gcc/bc-optab.c

   1 /* Bytecode conversion definitions for GNU C-compiler.
   2    Copyright (C) 1993, 1994 Free Software Foundation, Inc.
   3
   4 This file is part of GNU CC.
   5
   6 GNU CC is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU CC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU CC; see the file COPYING.  If not, write to
  18 the Free Software Foundation, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include "config.h"
  23 #include "tree.h"
  24 #include "rtl.h"
  25 #include "machmode.h"
  26 #include "obstack.h"
  27 #include "bytecode.h"
  28 #include "bc-typecd.h"
  29 #include "bc-opcode.h"
  30 #include "bc-optab.h"
  31
  32 #define obstack_chunk_alloc xmalloc
  33 #define obstack_chunk_free free
  34
  35 extern char *xmalloc ();
  36 extern void free ();
  37
  38 /* Table relating interpreter typecodes to machine modes.  */
  39 #define GET_TYPECODE_MODE(CODE) (typecode_mode[((int) CODE)])
  40 enum machine_mode typecode_mode[] = {
  41 #define DEFTYPECODE(CODE, NAME, MODE, TYPE) MODE,
  42 #include "bc-typecd.def"
  43 #undef DEFTYPECODE
  44 };
  45
  46 /* Machine mode to type code map */
  47 static enum typecode signed_mode_to_code_map[MAX_MACHINE_MODE+1];
  48 static enum typecode unsigned_mode_to_code_map[MAX_MACHINE_MODE+1];
  49
  50 #define GET_TYPECODE_SIZE(CODE) GET_MODE_SIZE (GET_TYPECODE_MODE (CODE))
  51
  52 #define BIG_ARBITRARY_NUMBER 100000
  53
  54 /* Table of recipes for conversions among scalar types, to be filled
  55    in as needed at run time.  */
  56 static struct conversion_recipe
  57 {
  58   unsigned char *opcodes;       /* Bytecodes to emit in order.  */
  59   int nopcodes;                 /* Count of bytecodes. */
  60   int cost;                     /* A rather arbitrary cost function. */
  61 } conversion_recipe[NUM_TYPECODES][NUM_TYPECODES];
  62
  63 /* Binary operator tables.  */
  64 struct binary_operator optab_plus_expr[] = {
  65   { addSI, SIcode, SIcode, SIcode },
  66   { addDI, DIcode, DIcode, DIcode },
  67   { addSF, SFcode, SFcode, SFcode },
  68   { addDF, DFcode, DFcode, DFcode },
  69   { addXF, XFcode, XFcode, XFcode },
  70   { addPSI, Pcode, Pcode, SIcode },
  71   { -1, -1, -1, -1 },
  72 };
  73
  74 struct binary_operator optab_minus_expr[] = {
  75   { subSI, SIcode, SIcode, SIcode },
  76   { subDI, DIcode, DIcode, DIcode },
  77   { subSF, SFcode, SFcode, SFcode },
  78   { subDF, DFcode, DFcode, DFcode },
  79   { subXF, XFcode, XFcode, XFcode },
  80   { subPP, SIcode, Pcode, Pcode },
  81   { -1, -1, -1, -1 },
  82 };
  83
  84 /* The ordering of the tables for multiplicative operators
  85    is such that unsigned operations will be preferred to signed
  86    operations when one argument is unsigned.  */
  87
  88 struct binary_operator optab_mult_expr[] = {
  89   { mulSU, SUcode, SUcode, SUcode },
  90   { mulDU, DUcode, DUcode, DUcode },
  91   { mulSI, SIcode, SIcode, SIcode },
  92   { mulDI, DIcode, DIcode, DIcode },
  93   { mulSF, SFcode, SFcode, SFcode },
  94   { mulDF, DFcode, DFcode, DFcode },
  95   { mulXF, XFcode, XFcode, XFcode },
  96   { -1, -1, -1, -1 },
  97 };
  98
  99 struct binary_operator optab_trunc_div_expr[] = {
 100   { divSU, SUcode, SUcode, SUcode },
 101   { divDU, DUcode, DUcode, DUcode },
 102   { divSI, SIcode, SIcode, SIcode },
