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 "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 INDEX_op_ext_i32_i64:
 357     case INDEX_op_ext32s_i64:
 358         return (int32_t)x;
 359
 360     case INDEX_op_extu_i32_i64:
 361     case INDEX_op_extrl_i64_i32:
 362     case INDEX_op_ext32u_i64:
 363         return (uint32_t)x;
 364
 365     case INDEX_op_extrh_i64_i32:
 366         return (uint64_t)x >> 32;
 367
 368     case INDEX_op_muluh_i32:
 369         return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
 370     case INDEX_op_mulsh_i32:
 371         return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
 372
 373     case INDEX_op_muluh_i64:
 374         mulu64(&l64, &h64, x, y);
 375         return h64;
 376     case INDEX_op_mulsh_i64:
 377         muls64(&l64, &h64, x, y);
 378         return h64;
 379
 380     case INDEX_op_div_i32:
 381         /* Avoid crashing on divide by zero, otherwise undefined.  */
 382         return (int32_t)x / ((int32_t)y ? : 1);
 383     case INDEX_op_divu_i32:
 384         return (uint32_t)x / ((uint32_t)y ? : 1);
 385     case INDEX_op_div_i64:
 386         return (int64_t)x / ((int64_t)y ? : 1);
 387     case INDEX_op_divu_i64:
 388         return (uint64_t)x / ((uint64_t)y ? : 1);
 389
 390     case INDEX_op_rem_i32:
 391         return (int32_t)x % ((int32_t)y ? : 1);
 392     case INDEX_op_remu_i32:
 393         return (uint32_t)x % ((uint32_t)y ? : 1);
 394     case INDEX_op_rem_i64:
 395         return (int64_t)x % ((int64_t)y ? : 1);
 396     case INDEX_op_remu_i64:
 397         return (uint64_t)x % ((uint64_t)y ? : 1);
 398
 399     default:
 400         fprintf(stderr,
 401                 "Unrecognized operation %d in do_constant_folding.\n", op);
 402         tcg_abort();
 403     }
 404 }
 405
 406 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 407 {
 408     const TCGOpDef *def = &tcg_op_defs[op];
 409     TCGArg res = do_constant_folding_2(op, x, y);
 410     if (!(def->flags & TCG_OPF_64BIT)) {
 411         res = (int32_t)res;
 412     }
 413     return res;
 414 }
 415
 416 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
 417 {
 418     switch (c) {
 419     case TCG_COND_EQ:
 420         return x == y;
 421     case TCG_COND_NE:
 422         return x != y;
 423     case TCG_COND_LT:
 424         return (int32_t)x < (int32_t)y;
 425     case TCG_COND_GE:
 426         return (int32_t)x >= (int32_t)y;
 427     case TCG_COND_LE:
 428         return (int32_t)x <= (int32_t)y;
 429     case TCG_COND_GT:
 430         return (int32_t)x > (int32_t)y;
 431     case TCG_COND_LTU:
 432         return x < y;
 433     case TCG_COND_GEU:
 434         return x >= y;
 435     case TCG_COND_LEU:
 436         return x <= y;
 437     case TCG_COND_GTU:
 438         return x > y;
 439     default:
 440         tcg_abort();
 441     }
 442 }
 443
 444 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
 445 {
 446     switch (c) {
 447     case TCG_COND_EQ:
 448         return x == y;
 449     case TCG_COND_NE:
 450         return x != y;
 451     case TCG_COND_LT:
 452         return (int64_t)x < (int64_t)y;
 453     case TCG_COND_GE:
 454         return (int64_t)x >= (int64_t)y;
 455     case TCG_COND_LE:
 456         return (int64_t)x <= (int64_t)y;
 457     case TCG_COND_GT:
 458         return (int64_t)x > (int64_t)y;
 459     case TCG_COND_LTU:
 460         return x < y;
 461     case TCG_COND_GEU:
 462         return x >= y;
 463     case TCG_COND_LEU:
 464         return x <= y;
 465     case TCG_COND_GTU:
 466         return x > y;
 467     default:
 468         tcg_abort();
 469     }
 470 }
 471
 472 static bool do_constant_folding_cond_eq(TCGCond c)
 473 {
 474     switch (c) {
 475     case TCG_COND_GT:
 476     case TCG_COND_LTU:
 477     case TCG_COND_LT:
 478     case TCG_COND_GTU:
 479     case TCG_COND_NE:
 480         return 0;
 481     case TCG_COND_GE:
 482     case TCG_COND_GEU:
 483     case TCG_COND_LE:
 484     case TCG_COND_LEU:
 485     case TCG_COND_EQ:
 486         return 1;
 487     default:
 488         tcg_abort();
 489     }
 490 }
 491
 492 /* Return 2 if the condition can't be simplified, and the result
 493    of the condition (0 or 1) if it can */
 494 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 495                                        TCGArg y, TCGCond c)
 496 {
 497     tcg_target_ulong xv = arg_info(x)->val;
 498     tcg_target_ulong yv = arg_info(y)->val;
 499     if (arg_is_const(x) && arg_is_const(y)) {
 500         const TCGOpDef *def = &tcg_op_defs[op];
 501         tcg_debug_assert(!(def->flags & TCG_OPF_VECTOR));
 502         if (def->flags & TCG_OPF_64BIT) {
 503             return do_constant_folding_cond_64(xv, yv, c);
 504         } else {
 505             return do_constant_folding_cond_32(xv, yv, c);
 506         }
 507     } else if (args_are_copies(x, y)) {
 508         return do_constant_folding_cond_eq(c);
 509     } else if (arg_is_const(y) && yv == 0) {
 510         switch (c) {
 511         case TCG_COND_LTU:
 512             return 0;
 513         case TCG_COND_GEU:
 514             return 1;
 515         default:
 516             return 2;
 517         }
 518     }
 519     return 2;
 520 }
 521
 522 /* Return 2 if the condition can't be simplified, and the result
 523    of the condition (0 or 1) if it can */
 524 static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
 525 {
 526     TCGArg al = p1[0], ah = p1[1];
 527     TCGArg bl = p2[0], bh = p2[1];
 528
 529     if (arg_is_const(bl) && arg_is_const(bh)) {
 530         tcg_target_ulong blv = arg_info(bl)->val;
 531         tcg_target_ulong bhv = arg_info(bh)->val;
