULL;
1531                 break;
1532             }
1533         } else if (opc == INDEX_op_mb) {
1534             prev_mb = op;
1535         }
1536     }
1537 }