 103   { divDI, DIcode, DIcode, DIcode },
 104   { -1, -1, -1, -1 },
 105 };
 106
 107 struct binary_operator optab_trunc_mod_expr[] = {
 108   { modSU, SUcode, SUcode, SUcode },
 109   { modDU, DUcode, DUcode, DUcode },
 110   { modSI, SIcode, SIcode, SIcode },
 111   { modDI, DIcode, DIcode, DIcode },
 112   { -1, -1, -1, -1 },
 113 };
 114
 115 struct binary_operator optab_rdiv_expr[] = {
 116   { divSF, SFcode, SFcode, SFcode },
 117   { divDF, DFcode, DFcode, DFcode },
 118   { divXF, XFcode, XFcode, XFcode },
 119   { -1, -1, -1, -1 },
 120 };
 121
 122 struct binary_operator optab_bit_and_expr[] = {
 123   { andSI, SIcode, SIcode, SIcode },
 124   { andDI, DIcode, DIcode, DIcode },
 125   { -1, -1, -1, -1 },
 126 };
 127
 128 struct binary_operator optab_bit_ior_expr[] = {
 129   { iorSI, SIcode, SIcode, SIcode },
 130   { iorDI, DIcode, DIcode, DIcode },
 131   { -1, -1, -1, -1 },
 132 };
 133
 134 struct binary_operator optab_bit_xor_expr[] = {
 135   { xorSI, SIcode, SIcode, SIcode },
 136   { xorDI, DIcode, DIcode, DIcode },
 137   { -1, -1, -1, -1 },
 138 };
 139
 140 struct binary_operator optab_lshift_expr[] = {
 141   { lshiftSI, SIcode, SIcode, SIcode },
 142   { lshiftSU, SUcode, SUcode, SIcode },
 143   { lshiftDI, DIcode, DIcode, SIcode },
 144   { lshiftDU, DUcode, DUcode, SIcode },
 145   { -1, -1, -1, -1 },
 146 };
 147
 148 struct binary_operator optab_rshift_expr[] = {
 149   { rshiftSI, SIcode, SIcode, SIcode },
 150   { rshiftSU, SUcode, SUcode, SIcode },
 151   { rshiftDI, DIcode, DIcode, SIcode },
 152   { rshiftDU, DUcode, DUcode, SIcode },
 153   { -1, -1, -1, -1 },
 154 };
 155
 156 struct binary_operator optab_truth_and_expr[] = {
 157   { andSI, SIcode, Tcode, Tcode },
 158   { -1, -1, -1, -1 },
 159 };
 160
 161 struct binary_operator optab_truth_or_expr[] = {
 162   { iorSI, SIcode, Tcode, Tcode },
 163   { -1, -1, -1, -1 },
 164 };
 165
 166 struct binary_operator optab_lt_expr[] = {
 167   { ltSI, Tcode, SIcode, SIcode },
 168   { ltSU, Tcode, SUcode, SUcode },
 169   { ltDI, Tcode, DIcode, DIcode },
 170   { ltDU, Tcode, DUcode, DUcode },
 171   { ltSF, Tcode, SFcode, SFcode },
 172   { ltDF, Tcode, DFcode, DFcode },
 173   { ltXF, Tcode, XFcode, XFcode },
 174   { ltP, Tcode, Pcode, Pcode },
 175   { -1, -1, -1, -1 },
 176 };
 177
 178 struct binary_operator optab_le_expr[] = {
 179   { leSI, Tcode, SIcode, SIcode },
 180   { leSU, Tcode, SUcode, SUcode },
 181   { leDI, Tcode, DIcode, DIcode },
 182   { leDU, Tcode, DUcode, DUcode },
 183   { leSF, Tcode, SFcode, SFcode },
 184   { leDF, Tcode, DFcode, DFcode },
 185   { leXF, Tcode, XFcode, XFcode },
 186   { leP, Tcode, Pcode, Pcode },
 187   { -1, -1, -1, -1 },
 188 };
 189
 190 struct binary_operator optab_ge_expr[] = {
 191   { geSI, Tcode, SIcode, SIcode },
 192   { geSU, Tcode, SUcode, SUcode },
 193   { geDI, Tcode, DIcode, DIcode },
 194   { geDU, Tcode, DUcode, DUcode },
 195   { geSF, Tcode, SFcode, SFcode },
 196   { geDF, Tcode, DFcode, DFcode },
 197   { geXF, Tcode, XFcode, XFcode },
 198   { geP, Tcode, Pcode, Pcode },
 199   { -1, -1, -1, -1 },
 200 };
 201
 202 struct binary_operator optab_gt_expr[] = {
 203   { gtSI, Tcode, SIcode, SIcode },
 204   { gtSU, Tcode, SUcode, SUcode },
 205   { gtDI, Tcode, DIcode, DIcode },
 206   { gtDU, Tcode, DUcode, DUcode },
 207   { gtSF, Tcode, SFcode, SFcode },
