gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992, 1997, 1998 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 "hconfig.h"
  23 #include "system.h"
  24 #include "rtl.h"
  25 #include "obstack.h"
  26
  27 static struct obstack obstack;
  28 struct obstack *rtl_obstack = &obstack;
  29
  30 #define obstack_chunk_alloc xmalloc
  31 #define obstack_chunk_free free
  32
  33 /* While tree-walking an instruction pattern, we keep a chain
  34    of these `struct link's to record how to get down to the
  35    current position.  In each one, POS is the operand number,
  36    and if the operand is a vector VEC is the element number.
  37    VEC is -1 if the operand is not a vector.  */
  38
  39 struct link
  40 {
  41   struct link *next;
  42   int pos;
  43   int vecelt;
  44 };
  45
  46 char *xmalloc PROTO((unsigned));
  47 static void match_rtx PROTO((rtx, struct link *, int));
  48 static void fatal ();
  49 void fancy_abort PROTO((void));
  50
  51 static int max_opno;
  52
  53 /* Number of operands used in current peephole definition.  */
  54
  55 static int n_operands;
  56
  57 /* Peephole optimizations get insn codes just like insn patterns.
  58    Count them so we know the code of the define_peephole we are handling.  */
  59
  60 static int insn_code_number = 0;
  61
  62 static void print_path PROTO((struct link *));
  63 static void print_code PROTO((RTX_CODE));
  64 \f
  65 static void
  66 gen_peephole (peep)
  67      rtx peep;
  68 {
  69   int ninsns = XVECLEN (peep, 0);
  70   int i;
  71
  72   n_operands = 0;
  73
  74   printf ("  insn = ins1;\n");
  75 #if 0
  76   printf ("  want_jump = 0;\n");
  77 #endif
  78
  79   for (i = 0; i < ninsns; i++)
  80     {
  81       if (i > 0)
  82         {
  83           printf ("  do { insn = NEXT_INSN (insn);\n");
  84           printf ("       if (insn == 0) goto L%d; }\n",
  85                   insn_code_number);
  86           printf ("  while (GET_CODE (insn) == NOTE\n");
  87           printf ("\t || (GET_CODE (insn) == INSN\n");
  88           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  89           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  90
  91           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  92       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  93                   insn_code_number);
  94         }
  95
  96 #if 0
  97       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
  98       printf ("    want_jump = JUMP_LABEL (insn);\n");
  99 #endif
 100
 101       printf ("  pat = PATTERN (insn);\n");
 102
 103       /* Walk the insn's pattern, remembering at all times the path
 104          down to the walking point.  */
 105
 106       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 107     }
 108
 109   /* We get this far if the pattern matches.
 110      Now test the extra condition.  */
 111
 112   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 113     printf ("  if (! (%s)) goto L%d;\n",
 114             XSTR (peep, 1), insn_code_number);
 115
 116   /* If that matches, construct new pattern and put it in the first insn.
 117      This new pattern will never be matched.
 118      It exists only so that insn-extract can get the operands back.
 119      So use a simple regular form: a PARALLEL containing a vector
 120      of all the operands.  */
 121
 122   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 123
 124 #if 0
 125   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 126   printf ("    {\n");
 127   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 128   printf ("      delete_insn (ins1);\n");
 129   printf ("      ins1 = ins2;\n");
 130   printf ("    }\n");
 131 #endif
 132
 133   /* Record this define_peephole's insn code in the insn,
 134      as if it had been recognized to match this.  */
 135   printf ("  INSN_CODE (ins1) = %d;\n",
 136           insn_code_number);
 137
 138   /* Delete the remaining insns.  */
 139   if (ninsns > 1)
 140     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 141
 142   /* See reload1.c for insertion of NOTE which guarantees that this
 143      cannot be zero.  */
 144   printf ("  return NEXT_INSN (insn);\n");
 145
 146   printf (" L%d:\n\n", insn_code_number);
 147 }
 148 \f
 149 static void
 150 match_rtx (x, path, fail_label)
 151      rtx x;
 152      struct link *path;
 153      int fail_label;
 154 {
 155   register RTX_CODE code;
 156   register int i;
 157   register int len;
 158   register char *fmt;
 159   struct link link;
 160
 161   if (x == 0)
 162     return;
 163
 164
 165   code = GET_CODE (x);
 166
 167   switch (code)
 168     {
 169     case MATCH_OPERAND:
 170       if (XINT (x, 0) > max_opno)
 171         max_opno = XINT (x, 0);
 172       if (XINT (x, 0) >= n_operands)
 173         n_operands = 1 + XINT (x, 0);
 174
 175       printf ("  x = ");
 176       print_path (path);
 177       printf (";\n");
 178
 179       printf ("  operands[%d] = x;\n", XINT (x, 0));
 180       if (XSTR (x, 1) && XSTR (x, 1)[0])
 181         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 182                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 183       return;
 184
 185     case MATCH_DUP:
 186     case MATCH_PAR_DUP:
 187       printf ("  x = ");
 188       print_path (path);
 189       printf (";\n");
 190
