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     uint64_t l64, h64;
 202
 203     switch (op) {
 204     CASE_OP_32_64(add):
 205         return x + y;
 206
 207     CASE_OP_32_64(sub):
 208         return x - y;
 209
 210     CASE_OP_32_64(mul):
 211         return x * y;
 212
 213     CASE_OP_32_64(and):
 214         return x & y;
 215
 216     CASE_OP_32_64(or):
 217         return x | y;
 218
 219     CASE_OP_32_64(xor):
 220         return x ^ y;
 221
 222     case INDEX_op_shl_i32:
 223         return (uint32_t)x << (uint32_t)y;
 224
 225     case INDEX_op_shl_i64:
 226         return (uint64_t)x << (uint64_t)y;
 227
 228     case INDEX_op_shr_i32:
 229         return (uint32_t)x >> (uint32_t)y;
 230
 231     case INDEX_op_shr_i64:
 232         return (uint64_t)x >> (uint64_t)y;
 233
 234     case INDEX_op_sar_i32:
 235         return (int32_t)x >> (int32_t)y;
 236
 237     case INDEX_op_sar_i64:
 238         return (int64_t)x >> (int64_t)y;
 239
 240     case INDEX_op_rotr_i32:
 241         return ror32(x, y);
 242
 243     case INDEX_op_rotr_i64:
 244         return ror64(x, y);
 245
 246     case INDEX_op_rotl_i32:
 247         return rol32(x, y);
 248
 249     case INDEX_op_rotl_i64:
 250         return rol64(x, y);
 251
 252     CASE_OP_32_64(not):
 253         return ~x;
 254
 255     CASE_OP_32_64(neg):
 256         return -x;
 257
 258     CASE_OP_32_64(andc):
 259         return x & ~y;
 260
 261     CASE_OP_32_64(orc):
 262         return x | ~y;
 263
 264     CASE_OP_32_64(eqv):
 265         return ~(x ^ y);
 266
 267     CASE_OP_32_64(nand):
 268         return ~(x & y);
 269
 270     CASE_OP_32_64(nor):
 271         return ~(x | y);
 272
 273     CASE_OP_32_64(ext8s):
 274         return (int8_t)x;
 275
 276     CASE_OP_32_64(ext16s):
 277         return (int16_t)x;
 278
 279     CASE_OP_32_64(ext8u):
 280         return (uint8_t)x;
 281
 282     CASE_OP_32_64(ext16u):
 283         return (uint16_t)x;
 284
 285     case INDEX_op_ext32s_i64:
 286         return (int32_t)x;
 287
 288     case INDEX_op_ext32u_i64:
 289         return (uint32_t)x;
 290
 291     case INDEX_op_muluh_i32:
 292         return ((uint64_t)(uint32_t)x * (uint32_t)y) >> 32;
 293     case INDEX_op_mulsh_i32:
 294         return ((int64_t)(int32_t)x * (int32_t)y) >> 32;
 295
 296     case INDEX_op_muluh_i64:
 297         mulu64(&l64, &h64, x, y);
 298         return h64;
 299     case INDEX_op_mulsh_i64:
 300         muls64(&l64, &h64, x, y);
 301         return h64;
 302
 303     case INDEX_op_div_i32:
 304         /* Avoid crashing on divide by zero, otherwise undefined.  */
 305         return (int32_t)x / ((int32_t)y ? : 1);
 306     case INDEX_op_divu_i32:
 307         return (uint32_t)x / ((uint32_t)y ? : 1);
 308     case INDEX_op_div_i64:
 309         return (int64_t)x / ((int64_t)y ? : 1);
 310     case INDEX_op_divu_i64:
 311         return (uint64_t)x / ((uint64_t)y ? : 1);
 312
 313     case INDEX_op_rem_i32:
 314         return (int32_t)x % ((int32_t)y ? : 1);
 315     case INDEX_op_remu_i32:
 316         return (uint32_t)x % ((uint32_t)y ? : 1);
 317     case INDEX_op_rem_i64:
 318         return (int64_t)x % ((int64_t)y ? : 1);
 319     case INDEX_op_remu_i64:
 320         return (uint64_t)x % ((uint64_t)y ? : 1);
 321
 322     default:
 323         fprintf(stderr,
 324                 "Unrecognized operation %d in do_constant_folding.\n", op);
 325         tcg_abort();
 326     }
 327 }
 328
 329 static TCGArg do_constant_folding(TCGOpcode op, TCGArg x, TCGArg y)
 330 {
 331     TCGArg res = do_constant_folding_2(op, x, y);
 332     if (op_bits(op) == 32) {
 333         res &= 0xffffffff;
 334     }
 335     return res;
 336 }
 337
 338 static bool do_constant_folding_cond_32(uint32_t x, uint32_t y, TCGCond c)
 339 {
 340     switch (c) {
 341     case TCG_COND_EQ:
 342         return x == y;
 343     case TCG_COND_NE:
 344         return x != y;
 345     case TCG_COND_LT:
 346         return (int32_t)x < (int32_t)y;
 347     case TCG_COND_GE:
 348         return (int32_t)x >= (int32_t)y;
 349     case TCG_COND_LE:
 350         return (int32_t)x <= (int32_t)y;
 351     case TCG_COND_GT:
 352         return (int32_t)x > (int32_t)y;
 353     case TCG_COND_LTU:
 354         return x < y;
 355     case TCG_COND_GEU:
 356         return x >= y;
 357     case TCG_COND_LEU:
 358         return x <= y;
 359     case TCG_COND_GTU:
 360         return x > y;