 532         uint64_t b = deposit64(blv, 32, 32, bhv);
 533
 534         if (arg_is_const(al) && arg_is_const(ah)) {
 535             tcg_target_ulong alv = arg_info(al)->val;
 536             tcg_target_ulong ahv = arg_info(ah)->val;
 537             uint64_t a = deposit64(alv, 32, 32, ahv);
 538             return do_constant_folding_cond_64(a, b, c);
 539         }
 540         if (b == 0) {
 541             switch (c) {
 542             case TCG_COND_LTU:
 543                 return 0;
 544             case TCG_COND_GEU:
 545                 return 1;
 546             default:
 547                 break;
 548             }
 549         }
 550     }
 551     if (args_are_copies(al, bl) && args_are_copies(ah, bh)) {
 552         return do_constant_folding_cond_eq(c);
 553     }
 554     return 2;
 555 }
 556
 557 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 558 {
 559     TCGArg a1 = *p1, a2 = *p2;
 560     int sum = 0;
 561     sum += arg_is_const(a1);
 562     sum -= arg_is_const(a2);
 563
 564     /* Prefer the constant in second argument, and then the form
 565        op a, a, b, which is better handled on non-RISC hosts. */
 566     if (sum > 0 || (sum == 0 && dest == a2)) {
 567         *p1 = a2;
 568         *p2 = a1;
 569         return true;
 570     }
 571     return false;
 572 }
 573
 574 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 575 {
 576     int sum = 0;
 577     sum += arg_is_const(p1[0]);
 578     sum += arg_is_const(p1[1]);
 579     sum -= arg_is_const(p2[0]);
 580     sum -= arg_is_const(p2[1]);
 581     if (sum > 0) {
 582         TCGArg t;
 583         t = p1[0], p1[0] = p2[0], p2[0] = t;
 584         t = p1[1], p1[1] = p2[1], p2[1] = t;
 585         return true;
 586     }
 587     return false;
 588 }
 589
 590 /* Propagate constants and copies, fold constant expressions. */
 591 void tcg_optimize(TCGContext *s)
 592 {
 593     int nb_temps, nb_globals;
 594     TCGOp *op, *op_next, *prev_mb = NULL;
 595     struct tcg_temp_info *infos;
 596     TCGTempSet temps_used;
 597
 598     /* Array VALS has an element for each temp.
 599        If this temp holds a constant then its value is kept in VALS' element.
 600        If this temp is a copy of other ones then the other copies are
 601        available through the doubly linked circular list. */
 602
 603     nb_temps = s->nb_temps;
 604     nb_globals = s->nb_globals;
 605     bitmap_zero(temps_used.l, nb_temps);
 606     infos = tcg_malloc(sizeof(struct tcg_temp_info) * nb_temps);
 607
 608     QTAILQ_FOREACH_SAFE(op, &s->ops, link, op_next) {
 609         tcg_target_ulong mask, partmask, affected;
 610         int nb_oargs, nb_iargs, i;
 611         TCGArg tmp;
 612         TCGOpcode opc = op->opc;
 613         const TCGOpDef *def = &tcg_op_defs[opc];
 614
 615         /* Count the arguments, and initialize the temps that are
 616            going to be used */
 617         if (opc == INDEX_op_call) {
 618             nb_oargs = TCGOP_CALLO(op);
 619             nb_iargs = TCGOP_CALLI(op);
 620             for (i = 0; i < nb_oargs + nb_iargs; i++) {
 621                 TCGTemp *ts = arg_temp(op->args[i]);
 622                 if (ts) {
 623                     init_ts_info(infos, &temps_used, ts);
 624                 }
 625             }
 626         } else {
 627             nb_oargs = def->nb_oargs;
 628             nb_iargs = def->nb_iargs;
 629             for (i = 0; i < nb_oargs + nb_iargs; i++) {
 630                 init_arg_info(infos, &temps_used, op->args[i]);
 631             }
 632         }
 633
 634         /* Do copy propagation */
 635         for (i = nb_oargs; i < nb_oargs + nb_iargs; i++) {
 636             TCGTemp *ts = arg_temp(op->args[i]);
 637             if (ts && ts_is_copy(ts)) {
 638                 op->args[i] = temp_arg(find_better_copy(s, ts));
 639             }
 640         }
 641
 642         /* For commutative operations make constant second argument */
 643         switch (opc) {
 644         CASE_OP_32_64_VEC(add):
 645         CASE_OP_32_64_VEC(mul):
 646         CASE_OP_32_64_VEC(and):
 647         CASE_OP_32_64_VEC(or):
 648         CASE_OP_32_64_VEC(xor):
 649         CASE_OP_32_64(eqv):
 650         CASE_OP_32_64(nand):
 651         CASE_OP_32_64(nor):
 652         CASE_OP_32_64(muluh):
 653         CASE_OP_32_64(mulsh):
 654             swap_commutative(op->args[0], &op->args[1], &op->args[2]);
 655             break;
 656         CASE_OP_32_64(brcond):
 657             if (swap_commutative(-1, &op->args[0], &op->args[1])) {
 658                 op->args[2] = tcg_swap_cond(op->args[2]);
 659             }
 660             break;
 661         CASE_OP_32_64(setcond):
 662             if (swap_commutative(op->args[0], &op->args[1], &op->args[2])) {
 663                 op->args[3] = tcg_swap_cond(op->args[3]);
 664             }
 665             break;
 666         CASE_OP_32_64(movcond):
 667             if (swap_commutative(-1, &op->args[1], &op->args[2])) {
 668                 op->args[5] = tcg_swap_cond(op->args[5]);
 669             }
 670             /* For movcond, we canonicalize the "false" input reg to match
 671                the destination reg so that the tcg backend can implement
 672                a "move if true" operation.  */
 673             if (swap_commutative(op->args[0], &op->args[4], &op->args[3])) {
 674                 op->args[5] = tcg_invert_cond(op->args[5]);
 675             }
 676             break;
 677         CASE_OP_32_64(add2):
 678             swap_commutative(op->args[0], &op->args[2], &op->args[4]);
 679             swap_commutative(op->args[1], &op->args[3], &op->args[5]);
 680             break;
 681         CASE_OP_32_64(mulu2):