 208   { gtDF, Tcode, DFcode, DFcode },
 209   { gtXF, Tcode, XFcode, XFcode },
 210   { gtP, Tcode, Pcode, Pcode },
 211   { -1, -1, -1, -1 },
 212 };
 213
 214 struct binary_operator optab_eq_expr[] = {
 215   { eqSI, Tcode, SIcode, SIcode },
 216   { eqDI, Tcode, DIcode, DIcode },
 217   { eqSF, Tcode, SFcode, SFcode },
 218   { eqDF, Tcode, DFcode, DFcode },
 219   { eqXF, Tcode, XFcode, XFcode },
 220   { eqP, Tcode, Pcode, Pcode },
 221   { -1, -1, -1, -1 },
 222 };
 223
 224 struct binary_operator optab_ne_expr[] = {
 225   { neSI, Tcode, SIcode, SIcode },
 226   { neDI, Tcode, DIcode, DIcode },
 227   { neSF, Tcode, SFcode, SFcode },
 228   { neDF, Tcode, DFcode, DFcode },
 229   { neXF, Tcode, XFcode, XFcode },
 230   { neP, Tcode, Pcode, Pcode },
 231   { -1, -1, -1, -1 },
 232 };
 233
 234 /* Unary operator tables.  */
 235 struct unary_operator optab_negate_expr[] = {
 236   { negSI, SIcode, SIcode },
 237   { negDI, DIcode, DIcode },
 238   { negSF, SFcode, SFcode },
 239   { negDF, DFcode, DFcode },
 240   { negXF, XFcode, XFcode },
 241   { -1, -1, -1 },
 242 };
 243
 244 struct unary_operator optab_bit_not_expr[] = {
 245   { notSI, SIcode, SIcode },
 246   { notDI, DIcode, DIcode },
 247   { -1, -1, -1 },
 248 };
 249
 250 struct unary_operator optab_truth_not_expr[] = {
 251   { notT, SIcode, SIcode },
 252   { -1, -1, -1 },
 253 };
 254
 255 /* Increment operator tables.  */
 256 struct increment_operator optab_predecrement_expr[] = {
 257   { predecQI, QIcode },
 258   { predecQI, QUcode },
 259   { predecHI, HIcode },
 260   { predecHI, HUcode },
 261   { predecSI, SIcode },
 262   { predecSI, SUcode },
 263   { predecDI, DIcode },
 264   { predecDI, DUcode },
 265   { predecP, Pcode },
 266   { predecSF, SFcode },
 267   { predecDF, DFcode },
 268   { predecXF, XFcode },
 269   { -1, -1 },
 270 };
 271
 272 struct increment_operator optab_preincrement_expr[] = {
 273   { preincQI, QIcode },
 274   { preincQI, QUcode },
 275   { preincHI, HIcode },
 276   { preincHI, HUcode },
 277   { preincSI, SIcode },
 278   { preincSI, SUcode },
 279   { preincDI, DIcode },
 280   { preincDI, DUcode },
 281   { preincP, Pcode },
 282   { preincSF, SFcode },
 283   { preincDF, DFcode },
 284   { preincXF, XFcode },
 285   { -1, -1 },
 286 };
 287
 288 struct increment_operator optab_postdecrement_expr[] = {
 289   { postdecQI, QIcode },
 290   { postdecQI, QUcode },
 291   { postdecHI, HIcode },
 292   { postdecHI, HUcode },
 293   { postdecSI, SIcode },
 294   { postdecSI, SUcode },
 295   { postdecDI, DIcode },
 296   { postdecDI, DUcode },
 297   { postdecP, Pcode },
 298   { postdecSF, SFcode },
 299   { postdecDF, DFcode },
 300   { postdecXF, XFcode },
 301   { -1, -1 },
 302 };
 303
 304 struct increment_operator optab_postincrement_expr[] = {
 305   { postincQI, QIcode },
 306   { postincQI, QUcode },
 307   { postincHI, HIcode },
 308   { postincHI, HUcode },
 309   { postincSI, SIcode },
 310   { postincSI, SUcode },
 311   { postincDI, DIcode },
 312   { postincDI, DUcode },
 313   { postincP, Pcode },
 314   { postincSF, SFcode },
 315   { postincDF, DFcode },
 316   { postincXF, XFcode },
 317   { -1, -1 },
 318 };
 319
 320 /* Table of conversions supported by the interpreter.  */
 321 static struct conversion_info
 322 {