 361     default:
 362         tcg_abort();
 363     }
 364 }
 365
 366 static bool do_constant_folding_cond_64(uint64_t x, uint64_t y, TCGCond c)
 367 {
 368     switch (c) {
 369     case TCG_COND_EQ:
 370         return x == y;
 371     case TCG_COND_NE:
 372         return x != y;
 373     case TCG_COND_LT:
 374         return (int64_t)x < (int64_t)y;
 375     case TCG_COND_GE:
 376         return (int64_t)x >= (int64_t)y;
 377     case TCG_COND_LE:
 378         return (int64_t)x <= (int64_t)y;
 379     case TCG_COND_GT:
 380         return (int64_t)x > (int64_t)y;
 381     case TCG_COND_LTU:
 382         return x < y;
 383     case TCG_COND_GEU:
 384         return x >= y;
 385     case TCG_COND_LEU:
 386         return x <= y;
 387     case TCG_COND_GTU:
 388         return x > y;
 389     default:
 390         tcg_abort();
 391     }
 392 }
 393
 394 static bool do_constant_folding_cond_eq(TCGCond c)
 395 {
 396     switch (c) {
 397     case TCG_COND_GT:
 398     case TCG_COND_LTU:
 399     case TCG_COND_LT:
 400     case TCG_COND_GTU:
 401     case TCG_COND_NE:
 402         return 0;
 403     case TCG_COND_GE:
 404     case TCG_COND_GEU:
 405     case TCG_COND_LE:
 406     case TCG_COND_LEU:
 407     case TCG_COND_EQ:
 408         return 1;
 409     default:
 410         tcg_abort();
 411     }
 412 }
 413
 414 /* Return 2 if the condition can't be simplified, and the result
 415    of the condition (0 or 1) if it can */
 416 static TCGArg do_constant_folding_cond(TCGOpcode op, TCGArg x,
 417                                        TCGArg y, TCGCond c)
 418 {
 419     if (temps[x].state == TCG_TEMP_CONST && temps[y].state == TCG_TEMP_CONST) {
 420         switch (op_bits(op)) {
 421         case 32:
 422             return do_constant_folding_cond_32(temps[x].val, temps[y].val, c);
 423         case 64:
 424             return do_constant_folding_cond_64(temps[x].val, temps[y].val, c);
 425         default:
 426             tcg_abort();
 427         }
 428     } else if (temps_are_copies(x, y)) {
 429         return do_constant_folding_cond_eq(c);
 430     } else if (temps[y].state == TCG_TEMP_CONST && temps[y].val == 0) {
 431         switch (c) {
 432         case TCG_COND_LTU:
 433             return 0;
 434         case TCG_COND_GEU:
 435             return 1;
 436         default:
 437             return 2;
 438         }
 439     } else {
 440         return 2;
 441     }
 442 }
 443
 444 /* Return 2 if the condition can't be simplified, and the result
 445    of the condition (0 or 1) if it can */
 446 static TCGArg do_constant_folding_cond2(TCGArg *p1, TCGArg *p2, TCGCond c)
 447 {
 448     TCGArg al = p1[0], ah = p1[1];
 449     TCGArg bl = p2[0], bh = p2[1];
 450
 451     if (temps[bl].state == TCG_TEMP_CONST
 452         && temps[bh].state == TCG_TEMP_CONST) {
 453         uint64_t b = ((uint64_t)temps[bh].val << 32) | (uint32_t)temps[bl].val;
 454
 455         if (temps[al].state == TCG_TEMP_CONST
 456             && temps[ah].state == TCG_TEMP_CONST) {
 457             uint64_t a;
 458             a = ((uint64_t)temps[ah].val << 32) | (uint32_t)temps[al].val;
 459             return do_constant_folding_cond_64(a, b, c);
 460         }
 461         if (b == 0) {
 462             switch (c) {
 463             case TCG_COND_LTU:
 464                 return 0;
 465             case TCG_COND_GEU:
 466                 return 1;
 467             default:
 468                 break;
 469             }
 470         }
 471     }
 472     if (temps_are_copies(al, bl) && temps_are_copies(ah, bh)) {
 473         return do_constant_folding_cond_eq(c);
 474     }
 475     return 2;
 476 }
 477
 478 static bool swap_commutative(TCGArg dest, TCGArg *p1, TCGArg *p2)
 479 {
 480     TCGArg a1 = *p1, a2 = *p2;
 481     int sum = 0;
 482     sum += temps[a1].state == TCG_TEMP_CONST;
 483     sum -= temps[a2].state == TCG_TEMP_CONST;
 484
 485     /* Prefer the constant in second argument, and then the form
 486        op a, a, b, which is better handled on non-RISC hosts. */
 487     if (sum > 0 || (sum == 0 && dest == a2)) {
 488         *p1 = a2;
 489         *p2 = a1;
 490         return true;
 491     }
 492     return false;
 493 }
 494
 495 static bool swap_commutative2(TCGArg *p1, TCGArg *p2)
 496 {
 497     int sum = 0;
 498     sum += temps[p1[0]].state == TCG_TEMP_CONST;
 499     sum += temps[p1[1]].state == TCG_TEMP_CONST;
 500     sum -= temps[p2[0]].state == TCG_TEMP_CONST;
