gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992 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, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  19
  20
  21 #include <stdio.h>
  22 #include "hconfig.h"
  23 #include "rtl.h"
  24 #include "obstack.h"
  25
  26 static struct obstack obstack;
  27 struct obstack *rtl_obstack = &obstack;
  28
  29 #define obstack_chunk_alloc xmalloc
  30 #define obstack_chunk_free free
  31
  32 extern void free ();
  33 extern rtx read_rtx ();
  34
  35 /* While tree-walking an instruction pattern, we keep a chain
  36    of these `struct link's to record how to get down to the
  37    current position.  In each one, POS is the operand number,
  38    and if the operand is a vector VEC is the element number.
  39    VEC is -1 if the operand is not a vector.  */
  40
  41 struct link
  42 {
  43   struct link *next;
  44   int pos;
  45   int vecelt;
  46 };
  47
  48 char *xmalloc ();
  49 static void match_rtx ();
  50 static void gen_exp ();
  51 static void fatal ();
  52 void fancy_abort ();
  53
  54 static int max_opno;
  55
  56 /* Number of operands used in current peephole definition.  */
  57
  58 static int n_operands;
  59
  60 /* Peephole optimizations get insn codes just like insn patterns.
  61    Count them so we know the code of the define_peephole we are handling.  */
  62
  63 static int insn_code_number = 0;
  64
  65 static void print_path ();
  66 static void print_code ();
  67 \f
  68 static void
  69 gen_peephole (peep)
  70      rtx peep;
  71 {
  72   int ninsns = XVECLEN (peep, 0);
  73   int i;
  74
  75   n_operands = 0;
  76
  77   printf ("  insn = ins1;\n");
  78 #if 0
  79   printf ("  want_jump = 0;\n");
  80 #endif
  81
  82   for (i = 0; i < ninsns; i++)
  83     {
  84       if (i > 0)
  85         {
  86           printf ("  do { insn = NEXT_INSN (insn);\n");
  87           printf ("       if (insn == 0) goto L%d; }\n",
  88                   insn_code_number);
  89           printf ("  while (GET_CODE (insn) == NOTE\n");
  90           printf ("\t || (GET_CODE (insn) == INSN\n");
  91           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  92           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  93
  94           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  95       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  96                   insn_code_number);
  97         }
  98
  99 #if 0
 100       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 101       printf ("    want_jump = JUMP_LABEL (insn);\n");
 102 #endif
 103
 104       printf ("  pat = PATTERN (insn);\n");
 105
 106       /* Walk the insn's pattern, remembering at all times the path
 107          down to the walking point.  */
 108
 109       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 110     }
 111
 112   /* We get this far if the pattern matches.
 113      Now test the extra condition.  */
 114
 115   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 116     printf ("  if (! (%s)) goto L%d;\n",
 117             XSTR (peep, 1), insn_code_number);
 118
 119   /* If that matches, construct new pattern and put it in the first insn.
 120      This new pattern will never be matched.
 121      It exists only so that insn-extract can get the operands back.
 122      So use a simple regular form: a PARALLEL containing a vector
 123      of all the operands.  */
 124
 125   printf ("  PATTERN (ins1) = gen_rtx (PARALLEL, VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 126
 127 #if 0
 128   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 129   printf ("    {\n");
 130   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 131   printf ("      delete_insn (ins1);\n");
 132   printf ("      ins1 = ins2;\n");
 133   printf ("    }\n");
 134 #endif
 135
 136   /* Record this define_peephole's insn code in the insn,
 137      as if it had been recognized to match this.  */
 138   printf ("  INSN_CODE (ins1) = %d;\n",
 139           insn_code_number);
 140
 141   /* Delete the remaining insns.  */
 142   if (ninsns > 1)
 143     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 144
 145   /* See reload1.c for insertion of NOTE which guarantees that this
 146      cannot be zero.  */
 147   printf ("  return NEXT_INSN (insn);\n");
 148
 149   printf (" L%d:\n\n", insn_code_number);
 150 }
 151 \f
 152 static void
 153 match_rtx (x, path, fail_label)
 154      rtx x;
 155      struct link *path;
 156      int fail_label;
 157 {
 158   register RTX_CODE code;
 159   register int i;
 160   register int len;
 161   register char *fmt;
 162   struct link link;
 163
 164   if (x == 0)
 165     return;
 166
 167
 168   code = GET_CODE (x);
 169
 170   switch (code)
 171     {
 172     case MATCH_OPERAND:
 173       if (XINT (x, 0) > max_opno)
 174         max_opno = XINT (x, 0);
 175       if (XINT (x, 0) >= n_operands)
