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 };
  50
  51 static struct tcg_temp_info temps[TCG_MAX_TEMPS];
  52
  53 /* Reset TEMP's state to TCG_TEMP_UNDEF.  If TEMP only had one copy, remove
  54    the copy flag from the left temp.  */
  55 static void reset_temp(TCGArg temp)
  56 {
  57     if (temps[temp].state == TCG_TEMP_COPY) {
  58         if (temps[temp].prev_copy == temps[temp].next_copy) {
  59             temps[temps[temp].next_copy].state = TCG_TEMP_UNDEF;
  60         } else {
  61             temps[temps[temp].next_copy].prev_copy = temps[temp].prev_copy;
  62             temps[temps[temp].prev_copy].next_copy = temps[temp].next_copy;
  63         }
  64     }
  65     temps[temp].state = TCG_TEMP_UNDEF;
  66 }
  67
  68 static int op_bits(TCGOpcode op)
  69 {
  70     const TCGOpDef *def = &tcg_op_defs[op];
  71     return def->flags & TCG_OPF_64BIT ? 64 : 32;
  72 }
  73
  74 static TCGOpcode op_to_movi(TCGOpcode op)
  75 {
  76     switch (op_bits(op)) {
  77     case 32:
  78         return INDEX_op_movi_i32;
  79     case 64:
  80         return INDEX_op_movi_i64;
  81     default:
  82         fprintf(stderr, "op_to_movi: unexpected return value of "
  83                 "function op_bits.\n");
  84         tcg_abort();
  85     }
  86 }
  87
  88 static TCGArg find_better_copy(TCGContext *s, TCGArg temp)
  89 {
  90     TCGArg i;
  91
  92     /* If this is already a global, we can't do better. */
  93     if (temp < s->nb_globals) {
  94         return temp;
  95     }
  96
  97     /* Search for a global first. */
  98     for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) {
  99         if (i < s->nb_globals) {
 100             return i;
 101         }
 102     }
 103
 104     /* If it is a temp, search for a temp local. */
 105     if (!s->temps[temp].temp_local) {
 106         for (i = temps[temp].next_copy ; i != temp ; i = temps[i].next_copy) {
 107             if (s->temps[i].temp_local) {
 108                 return i;
 109             }
 110         }
 111     }
 112
 113     /* Failure to find a better representation, return the same temp. */
 114     return temp;
 115 }
 116
 117 static bool temps_are_copies(TCGArg arg1, TCGArg arg2)
 118 {
 119     TCGArg i;
 120
 121     if (arg1 == arg2) {
 122         return true;
 123     }
 124
 125     if (temps[arg1].state != TCG_TEMP_COPY
 126         || temps[arg2].state != TCG_TEMP_COPY) {
 127         return false;
 128     }
 129
 130     for (i = temps[arg1].next_copy ; i != arg1 ; i = temps[i].next_copy) {
 131         if (i == arg2) {
 132             return true;
 133         }
 134     }
 135
 136     return false;
 137 }
 138
 139 static void tcg_opt_gen_mov(TCGContext *s, TCGArg *gen_args,
 140                             TCGArg dst, TCGArg src)
 141 {
 142         reset_temp(dst);
 143         assert(temps[src].state != TCG_TEMP_CONST);
 144
 145         if (s->temps[src].type == s->temps[dst].type) {
 146             if (temps[src].state != TCG_TEMP_COPY) {
 147                 temps[src].state = TCG_TEMP_COPY;
 148                 temps[src].next_copy = src;
 149                 temps[src].prev_copy = src;
 150             }
 151             temps[dst].state = TCG_TEMP_COPY;
 152             temps[dst].next_copy = temps[src].next_copy;
 153             temps[dst].prev_copy = src;
 154             temps[temps[dst].next_copy].prev_copy = dst;
 155             temps[src].next_copy = dst;
 156         }
 157
 158         gen_args[0] = dst;
 159         gen_args[1] = src;
 160 }
 161
 162 static void tcg_opt_gen_movi(TCGArg *gen_args, TCGArg dst, TCGArg val)
 163 {
 164         reset_temp(dst);
 165         temps[dst].state = TCG_TEMP_CONST;
 166         temps[dst].val = val;
 167         gen_args[0] = dst;
 168         gen_args[1] = val;
 169 }
 170
 171 static TCGOpcode op_to_mov(TCGOpcode op)
 172 {
 173     switch (op_bits(op)) {
 174     case 32:
 175         return INDEX_op_mov_i32;
 176     case 64:
 177         return INDEX_op_mov_i64;
 178     default:
 179         fprintf(stderr, "op_to_mov: unexpected return value of "
 180                 "function op_bits.\n");