 323   enum bytecode_opcode opcode;  /*  here indicates the conversion needs no opcode.  */
 324   enum typecode from;
 325   enum typecode to;
 326   int cost;                     /* 1 for no-op conversions, 2 for widening conversions,
 327                                    4 for int/float conversions, 8 for narrowing conversions.  */
 328 } conversion_info[] = {
 329   { -1, QIcode, QUcode, 1 },
 330   { -1, HIcode, HUcode, 1 },
 331   { -1, SIcode, SUcode, 1 },
 332   { -1, DIcode, DUcode, 1 },
 333   { -1, QUcode, QIcode, 1 },
 334   { -1, HUcode, HIcode, 1 },
 335   { -1, SUcode, SIcode, 1 },
 336   { -1, DUcode, DIcode, 1 },
 337   { -1, Tcode, SIcode, 1 },
 338   { convertQIHI, QIcode, HIcode, 2 },
 339   { convertQUHU, QUcode, HUcode, 2 },
 340   { convertQUSU, QUcode, SUcode, 2 },
 341   { convertHISI, HIcode, SIcode, 2 },
 342   { convertHUSU, HUcode, SUcode, 2 },
 343   { convertSIDI, SIcode, DIcode, 2 },
 344   { convertSUDU, SUcode, DUcode, 2 },
 345   { convertSFDF, SFcode, DFcode, 2 },
 346   { convertDFXF, DFcode, XFcode, 2 },
 347   { convertHIQI, HIcode, QIcode, 8 },
 348   { convertSIQI, SIcode, QIcode, 8 },
 349   { convertSIHI, SIcode, HIcode, 8 },
 350   { convertSUQU, SUcode, QUcode, 8 },
 351   { convertDISI, DIcode, SIcode, 8 },
 352   { convertDFSF, DFcode, SFcode, 8 },
 353   { convertXFDF, XFcode, DFcode, 8 },
 354   { convertPSI, Pcode, SIcode, 2 },
 355   { convertSIP, SIcode, Pcode, 2 },
 356   { convertSIT, SIcode, Tcode, 2 },
 357   { convertDIT, DIcode, Tcode, 2 },
 358   { convertSFT, SFcode, Tcode, 2 },
 359   { convertDFT, DFcode, Tcode, 2 },
 360   { convertXFT, XFcode, Tcode, 2 },
 361   { convertQISI, QIcode, SIcode, 2 },
 362   { convertPT, Pcode, Tcode, 2 },
 363   { convertSISF, SIcode, SFcode, 4 },
 364   { convertSIDF, SIcode, DFcode, 4 },
 365   { convertSIXF, SIcode, XFcode, 4 },
 366   { convertSUSF, SUcode, SFcode, 4 },
 367   { convertSUDF, SUcode, DFcode, 4 },
 368   { convertSUXF, SUcode, XFcode, 4 },
 369   { convertDISF, DIcode, SFcode, 4 },
 370   { convertDIDF, DIcode, DFcode, 4 },
 371   { convertDIXF, DIcode, XFcode, 4 },
 372   { convertDUSF, DUcode, SFcode, 4 },
 373   { convertDUDF, DUcode, DFcode, 4 },
 374   { convertDUXF, DUcode, XFcode, 4 },
 375   { convertSFSI, SFcode, SIcode, 4 },
 376   { convertDFSI, DFcode, SIcode, 4 },
 377   { convertXFSI, XFcode, SIcode, 4 },
 378   { convertSFSU, SFcode, SUcode, 4 },
 379   { convertDFSU, DFcode, SUcode, 4 },
 380   { convertXFSU, XFcode, SUcode, 4 },
 381   { convertSFDI, SFcode, DIcode, 4 },
 382   { convertDFDI, DFcode, DIcode, 4 },
 383   { convertXFDI, XFcode, DIcode, 4 },
 384   { convertSFDU, SFcode, DUcode, 4 },
 385   { convertDFDU, DFcode, DUcode, 4 },
 386   { convertXFDU, XFcode, DUcode, 4 },
 387   { convertSIQI, SIcode, QIcode, 8 },
 388 };
 389
 390 #define NUM_CONVERSIONS (sizeof conversion_info / sizeof (struct conversion_info))
 391
 392 /* List form of a conversion recipe.  */
 393 struct conversion_list
 394 {
 395   enum bytecode_opcode opcode;
 396   enum typecode to;
 397   int cost;
 398   struct conversion_list *prev;
 399 };
 400
 401 /* Determine if it is "reasonable" to add a given conversion to
 402    a given list of conversions.  The following criteria define
 403    "reasonable" conversion lists:
 404    * No typecode appears more than once in the sequence (no loops).
