gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992, 1997, 1998,
   3    1999, 2000 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  20 02111-1307, USA.  */
  21
  22
  23 #include "bconfig.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "rtl.h"
  28 #include "errors.h"
  29 #include "gensupport.h"
  30
  31
  32 /* While tree-walking an instruction pattern, we keep a chain
  33    of these `struct link's to record how to get down to the
  34    current position.  In each one, POS is the operand number,
  35    and if the operand is a vector VEC is the element number.
  36    VEC is -1 if the operand is not a vector.  */
  37
  38 struct link
  39 {
  40   struct link *next;
  41   int pos;
  42   int vecelt;
  43 };
  44
  45 static int max_opno;
  46
  47 /* Number of operands used in current peephole definition.  */
  48
  49 static int n_operands;
  50
  51 /* Peephole optimizations get insn codes just like insn patterns.
  52    Count them so we know the code of the define_peephole we are handling.  */
  53
  54 static int insn_code_number = 0;
  55
  56 static void gen_peephole PARAMS ((rtx));
  57 static void match_rtx PARAMS ((rtx, struct link *, int));
  58 static void print_path PARAMS ((struct link *));
  59 static void print_code PARAMS ((RTX_CODE));
  60 \f
  61 static void
  62 gen_peephole (peep)
  63      rtx peep;
  64 {
  65   int ninsns = XVECLEN (peep, 0);
  66   int i;
  67
  68   n_operands = 0;
  69
  70   printf ("  insn = ins1;\n");
  71 #if 0
  72   printf ("  want_jump = 0;\n");
  73 #endif
  74
  75   for (i = 0; i < ninsns; i++)
  76     {
  77       if (i > 0)
  78         {
  79           printf ("  do { insn = NEXT_INSN (insn);\n");
  80           printf ("       if (insn == 0) goto L%d; }\n",
  81                   insn_code_number);
  82           printf ("  while (GET_CODE (insn) == NOTE\n");
  83           printf ("\t || (GET_CODE (insn) == INSN\n");
  84           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  85           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  86
  87           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  88       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  89                   insn_code_number);
  90         }
  91
  92 #if 0
  93       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
  94       printf ("    want_jump = JUMP_LABEL (insn);\n");
  95 #endif
  96
  97       printf ("  pat = PATTERN (insn);\n");
  98
  99       /* Walk the insn's pattern, remembering at all times the path
 100          down to the walking point.  */
 101
 102       match_rtx (XVECEXP (peep, 0, i), NULL, insn_code_number);
 103     }
 104
 105   /* We get this far if the pattern matches.
 106      Now test the extra condition.  */
 107
 108   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 109     printf ("  if (! (%s)) goto L%d;\n",
 110             XSTR (peep, 1), insn_code_number);
 111
 112   /* If that matches, construct new pattern and put it in the first insn.
 113      This new pattern will never be matched.
 114      It exists only so that insn-extract can get the operands back.
 115      So use a simple regular form: a PARALLEL containing a vector
 116      of all the operands.  */
 117
 118   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 119
 120 #if 0
 121   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 122   printf ("    {\n");
 123   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 124   printf ("      delete_related_insns (ins1);\n");
 125   printf ("      ins1 = ins2;\n");
 126   printf ("    }\n");
 127 #endif
 128
 129   /* Record this define_peephole's insn code in the insn,
 130      as if it had been recognized to match this.  */
 131   printf ("  INSN_CODE (ins1) = %d;\n",
 132           insn_code_number);
 133
 134   /* Delete the remaining insns.  */
 135   if (ninsns > 1)
 136     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 137
 138   /* See reload1.c for insertion of NOTE which guarantees that this
 139      cannot be zero.  */
 140   printf ("  return NEXT_INSN (insn);\n");
 141
 142   printf (" L%d:\n\n", insn_code_number);
 143 }
 144 \f
 145 static void
 146 match_rtx (x, path, fail_label)
 147      rtx x;
 148      struct link *path;
 149      int fail_label;
 150 {
 151   RTX_CODE code;
 152   int i;
 153   int len;
 154   const char *fmt;
 155   struct link link;
 156
 157   if (x == 0)
 158     return;
 159
 160
 161   code = GET_CODE (x);
 162
 163   switch (code)
 164     {
 165     case MATCH_OPERAND:
 166       if (XINT (x, 0) > max_opno)
 167         max_opno = XINT (x, 0);