 181         tcg_abort();
 182     }
 183 }
 184
 185 static TCGArg do_constant_folding_2(TCGOpcode op, TCGArg x, TCGArg y)
 186 {
 187     switch (op) {
 188     CASE_OP_32_64(add):
 189         return x + y;
 190
 191     CASE_OP_32_64(sub):
 192         return x - y;
 193
 194     CASE_OP_32_64(mul):
 195         return x * y;
 196
 197     CASE_OP_32_64(and):
 198         return x & y;
 199
 200     CASE_OP_32_64(or):
 201         return x | y;
 202
 203     CASE_OP_32_64(xor):
 204         return x ^ y;
 205
 206     case INDEX_op_shl_i32:
 207         return (uint32_t)x << (uint32_t)y;
 208
 209     case INDEX_op_shl_i64:
 210         return (uint64_t)x << (uint64_t)y;
 211
 212     case INDEX_op_shr_i32:
 213         return (uint32_t)x >> (uint32_t)y;
 214
 215     case INDEX_op_shr_i64:
 216         return (uint64_t)x >> (uint64_t)y;
 217
 218     case INDEX_op_sar_i32:
 219         return (int32_t)x >> (int32_t)y;
 220
 221     case INDEX_op_sar_i64:
 222         return (int64_t)x >> (int64_t)y;
 223
 224     case INDEX_op_rotr_i32:
 225         x = ((uint32_t)x << (32 - y)) | ((uint32_t)x >> y);
 226         return x;
 227
 228     case INDEX_op_rotr_i64:
 229         x = ((uint64_t)x << (64 - y)) | ((uint64_t)x >> y);
 230         return x;
 231
 232     case INDEX_op_rotl_i32:
 233         x = ((uint32_t)x << y) | ((uint32_t)x >> (32 - y));
 234         return x;
 235
 236     case INDEX_op_rotl_i64:
 237         x = ((uint64_t)x << y) | ((uint64_t)x >> (64 - y));
 238         return x;
 239
 240     CASE_OP_32_64(not):
 241         return ~x;
 242
 243     CASE_OP_32_64(neg):
 244         return -x;
 245
 246     CASE_OP_32_64(andc):
 247         return x & ~y;
 248
 249     CASE_OP_32_64(orc):
 250         return x | ~y;
 251
 252     CASE_OP_32_64(eqv):
 253         return ~(x ^ y);
 254
 255     CASE_OP_32_64(nand):
 256         return ~(x & y);
 257
 258     CASE_OP_32_64(nor):
 259         return ~(x | y);
 260
 261     CASE_OP_32_64(ext8s):
 262         return (int8_t)x;
 263
 264     CASE_OP_32_64(ext16s):
 265         return (int16_t)x;
 266
 267     CASE_OP_32_64(ext8u):
 268         return (uint8_t)x;
 269
 270     CASE_OP_32_64(ext16u):
 271         return (uint16_t)x;
 272
 273     case INDEX_op_ext32s_i64:
 274         return (int32_t)x;
 275
 276     case INDEX_op_ext32u_i64:
 277         return (uint32_t)x;
 278
 279     default:
 280         fprintf(stderr,
 281                 "Unrecognized operation %d in do_constant_folding.\n", op);
 282         tcg_abort();
 283     }
 284 }
 285
 286 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 287 {
 288     TCGArg res = do_constant_folding_2(op, x, y);
 289     if (op_bits(op) == 32) {
 290         res &= 0xffffffff;
 291     }
 292     return res;
 293 }
 294
 295 /* Return 2 if the condition can't be simplified, and the result
 296    of the condition (0 or 1) if it can */
 297 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 298                                        TCGArg y, TCGCond c)
 299 {
 300     if (temps[x].state == TCG_TEMP_CONST && temps[y].state == TCG_TEMP_CONST) {
 301         switch (op_bits(op)) {
 302         case 32:
 303             switch (c) {
 304             case TCG_COND_EQ:
 305                 return (uint32_t)temps[x].val == (uint32_t)temps[y].val;
 306             case TCG_COND_NE:
 307                 return (uint32_t)temps[x].val != (uint32_t)temps[y].val;
 308             case TCG_COND_LT:
 309                 return (int32_t)temps[x].val < (int32_t)temps[y].val;
 310             case TCG_COND_GE:
 311                 return (int32_t)temps[x].val >= (int32_t)temps[y].val;
 312             case TCG_COND_LE:
 313                 return (int32_t)temps[x].val <= (int32_t)temps[y].val;
 314             case TCG_COND_GT:
 315                 return (int32_t)temps[x].val > (int32_t)temps[y].val;
 316             case TCG_COND_LTU:
 317                 return (uint32_t)temps[x].val < (uint32_t)temps[y].val;
 318             case TCG_COND_GEU:
 319                 return (uint32_t)temps[x].val >= (uint32_t)temps[y].val;
