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 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 296                                        TCGArg y, TCGCond c)
 297 {
 298     switch (op_bits(op)) {
 299     case 32:
 300         switch (c) {
 301         case TCG_COND_EQ:
 302             return (uint32_t)x == (uint32_t)y;
 303         case TCG_COND_NE:
 304             return (uint32_t)x != (uint32_t)y;
 305         case TCG_COND_LT:
 306             return (int32_t)x < (int32_t)y;
 307         case TCG_COND_GE:
 308             return (int32_t)x >= (int32_t)y;
 309         case TCG_COND_LE:
 310             return (int32_t)x <= (int32_t)y;
 311         case TCG_COND_GT:
 312             return (int32_t)x > (int32_t)y;
 313         case TCG_COND_LTU:
 314             return (uint32_t)x < (uint32_t)y;
 315         case TCG_COND_GEU:
 316             return (uint32_t)x >= (uint32_t)y;
 317         case TCG_COND_LEU:
 318             return (uint32_t)x <= (uint32_t)y;
 319         case TCG_COND_GTU:
 320             return (uint32_t)x > (uint32_t)y;
 321         }
 322         break;
 323     case 64:
 324         switch (c) {
 325         case TCG_COND_EQ:
 326             return (uint64_t)x == (uint64_t)y;
 327         case TCG_COND_NE:
 328             return (uint64_t)x != (uint64_t)y;
 329         case TCG_COND_LT:
 330             return (int64_t)x < (int64_t)y;
 331         case TCG_COND_GE:
 332             return (int64_t)x >= (int64_t)y;
 333         case TCG_COND_LE:
 334             return (int64_t)x <= (int64_t)y;
 335         case TCG_COND_GT:
 336             return (int64_t)x > (int64_t)y;
 337         case TCG_COND_LTU:
 338             return (uint64_t)x < (uint64_t)y;
 339         case TCG_COND_GEU:
 340             return (uint64_t)x >= (uint64_t)y;
 341         case TCG_COND_LEU:
 342             return (uint64_t)x <= (uint64_t)y;
 343         case TCG_COND_GTU:
 344             return (uint64_t)x > (uint64_t)y;
 345         }
 346         break;
 347     }
 348
 349     fprintf(stderr,
 350             "Unrecognized bitness %d or condition %d in "
 351             "do_constant_folding_cond.\n", op_bits(op), c);
 352     tcg_abort();
 353 }
 354
 355 /* Propagate constants and copies, fold constant expressions. */
 356 static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 357                                     TCGArg *args, TCGOpDef *tcg_op_defs)
 358 {
 359     int i, nb_ops, op_index, nb_temps, nb_globals, nb_call_args;
 360     TCGOpcode op;
 361     const TCGOpDef *def;
 362     TCGArg *gen_args;
 363     TCGArg tmp;
 364     TCGCond cond;
 365
 366     /* Array VALS has an element for each temp.
 367        If this temp holds a constant then its value is kept in VALS' element.
 368        If this temp is a copy of other ones then the other copies are
 369        available through the doubly linked circular list. */
 370
 371     nb_temps = s->nb_temps;
 372     nb_globals = s->nb_globals;
 373     memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 374
 375     nb_ops = tcg_opc_ptr - gen_opc_buf;
 376     gen_args = args;
 377     for (op_index = 0; op_index < nb_ops; op_index++) {
 378         op = gen_opc_buf[op_index];
 379         def = &tcg_op_defs[op];
 380         /* Do copy propagation */
 381         if (op == INDEX_op_call) {
 382             int nb_oargs = args[0] >> 16;
 383             int nb_iargs = args[0] & 0xffff;
 384             for (i = nb_oargs + 1; i < nb_oargs + nb_iargs + 1; i++) {
 385                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 386                     args[i] = find_better_copy(s, args[i]);
 387                 }
 388             }
 389         } else {
 390             for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) {
 391                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 392                     args[i] = find_better_copy(s, args[i]);
 393                 }
 394             }
 395         }
 396
 397         /* For commutative operations make constant second argument */
 398         switch (op) {
 399         CASE_OP_32_64(add):
 400         CASE_OP_32_64(mul):
 401         CASE_OP_32_64(and):
 402         CASE_OP_32_64(or):
 403         CASE_OP_32_64(xor):
 404         CASE_OP_32_64(eqv):
 405         CASE_OP_32_64(nand):
 406         CASE_OP_32_64(nor):
 407             if (temps[args[1]].state == TCG_TEMP_CONST) {
 408                 tmp = args[1];
 409                 args[1] = args[2];