 168       if (XINT (x, 0) >= n_operands)
 169         n_operands = 1 + XINT (x, 0);
 170
 171       printf ("  x = ");
 172       print_path (path);
 173       printf (";\n");
 174
 175       printf ("  operands[%d] = x;\n", XINT (x, 0));
 176       if (XSTR (x, 1) && XSTR (x, 1)[0])
 177         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 178                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 179       return;
 180
 181     case MATCH_DUP:
 182     case MATCH_PAR_DUP:
 183       printf ("  x = ");
 184       print_path (path);
 185       printf (";\n");
 186
 187       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 188               XINT (x, 0), fail_label);
 189       return;
 190
 191     case MATCH_OP_DUP:
 192       printf ("  x = ");
 193       print_path (path);
 194       printf (";\n");
 195
 196       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 197       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 198               XINT (x, 0), fail_label);
 199       printf ("  operands[%d] = x;\n", XINT (x, 0));
 200       link.next = path;
 201       link.vecelt = -1;
 202       for (i = 0; i < XVECLEN (x, 1); i++)
 203         {
 204           link.pos = i;
 205           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 206         }
 207       return;
 208
 209     case MATCH_OPERATOR:
 210       if (XINT (x, 0) > max_opno)
 211         max_opno = XINT (x, 0);
 212       if (XINT (x, 0) >= n_operands)
 213         n_operands = 1 + XINT (x, 0);
 214
 215       printf ("  x = ");
 216       print_path (path);
 217       printf (";\n");
 218
 219       printf ("  operands[%d] = x;\n", XINT (x, 0));
 220       if (XSTR (x, 1) && XSTR (x, 1)[0])
 221         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 222                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 223       link.next = path;
 224       link.vecelt = -1;
 225       for (i = 0; i < XVECLEN (x, 2); i++)
 226         {
 227           link.pos = i;
 228           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 229         }
 230       return;
 231
 232     case MATCH_PARALLEL:
 233       if (XINT (x, 0) > max_opno)
 234         max_opno = XINT (x, 0);
 235       if (XINT (x, 0) >= n_operands)
 236         n_operands = 1 + XINT (x, 0);
 237
 238       printf ("  x = ");
 239       print_path (path);
 240       printf (";\n");
 241
 242       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 243       printf ("  operands[%d] = x;\n", XINT (x, 0));
 244       if (XSTR (x, 1) && XSTR (x, 1)[0])
 245         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 246                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 247       link.next = path;
 248       link.pos = 0;
 249       for (i = 0; i < XVECLEN (x, 2); i++)
 250         {
 251           link.vecelt = i;
 252           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 253         }
 254       return;
 255
 256     case ADDRESS:
 257       match_rtx (XEXP (x, 0), path, fail_label);
 258       return;
 259
 260     default:
 261       break;
 262     }
 263
 264   printf ("  x = ");
 265   print_path (path);
 266   printf (";\n");
 267
 268   printf ("  if (GET_CODE (x) != ");
 269   print_code (code);
 270   printf (") goto L%d;\n", fail_label);
 271
 272   if (GET_MODE (x) != VOIDmode)
 273     {
 274       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 275               GET_MODE_NAME (GET_MODE (x)), fail_label);
 276     }
 277
 278   link.next = path;
 279   link.vecelt = -1;
 280   fmt = GET_RTX_FORMAT (code);
 281   len = GET_RTX_LENGTH (code);
 282   for (i = 0; i < len; i++)
 283     {
 284       link.pos = i;
 285       if (fmt[i] == 'e' || fmt[i] == 'u')
 286         match_rtx (XEXP (x, i), &link, fail_label);
 287       else if (fmt[i] == 'E')
 288         {
 289           int j;
 290           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 291                   i, XVECLEN (x, i), fail_label);
 292           for (j = 0; j < XVECLEN (x, i); j++)
 293             {
 294               link.vecelt = j;
 295               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 296             }
 297         }
 298       else if (fmt[i] == 'i')
 299         {
 300           /* Make sure that at run time `x' is the RTX we want to test.  */
 301           if (i != 0)
 302             {
 303               printf ("  x = ");
 304               print_path (path);
 305               printf (";\n");
 306             }
 307
 308           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 309                   i, XINT (x, i), fail_label);