 501     sum -= temps[p2[1]].state == TCG_TEMP_CONST;
 502     if (sum > 0) {
 503         TCGArg t;
 504         t = p1[0], p1[0] = p2[0], p2[0] = t;
 505         t = p1[1], p1[1] = p2[1], p2[1] = t;
 506         return true;
 507     }
 508     return false;
 509 }
 510
 511 /* Propagate constants and copies, fold constant expressions. */
 512 static TCGArg *tcg_constant_folding(TCGContext *s, uint16_t *tcg_opc_ptr,
 513                                     TCGArg *args, TCGOpDef *tcg_op_defs)
 514 {
 515     int i, nb_ops, op_index, nb_temps, nb_globals, nb_call_args;
 516     tcg_target_ulong mask, affected;
 517     TCGOpcode op;
 518     const TCGOpDef *def;
 519     TCGArg *gen_args;
 520     TCGArg tmp;
 521
 522     /* Array VALS has an element for each temp.
 523        If this temp holds a constant then its value is kept in VALS' element.
 524        If this temp is a copy of other ones then the other copies are
 525        available through the doubly linked circular list. */
 526
 527     nb_temps = s->nb_temps;
 528     nb_globals = s->nb_globals;
 529     reset_all_temps(nb_temps);
 530
 531     nb_ops = tcg_opc_ptr - s->gen_opc_buf;
 532     gen_args = args;
 533     for (op_index = 0; op_index < nb_ops; op_index++) {
 534         op = s->gen_opc_buf[op_index];
 535         def = &tcg_op_defs[op];
 536         /* Do copy propagation */
 537         if (op == INDEX_op_call) {
 538             int nb_oargs = args[0] >> 16;
 539             int nb_iargs = args[0] & 0xffff;
 540             for (i = nb_oargs + 1; i < nb_oargs + nb_iargs + 1; i++) {
 541                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 542                     args[i] = find_better_copy(s, args[i]);
 543                 }
 544             }
 545         } else {
 546             for (i = def->nb_oargs; i < def->nb_oargs + def->nb_iargs; i++) {
 547                 if (temps[args[i]].state == TCG_TEMP_COPY) {
 548                     args[i] = find_better_copy(s, args[i]);
 549                 }
 550             }
 551         }
 552
 553         /* For commutative operations make constant second argument */
 554         switch (op) {
 555         CASE_OP_32_64(add):
 556         CASE_OP_32_64(mul):
 557         CASE_OP_32_64(and):
 558         CASE_OP_32_64(or):
 559         CASE_OP_32_64(xor):
 560         CASE_OP_32_64(eqv):
 561         CASE_OP_32_64(nand):
 562         CASE_OP_32_64(nor):
 563         CASE_OP_32_64(muluh):
 564         CASE_OP_32_64(mulsh):
 565             swap_commutative(args[0], &args[1], &args[2]);
 566             break;
 567         CASE_OP_32_64(brcond):
 568             if (swap_commutative(-1, &args[0], &args[1])) {
 569                 args[2] = tcg_swap_cond(args[2]);
 570             }
 571             break;
 572         CASE_OP_32_64(setcond):
 573             if (swap_commutative(args[0], &args[1], &args[2])) {
 574                 args[3] = tcg_swap_cond(args[3]);
 575             }
 576             break;
 577         CASE_OP_32_64(movcond):
 578             if (swap_commutative(-1, &args[1], &args[2])) {
 579                 args[5] = tcg_swap_cond(args[5]);
 580             }
 581             /* For movcond, we canonicalize the "false" input reg to match
 582                the destination reg so that the tcg backend can implement
 583                a "move if true" operation.  */
 584             if (swap_commutative(args[0], &args[4], &args[3])) {
 585                 args[5] = tcg_invert_cond(args[5]);
 586             }
 587             break;
 588         CASE_OP_32_64(add2):
 589             swap_commutative(args[0], &args[2], &args[4]);
 590             swap_commutative(args[1], &args[3], &args[5]);
 591             break;
 592         CASE_OP_32_64(mulu2):
 593         CASE_OP_32_64(muls2):
 594             swap_commutative(args[0], &args[2], &args[3]);
 595             break;
 596         case INDEX_op_brcond2_i32:
 597             if (swap_commutative2(&args[0], &args[2])) {
 598                 args[4] = tcg_swap_cond(args[4]);
 599             }
 600             break;
 601         case INDEX_op_setcond2_i32:
 602             if (swap_commutative2(&args[1], &args[3])) {
 603                 args[5] = tcg_swap_cond(args[5]);
 604             }
 605             break;
 606         default:
 607             break;
 608         }
 609
 610         /* Simplify expressions for "shift/rot r, 0, a => movi r, 0",