 320             case TCG_COND_LEU:
 321                 return (uint32_t)temps[x].val <= (uint32_t)temps[y].val;
 322             case TCG_COND_GTU:
 323                 return (uint32_t)temps[x].val > (uint32_t)temps[y].val;
 324             default:
 325                 break;
 326             }
 327             break;
 328         case 64:
 329             switch (c) {
 330             case TCG_COND_EQ:
 331                 return (uint64_t)temps[x].val == (uint64_t)temps[y].val;
 332             case TCG_COND_NE:
 333                 return (uint64_t)temps[x].val != (uint64_t)temps[y].val;
 334             case TCG_COND_LT:
 335                 return (int64_t)temps[x].val < (int64_t)temps[y].val;
 336             case TCG_COND_GE:
 337                 return (int64_t)temps[x].val >= (int64_t)temps[y].val;
 338             case TCG_COND_LE:
 339                 return (int64_t)temps[x].val <= (int64_t)temps[y].val;
 340             case TCG_COND_GT:
 341                 return (int64_t)temps[x].val > (int64_t)temps[y].val;
 342             case TCG_COND_LTU:
 343                 return (uint64_t)temps[x].val < (uint64_t)temps[y].val;
 344             case TCG_COND_GEU:
 345                 return (uint64_t)temps[x].val >= (uint64_t)temps[y].val;
 346             case TCG_COND_LEU:
 347                 return (uint64_t)temps[x].val <= (uint64_t)temps[y].val;
 348             case TCG_COND_GTU:
 349                 return (uint64_t)temps[x].val > (uint64_t)temps[y].val;
 350             default:
 351                 break;
 352             }
 353             break;
 354         }
 355     } else if (temps_are_copies(x, y)) {
 356         switch (c) {
 357         case TCG_COND_GT:
 358         case TCG_COND_LTU:
 359         case TCG_COND_LT:
 360         case TCG_COND_GTU:
 361         case TCG_COND_NE:
 362             return 0;
 363         case TCG_COND_GE:
 364         case TCG_COND_GEU:
 365         case TCG_COND_LE:
 366         case TCG_COND_LEU:
 367         case TCG_COND_EQ:
 368             return 1;
 369         default:
 370             break;
 371         }
 372     } else if (temps[y].state == TCG_TEMP_CONST && temps[y].val == 0) {
 373         switch (c) {
 374         case TCG_COND_LTU:
 375             return 0;
 376         case TCG_COND_GEU:
 377             return 1;
 378         default:
 379             return 2;
 380         }
 381     } else {
 382         return 2;
 383     }
 384
 385     fprintf(stderr,
 386             "Unrecognized bitness %d or condition %d in "
 387             "do_constant_folding_cond.\n", op_bits(op), c);
 388     tcg_abort();
 389 }
 390
 391 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 392 {
 393     TCGArg a1 = *p1, a2 = *p2;
 394     int sum = 0;
 395     sum += temps[a1].state == TCG_TEMP_CONST;
 396     sum -= temps[a2].state == TCG_TEMP_CONST;
 397
 398     /* Prefer the constant in second argument, and then the form
 399        op a, a, b, which is better handled on non-RISC hosts. */
 400     if (sum > 0 || (sum == 0 && dest == a2)) {
 401         *p1 = a2;
 402         *p2 = a1;
 403         return true;
 404     }
 405     return false;
 406 }
 407
 408 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 409 {
 410     int sum = 0;
 411     sum += temps[p1[0]].state == TCG_TEMP_CONST;
 412     sum += temps[p1[1]].state == TCG_TEMP_CONST;
 413     sum -= temps[p2[0]].state == TCG_TEMP_CONST;
 414     sum -= temps[p2[1]].state == TCG_TEMP_CONST;
 415     if (sum > 0) {
 416         TCGArg t;
 417         t = p1[0], p1[0] = p2[0], p2[0] = t;
 418         t = p1[1], p1[1] = p2[1], p2[1] = t;
 419         return true;
 420     }
 421     return false;
 422 }
 423
 424 /* Propagate constants and copies, fold constant expressions. */
 425 static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 426                                     TCGArg *args, TCGOpDef *tcg_op_defs)
 427 {
 428     int i, nb_ops, op_index, nb_temps, nb_globals, nb_call_args;
 429     TCGOpcode op;
 430     const TCGOpDef *def;
 431     TCGArg *gen_args;
 432     TCGArg tmp;
 433
 434     /* Array VALS has an element for each temp.