 410                 args[2] = tmp;
 411             }
 412             break;
 413         CASE_OP_32_64(brcond):
 414             if (temps[args[0]].state == TCG_TEMP_CONST
 415                 && temps[args[1]].state != TCG_TEMP_CONST) {
 416                 tmp = args[0];
 417                 args[0] = args[1];
 418                 args[1] = tmp;
 419                 args[2] = tcg_swap_cond(args[2]);
 420             }
 421             break;
 422         CASE_OP_32_64(setcond):
 423             if (temps[args[1]].state == TCG_TEMP_CONST
 424                 && temps[args[2]].state != TCG_TEMP_CONST) {
 425                 tmp = args[1];
 426                 args[1] = args[2];
 427                 args[2] = tmp;
 428                 args[3] = tcg_swap_cond(args[3]);
 429             }
 430             break;
 431         CASE_OP_32_64(movcond):
 432             cond = args[5];
 433             if (temps[args[1]].state == TCG_TEMP_CONST
 434                 && temps[args[2]].state != TCG_TEMP_CONST) {
 435                 tmp = args[1];
 436                 args[1] = args[2];
 437                 args[2] = tmp;
 438                 cond = tcg_swap_cond(cond);
 439             }
 440             /* For movcond, we canonicalize the "false" input reg to match
 441                the destination reg so that the tcg backend can implement
 442                a "move if true" operation.  */
 443             if (args[0] == args[3]) {
 444                 tmp = args[3];
 445                 args[3] = args[4];
 446                 args[4] = tmp;
 447                 cond = tcg_invert_cond(cond);
 448             }
 449             args[5] = cond;
 450         default:
 451             break;
 452         }
 453
 454         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0" */
 455         switch (op) {
 456         CASE_OP_32_64(shl):
 457         CASE_OP_32_64(shr):
 458         CASE_OP_32_64(sar):
 459         CASE_OP_32_64(rotl):
 460         CASE_OP_32_64(rotr):
 461             if (temps[args[1]].state == TCG_TEMP_CONST
 462                 && temps[args[1]].val == 0) {
 463                 gen_opc_buf[op_index] = op_to_movi(op);
 464                 tcg_opt_gen_movi(gen_args, args[0], 0);
 465                 args += 3;
 466                 gen_args += 2;
 467                 continue;
 468             }
 469             break;
 470         default:
 471             break;
 472         }
 473
 474         /* Simplify expression for "op r, a, 0 => mov r, a" cases */
 475         switch (op) {
 476         CASE_OP_32_64(add):
 477         CASE_OP_32_64(sub):
 478         CASE_OP_32_64(shl):
 479         CASE_OP_32_64(shr):
 480         CASE_OP_32_64(sar):
 481         CASE_OP_32_64(rotl):
 482         CASE_OP_32_64(rotr):
 483         CASE_OP_32_64(or):
 484         CASE_OP_32_64(xor):
 485             if (temps[args[1]].state == TCG_TEMP_CONST) {
 486                 /* Proceed with possible constant folding. */
 487                 break;
 488             }
 489             if (temps[args[2]].state == TCG_TEMP_CONST
 490                 && temps[args[2]].val == 0) {
 491                 if (temps_are_copies(args[0], args[1])) {
 492                     gen_opc_buf[op_index] = INDEX_op_nop;
 493                 } else {
 494                     gen_opc_buf[op_index] = op_to_mov(op);
 495                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 496                     gen_args += 2;
 497                 }
 498                 args += 3;
 499                 continue;
 500             }
 501             break;
 502         default:
 503             break;
 504         }
 505
 506         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
 507         switch (op) {
 508         CASE_OP_32_64(and):
 509         CASE_OP_32_64(mul):
 510             if ((temps[args[2]].state == TCG_TEMP_CONST
 511                 && temps[args[2]].val == 0)) {
 512                 gen_opc_buf[op_index] = op_to_movi(op);
 513                 tcg_opt_gen_movi(gen_args, args[0], 0);
 514                 args += 3;
 515                 gen_args += 2;
 516                 continue;
 517             }
 518             break;
 519         default:
 520             break;
 521         }
 522
 523         /* Simplify expression for "op r, a, a => mov r, a" cases */
 524         switch (op) {
 525         CASE_OP_32_64(or):
 526         CASE_OP_32_64(and):
 527             if (args[1] == args[2]) {