 611            and "sub r, 0, a => neg r, a" case.  */
 612         switch (op) {
 613         CASE_OP_32_64(shl):
 614         CASE_OP_32_64(shr):
 615         CASE_OP_32_64(sar):
 616         CASE_OP_32_64(rotl):
 617         CASE_OP_32_64(rotr):
 618             if (temps[args[1]].state == TCG_TEMP_CONST
 619                 && temps[args[1]].val == 0) {
 620                 s->gen_opc_buf[op_index] = op_to_movi(op);
 621                 tcg_opt_gen_movi(gen_args, args[0], 0);
 622                 args += 3;
 623                 gen_args += 2;
 624                 continue;
 625             }
 626             break;
 627         CASE_OP_32_64(sub):
 628             {
 629                 TCGOpcode neg_op;
 630                 bool have_neg;
 631
 632                 if (temps[args[2]].state == TCG_TEMP_CONST) {
 633                     /* Proceed with possible constant folding. */
 634                     break;
 635                 }
 636                 if (op == INDEX_op_sub_i32) {
 637                     neg_op = INDEX_op_neg_i32;
 638                     have_neg = TCG_TARGET_HAS_neg_i32;
 639                 } else {
 640                     neg_op = INDEX_op_neg_i64;
 641                     have_neg = TCG_TARGET_HAS_neg_i64;
 642                 }
 643                 if (!have_neg) {
 644                     break;
 645                 }
 646                 if (temps[args[1]].state == TCG_TEMP_CONST
 647                     && temps[args[1]].val == 0) {
 648                     s->gen_opc_buf[op_index] = neg_op;
 649                     reset_temp(args[0]);
 650                     gen_args[0] = args[0];
 651                     gen_args[1] = args[2];
 652                     args += 3;
 653                     gen_args += 2;
 654                     continue;
 655                 }
 656             }
 657             break;
 658         default:
 659             break;
 660         }
 661
 662         /* Simplify expression for "op r, a, 0 => mov r, a" cases */
 663         switch (op) {
 664         CASE_OP_32_64(add):
 665         CASE_OP_32_64(sub):
 666         CASE_OP_32_64(shl):
 667         CASE_OP_32_64(shr):
 668         CASE_OP_32_64(sar):
 669         CASE_OP_32_64(rotl):
 670         CASE_OP_32_64(rotr):
 671         CASE_OP_32_64(or):
 672         CASE_OP_32_64(xor):
 673             if (temps[args[1]].state == TCG_TEMP_CONST) {
 674                 /* Proceed with possible constant folding. */
 675                 break;
 676             }
 677             if (temps[args[2]].state == TCG_TEMP_CONST
 678                 && temps[args[2]].val == 0) {
 679                 if (temps_are_copies(args[0], args[1])) {
 680                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 681                 } else {
 682                     s->gen_opc_buf[op_index] = op_to_mov(op);
 683                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 684                     gen_args += 2;
 685                 }
 686                 args += 3;
 687                 continue;
 688             }
 689             break;
 690         default:
 691             break;
 692         }
 693
 694         /* Simplify using known-zero bits */
 695         mask = -1;
 696         affected = -1;
 697         switch (op) {
 698         CASE_OP_32_64(ext8s):
 699             if ((temps[args[1]].mask & 0x80) != 0) {
 700                 break;
 701             }
 702         CASE_OP_32_64(ext8u):
 703             mask = 0xff;
 704             goto and_const;
 705         CASE_OP_32_64(ext16s):
 706             if ((temps[args[1]].mask & 0x8000) != 0) {
 707                 break;
 708             }
 709         CASE_OP_32_64(ext16u):
 710             mask = 0xffff;
 711             goto and_const;
 712         case INDEX_op_ext32s_i64:
 713             if ((temps[args[1]].mask & 0x80000000) != 0) {
 714                 break;
 715             }
 716         case INDEX_op_ext32u_i64:
 717             mask = 0xffffffffU;
 718             goto and_const;
 719
 720         CASE_OP_32_64(and):
 721             mask = temps[args[2]].mask;
 722             if (temps[args[2]].state == TCG_TEMP_CONST) {
 723         and_const:
 724                 affected = temps[args[1]].mask & ~mask;
 725             }
 726             mask = temps[args[1]].mask & mask;
 727             break;
 728
 729         CASE_OP_32_64(sar):
 730             if (temps[args[2]].state == TCG_TEMP_CONST) {