 682         CASE_OP_32_64(muls2):
 683             swap_commutative(op->args[0], &op->args[2], &op->args[3]);
 684             break;
 685         case INDEX_op_brcond2_i32:
 686             if (swap_commutative2(&op->args[0], &op->args[2])) {
 687                 op->args[4] = tcg_swap_cond(op->args[4]);
 688             }
 689             break;
 690         case INDEX_op_setcond2_i32:
 691             if (swap_commutative2(&op->args[1], &op->args[3])) {
 692                 op->args[5] = tcg_swap_cond(op->args[5]);
 693             }
 694             break;
 695         default:
 696             break;
 697         }
 698
 699         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
 700            and "sub r, 0, a => neg r, a" case.  */
 701         switch (opc) {
 702         CASE_OP_32_64(shl):
 703         CASE_OP_32_64(shr):
 704         CASE_OP_32_64(sar):
 705         CASE_OP_32_64(rotl):
 706         CASE_OP_32_64(rotr):
 707             if (arg_is_const(op->args[1])
 708                 && arg_info(op->args[1])->val == 0) {
 709                 tcg_opt_gen_movi(s, op, op->args[0], 0);
 710                 continue;
 711             }
 712             break;
 713         CASE_OP_32_64_VEC(sub):
 714             {
 715                 TCGOpcode neg_op;
 716                 bool have_neg;
 717
 718                 if (arg_is_const(op->args[2])) {
 719                     /* Proceed with possible constant folding. */
 720                     break;
 721                 }
 722                 if (opc == INDEX_op_sub_i32) {
 723                     neg_op = INDEX_op_neg_i32;
 724                     have_neg = TCG_TARGET_HAS_neg_i32;
 725                 } else if (opc == INDEX_op_sub_i64) {
 726                     neg_op = INDEX_op_neg_i64;
 727                     have_neg = TCG_TARGET_HAS_neg_i64;
 728                 } else {
 729                     neg_op = INDEX_op_neg_vec;
 730                     have_neg = TCG_TARGET_HAS_neg_vec;
 731                 }
 732                 if (!have_neg) {
 733                     break;
 734                 }
 735                 if (arg_is_const(op->args[1])
 736                     && arg_info(op->args[1])->val == 0) {
 737                     op->opc = neg_op;
 738                     reset_temp(op->args[0]);
 739                     op->args[1] = op->args[2];
 740                     continue;
 741                 }
 742             }
 743             break;
 744         CASE_OP_32_64_VEC(xor):
 745         CASE_OP_32_64(nand):
 746             if (!arg_is_const(op->args[1])
 747                 && arg_is_const(op->args[2])
 748                 && arg_info(op->args[2])->val == -1) {
 749                 i = 1;
 750                 goto try_not;
 751             }
 752             break;
 753         CASE_OP_32_64(nor):
 754             if (!arg_is_const(op->args[1])
 755                 && arg_is_const(op->args[2])
 756                 && arg_info(op->args[2])->val == 0) {
 757                 i = 1;
 758                 goto try_not;
 759             }
 760             break;
 761         CASE_OP_32_64_VEC(andc):
 762             if (!arg_is_const(op->args[2])
 763                 && arg_is_const(op->args[1])
 764                 && arg_info(op->args[1])->val == -1) {
 765                 i = 2;
 766                 goto try_not;
 767             }
 768             break;
 769         CASE_OP_32_64_VEC(orc):
 770         CASE_OP_32_64(eqv):
 771             if (!arg_is_const(op->args[2])
 772                 && arg_is_const(op->args[1])
 773                 && arg_info(op->args[1])->val == 0) {
 774                 i = 2;
 775                 goto try_not;
 776             }
 777             break;
 778         try_not:
 779             {
 780                 TCGOpcode not_op;
 781                 bool have_not;
 782
 783                 if (def->flags & TCG_OPF_VECTOR) {
 784                     not_op = INDEX_op_not_vec;
 785                     have_not = TCG_TARGET_HAS_not_vec;
 786                 } else if (def->flags & TCG_OPF_64BIT) {
 787                     not_op = INDEX_op_not_i64;
 788                     have_not = TCG_TARGET_HAS_not_i64;
 789                 } else {
 790                     not_op = INDEX_op_not_i32;
 791                     have_not = TCG_TARGET_HAS_not_i32;
 792                 }
 793                 if (!have_not) {
 794                     break;
 795                 }
 796                 op->opc = not_op;
 797                 reset_temp(op->args[0]);
 798                 op->args[1] = op->args[i];
 799                 continue;
 800             }
 801         default:
 802             break;
 803         }
 804
 805         /* Simplify expression for "op r, a, const => mov r, a" cases */
 806         switch (opc) {
 807         CASE_OP_32_64_VEC(add):
 808         CASE_OP_32_64_VEC(sub):
 809         CASE_OP_32_64_VEC(or):
 810         CASE_OP_32_64_VEC(xor):
 811         CASE_OP_32_64_VEC(andc):
 812         CASE_OP_32_64(shl):
 813         CASE_OP_32_64(shr):
 814         CASE_OP_32_64(sar):
 815         CASE_OP_32_64(rotl):
 816         CASE_OP_32_64(rotr):
 817             if (!arg_is_const(op->args[1])
 818                 && arg_is_const(op->args[2])
 819                 && arg_info(op->args[2])->val == 0) {
 820                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
 821                 continue;
 822             }
 823             break;
 824         CASE_OP_32_64_VEC(and):
 825         CASE_OP_32_64_VEC(orc):
 826         CASE_OP_32_64(eqv):
 827             if (!arg_is_const(op->args[1])
 828                 && arg_is_const(op->args[2])
 829                 && arg_info(op->args[2])->val == -1) {