 405    * At most one conversion from integer to float or vice versa is present.
 406    * Either sign extensions or zero extensions may be present, but not both.
 407    * No widening conversions occur after a signed/unsigned conversion.
 408    * The sequence of sizes must be strict nonincreasing or nondecreasing.  */
 409 static int
 410 conversion_reasonable_p (conversion, list)
 411      struct conversion_info *conversion;
 412      struct conversion_list *list;
 413 {
 414   struct conversion_list *curr;
 415   int curr_size, prev_size;
 416   int has_int_float, has_float_int;
 417   int has_sign_extend, has_zero_extend;
 418   int has_signed_unsigned, has_unsigned_signed;
 419
 420   has_int_float = 0;
 421   has_float_int = 0;
 422   has_sign_extend = 0;
 423   has_zero_extend = 0;
 424   has_signed_unsigned = 0;
 425   has_unsigned_signed = 0;
 426
 427   /* Make sure the destination typecode doesn't already appear in
 428      the list.  */
 429   for (curr = list; curr; curr = curr->prev)
 430     if (conversion->to == curr->to)
 431       return 0;
 432
 433   /* Check for certain kinds of conversions.  */
 434   if (TYPECODE_INTEGER_P (conversion->from)
 435       && TYPECODE_FLOAT_P (conversion->to))
 436     has_int_float = 1;
 437   if (TYPECODE_FLOAT_P (conversion->from)
 438       && TYPECODE_INTEGER_P (conversion->to))
 439     has_float_int = 1;
 440   if (TYPECODE_SIGNED_P (conversion->from)
 441       && TYPECODE_SIGNED_P (conversion->to)
 442       && GET_TYPECODE_SIZE (conversion->from)
 443       < GET_TYPECODE_SIZE (conversion->to))
 444     has_sign_extend = 1;
 445   if (TYPECODE_UNSIGNED_P (conversion->from)
 446       && TYPECODE_UNSIGNED_P (conversion->to)
 447       && GET_TYPECODE_SIZE (conversion->from)
 448       < GET_TYPECODE_SIZE (conversion->to))
 449     has_zero_extend = 1;
 450
 451   for (curr = list; curr && curr->prev; curr = curr->prev)
 452     {
 453       if (TYPECODE_INTEGER_P (curr->prev->to)
 454           && TYPECODE_FLOAT_P (curr->to))
 455         has_int_float = 1;
 456       if (TYPECODE_FLOAT_P (curr->prev->to)
 457           && TYPECODE_INTEGER_P (curr->to))
 458         has_float_int = 1;
 459       if (TYPECODE_SIGNED_P (curr->prev->to)
 460           && TYPECODE_SIGNED_P (curr->to)
 461           && GET_TYPECODE_SIZE (curr->prev->to)
 462           < GET_TYPECODE_SIZE (curr->to))
 463         has_sign_extend = 1;
 464       if (TYPECODE_UNSIGNED_P (curr->prev->to)
 465           && TYPECODE_UNSIGNED_P (curr->to)
 466           && GET_TYPECODE_SIZE (curr->prev->to)
 467           < GET_TYPECODE_SIZE (curr->to))
 468         has_zero_extend = 1;
 469       if (TYPECODE_SIGNED_P (curr->prev->to)
 470           && TYPECODE_UNSIGNED_P (curr->to))
 471         has_signed_unsigned = 1;
 472       if (TYPECODE_UNSIGNED_P (curr->prev->to)
 473           && TYPECODE_SIGNED_P (curr->to))
 474         has_unsigned_signed = 1;
 475     }
 476
 477   if (TYPECODE_INTEGER_P (conversion->from)
 478       && TYPECODE_INTEGER_P (conversion->to)
 479       && GET_TYPECODE_SIZE (conversion->to)
 480       > GET_TYPECODE_SIZE (conversion->from)
 481       && (has_signed_unsigned || has_unsigned_signed))
 482     return 0;
 483
 484   if (has_float_int && has_int_float || has_sign_extend && has_zero_extend)
 485     return 0;
 486
 487   /* Make sure the sequence of destination typecode sizes is