 731                 mask = ((tcg_target_long)temps[args[1]].mask
 732                         >> temps[args[2]].val);
 733             }
 734             break;
 735
 736         CASE_OP_32_64(shr):
 737             if (temps[args[2]].state == TCG_TEMP_CONST) {
 738                 mask = temps[args[1]].mask >> temps[args[2]].val;
 739             }
 740             break;
 741
 742         CASE_OP_32_64(shl):
 743             if (temps[args[2]].state == TCG_TEMP_CONST) {
 744                 mask = temps[args[1]].mask << temps[args[2]].val;
 745             }
 746             break;
 747
 748         CASE_OP_32_64(neg):
 749             /* Set to 1 all bits to the left of the rightmost.  */
 750             mask = -(temps[args[1]].mask & -temps[args[1]].mask);
 751             break;
 752
 753         CASE_OP_32_64(deposit):
 754             tmp = ((1ull << args[4]) - 1);
 755             mask = ((temps[args[1]].mask & ~(tmp << args[3]))
 756                     | ((temps[args[2]].mask & tmp) << args[3]));
 757             break;
 758
 759         CASE_OP_32_64(or):
 760         CASE_OP_32_64(xor):
 761             mask = temps[args[1]].mask | temps[args[2]].mask;
 762             break;
 763
 764         CASE_OP_32_64(setcond):
 765             mask = 1;
 766             break;
 767
 768         CASE_OP_32_64(movcond):
 769             mask = temps[args[3]].mask | temps[args[4]].mask;
 770             break;
 771
 772         default:
 773             break;
 774         }
 775
 776         if (mask == 0) {
 777             assert(def->nb_oargs == 1);
 778             s->gen_opc_buf[op_index] = op_to_movi(op);
 779             tcg_opt_gen_movi(gen_args, args[0], 0);
 780             args += def->nb_oargs + def->nb_iargs + def->nb_cargs;
 781             gen_args += 2;
 782             continue;
 783         }
 784         if (affected == 0) {
 785             assert(def->nb_oargs == 1);
 786             if (temps_are_copies(args[0], args[1])) {
 787                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 788             } else if (temps[args[1]].state != TCG_TEMP_CONST) {
 789                 s->gen_opc_buf[op_index] = op_to_mov(op);
 790                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 791                 gen_args += 2;
 792             } else {
 793                 s->gen_opc_buf[op_index] = op_to_movi(op);
 794                 tcg_opt_gen_movi(gen_args, args[0], temps[args[1]].val);
 795                 gen_args += 2;
 796             }
 797             args += def->nb_iargs + 1;
 798             continue;
 799         }
 800
 801         /* Simplify expression for "op r, a, 0 => movi r, 0" cases */
 802         switch (op) {
 803         CASE_OP_32_64(and):
 804         CASE_OP_32_64(mul):
 805         CASE_OP_32_64(muluh):
 806         CASE_OP_32_64(mulsh):
 807             if ((temps[args[2]].state == TCG_TEMP_CONST
 808                 && temps[args[2]].val == 0)) {
 809                 s->gen_opc_buf[op_index] = op_to_movi(op);
 810                 tcg_opt_gen_movi(gen_args, args[0], 0);
 811                 args += 3;
 812                 gen_args += 2;
 813                 continue;
 814             }
 815             break;
 816         default:
 817             break;
 818         }
 819
 820         /* Simplify expression for "op r, a, a => mov r, a" cases */
 821         switch (op) {
 822         CASE_OP_32_64(or):
 823         CASE_OP_32_64(and):
 824             if (temps_are_copies(args[1], args[2])) {
 825                 if (temps_are_copies(args[0], args[1])) {
 826                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 827                 } else {
 828                     s->gen_opc_buf[op_index] = op_to_mov(op);
 829                     tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 830                     gen_args += 2;
 831                 }
 832                 args += 3;
 833                 continue;
 834             }
 835             break;
 836         default:
 837             break;
 838         }
 839
 840         /* Simplify expression for "op r, a, a => movi r, 0" cases */
 841         switch (op) {
 842         CASE_OP_32_64(sub):
 843         CASE_OP_32_64(xor):
 844             if (temps_are_copies(args[1], args[2])) {
 845                 s->gen_opc_buf[op_index] = op_to_movi(op);
 846                 tcg_opt_gen_movi(gen_args, args[0], 0);