 528                 if (temps_are_copies(args[0], args[1])) {
 529                     gen_opc_buf[op_index] = INDEX_op_nop;
 530                 } else {
 531                     gen_opc_buf[op_index] = op_to_mov(op);
 532                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 533                     gen_args += 2;
 534                 }
 535                 args += 3;
 536                 continue;
 537             }
 538             break;
 539         default:
 540             break;
 541         }
 542
 543         /* Propagate constants through copy operations and do constant
 544            folding.  Constants will be substituted to arguments by register
 545            allocator where needed and possible.  Also detect copies. */
 546         switch (op) {
 547         CASE_OP_32_64(mov):
 548             if (temps_are_copies(args[0], args[1])) {
 549                 args += 2;
 550                 gen_opc_buf[op_index] = INDEX_op_nop;
 551                 break;
 552             }
 553             if (temps[args[1]].state != TCG_TEMP_CONST) {
 554                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 555                 gen_args += 2;
 556                 args += 2;
 557                 break;
 558             }
 559             /* Source argument is constant.  Rewrite the operation and
 560                let movi case handle it. */
 561             op = op_to_movi(op);
 562             gen_opc_buf[op_index] = op;
 563             args[1] = temps[args[1]].val;
 564             /* fallthrough */
 565         CASE_OP_32_64(movi):
 566             tcg_opt_gen_movi(gen_args, args[0], args[1]);
 567             gen_args += 2;
 568             args += 2;
 569             break;
 570         CASE_OP_32_64(not):
 571         CASE_OP_32_64(neg):
 572         CASE_OP_32_64(ext8s):
 573         CASE_OP_32_64(ext8u):
 574         CASE_OP_32_64(ext16s):
 575         CASE_OP_32_64(ext16u):
 576         case INDEX_op_ext32s_i64:
 577         case INDEX_op_ext32u_i64:
 578             if (temps[args[1]].state == TCG_TEMP_CONST) {
 579                 gen_opc_buf[op_index] = op_to_movi(op);
 580                 tmp = do_constant_folding(op, temps[args[1]].val, 0);
 581                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 582             } else {
 583                 reset_temp(args[0]);
 584                 gen_args[0] = args[0];
 585                 gen_args[1] = args[1];
 586             }
 587             gen_args += 2;
 588             args += 2;
 589             break;
 590         CASE_OP_32_64(add):
 591         CASE_OP_32_64(sub):
 592         CASE_OP_32_64(mul):
 593         CASE_OP_32_64(or):
 594         CASE_OP_32_64(and):
 595         CASE_OP_32_64(xor):
 596         CASE_OP_32_64(shl):
 597         CASE_OP_32_64(shr):
 598         CASE_OP_32_64(sar):
 599         CASE_OP_32_64(rotl):
 600         CASE_OP_32_64(rotr):
 601         CASE_OP_32_64(andc):
 602         CASE_OP_32_64(orc):
 603         CASE_OP_32_64(eqv):
 604         CASE_OP_32_64(nand):
 605         CASE_OP_32_64(nor):
 606             if (temps[args[1]].state == TCG_TEMP_CONST
 607                 && temps[args[2]].state == TCG_TEMP_CONST) {
 608                 gen_opc_buf[op_index] = op_to_movi(op);
 609                 tmp = do_constant_folding(op, temps[args[1]].val,
 610                                           temps[args[2]].val);
 611                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 612                 gen_args += 2;
 613             } else {
 614                 reset_temp(args[0]);
 615                 gen_args[0] = args[0];
 616                 gen_args[1] = args[1];
 617                 gen_args[2] = args[2];
 618                 gen_args += 3;
 619             }
 620             args += 3;
 621             break;
 622         CASE_OP_32_64(setcond):
 623             if (temps[args[1]].state == TCG_TEMP_CONST
 624                 && temps[args[2]].state == TCG_TEMP_CONST) {
 625                 gen_opc_buf[op_index] = op_to_movi(op);
 626                 tmp = do_constant_folding_cond(op, temps[args[1]].val,
 627                                                temps[args[2]].val, args[3]);
 628                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 629                 gen_args += 2;
 630             } else {
 631                 reset_temp(args[0]);
 632                 gen_args[0] = args[0];
 633                 gen_args[1] = args[1];