 830                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
 831                 continue;
 832             }
 833             break;
 834         default:
 835             break;
 836         }
 837
 838         /* Simplify using known-zero bits. Currently only ops with a single
 839            output argument is supported. */
 840         mask = -1;
 841         affected = -1;
 842         switch (opc) {
 843         CASE_OP_32_64(ext8s):
 844             if ((arg_info(op->args[1])->mask & 0x80) != 0) {
 845                 break;
 846             }
 847         CASE_OP_32_64(ext8u):
 848             mask = 0xff;
 849             goto and_const;
 850         CASE_OP_32_64(ext16s):
 851             if ((arg_info(op->args[1])->mask & 0x8000) != 0) {
 852                 break;
 853             }
 854         CASE_OP_32_64(ext16u):
 855             mask = 0xffff;
 856             goto and_const;
 857         case INDEX_op_ext32s_i64:
 858             if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
 859                 break;
 860             }
 861         case INDEX_op_ext32u_i64:
 862             mask = 0xffffffffU;
 863             goto and_const;
 864
 865         CASE_OP_32_64(and):
 866             mask = arg_info(op->args[2])->mask;
 867             if (arg_is_const(op->args[2])) {
 868         and_const:
 869                 affected = arg_info(op->args[1])->mask & ~mask;
 870             }
 871             mask = arg_info(op->args[1])->mask & mask;
 872             break;
 873
 874         case INDEX_op_ext_i32_i64:
 875             if ((arg_info(op->args[1])->mask & 0x80000000) != 0) {
 876                 break;
 877             }
 878         case INDEX_op_extu_i32_i64:
 879             /* We do not compute affected as it is a size changing op.  */
 880             mask = (uint32_t)arg_info(op->args[1])->mask;
 881             break;
 882
 883         CASE_OP_32_64(andc):
 884             /* Known-zeros does not imply known-ones.  Therefore unless
 885                op->args[2] is constant, we can't infer anything from it.  */
 886             if (arg_is_const(op->args[2])) {
 887                 mask = ~arg_info(op->args[2])->mask;
 888                 goto and_const;
 889             }
 890             /* But we certainly know nothing outside args[1] may be set. */
 891             mask = arg_info(op->args[1])->mask;
 892             break;
 893
 894         case INDEX_op_sar_i32:
 895             if (arg_is_const(op->args[2])) {
 896                 tmp = arg_info(op->args[2])->val & 31;
 897                 mask = (int32_t)arg_info(op->args[1])->mask >> tmp;
 898             }
 899             break;
 900         case INDEX_op_sar_i64:
 901             if (arg_is_const(op->args[2])) {
 902                 tmp = arg_info(op->args[2])->val & 63;
 903                 mask = (int64_t)arg_info(op->args[1])->mask >> tmp;
 904             }
 905             break;
 906
 907         case INDEX_op_shr_i32:
 908             if (arg_is_const(op->args[2])) {
 909                 tmp = arg_info(op->args[2])->val & 31;
 910                 mask = (uint32_t)arg_info(op->args[1])->mask >> tmp;
 911             }
 912             break;
 913         case INDEX_op_shr_i64:
 914             if (arg_is_const(op->args[2])) {
 915                 tmp = arg_info(op->args[2])->val & 63;
 916                 mask = (uint64_t)arg_info(op->args[1])->mask >> tmp;
 917             }
 918             break;
 919
 920         case INDEX_op_extrl_i64_i32:
 921             mask = (uint32_t)arg_info(op->args[1])->mask;
 922             break;
 923         case INDEX_op_extrh_i64_i32:
 924             mask = (uint64_t)arg_info(op->args[1])->mask >> 32;
 925             break;
 926
 927         CASE_OP_32_64(shl):
 928             if (arg_is_const(op->args[2])) {
 929                 tmp = arg_info(op->args[2])->val & (TCG_TARGET_REG_BITS - 1);
 930                 mask = arg_info(op->args[1])->mask << tmp;
 931             }
 932             break;
 933
 934         CASE_OP_32_64(neg):
 935             /* Set to 1 all bits to the left of the rightmost.  */
 936             mask = -(arg_info(op->args[1])->mask
 937                      & -arg_info(op->args[1])->mask);
 938             break;
 939
 940         CASE_OP_32_64(deposit):
 941             mask = deposit64(arg_info(op->args[1])->mask,
 942                              op->args[3], op->args[4],
 943                              arg_info(op->args[2])->mask);
 944             break;
 945
 946         CASE_OP_32_64(extract):
 947             mask = extract64(arg_info(op->args[1])->mask,
 948                              op->args[2], op->args[3]);
 949             if (op->args[2] == 0) {
 950                 affected = arg_info(op->args[1])->mask & ~mask;
 951             }
 952             break;
 953         CASE_OP_32_64(sextract):
 954             mask = sextract64(arg_info(op->args[1])->mask,
 955                               op->args[2], op->args[3]);
 956             if (op->args[2] == 0 && (tcg_target_long)mask >= 0) {
 957                 affected = arg_info(op->args[1])->mask & ~mask;
 958             }
 959             break;
 960
 961         CASE_OP_32_64(or):
 962         CASE_OP_32_64(xor):
 963             mask = arg_info(op->args[1])->mask | arg_info(op->args[2])->mask;
 964             break;
 965
 966         case INDEX_op_clz_i32:
 967         case INDEX_op_ctz_i32:
 968             mask = arg_info(op->args[2])->mask | 31;
 969             break;
 970
 971         case INDEX_op_clz_i64:
 972         case INDEX_op_ctz_i64:
 973             mask = arg_info(op->args[2])->mask | 63;
 974             break;