 847                 gen_args += 2;
 848                 args += 3;
 849                 continue;
 850             }
 851             break;
 852         default:
 853             break;
 854         }
 855
 856         /* Propagate constants through copy operations and do constant
 857            folding.  Constants will be substituted to arguments by register
 858            allocator where needed and possible.  Also detect copies. */
 859         switch (op) {
 860         CASE_OP_32_64(mov):
 861             if (temps_are_copies(args[0], args[1])) {
 862                 args += 2;
 863                 s->gen_opc_buf[op_index] = INDEX_op_nop;
 864                 break;
 865             }
 866             if (temps[args[1]].state != TCG_TEMP_CONST) {
 867                 tcg_opt_gen_mov(s, gen_args, args[0], args[1]);
 868                 gen_args += 2;
 869                 args += 2;
 870                 break;
 871             }
 872             /* Source argument is constant.  Rewrite the operation and
 873                let movi case handle it. */
 874             op = op_to_movi(op);
 875             s->gen_opc_buf[op_index] = op;
 876             args[1] = temps[args[1]].val;
 877             /* fallthrough */
 878         CASE_OP_32_64(movi):
 879             tcg_opt_gen_movi(gen_args, args[0], args[1]);
 880             gen_args += 2;
 881             args += 2;
 882             break;
 883
 884         CASE_OP_32_64(not):
 885         CASE_OP_32_64(neg):
 886         CASE_OP_32_64(ext8s):
 887         CASE_OP_32_64(ext8u):
 888         CASE_OP_32_64(ext16s):
 889         CASE_OP_32_64(ext16u):
 890         case INDEX_op_ext32s_i64:
 891         case INDEX_op_ext32u_i64:
 892             if (temps[args[1]].state == TCG_TEMP_CONST) {
 893                 s->gen_opc_buf[op_index] = op_to_movi(op);
 894                 tmp = do_constant_folding(op, temps[args[1]].val, 0);
 895                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 896                 gen_args += 2;
 897                 args += 2;
 898                 break;
 899             }
 900             goto do_default;
 901
 902         CASE_OP_32_64(add):
 903         CASE_OP_32_64(sub):
 904         CASE_OP_32_64(mul):
 905         CASE_OP_32_64(or):
 906         CASE_OP_32_64(and):
 907         CASE_OP_32_64(xor):
 908         CASE_OP_32_64(shl):
 909         CASE_OP_32_64(shr):
 910         CASE_OP_32_64(sar):
 911         CASE_OP_32_64(rotl):
 912         CASE_OP_32_64(rotr):
 913         CASE_OP_32_64(andc):
 914         CASE_OP_32_64(orc):
 915         CASE_OP_32_64(eqv):
 916         CASE_OP_32_64(nand):
 917         CASE_OP_32_64(nor):
 918         CASE_OP_32_64(muluh):
 919         CASE_OP_32_64(mulsh):
 920         CASE_OP_32_64(div):
 921         CASE_OP_32_64(divu):
 922         CASE_OP_32_64(rem):
 923         CASE_OP_32_64(remu):
 924             if (temps[args[1]].state == TCG_TEMP_CONST
 925                 && temps[args[2]].state == TCG_TEMP_CONST) {
 926                 s->gen_opc_buf[op_index] = op_to_movi(op);
 927                 tmp = do_constant_folding(op, temps[args[1]].val,
 928                                           temps[args[2]].val);
 929                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 930                 gen_args += 2;
 931                 args += 3;
 932                 break;
 933             }
 934             goto do_default;
 935
 936         CASE_OP_32_64(deposit):
 937             if (temps[args[1]].state == TCG_TEMP_CONST
 938                 && temps[args[2]].state == TCG_TEMP_CONST) {
 939                 s->gen_opc_buf[op_index] = op_to_movi(op);
 940                 tmp = ((1ull << args[4]) - 1);
 941                 tmp = (temps[args[1]].val & ~(tmp << args[3]))
 942                       | ((temps[args[2]].val & tmp) << args[3]);
 943                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 944                 gen_args += 2;
 945                 args += 5;
 946                 break;
 947             }
 948             goto do_default;
 949
 950         CASE_OP_32_64(setcond):
 951             tmp = do_constant_folding_cond(op, args[1], args[2], args[3]);
 952             if (tmp != 2) {
 953                 s->gen_opc_buf[op_index] = op_to_movi(op);
 954                 tcg_opt_gen_movi(gen_args, args[0], tmp);
 955                 gen_args += 2;
 956                 args += 4;
 957                 break;
 958             }