 488      strictly nondecreasing or strictly nonincreasing.  */
 489   prev_size = GET_TYPECODE_SIZE (conversion->to);
 490   for (curr = list; curr; curr = curr->prev)
 491     {
 492       curr_size = GET_TYPECODE_SIZE (curr->to);
 493       if (curr_size != prev_size)
 494         break;
 495     }
 496   if (!curr)
 497     return 1;
 498
 499   if (curr_size < prev_size)
 500     for (prev_size = curr_size; curr; curr = curr->prev)
 501       {
 502         curr_size = GET_TYPECODE_SIZE (curr->to);
 503         if (curr_size > prev_size)
 504           return 0;
 505         prev_size = curr_size;
 506       }
 507   else
 508     for (prev_size = curr_size; curr; curr = curr->prev)
 509       {
 510         curr_size = GET_TYPECODE_SIZE (curr->to);
 511         if (curr_size < prev_size)
 512           return 0;
 513         prev_size = curr_size;
 514       }
 515   return 1;
 516 }
 517
 518
 519 /* Exhaustively search all reasonable conversions to find one to
 520    convert the given types.  */
 521 static struct conversion_recipe
 522 deduce_conversion (from, to)
 523      enum typecode from, to;
 524 {
 525   struct rl
 526     {
 527       struct conversion_list *list;
 528       struct rl *next;
 529     } *prev, curr, *good, *temp;
 530   struct conversion_list *conv, *best;
 531   int i, cost, bestcost;
 532   struct conversion_recipe result;
 533   struct obstack recipe_obstack;
 534
 535
 536   obstack_init (&recipe_obstack);
 537   curr.next = (struct rl *) obstack_alloc (&recipe_obstack, sizeof (struct rl));
 538   curr.next->list =
 539     (struct conversion_list *) obstack_alloc (&recipe_obstack,
 540                                               sizeof (struct conversion_list));
 541   curr.next->list->opcode = -1;
 542   curr.next->list->to = from;
 543   curr.next->list->cost = 0;
 544   curr.next->list->prev = 0;
 545   curr.next->next = 0;
 546   good = 0;
 547
 548   while (curr.next)
 549     {
 550       /* Remove successful conversions from further consideration.  */
 551       for (prev = &curr; prev; prev = prev->next)
 552         if (prev->next && prev->next->list->to == to)
 553           {
 554             temp = prev->next->next;
 555             prev->next->next = good;
 556             good = prev->next;
 557             prev->next = temp;
 558           }
 559
 560       /* Go through each of the pending conversion chains, trying
 561          all possible candidate conversions on them.  */
 562       for (prev = curr.next, curr.next = 0; prev; prev = prev->next)
 563         for (i = 0; i < NUM_CONVERSIONS; ++i)
 564           if (conversion_info[i].from == prev->list->to
 565               && conversion_reasonable_p (&conversion_info[i], prev->list))
 566             {
 567               temp = (struct rl *) obstack_alloc (&recipe_obstack,
 568                                                   sizeof (struct rl));
 569               temp->list = (struct conversion_list *)
 570                 obstack_alloc (&recipe_obstack,
 571                                sizeof (struct conversion_list));
 572               temp->list->opcode = conversion_info[i].opcode;
 573               temp->list->to = conversion_info[i].to;
 574               temp->list->cost = conversion_info[i].cost;
 575               temp->list->prev = prev->list;