 310         }
 311       else if (fmt[i] == 'w')
 312         {
 313           /* Make sure that at run time `x' is the RTX we want to test.  */
 314           if (i != 0)
 315             {
 316               printf ("  x = ");
 317               print_path (path);
 318               printf (";\n");
 319             }
 320
 321           printf ("  if (XWINT (x, %d) != ", i);
 322           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 323           printf (") goto L%d;\n", fail_label);
 324         }
 325       else if (fmt[i] == 's')
 326         {
 327           /* Make sure that at run time `x' is the RTX we want to test.  */
 328           if (i != 0)
 329             {
 330               printf ("  x = ");
 331               print_path (path);
 332               printf (";\n");
 333             }
 334
 335           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 336                   i, XSTR (x, i), fail_label);
 337         }
 338     }
 339 }
 340
 341 /* Given a PATH, representing a path down the instruction's
 342    pattern from the root to a certain point, output code to
 343    evaluate to the rtx at that point.  */
 344
 345 static void
 346 print_path (path)
 347      struct link *path;
 348 {
 349   if (path == 0)
 350     printf ("pat");
 351   else if (path->vecelt >= 0)
 352     {
 353       printf ("XVECEXP (");
 354       print_path (path->next);
 355       printf (", %d, %d)", path->pos, path->vecelt);
 356     }
 357   else
 358     {
 359       printf ("XEXP (");
 360       print_path (path->next);
 361       printf (", %d)", path->pos);
 362     }
 363 }
 364 \f
 365 static void
 366 print_code (code)
 367      RTX_CODE code;
 368 {
 369   const char *p1;
 370   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 371     putchar (TOUPPER(*p1));
 372 }
 373
 374 extern int main PARAMS ((int, char **));
 375
 376 int
 377 main (argc, argv)
 378      int argc;
 379      char **argv;
 380 {
 381   rtx desc;
 382
 383   max_opno = -1;
 384
 385   progname = "genpeep";
 386
 387   if (argc <= 1)
 388     fatal ("no input file name");
 389
 390   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 391     return (FATAL_EXIT_CODE);
 392
 393   printf ("/* Generated automatically by the program `genpeep'\n\
 394 from the machine description file `md'.  */\n\n");
 395
 396   printf ("#include \"config.h\"\n");
 397   printf ("#include \"system.h\"\n");
 398   printf ("#include \"coretypes.h\"\n");
 399   printf ("#include \"tm.h\"\n");
 400   printf ("#include \"insn-config.h\"\n");
 401   printf ("#include \"rtl.h\"\n");
 402   printf ("#include \"tm_p.h\"\n");
 403   printf ("#include \"regs.h\"\n");
 404   printf ("#include \"output.h\"\n");
 405   printf ("#include \"real.h\"\n");
 406   printf ("#include \"recog.h\"\n");
 407   printf ("#include \"except.h\"\n\n");
 408   printf ("#include \"function.h\"\n\n");
 409
 410   printf ("#ifdef HAVE_peephole\n");
 411   printf ("extern rtx peep_operand[];\n\n");
 412   printf ("#define operands peep_operand\n\n");
 413
 414   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 415   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 416
 417   /* Early out: no peepholes for insns followed by barriers.  */
 418   printf ("  if (NEXT_INSN (ins1)\n");
 419   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 420   printf ("    return 0;\n\n");
 421
 422   /* Read the machine description.  */
 423
 424   while (1)
 425     {
 426       int line_no, rtx_number = 0;
 427
 428       desc = read_md_rtx (&line_no, &rtx_number);
 429       if (desc == NULL)
 430         break;
 431
 432        if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 433         {
 434           gen_peephole (desc);
 435           insn_code_number++;
 436         }
 437       if (GET_CODE (desc) == DEFINE_INSN
 438           || GET_CODE (desc) == DEFINE_EXPAND
 439           || GET_CODE (desc) == DEFINE_SPLIT
 440           || GET_CODE (desc) == DEFINE_PEEPHOLE2)
 441         {
 442           insn_code_number++;
 443         }
 444     }
 445
 446   printf ("  return 0;\n}\n\n");
 447
 448   if (max_opno == -1)
 449     max_opno = 1;
 450
 451   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 452   printf ("#endif\n");
 453
 454   fflush (stdout);
 455   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 456 }
 457
 458 /* Define this so we can link with print-rtl.o to get debug_rtx function.  */
 459 const char *
 460 get_insn_name (code)
 461      int code ATTRIBUTE_UNUSED;
 462 {
 463   return NULL;
 464 }