 975
 976         case INDEX_op_ctpop_i32:
 977             mask = 32 | 31;
 978             break;
 979         case INDEX_op_ctpop_i64:
 980             mask = 64 | 63;
 981             break;
 982
 983         CASE_OP_32_64(setcond):
 984         case INDEX_op_setcond2_i32:
 985             mask = 1;
 986             break;
 987
 988         CASE_OP_32_64(movcond):
 989             mask = arg_info(op->args[3])->mask | arg_info(op->args[4])->mask;
 990             break;
 991
 992         CASE_OP_32_64(ld8u):
 993             mask = 0xff;
 994             break;
 995         CASE_OP_32_64(ld16u):
 996             mask = 0xffff;
 997             break;
 998         case INDEX_op_ld32u_i64:
 999             mask = 0xffffffffu;
1000             break;
1001
1002         CASE_OP_32_64(qemu_ld):
1003             {
1004                 TCGMemOpIdx oi = op->args[nb_oargs + nb_iargs];
1005                 TCGMemOp mop = get_memop(oi);
1006                 if (!(mop & MO_SIGN)) {
1007                     mask = (2ULL << ((8 << (mop & MO_SIZE)) - 1)) - 1;
1008                 }
1009             }
1010             break;
1011
1012         default:
1013             break;
1014         }
1015
1016         /* 32-bit ops generate 32-bit results.  For the result is zero test
1017            below, we can ignore high bits, but for further optimizations we
1018            need to record that the high bits contain garbage.  */
1019         partmask = mask;
1020         if (!(def->flags & TCG_OPF_64BIT)) {
1021             mask |= ~(tcg_target_ulong)0xffffffffu;
1022             partmask &= 0xffffffffu;
1023             affected &= 0xffffffffu;
1024         }
1025
1026         if (partmask == 0) {
1027             tcg_debug_assert(nb_oargs == 1);
1028             tcg_opt_gen_movi(s, op, op->args[0], 0);
1029             continue;
1030         }
1031         if (affected == 0) {
1032             tcg_debug_assert(nb_oargs == 1);
1033             tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1034             continue;
1035         }
1036
1037         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
1038         switch (opc) {
1039         CASE_OP_32_64_VEC(and):
1040         CASE_OP_32_64_VEC(mul):
1041         CASE_OP_32_64(muluh):
1042         CASE_OP_32_64(mulsh):
1043             if (arg_is_const(op->args[2])
1044                 && arg_info(op->args[2])->val == 0) {
1045                 tcg_opt_gen_movi(s, op, op->args[0], 0);
1046                 continue;
1047             }
1048             break;
1049         default:
1050             break;
1051         }
1052
1053         /* Simplify expression for "op r, a, a => mov r, a" cases */
1054         switch (opc) {
1055         CASE_OP_32_64_VEC(or):
1056         CASE_OP_32_64_VEC(and):
1057             if (args_are_copies(op->args[1], op->args[2])) {
1058                 tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1059                 continue;
1060             }
1061             break;
1062         default:
1063             break;
1064         }
1065
1066         /* Simplify expression for "op r, a, a => movi r, 0" cases */
1067         switch (opc) {
1068         CASE_OP_32_64_VEC(andc):
1069         CASE_OP_32_64_VEC(sub):
1070         CASE_OP_32_64_VEC(xor):
1071             if (args_are_copies(op->args[1], op->args[2])) {
1072                 tcg_opt_gen_movi(s, op, op->args[0], 0);
1073                 continue;
1074             }
1075             break;
1076         default:
1077             break;
1078         }
1079
1080         /* Propagate constants through copy operations and do constant
1081            folding.  Constants will be substituted to arguments by register
1082            allocator where needed and possible.  Also detect copies. */
1083         switch (opc) {
1084         CASE_OP_32_64_VEC(mov):
1085             tcg_opt_gen_mov(s, op, op->args[0], op->args[1]);
1086             break;
1087         CASE_OP_32_64(movi):
1088         case INDEX_op_dupi_vec:
1089             tcg_opt_gen_movi(s, op, op->args[0], op->args[1]);
1090             break;
1091
1092         case INDEX_op_dup_vec:
1093             if (arg_is_const(op->args[1])) {
1094                 tmp = arg_info(op->args[1])->val;
1095                 tmp = dup_const(TCGOP_VECE(op), tmp);
1096                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1097                 continue;
1098             }
1099             break;
1100
1101         CASE_OP_32_64(not):
1102         CASE_OP_32_64(neg):
1103         CASE_OP_32_64(ext8s):
1104         CASE_OP_32_64(ext8u):
1105         CASE_OP_32_64(ext16s):
1106         CASE_OP_32_64(ext16u):
1107         CASE_OP_32_64(ctpop):
1108         case INDEX_op_ext32s_i64:
1109         case INDEX_op_ext32u_i64:
1110         case INDEX_op_ext_i32_i64:
1111         case INDEX_op_extu_i32_i64:
1112         case INDEX_op_extrl_i64_i32:
1113         case INDEX_op_extrh_i64_i32:
1114             if (arg_is_const(op->args[1])) {
1115                 tmp = do_constant_folding(opc, arg_info(op->args[1])->val, 0);
1116                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1117                 break;
1118             }
1119             goto do_default;
1120
1121         CASE_OP_32_64(add):
1122         CASE_OP_32_64(sub):
1123         CASE_OP_32_64(mul):
1124         CASE_OP_32_64(or):
1125         CASE_OP_32_64(and):
1126         CASE_OP_32_64(xor):
1127         CASE_OP_32_64(shl):
1128         CASE_OP_32_64(shr):
1129         CASE_OP_32_64(sar):
1130         CASE_OP_32_64(rotl):
1131         CASE_OP_32_64(rotr):
1132         CASE_OP_32_64(andc):
1133         CASE_OP_32_64(orc):
1134         CASE_OP_32_64(eqv):