 576               temp->next = curr.next;
 577               curr.next = temp;
 578             }
 579     }
 580
 581   bestcost = BIG_ARBITRARY_NUMBER;
 582   best = 0;
 583   for (temp = good; temp; temp = temp->next)
 584     {
 585       for (conv = temp->list, cost = 0; conv; conv = conv->prev)
 586         cost += conv->cost;
 587       if (cost < bestcost)
 588         {
 589           bestcost = cost;
 590           best = temp->list;
 591         }
 592     }
 593
 594   if (!best)
 595     abort ();
 596
 597   for (i = 0, conv = best; conv; conv = conv->prev)
 598     if (conv->opcode != -1)
 599       ++i;
 600
 601   result.opcodes = (unsigned char *) xmalloc (i);
 602   result.nopcodes = i;
 603   for (conv = best; conv; conv = conv->prev)
 604     if (conv->opcode != -1)
 605       result.opcodes[--i] = conv->opcode;
 606   result.cost = bestcost;
 607   obstack_free (&recipe_obstack, 0);
 608   return result;
 609 }
 610
 611 #define DEDUCE_CONVERSION(FROM, TO)                             \
 612   (conversion_recipe[(int) FROM][(int) TO].opcodes ? 0          \
 613    : (conversion_recipe[(int) FROM][(int) TO]                   \
 614        = deduce_conversion (FROM, TO), 0))
 615
 616
 617 /* Emit a conversion between the given scalar types.  */
 618 void
 619 emit_typecode_conversion (from, to)
 620      enum typecode from, to;
 621 {
 622   int i;
 623
 624   DEDUCE_CONVERSION (from, to);
 625   for (i = 0; i < conversion_recipe[(int) from][(int) to].nopcodes; ++i)
 626     bc_emit_instruction (conversion_recipe[(int) from][(int) to].opcodes[i]);
 627 }
 628
 629
 630 /* Initialize mode_to_code_map[] */
 631 void
 632 bc_init_mode_to_code_map ()
 633 {
 634   int mode;
 635
 636   for (mode = 0; mode < MAX_MACHINE_MODE + 1; mode++)
 637     {
 638       signed_mode_to_code_map[mode] =
 639         unsigned_mode_to_code_map[mode] =
 640           LAST_AND_UNUSED_TYPECODE;
 641     }
 642
 643 #define DEF_MODEMAP(SYM, CODE, UCODE, CONST, LOAD, STORE) \
 644   { signed_mode_to_code_map[(int) SYM] = CODE; \
 645     unsigned_mode_to_code_map[(int) SYM] = UCODE; }
 646 #include "modemap.def"
 647 #undef DEF_MODEMAP
 648
 649   /* Initialize opcode maps for const, load, and store */
 650   bc_init_mode_to_opcode_maps ();
 651 }
 652
 653 /* Given a machine mode return the preferred typecode.  */
 654 enum typecode
 655 preferred_typecode (mode, unsignedp)
 656      enum machine_mode mode;
 657      int unsignedp;
 658 {
 659   enum typecode code = (unsignedp
 660                         ? unsigned_mode_to_code_map
 661                         : signed_mode_to_code_map) [MIN ((int) mode,
 662                                                          (int) MAX_MACHINE_MODE)];
 663
 664   if (code == LAST_AND_UNUSED_TYPECODE)
 665     abort ();
 666
 667   return code;
 668 }
 669
 670
 671 /* Expand a conversion between the given types.  */
 672 void
 673 bc_expand_conversion (from, to)
 674      tree from, to;
 675 {
 676   enum typecode fcode, tcode;
 677
 678   fcode = preferred_typecode (TYPE_MODE (from), TREE_UNSIGNED (from));
 679   tcode = preferred_typecode (TYPE_MODE (to), TREE_UNSIGNED (to));
 680
 681   emit_typecode_conversion (fcode, tcode);
 682 }
 683
 684 /* Expand a conversion of the given type to a truth value.  */
 685 void
 686 bc_expand_truth_conversion (from)
 687      tree from;
 688 {