 634                 gen_args[2] = args[2];
 635                 gen_args[3] = args[3];
 636                 gen_args += 4;
 637             }
 638             args += 4;
 639             break;
 640         CASE_OP_32_64(brcond):
 641             if (temps[args[0]].state == TCG_TEMP_CONST
 642                 && temps[args[1]].state == TCG_TEMP_CONST) {
 643                 if (do_constant_folding_cond(op, temps[args[0]].val,
 644                                              temps[args[1]].val, args[2])) {
 645                     memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 646                     gen_opc_buf[op_index] = INDEX_op_br;
 647                     gen_args[0] = args[3];
 648                     gen_args += 1;
 649                 } else {
 650                     gen_opc_buf[op_index] = INDEX_op_nop;
 651                 }
 652             } else {
 653                 memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 654                 reset_temp(args[0]);
 655                 gen_args[0] = args[0];
 656                 gen_args[1] = args[1];
 657                 gen_args[2] = args[2];
 658                 gen_args[3] = args[3];
 659                 gen_args += 4;
 660             }
 661             args += 4;
 662             break;
 663         CASE_OP_32_64(movcond):
 664             if (temps[args[1]].state == TCG_TEMP_CONST
 665                 && temps[args[2]].state == TCG_TEMP_CONST) {
 666                 tmp = do_constant_folding_cond(op, temps[args[1]].val,
 667                                                temps[args[2]].val, args[5]);
 668                 if (temps_are_copies(args[0], args[4-tmp])) {
 669                     gen_opc_buf[op_index] = INDEX_op_nop;
 670                 } else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
 671                     gen_opc_buf[op_index] = op_to_movi(op);
 672                     tcg_opt_gen_movi(gen_args, args[0], temps[args[4-tmp]].val);
 673                     gen_args += 2;
 674                 } else {
 675                     gen_opc_buf[op_index] = op_to_mov(op);
 676                     tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
 677                     gen_args += 2;
 678                 }
 679             } else {
 680                 reset_temp(args[0]);
 681                 gen_args[0] = args[0];
 682                 gen_args[1] = args[1];
 683                 gen_args[2] = args[2];
 684                 gen_args[3] = args[3];
 685                 gen_args[4] = args[4];
 686                 gen_args[5] = args[5];
 687                 gen_args += 6;
 688             }
 689             args += 6;
 690             break;
 691         case INDEX_op_call:
 692             nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);
 693             if (!(args[nb_call_args + 1] & (TCG_CALL_CONST | TCG_CALL_PURE))) {
 694                 for (i = 0; i < nb_globals; i++) {
 695                     reset_temp(i);
 696                 }
 697             }
 698             for (i = 0; i < (args[0] >> 16); i++) {
 699                 reset_temp(args[i + 1]);
 700             }
 701             i = nb_call_args + 3;
 702             while (i) {
 703                 *gen_args = *args;
 704                 args++;
 705                 gen_args++;
 706                 i--;
 707             }
 708             break;
 709         default:
 710             /* Default case: we do know nothing about operation so no
 711                propagation is done.  We trash everything if the operation
 712                is the end of a basic block, otherwise we only trash the
 713                output args.  */
 714             if (def->flags & TCG_OPF_BB_END) {
 715                 memset(temps, 0, nb_temps * sizeof(struct tcg_temp_info));
 716             } else {
 717                 for (i = 0; i < def->nb_oargs; i++) {
 718                     reset_temp(args[i]);
 719                 }
 720             }
 721             for (i = 0; i < def->nb_args; i++) {
 722                 gen_args[i] = args[i];
 723             }
 724             args += def->nb_args;
 725             gen_args += def->nb_args;
 726             break;
 727         }
 728     }
 729
 730     return gen_args;
 731 }
 732
 733 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr,
 734         TCGArg *args, TCGOpDef *tcg_op_defs)
 735 {
 736     TCGArg *res;
 737     res = tcg_constant_folding(s, tcg_opc_ptr, args, tcg_op_defs);
 738     return res;
 739 }