1135         CASE_OP_32_64(nand):
1136         CASE_OP_32_64(nor):
1137         CASE_OP_32_64(muluh):
1138         CASE_OP_32_64(mulsh):
1139         CASE_OP_32_64(div):
1140         CASE_OP_32_64(divu):
1141         CASE_OP_32_64(rem):
1142         CASE_OP_32_64(remu):
1143             if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1144                 tmp = do_constant_folding(opc, arg_info(op->args[1])->val,
1145                                           arg_info(op->args[2])->val);
1146                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1147                 break;
1148             }
1149             goto do_default;
1150
1151         CASE_OP_32_64(clz):
1152         CASE_OP_32_64(ctz):
1153             if (arg_is_const(op->args[1])) {
1154                 TCGArg v = arg_info(op->args[1])->val;
1155                 if (v != 0) {
1156                     tmp = do_constant_folding(opc, v, 0);
1157                     tcg_opt_gen_movi(s, op, op->args[0], tmp);
1158                 } else {
1159                     tcg_opt_gen_mov(s, op, op->args[0], op->args[2]);
1160                 }
1161                 break;
1162             }
1163             goto do_default;
1164
1165         CASE_OP_32_64(deposit):
1166             if (arg_is_const(op->args[1]) && arg_is_const(op->args[2])) {
1167                 tmp = deposit64(arg_info(op->args[1])->val,
1168                                 op->args[3], op->args[4],
1169                                 arg_info(op->args[2])->val);
1170                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1171                 break;
1172             }
1173             goto do_default;
1174
1175         CASE_OP_32_64(extract):
1176             if (arg_is_const(op->args[1])) {
1177                 tmp = extract64(arg_info(op->args[1])->val,
1178                                 op->args[2], op->args[3]);
1179                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1180                 break;
1181             }
1182             goto do_default;
1183
1184         CASE_OP_32_64(sextract):
1185             if (arg_is_const(op->args[1])) {
1186                 tmp = sextract64(arg_info(op->args[1])->val,
1187                                  op->args[2], op->args[3]);
1188                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1189                 break;
1190             }
1191             goto do_default;
1192
1193         CASE_OP_32_64(setcond):
1194             tmp = do_constant_folding_cond(opc, op->args[1],
1195                                            op->args[2], op->args[3]);
1196             if (tmp != 2) {
1197                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1198                 break;
1199             }
1200             goto do_default;
1201
1202         CASE_OP_32_64(brcond):
1203             tmp = do_constant_folding_cond(opc, op->args[0],
1204                                            op->args[1], op->args[2]);
1205             if (tmp != 2) {
1206                 if (tmp) {
1207                     bitmap_zero(temps_used.l, nb_temps);
1208                     op->opc = INDEX_op_br;
1209                     op->args[0] = op->args[3];
1210                 } else {
1211                     tcg_op_remove(s, op);
1212                 }
1213                 break;
1214             }
1215             goto do_default;
1216
1217         CASE_OP_32_64(movcond):
1218             tmp = do_constant_folding_cond(opc, op->args[1],
1219                                            op->args[2], op->args[5]);
1220             if (tmp != 2) {
1221                 tcg_opt_gen_mov(s, op, op->args[0], op->args[4-tmp]);
1222                 break;
1223             }
1224             if (arg_is_const(op->args[3]) && arg_is_const(op->args[4])) {
1225                 tcg_target_ulong tv = arg_info(op->args[3])->val;
1226                 tcg_target_ulong fv = arg_info(op->args[4])->val;
1227                 TCGCond cond = op->args[5];
1228                 if (fv == 1 && tv == 0) {
1229                     cond = tcg_invert_cond(cond);
1230                 } else if (!(tv == 1 && fv == 0)) {
1231                     goto do_default;
1232                 }
1233                 op->args[3] = cond;
1234                 op->opc = opc = (opc == INDEX_op_movcond_i32
1235                                  ? INDEX_op_setcond_i32
1236                                  : INDEX_op_setcond_i64);
1237                 nb_iargs = 2;
1238             }
1239             goto do_default;
1240
1241         case INDEX_op_add2_i32:
1242         case INDEX_op_sub2_i32:
1243             if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])
1244                 && arg_is_const(op->args[4]) && arg_is_const(op->args[5])) {
1245                 uint32_t al = arg_info(op->args[2])->val;
1246                 uint32_t ah = arg_info(op->args[3])->val;
1247                 uint32_t bl = arg_info(op->args[4])->val;
1248                 uint32_t bh = arg_info(op->args[5])->val;
1249                 uint64_t a = ((uint64_t)ah << 32) | al;
1250                 uint64_t b = ((uint64_t)bh << 32) | bl;
1251                 TCGArg rl, rh;
1252                 TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32, 2);
1253
1254                 if (opc == INDEX_op_add2_i32) {
1255                     a += b;
1256                 } else {
1257                     a -= b;
1258                 }
1259
1260                 rl = op->args[0];
1261                 rh = op->args[1];
1262                 tcg_opt_gen_movi(s, op, rl, (int32_t)a);
1263                 tcg_opt_gen_movi(s, op2, rh, (int32_t)(a >> 32));
1264                 break;
1265             }