 959             goto do_default;
 960
 961         CASE_OP_32_64(brcond):
 962             tmp = do_constant_folding_cond(op, args[0], args[1], args[2]);
 963             if (tmp != 2) {
 964                 if (tmp) {
 965                     reset_all_temps(nb_temps);
 966                     s->gen_opc_buf[op_index] = INDEX_op_br;
 967                     gen_args[0] = args[3];
 968                     gen_args += 1;
 969                 } else {
 970                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 971                 }
 972                 args += 4;
 973                 break;
 974             }
 975             goto do_default;
 976
 977         CASE_OP_32_64(movcond):
 978             tmp = do_constant_folding_cond(op, args[1], args[2], args[5]);
 979             if (tmp != 2) {
 980                 if (temps_are_copies(args[0], args[4-tmp])) {
 981                     s->gen_opc_buf[op_index] = INDEX_op_nop;
 982                 } else if (temps[args[4-tmp]].state == TCG_TEMP_CONST) {
 983                     s->gen_opc_buf[op_index] = op_to_movi(op);
 984                     tcg_opt_gen_movi(gen_args, args[0], temps[args[4-tmp]].val);
 985                     gen_args += 2;
 986                 } else {
 987                     s->gen_opc_buf[op_index] = op_to_mov(op);
 988                     tcg_opt_gen_mov(s, gen_args, args[0], args[4-tmp]);
 989                     gen_args += 2;
 990                 }
 991                 args += 6;
 992                 break;
 993             }
 994             goto do_default;
 995
 996         case INDEX_op_add2_i32:
 997         case INDEX_op_sub2_i32:
 998             if (temps[args[2]].state == TCG_TEMP_CONST
 999                 && temps[args[3]].state == TCG_TEMP_CONST
1000                 && temps[args[4]].state == TCG_TEMP_CONST
1001                 && temps[args[5]].state == TCG_TEMP_CONST) {
1002                 uint32_t al = temps[args[2]].val;
1003                 uint32_t ah = temps[args[3]].val;
1004                 uint32_t bl = temps[args[4]].val;
1005                 uint32_t bh = temps[args[5]].val;
1006                 uint64_t a = ((uint64_t)ah << 32) | al;
1007                 uint64_t b = ((uint64_t)bh << 32) | bl;
1008                 TCGArg rl, rh;
1009
1010                 if (op == INDEX_op_add2_i32) {
1011                     a += b;
1012                 } else {
1013                     a -= b;
1014                 }
1015
1016                 /* We emit the extra nop when we emit the add2/sub2.  */
1017                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
1018
1019                 rl = args[0];
1020                 rh = args[1];
1021                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1022                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
1023                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)a);
1024                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(a >> 32));
1025                 gen_args += 4;
1026                 args += 6;
1027                 break;
1028             }
1029             goto do_default;
1030
1031         case INDEX_op_mulu2_i32:
1032             if (temps[args[2]].state == TCG_TEMP_CONST
1033                 && temps[args[3]].state == TCG_TEMP_CONST) {
1034                 uint32_t a = temps[args[2]].val;
1035                 uint32_t b = temps[args[3]].val;
1036                 uint64_t r = (uint64_t)a * b;
1037                 TCGArg rl, rh;
1038
1039                 /* We emit the extra nop when we emit the mulu2.  */
1040                 assert(s->gen_opc_buf[op_index + 1] == INDEX_op_nop);
1041
1042                 rl = args[0];
1043                 rh = args[1];
1044                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1045                 s->gen_opc_buf[++op_index] = INDEX_op_movi_i32;
1046                 tcg_opt_gen_movi(&gen_args[0], rl, (uint32_t)r);
1047                 tcg_opt_gen_movi(&gen_args[2], rh, (uint32_t)(r >> 32));
1048                 gen_args += 4;
1049                 args += 4;
1050                 break;
1051             }
1052             goto do_default;
1053
1054         case INDEX_op_brcond2_i32:
1055             tmp = do_constant_folding_cond2(&args[0], &args[2], args[4]);
1056             if (tmp != 2) {
1057                 if (tmp) {
1058                     reset_all_temps(nb_temps);