 176         n_operands = 1 + XINT (x, 0);
 177
 178       printf ("  x = ");
 179       print_path (path);
 180       printf (";\n");
 181
 182       printf ("  operands[%d] = x;\n", XINT (x, 0));
 183       if (XSTR (x, 1) && XSTR (x, 1)[0])
 184         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 185                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 186       return;
 187
 188     case MATCH_DUP:
 189     case MATCH_PAR_DUP:
 190       printf ("  x = ");
 191       print_path (path);
 192       printf (";\n");
 193
 194       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 195               XINT (x, 0), fail_label);
 196       return;
 197
 198     case MATCH_OP_DUP:
 199       printf ("  x = ");
 200       print_path (path);
 201       printf (";\n");
 202
 203       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 204       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 205               XINT (x, 0), fail_label);
 206       printf ("  operands[%d] = x;\n", XINT (x, 0));
 207       link.next = path;
 208       link.vecelt = -1;
 209       for (i = 0; i < XVECLEN (x, 1); i++)
 210         {
 211           link.pos = i;
 212           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 213         }
 214       return;
 215
 216     case MATCH_OPERATOR:
 217       if (XINT (x, 0) > max_opno)
 218         max_opno = XINT (x, 0);
 219       if (XINT (x, 0) >= n_operands)
 220         n_operands = 1 + XINT (x, 0);
 221
 222       printf ("  x = ");
 223       print_path (path);
 224       printf (";\n");
 225
 226       printf ("  operands[%d] = x;\n", XINT (x, 0));
 227       if (XSTR (x, 1) && XSTR (x, 1)[0])
 228         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 229                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 230       link.next = path;
 231       link.vecelt = -1;
 232       for (i = 0; i < XVECLEN (x, 2); i++)
 233         {
 234           link.pos = i;
 235           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 236         }
 237       return;
 238
 239     case MATCH_PARALLEL:
 240       if (XINT (x, 0) > max_opno)
 241         max_opno = XINT (x, 0);
 242       if (XINT (x, 0) >= n_operands)
 243         n_operands = 1 + XINT (x, 0);
 244
 245       printf ("  x = ");
 246       print_path (path);
 247       printf (";\n");
 248
 249       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 250       printf ("  operands[%d] = x;\n", XINT (x, 0));
 251       if (XSTR (x, 1) && XSTR (x, 1)[0])
 252         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 253                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 254       link.next = path;
 255       link.pos = 0;
 256       for (i = 0; i < XVECLEN (x, 2); i++)
 257         {
 258           link.vecelt = i;
 259           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 260         }
 261       return;
 262
 263     case ADDRESS:
 264       match_rtx (XEXP (x, 0), path, fail_label);
 265       return;
 266     }
 267
 268   printf ("  x = ");
 269   print_path (path);
 270   printf (";\n");
 271
 272   printf ("  if (GET_CODE (x) != ");
 273   print_code (code);
 274   printf (") goto L%d;\n", fail_label);
 275
 276   if (GET_MODE (x) != VOIDmode)
 277     {
 278       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 279               GET_MODE_NAME (GET_MODE (x)), fail_label);
 280     }
 281
 282   link.next = path;
 283   link.vecelt = -1;
 284   fmt = GET_RTX_FORMAT (code);
 285   len = GET_RTX_LENGTH (code);
 286   for (i = 0; i < len; i++)
 287     {
 288       link.pos = i;
 289       if (fmt[i] == 'e' || fmt[i] == 'u')
 290         match_rtx (XEXP (x, i), &link, fail_label);
 291       else if (fmt[i] == 'E')
 292         {
 293           int j;
 294           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 295                   i, XVECLEN (x, i), fail_label);
 296           for (j = 0; j < XVECLEN (x, i); j++)
 297             {
 298               link.vecelt = j;
 299               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 300             }
 301         }
 302       else if (fmt[i] == 'i')
 303         {
 304           /* Make sure that at run time `x' is the RTX we want to test.  */
 305           if (i != 0)
 306             {
 307               printf ("  x = ");
 308               print_path (path);
 309               printf (";\n");
 310             }
 311
 312           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 313                   i, XINT (x, i), fail_label);
 314         }
 315       else if (fmt[i] == 'w')
 316         {
 317           /* Make sure that at run time `x' is the RTX we want to test.  */
 318           if (i != 0)
 319             {
 320               printf ("  x = ");
 321               print_path (path);
 322               printf (";\n");