1266             goto do_default;
1267
1268         case INDEX_op_mulu2_i32:
1269             if (arg_is_const(op->args[2]) && arg_is_const(op->args[3])) {
1270                 uint32_t a = arg_info(op->args[2])->val;
1271                 uint32_t b = arg_info(op->args[3])->val;
1272                 uint64_t r = (uint64_t)a * b;
1273                 TCGArg rl, rh;
1274                 TCGOp *op2 = tcg_op_insert_before(s, op, INDEX_op_movi_i32, 2);
1275
1276                 rl = op->args[0];
1277                 rh = op->args[1];
1278                 tcg_opt_gen_movi(s, op, rl, (int32_t)r);
1279                 tcg_opt_gen_movi(s, op2, rh, (int32_t)(r >> 32));
1280                 break;
1281             }
1282             goto do_default;
1283
1284         case INDEX_op_brcond2_i32:
1285             tmp = do_constant_folding_cond2(&op->args[0], &op->args[2],
1286                                             op->args[4]);
1287             if (tmp != 2) {
1288                 if (tmp) {
1289             do_brcond_true:
1290                     bitmap_zero(temps_used.l, nb_temps);
1291                     op->opc = INDEX_op_br;
1292                     op->args[0] = op->args[5];
1293                 } else {
1294             do_brcond_false:
1295                     tcg_op_remove(s, op);
1296                 }
1297             } else if ((op->args[4] == TCG_COND_LT
1298                         || op->args[4] == TCG_COND_GE)
1299                        && arg_is_const(op->args[2])
1300                        && arg_info(op->args[2])->val == 0
1301                        && arg_is_const(op->args[3])
1302                        && arg_info(op->args[3])->val == 0) {
1303                 /* Simplify LT/GE comparisons vs zero to a single compare
1304                    vs the high word of the input.  */
1305             do_brcond_high:
1306                 bitmap_zero(temps_used.l, nb_temps);
1307                 op->opc = INDEX_op_brcond_i32;
1308                 op->args[0] = op->args[1];
1309                 op->args[1] = op->args[3];
1310                 op->args[2] = op->args[4];
1311                 op->args[3] = op->args[5];
1312             } else if (op->args[4] == TCG_COND_EQ) {
1313                 /* Simplify EQ comparisons where one of the pairs
1314                    can be simplified.  */
1315                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1316                                                op->args[0], op->args[2],
1317                                                TCG_COND_EQ);
1318                 if (tmp == 0) {
1319                     goto do_brcond_false;
1320                 } else if (tmp == 1) {
1321                     goto do_brcond_high;
1322                 }
1323                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1324                                                op->args[1], op->args[3],
1325                                                TCG_COND_EQ);
1326                 if (tmp == 0) {
1327                     goto do_brcond_false;
1328                 } else if (tmp != 1) {
1329                     goto do_default;
1330                 }
1331             do_brcond_low:
1332                 bitmap_zero(temps_used.l, nb_temps);
1333                 op->opc = INDEX_op_brcond_i32;
1334                 op->args[1] = op->args[2];
1335                 op->args[2] = op->args[4];
1336                 op->args[3] = op->args[5];
1337             } else if (op->args[4] == TCG_COND_NE) {
1338                 /* Simplify NE comparisons where one of the pairs
1339                    can be simplified.  */
1340                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1341                                                op->args[0], op->args[2],
1342                                                TCG_COND_NE);
1343                 if (tmp == 0) {
1344                     goto do_brcond_high;
1345                 } else if (tmp == 1) {
1346                     goto do_brcond_true;
1347                 }
1348                 tmp = do_constant_folding_cond(INDEX_op_brcond_i32,
1349                                                op->args[1], op->args[3],
1350                                                TCG_COND_NE);
1351                 if (tmp == 0) {
1352                     goto do_brcond_low;
1353                 } else if (tmp == 1) {
1354                     goto do_brcond_true;
1355                 }
1356                 goto do_default;
1357             } else {
1358                 goto do_default;
1359             }
1360             break;
1361
1362         case INDEX_op_setcond2_i32:
1363             tmp = do_constant_folding_cond2(&op->args[1], &op->args[3],
1364                                             op->args[5]);
1365             if (tmp != 2) {
1366             do_setcond_const:
1367                 tcg_opt_gen_movi(s, op, op->args[0], tmp);
1368             } else if ((op->args[5] == TCG_COND_LT
1369                         || op->args[5] == TCG_COND_GE)
1370                        && arg_is_const(op->args[3])
1371                        && arg_info(op->args[3])->val == 0
1372                        && arg_is_const(op->args[4])
1373                        && arg_info(op->args[4])->val == 0) {
1374                 /* Simplify LT/GE comparisons vs zero to a single compare
1375                    vs the high word of the input.  */
1376             do_setcond_high:
1377                 reset_temp(op->args[0]);
1378                 arg_info(op->args[0])->mask = 1;
1379                 op->opc = INDEX_op_setcond_i32;
1380                 op->args[1] = op->args[2];
1381                 op->args[2] = op->args[4];