 435        If this temp holds a constant then its value is kept in VALS' element.
 436        If this temp is a copy of other ones then the other copies are
 437        available through the doubly linked circular list. */
 438
 439     nb_temps = s->nb_temps;
 440     nb_globals = s->nb_globals;
 441     memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 442
 443     nb_ops = tcg_opc_ptr - gen_opc_buf;
 444     gen_args = args;
 445     for (op_index = 0; op_index < nb_ops; op_index++) {
 446         op = gen_opc_buf[op_index];
 447         def = &tcg_op_defs[op];
 448         /* Do copy propagation */
 449         if (op == INDEX_op_call) {
 450             int nb_oargs = args[0] >> 16;
 451             int nb_iargs = args[0] & 0xffff;
 452             for (i = nb_oargs + 1; i < nb_oargs + nb_iargs + 1; i++) {
 453                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 454                     args[i] = find_better_copy(s, args[i]);
 455                 }
 456             }
 457         } else {
 458             for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) {
 459                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 460                     args[i] = find_better_copy(s, args[i]);
 461                 }
 462             }
 463         }
 464
 465         /* For commutative operations make constant second argument */
 466         switch (op) {
 467         CASE_OP_32_64(add):
 468         CASE_OP_32_64(mul):
 469         CASE_OP_32_64(and):
 470         CASE_OP_32_64(or):
 471         CASE_OP_32_64(xor):
 472         CASE_OP_32_64(eqv):
 473         CASE_OP_32_64(nand):
 474         CASE_OP_32_64(nor):
 475             swap_commutative(args[0], &args[1], &args[2]);
 476             break;
 477         CASE_OP_32_64(brcond):
 478             if (swap_commutative(-1, &args[0], &args[1])) {
 479                 args[2] = tcg_swap_cond(args[2]);
 480             }
 481             break;
 482         CASE_OP_32_64(setcond):
 483             if (swap_commutative(args[0], &args[1], &args[2])) {
 484                 args[3] = tcg_swap_cond(args[3]);
 485             }
 486             break;
 487         CASE_OP_32_64(movcond):
 488             if (swap_commutative(-1, &args[1], &args[2])) {
 489                 args[5] = tcg_swap_cond(args[5]);
 490             }
 491             /* For movcond, we canonicalize the "false" input reg to match
 492                the destination reg so that the tcg backend can implement
 493                a "move if true" operation.  */
 494             if (swap_commutative(args[0], &args[4], &args[3])) {
 495                 args[5] = tcg_invert_cond(args[5]);
 496             }
 497             break;
 498         case INDEX_op_add2_i32:
 499             swap_commutative(args[0], &args[2], &args[4]);
 500             swap_commutative(args[1], &args[3], &args[5]);
 501             break;
 502         case INDEX_op_brcond2_i32:
 503             if (swap_commutative2(&args[0], &args[2])) {
 504                 args[4] = tcg_swap_cond(args[4]);
 505             }
 506             break;
 507         case INDEX_op_setcond2_i32:
 508             if (swap_commutative2(&args[1], &args[3])) {
 509                 args[5] = tcg_swap_cond(args[5]);
 510             }
 511             break;
 512         default:
 513             break;
 514         }
 515
 516         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0" */
 517         switch (op) {
 518         CASE_OP_32_64(shl):
 519         CASE_OP_32_64(shr):
 520         CASE_OP_32_64(sar):
 521         CASE_OP_32_64(rotl):
 522         CASE_OP_32_64(rotr):
 523             if (temps[args[1]].state == TCG_TEMP_CONST
 524                 && temps[args[1]].val == 0) {
 525                 gen_opc_buf[op_index] = op_to_movi(op);
 526                 tcg_opt_gen_movi(gen_args, args[0], 0);
 527                 args += 3;
 528                 gen_args += 2;
 529                 continue;
 530             }
 531             break;
 532         default:
 533             break;
 534         }
 535
 536         /* Simplify expression for "op r, a, 0 => mov r, a" cases */