 323             }
 324
 325 #if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
 326           printf ("  if (XWINT (x, %d) != %d) goto L%d;\n",
 327                   i, XWINT (x, i), fail_label);
 328 #else
 329           printf ("  if (XWINT (x, %d) != %ld) goto L%d;\n",
 330                   i, XWINT (x, i), fail_label);
 331 #endif
 332         }
 333       else if (fmt[i] == 's')
 334         {
 335           /* Make sure that at run time `x' is the RTX we want to test.  */
 336           if (i != 0)
 337             {
 338               printf ("  x = ");
 339               print_path (path);
 340               printf (";\n");
 341             }
 342
 343           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 344                   i, XSTR (x, i), fail_label);
 345         }
 346     }
 347 }
 348
 349 /* Given a PATH, representing a path down the instruction's
 350    pattern from the root to a certain point, output code to
 351    evaluate to the rtx at that point.  */
 352
 353 static void
 354 print_path (path)
 355      struct link *path;
 356 {
 357   if (path == 0)
 358     printf ("pat");
 359   else if (path->vecelt >= 0)
 360     {
 361       printf ("XVECEXP (");
 362       print_path (path->next);
 363       printf (", %d, %d)", path->pos, path->vecelt);
 364     }
 365   else
 366     {
 367       printf ("XEXP (");
 368       print_path (path->next);
 369       printf (", %d)", path->pos);
 370     }
 371 }
 372 \f
 373 static void
 374 print_code (code)
 375      RTX_CODE code;
 376 {
 377   register char *p1;
 378   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 379     {
 380       if (*p1 >= 'a' && *p1 <= 'z')
 381         putchar (*p1 + 'A' - 'a');
 382       else
 383         putchar (*p1);
 384     }
 385 }
 386 \f
 387 char *
 388 xmalloc (size)
 389      unsigned size;
 390 {
 391   register char *val = (char *) malloc (size);
 392
 393   if (val == 0)
 394     fatal ("virtual memory exhausted");
 395   return val;
 396 }
 397
 398 char *
 399 xrealloc (ptr, size)
 400      char *ptr;
 401      unsigned size;
 402 {
 403   char *result = (char *) realloc (ptr, size);
 404   if (!result)
 405     fatal ("virtual memory exhausted");
 406   return result;
 407 }
 408
 409 static void
 410 fatal (s, a1, a2)
 411      char *s;
 412 {
 413   fprintf (stderr, "genpeep: ");
 414   fprintf (stderr, s, a1, a2);
 415   fprintf (stderr, "\n");
 416   exit (FATAL_EXIT_CODE);
 417 }
 418
 419 /* More 'friendly' abort that prints the line and file.
 420    config.h can #define abort fancy_abort if you like that sort of thing.  */
 421
 422 void
 423 fancy_abort ()
 424 {
 425   fatal ("Internal gcc abort.");
 426 }
 427 \f
 428 int
 429 main (argc, argv)
 430      int argc;
 431      char **argv;
 432 {
 433   rtx desc;
 434   FILE *infile;
 435   register int c;
 436
 437   max_opno = -1;
 438
 439   obstack_init (rtl_obstack);
 440
 441   if (argc <= 1)
 442     fatal ("No input file name.");
 443
 444   infile = fopen (argv[1], "r");
 445   if (infile == 0)
 446     {
 447       perror (argv[1]);
 448       exit (FATAL_EXIT_CODE);
 449     }
 450
 451   init_rtl ();
 452
 453   printf ("/* Generated automatically by the program `genpeep'\n\
 454 from the machine description file `md'.  */\n\n");
 455
 456   printf ("#include \"config.h\"\n");
 457   printf ("#include \"rtl.h\"\n");
 458   printf ("#include \"regs.h\"\n");
 459   printf ("#include \"output.h\"\n");
 460   printf ("#include \"real.h\"\n\n");
 461
 462   printf ("extern rtx peep_operand[];\n\n");
 463   printf ("#define operands peep_operand\n\n");
 464
 465   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 466   printf ("  rtx insn, x, pat;\n");
 467   printf ("  int i;\n\n");
 468
 469   /* Early out: no peepholes for insns followed by barriers.  */
 470   printf ("  if (NEXT_INSN (ins1)\n");
 471   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 472   printf ("    return 0;\n\n");
 473
 474   /* Read the machine description.  */
 475
 476   while (1)
 477     {
 478       c = read_skip_spaces (infile);
 479       if (c == EOF)
 480         break;
 481       ungetc (c, infile);
 482
 483       desc = read_rtx (infile);
 484       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 485         {
 486           gen_peephole (desc);
 487           insn_code_number++;
 488         }
 489       if (GET_CODE (desc) == DEFINE_INSN
 490           || GET_CODE (desc) == DEFINE_EXPAND
 491           || GET_CODE (desc) == DEFINE_SPLIT)
 492         {
 493           insn_code_number++;
 494         }
 495     }
 496
 497   printf ("  return 0;\n}\n\n");
 498
 499   if (max_opno == -1)
 500     max_opno = 1;
 501
 502   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 503
 504   fflush (stdout);
 505   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 506   /* NOTREACHED */
 507   return 0;
 508 }