1382                 op->args[3] = op->args[5];
1383             } else if (op->args[5] == TCG_COND_EQ) {
1384                 /* Simplify EQ comparisons where one of the pairs
1385                    can be simplified.  */
1386                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1387                                                op->args[1], op->args[3],
1388                                                TCG_COND_EQ);
1389                 if (tmp == 0) {
1390                     goto do_setcond_const;
1391                 } else if (tmp == 1) {
1392                     goto do_setcond_high;
1393                 }
1394                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1395                                                op->args[2], op->args[4],
1396                                                TCG_COND_EQ);
1397                 if (tmp == 0) {
1398                     goto do_setcond_high;
1399                 } else if (tmp != 1) {
1400                     goto do_default;
1401                 }
1402             do_setcond_low:
1403                 reset_temp(op->args[0]);
1404                 arg_info(op->args[0])->mask = 1;
1405                 op->opc = INDEX_op_setcond_i32;
1406                 op->args[2] = op->args[3];
1407                 op->args[3] = op->args[5];
1408             } else if (op->args[5] == TCG_COND_NE) {
1409                 /* Simplify NE comparisons where one of the pairs
1410                    can be simplified.  */
1411                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1412                                                op->args[1], op->args[3],
1413                                                TCG_COND_NE);
1414                 if (tmp == 0) {
1415                     goto do_setcond_high;
1416                 } else if (tmp == 1) {
1417                     goto do_setcond_const;
1418                 }
1419                 tmp = do_constant_folding_cond(INDEX_op_setcond_i32,
1420                                                op->args[2], op->args[4],
1421                                                TCG_COND_NE);
1422                 if (tmp == 0) {
1423                     goto do_setcond_low;
1424                 } else if (tmp == 1) {
1425                     goto do_setcond_const;
1426                 }
1427                 goto do_default;
1428             } else {
1429                 goto do_default;
1430             }
1431             break;
1432
1433         case INDEX_op_call:
1434             if (!(op->args[nb_oargs + nb_iargs + 1]
1435                   & (TCG_CALL_NO_READ_GLOBALS | TCG_CALL_NO_WRITE_GLOBALS))) {
1436                 for (i = 0; i < nb_globals; i++) {
1437                     if (test_bit(i, temps_used.l)) {
1438                         reset_ts(&s->temps[i]);
1439                     }
1440                 }
1441             }
1442             goto do_reset_output;
1443
1444         default:
1445         do_default:
1446             /* Default case: we know nothing about operation (or were unable
1447                to compute the operation result) so no propagation is done.
1448                We trash everything if the operation is the end of a basic
1449                block, otherwise we only trash the output args.  "mask" is
1450                the non-zero bits mask for the first output arg.  */
1451             if (def->flags & TCG_OPF_BB_END) {
1452                 bitmap_zero(temps_used.l, nb_temps);
1453             } else {
1454         do_reset_output:
1455                 for (i = 0; i < nb_oargs; i++) {
1456                     reset_temp(op->args[i]);
1457                     /* Save the corresponding known-zero bits mask for the
1458                        first output argument (only one supported so far). */
1459                     if (i == 0) {
1460                         arg_info(op->args[i])->mask = mask;
1461                     }
1462                 }
1463             }
1464             break;
1465         }
1466
1467         /* Eliminate duplicate and redundant fence instructions.  */
1468         if (prev_mb) {
1469             switch (opc) {
1470             case INDEX_op_mb:
1471                 /* Merge two barriers of the same type into one,
1472                  * or a weaker barrier into a stronger one,
1473                  * or two weaker barriers into a stronger one.
1474                  *   mb X; mb Y => mb X|Y
1475                  *   mb; strl => mb; st
1476                  *   ldaq; mb => ld; mb
1477                  *   ldaq; strl => ld; mb; st
1478                  * Other combinations are also merged into a strong
1479                  * barrier.  This is stricter than specified but for
1480                  * the purposes of TCG is better than not optimizing.
1481                  */
1482                 prev_mb->args[0] |= op->args[0];
1483                 tcg_op_remove(s, op);
1484                 break;
1485
1486             default:
1487                 /* Opcodes that end the block stop the optimization.  */
1488                 if ((def->flags & TCG_OPF_BB_END) == 0) {
1489                     break;
1490                 }
1491                 /* fallthru */
1492             case INDEX_op_qemu_ld_i32:
1493             case INDEX_op_qemu_ld_i64:
1494             case INDEX_op_qemu_st_i32:
1495             case INDEX_op_qemu_st_i64:
1496             case INDEX_op_call:
1497                 /* Opcodes that touch guest memory stop the optimization.  */
1498                 prev_mb = NULL;
1499                 break;
1500             }
1501         } else if (opc == INDEX_op_mb) {
1502             prev_mb = op;
1503         }
1504     }
1505 }