 537         switch (op) {
 538         CASE_OP_32_64(add):
 539         CASE_OP_32_64(sub):
 540         CASE_OP_32_64(shl):
 541         CASE_OP_32_64(shr):
 542         CASE_OP_32_64(sar):
 543         CASE_OP_32_64(rotl):
 544         CASE_OP_32_64(rotr):
 545         CASE_OP_32_64(or):
 546         CASE_OP_32_64(xor):
 547             if (temps[args[1]].state == TCG_TEMP_CONST) {
 548                 /* Proceed with possible constant folding. */
 549                 break;
 550             }
 551             if (temps[args[2]].state == TCG_TEMP_CONST
 552                 && temps[args[2]].val == 0) {
 553                 if (temps_are_copies(args[0], args[1])) {
 554                     gen_opc_buf[op_index] = INDEX_op_nop;
 555                 } else {
 556                     gen_opc_buf[op_index] = op_to_mov(op);
 557                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 558                     gen_args += 2;
 559                 }
 560                 args += 3;
 561                 continue;
 562             }
 563             break;
 564         default:
 565             break;
 566         }
 567
 568         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
 569         switch (op) {
 570         CASE_OP_32_64(and):
 571         CASE_OP_32_64(mul):
 572             if ((temps[args[2]].state == TCG_TEMP_CONST
 573                 && temps[args[2]].val == 0)) {
 574                 gen_opc_buf[op_index] = op_to_movi(op);
 575                 tcg_opt_gen_movi(gen_args, args[0], 0);
 576                 args += 3;
 577                 gen_args += 2;
 578                 continue;
 579             }
 580             break;
 581         default:
 582             break;
 583         }
 584
 585         /* Simplify expression for "op r, a, a => mov r, a" cases */
 586         switch (op) {
 587         CASE_OP_32_64(or):
 588         CASE_OP_32_64(and):
 589             if (temps_are_copies(args[1], args[2])) {
 590                 if (temps_are_copies(args[0], args[1])) {
 591                     gen_opc_buf[op_index] = INDEX_op_nop;
 592                 } else {
 593                     gen_opc_buf[op_index] = op_to_mov(op);
 594                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 595                     gen_args += 2;
 596                 }
 597                 args += 3;
 598                 continue;
 599             }
 600             break;
 601         default:
 602             break;
 603         }
 604
 605         /* Simplify expression for "op r, a, a => movi r, 0" cases */
 606         switch (op) {
 607         CASE_OP_32_64(sub):
 608         CASE_OP_32_64(xor):
 609             if (temps_are_copies(args[1], args[2])) {
 610                 gen_opc_buf[op_index] = op_to_movi(op);
 611                 tcg_opt_gen_movi(gen_args, args[0], 0);
 612                 gen_args += 2;
 613                 args += 3;
 614                 continue;
 615             }
 616             break;
 617         default:
 618             break;
 619         }
 620
 621         /* Propagate constants through copy operations and do constant
 622            folding.  Constants will be substituted to arguments by register
 623            allocator where needed and possible.  Also detect copies. */
 624         switch (op) {
 625         CASE_OP_32_64(mov):
 626             if (temps_are_copies(args[0], args[1])) {
 627                 args += 2;
 628                 gen_opc_buf[op_index] = INDEX_op_nop;
 629                 break;
 630             }
 631             if (temps[args[1]].state != TCG_TEMP_CONST) {
 632                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 633                 gen_args += 2;
 634                 args += 2;
 635                 break;
 636             }
 637             /* Source argument is constant.  Rewrite the operation and
 638                let movi case handle it. */
 639             op = op_to_movi(op);
 640             gen_opc_buf[op_index] = op;
 641             args[1] = temps[args[1]].val;
 642             /* fallthrough */
 643         CASE_OP_32_64(movi):