1059                     s->gen_opc_buf[op_index] = INDEX_op_br;
1060                     gen_args[0] = args[5];
1061                     gen_args += 1;
1062                 } else {
1063                     s->gen_opc_buf[op_index] = INDEX_op_nop;
1064                 }
1065             } else if ((args[4] == TCG_COND_LT || args[4] == TCG_COND_GE)
1066                        && temps[args[2]].state == TCG_TEMP_CONST
1067                        && temps[args[3]].state == TCG_TEMP_CONST
1068                        && temps[args[2]].val == 0
1069                        && temps[args[3]].val == 0) {
1070                 /* Simplify LT/GE comparisons vs zero to a single compare
1071                    vs the high word of the input.  */
1072                 reset_all_temps(nb_temps);
1073                 s->gen_opc_buf[op_index] = INDEX_op_brcond_i32;
1074                 gen_args[0] = args[1];
1075                 gen_args[1] = args[3];
1076                 gen_args[2] = args[4];
1077                 gen_args[3] = args[5];
1078                 gen_args += 4;
1079             } else {
1080                 goto do_default;
1081             }
1082             args += 6;
1083             break;
1084
1085         case INDEX_op_setcond2_i32:
1086             tmp = do_constant_folding_cond2(&args[1], &args[3], args[5]);
1087             if (tmp != 2) {
1088                 s->gen_opc_buf[op_index] = INDEX_op_movi_i32;
1089                 tcg_opt_gen_movi(gen_args, args[0], tmp);
1090                 gen_args += 2;
1091             } else if ((args[5] == TCG_COND_LT || args[5] == TCG_COND_GE)
1092                        && temps[args[3]].state == TCG_TEMP_CONST
1093                        && temps[args[4]].state == TCG_TEMP_CONST
1094                        && temps[args[3]].val == 0
1095                        && temps[args[4]].val == 0) {
1096                 /* Simplify LT/GE comparisons vs zero to a single compare
1097                    vs the high word of the input.  */
1098                 s->gen_opc_buf[op_index] = INDEX_op_setcond_i32;
1099                 reset_temp(args[0]);
1100                 gen_args[0] = args[0];
1101                 gen_args[1] = args[2];
1102                 gen_args[2] = args[4];
1103                 gen_args[3] = args[5];
1104                 gen_args += 4;
1105             } else {
1106                 goto do_default;
1107             }
1108             args += 6;
1109             break;
1110
1111         case INDEX_op_call:
1112             nb_call_args = (args[0] >> 16) + (args[0] & 0xffff);
1113             if (!(args[nb_call_args + 1] & (TCG_CALL_NO_READ_GLOBALS |
1114                                             TCG_CALL_NO_WRITE_GLOBALS))) {
1115                 for (i = 0; i < nb_globals; i++) {
1116                     reset_temp(i);
1117                 }
1118             }
1119             for (i = 0; i < (args[0] >> 16); i++) {
1120                 reset_temp(args[i + 1]);
1121             }
1122             i = nb_call_args + 3;
1123             while (i) {
1124                 *gen_args = *args;
1125                 args++;
1126                 gen_args++;
1127                 i--;
1128             }
1129             break;
1130
1131         default:
1132         do_default:
1133             /* Default case: we know nothing about operation (or were unable
1134                to compute the operation result) so no propagation is done.
1135                We trash everything if the operation is the end of a basic
1136                block, otherwise we only trash the output args.  "mask" is
1137                the non-zero bits mask for the first output arg.  */
1138             if (def->flags & TCG_OPF_BB_END) {
1139                 reset_all_temps(nb_temps);
1140             } else {
1141                 for (i = 0; i < def->nb_oargs; i++) {
1142                     reset_temp(args[i]);
1143                 }
1144             }
1145             for (i = 0; i < def->nb_args; i++) {
1146                 gen_args[i] = args[i];
1147             }
1148             args += def->nb_args;
1149             gen_args += def->nb_args;
1150             break;
1151         }
1152     }
1153
1154     return gen_args;
1155 }
1156
1157 TCGArg *tcg_optimize(TCGContext *s, uint16_t *tcg_opc_ptr,
1158         TCGArg *args, TCGOpDef *tcg_op_defs)
1159 {
1160     TCGArg *res;
1161     res = tcg_constant_folding(s, tcg_opc_ptr, args, tcg_op_defs);
1162     return res;
1163 }