tcg/optimize.c

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