 644             tcg_opt_gen_movi(gen_args, args[0], args[1]);
 645             gen_args += 2;
 646             args += 2;
 647             break;
 648
 649         CASE_OP_32_64(not):
 650         CASE_OP_32_64(neg):
 651         CASE_OP_32_64(ext8s):
 652         CASE_OP_32_64(ext8u):
 653         CASE_OP_32_64(ext16s):
 654         CASE_OP_32_64(ext16u):
 655         case INDEX_op_ext32s_i64:
 656         case INDEX_op_ext32u_i64:
 657             if (temps[args[1]].state == TCG_TEMP_CONST) {
 658                 gen_opc_buf[op_index] = op_to_movi(op);
 659                 tmp = do_constant_folding(op, temps[args[1]].val, 0);
 660                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 661                 gen_args += 2;
 662                 args += 2;
 663                 break;
 664             }
 665             goto do_default;
 666
 667         CASE_OP_32_64(add):
 668         CASE_OP_32_64(sub):
 669         CASE_OP_32_64(mul):
 670         CASE_OP_32_64(or):
 671         CASE_OP_32_64(and):
 672         CASE_OP_32_64(xor):
 673         CASE_OP_32_64(shl):
 674         CASE_OP_32_64(shr):
 675         CASE_OP_32_64(sar):
 676         CASE_OP_32_64(rotl):
 677         CASE_OP_32_64(rotr):
 678         CASE_OP_32_64(andc):
 679         CASE_OP_32_64(orc):
 680         CASE_OP_32_64(eqv):
 681         CASE_OP_32_64(nand):
 682         CASE_OP_32_64(nor):
 683             if (temps[args[1]].state == TCG_TEMP_CONST
 684                 && temps[args[2]].state == TCG_TEMP_CONST) {
 685                 gen_opc_buf[op_index] = op_to_movi(op);
 686                 tmp = do_constant_folding(op, temps[args[1]].val,
 687                                           temps[args[2]].val);
 688                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 689                 gen_args += 2;
 690                 args += 3;
 691                 break;
 692             }
 693             goto do_default;
 694
 695         CASE_OP_32_64(deposit):
 696             if (temps[args[1]].state == TCG_TEMP_CONST
 697                 && temps[args[2]].state == TCG_TEMP_CONST) {
 698                 gen_opc_buf[op_index] = op_to_movi(op);
 699                 tmp = ((1ull << args[4]) - 1);
 700                 tmp = (temps[args[1]].val & ~(tmp << args[3]))
 701                       | ((temps[args[2]].val & tmp) << args[3]);
 702                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 703                 gen_args += 2;
 704                 args += 5;
 705                 break;
 706             }
 707             goto do_default;
 708
 709         CASE_OP_32_64(setcond):
 710             tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
 711             if (tmp != 2) {
 712                 gen_opc_buf[op_index] = op_to_movi(op);
 713                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 714                 gen_args += 2;
 715                 args += 4;
 716                 break;
 717             }
 718             goto do_default;
 719
 720         CASE_OP_32_64(brcond):
 721             tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
 722             if (tmp != 2) {
 723                 if (tmp) {
 724                     memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 725                     gen_opc_buf[op_index] = INDEX_op_br;
 726                     gen_args[0] = args[3];
 727                     gen_args += 1;
 728                 } else {
 729                     gen_opc_buf[op_index] = INDEX_op_nop;
 730                 }
 731                 args += 4;
 732                 break;
 733             }
 734             goto do_default;
 735
 736         CASE_OP_32_64(movcond):
 737             tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
 738             if (tmp != 2) {
 739                 if (temps_are_copies(args[0], args[4-tmp])) {
 740                     gen_opc_buf[op_index] = INDEX_op_nop;
 741                 } else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
 742                     gen_opc_buf[op_index] = op_to_movi(op);