 689   enum typecode fcode;
 690
 691   fcode = preferred_typecode (TYPE_MODE (from), TREE_UNSIGNED (from));
 692   emit_typecode_conversion (fcode, Tcode);
 693 }
 694
 695 /* Emit an appropriate binary operation.  */
 696 void
 697 bc_expand_binary_operation (optab, resulttype, arg0, arg1)
 698      struct binary_operator optab[];
 699      tree resulttype, arg0, arg1;
 700 {
 701   int i, besti, cost, bestcost;
 702   enum typecode resultcode, arg0code, arg1code;
 703
 704   resultcode = preferred_typecode (TYPE_MODE (resulttype), TREE_UNSIGNED (resulttype));
 705   arg0code = preferred_typecode (TYPE_MODE (TREE_TYPE (arg0)), TREE_UNSIGNED (resulttype));
 706   arg1code = preferred_typecode (TYPE_MODE (TREE_TYPE (arg1)), TREE_UNSIGNED (resulttype));
 707
 708   besti = -1;
 709   bestcost = BIG_ARBITRARY_NUMBER;
 710
 711   for (i = 0; optab[i].opcode != -1; ++i)
 712     {
 713       cost = 0;
 714       DEDUCE_CONVERSION (arg0code, optab[i].arg0);
 715       cost += conversion_recipe[(int) arg0code][(int) optab[i].arg0].cost;
 716       DEDUCE_CONVERSION (arg1code, optab[i].arg1);
 717       cost += conversion_recipe[(int) arg1code][(int) optab[i].arg1].cost;
 718       if (cost < bestcost)
 719         {
 720           besti = i;
 721           bestcost = cost;
 722         }
 723     }
 724
 725   if (besti == -1)
 726     abort ();
 727
 728   expand_expr (arg1, 0, VOIDmode, 0);
 729   emit_typecode_conversion (arg1code, optab[besti].arg1);
 730   expand_expr (arg0, 0, VOIDmode, 0);
 731   emit_typecode_conversion (arg0code, optab[besti].arg0);
 732   bc_emit_instruction (optab[besti].opcode);
 733   emit_typecode_conversion (optab[besti].result, resultcode);
 734 }
 735
 736 /* Emit an appropriate unary operation.  */
 737 void
 738 bc_expand_unary_operation (optab, resulttype, arg0)
 739      struct unary_operator optab[];
 740      tree resulttype, arg0;
 741 {
 742   int i, besti, cost, bestcost;
 743   enum typecode resultcode, arg0code;
 744
 745   resultcode = preferred_typecode (TYPE_MODE (resulttype), TREE_UNSIGNED (resulttype));
 746   arg0code = preferred_typecode (TYPE_MODE (TREE_TYPE (arg0)), TREE_UNSIGNED (TREE_TYPE (arg0)));
 747
 748   besti = -1;
 749   bestcost = BIG_ARBITRARY_NUMBER;
 750
 751   for (i = 0; optab[i].opcode != -1; ++i)
 752     {
 753       DEDUCE_CONVERSION (arg0code, optab[i].arg0);
 754       cost = conversion_recipe[(int) arg0code][(int) optab[i].arg0].cost;
 755       if (cost < bestcost)
 756         {
 757           besti = i;
 758           bestcost = cost;
 759         }
 760     }
 761
 762   if (besti == -1)
 763     abort ();
 764
 765   expand_expr (arg0, 0, VOIDmode, 0);
 766   emit_typecode_conversion (arg0code, optab[besti].arg0);
 767   bc_emit_instruction (optab[besti].opcode);
 768   emit_typecode_conversion (optab[besti].result, resultcode);
 769 }
 770
 771
 772 /* Emit an appropriate increment.  */
 773 void
 774 bc_expand_increment (optab, type)
 775      struct increment_operator optab[];
 776      tree type;
 777 {
 778   enum typecode code;
 779   int i;
 780
 781   code = preferred_typecode (TYPE_MODE (type), TREE_UNSIGNED (type));
 782   for (i = 0; (int) optab[i].opcode >= 0; ++i)
 783     if (code == optab[i].arg)
 784       {
 785         bc_emit_instruction (optab[i].opcode);
 786         return;
 787       }
 788   abort ();
 789 }