 743                     tcg_opt_gen_movi(gen_args, args[0], temps[args[4-tmp]].val);
 744                     gen_args += 2;
 745                 } else {
 746                     gen_opc_buf[op_index] = op_to_mov(op);
 747                     tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
 748                     gen_args += 2;
 749                 }
 750                 args += 6;
 751                 break;
 752             }
 753             goto do_default;
 754
 755         case INDEX_op_brcond2_i32:
 756             /* Simplify LT/GE comparisons vs zero to a single compare
 757                vs the high word of the input.  */
 758             if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
 759                 && temps[args[2]].state == TCG_TEMP_CONST
 760                 && temps[args[3]].state == TCG_TEMP_CONST
 761                 && temps[args[2]].val == 0
 762                 && temps[args[3]].val == 0) {
 763                 gen_opc_buf[op_index] = INDEX_op_brcond_i32;
 764                 gen_args[0] = args[1];
 765                 gen_args[1] = args[3];
 766                 gen_args[2] = args[4];
 767                 gen_args[3] = args[5];
 768                 gen_args += 4;
 769                 args += 6;
 770                 memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 771                 break;
 772             }
 773             goto do_default;
 774
 775         case INDEX_op_setcond2_i32:
 776             /* Simplify LT/GE comparisons vs zero to a single compare
 777                vs the high word of the input.  */
 778             if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
 779                 && temps[args[3]].state == TCG_TEMP_CONST
 780                 && temps[args[4]].state == TCG_TEMP_CONST
 781                 && temps[args[3]].val == 0
 782                 && temps[args[4]].val == 0) {
 783                 gen_opc_buf[op_index] = INDEX_op_setcond_i32;
 784                 gen_args[0] = args[0];
 785                 gen_args[1] = args[2];
 786                 gen_args[2] = args[4];
 787                 gen_args[3] = args[5];
 788                 gen_args += 4;
 789                 args += 6;
 790                 break;
 791             }
 792             goto do_default;
 793
 794         case INDEX_op_call:
 795             nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);
 796             if (!(args[nb_call_args + 1] & (TCG_CALL_CONST | TCG_CALL_PURE))) {
 797                 for (i = 0; i < nb_globals; i++) {
 798                     reset_temp(i);
 799                 }
 800             }
 801             for (i = 0; i < (args[0] >> 16); i++) {
 802                 reset_temp(args[i + 1]);
 803             }
 804             i = nb_call_args + 3;
 805             while (i) {
 806                 *gen_args = *args;
 807                 args++;
 808                 gen_args++;
 809                 i--;
 810             }
 811             break;
 812
 813         default:
 814         do_default:
 815             /* Default case: we know nothing about operation (or were unable
 816                to compute the operation result) so no propagation is done.
 817                We trash everything if the operation is the end of a basic
 818                block, otherwise we only trash the output args.  */
 819             if (def->flags & TCG_OPF_BB_END) {
 820                 memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 821             } else {
 822                 for (i = 0; i < def->nb_oargs; i++) {
 823                     reset_temp(args[i]);
 824                 }
 825             }
 826             for (i = 0; i < def->nb_args; i++) {
 827                 gen_args[i] = args[i];
 828             }
 829             args += def->nb_args;
 830             gen_args += def->nb_args;
 831             break;
 832         }
 833     }
 834
 835     return gen_args;
 836 }
 837
 838 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr,
 839         TCGArg *args, TCGOpDef *tcg_op_defs)
 840 {
 841     TCGArg *res;
 842     res = tcg_constant_folding(s, tcg_opc_ptr, args, tcg_op_defs);
 843     return res;
 844 }