 191       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 192               XINT (x, 0), fail_label);
 193       return;
 194
 195     case MATCH_OP_DUP:
 196       printf ("  x = ");
 197       print_path (path);
 198       printf (";\n");
 199
 200       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 201       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 202               XINT (x, 0), fail_label);
 203       printf ("  operands[%d] = x;\n", XINT (x, 0));
 204       link.next = path;
 205       link.vecelt = -1;
 206       for (i = 0; i < XVECLEN (x, 1); i++)
 207         {
 208           link.pos = i;
 209           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 210         }
 211       return;
 212
 213     case MATCH_OPERATOR:
 214       if (XINT (x, 0) > max_opno)
 215         max_opno = XINT (x, 0);
 216       if (XINT (x, 0) >= n_operands)
 217         n_operands = 1 + XINT (x, 0);
 218
 219       printf ("  x = ");
 220       print_path (path);
 221       printf (";\n");
 222
 223       printf ("  operands[%d] = x;\n", XINT (x, 0));
 224       if (XSTR (x, 1) && XSTR (x, 1)[0])
 225         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 226                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 227       link.next = path;
 228       link.vecelt = -1;
 229       for (i = 0; i < XVECLEN (x, 2); i++)
 230         {
 231           link.pos = i;
 232           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 233         }
 234       return;
 235
 236     case MATCH_PARALLEL:
 237       if (XINT (x, 0) > max_opno)
 238         max_opno = XINT (x, 0);
 239       if (XINT (x, 0) >= n_operands)
 240         n_operands = 1 + XINT (x, 0);
 241
 242       printf ("  x = ");
 243       print_path (path);
 244       printf (";\n");
 245
 246       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 247       printf ("  operands[%d] = x;\n", XINT (x, 0));
 248       if (XSTR (x, 1) && XSTR (x, 1)[0])
 249         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 250                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 251       link.next = path;
 252       link.pos = 0;
 253       for (i = 0; i < XVECLEN (x, 2); i++)
 254         {
 255           link.vecelt = i;
 256           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 257         }
 258       return;
 259
 260     case ADDRESS:
 261       match_rtx (XEXP (x, 0), path, fail_label);
 262       return;
 263
 264     default:
 265       break;
 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           printf ("  if (XWINT (x, %d) != ", i);
 326           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 327           printf (") goto L%d;\n", fail_label);
 328         }
 329       else if (fmt[i] == 's')
 330         {
 331           /* Make sure that at run time `x' is the RTX we want to test.  */
 332           if (i != 0)
 333             {
 334               printf ("  x = ");
 335               print_path (path);
 336               printf (";\n");
 337             }
 338
 339           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 340                   i, XSTR (x, i), fail_label);
 341         }
 342     }
 343 }
 344
 345 /* Given a PATH, representing a path down the instruction's
 346    pattern from the root to a certain point, output code to
 347    evaluate to the rtx at that point.  */
 348
 349 static void
 350 print_path (path)
 351      struct link *path;
 352 {
 353   if (path == 0)
 354     printf ("pat");
 355   else if (path->vecelt >= 0)
 356     {
 357       printf ("XVECEXP (");
 358       print_path (path->next);
 359       printf (", %d, %d)", path->pos, path->vecelt);
 360     }
 361   else
 362     {
 363       printf ("XEXP (");
 364       print_path (path->next);
 365       printf (", %d)", path->pos);
 366     }
 367 }
 368 \f
 369 static void
 370 print_code (code)
 371      RTX_CODE code;
 372 {
 373   register char *p1;
 374   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 375     {
 376       if (*p1 >= 'a' && *p1 <= 'z')
 377         putchar (*p1 + 'A' - 'a');
 378       else
 379         putchar (*p1);
 380     }
 381 }
 382 \f
 383 char *
 384 xmalloc (size)
 385      unsigned size;
 386 {
 387   register char *val = (char *) malloc (size);
 388
 389   if (val == 0)
 390     fatal ("virtual memory exhausted");
 391   return val;
 392 }
 393
 394 char *
 395 xrealloc (ptr, size)
 396      char *ptr;
 397      unsigned size;
 398 {
 399   char *result = (char *) realloc (ptr, size);
 400   if (!result)
 401     fatal ("virtual memory exhausted");
 402   return result;
 403 }
 404
 405 static void
 406 fatal (s, a1, a2)
 407      char *s;
 408 {
 409   fprintf (stderr, "genpeep: ");
 410   fprintf (stderr, s, a1, a2);
 411   fprintf (stderr, "\n");
 412   exit (FATAL_EXIT_CODE);
 413 }
 414
 415 /* More 'friendly' abort that prints the line and file.
 416    config.h can #define abort fancy_abort if you like that sort of thing.  */
 417
 418 void
 419 fancy_abort ()
 420 {
 421   fatal ("Internal gcc abort.");
 422 }
 423 \f
 424 int
 425 main (argc, argv)
 426      int argc;
 427      char **argv;
 428 {
 429   rtx desc;
 430   FILE *infile;
 431   register int c;
 432
 433   max_opno = -1;
 434
 435   obstack_init (rtl_obstack);
 436
 437   if (argc <= 1)
 438     fatal ("No input file name.");
 439
 440   infile = fopen (argv[1], "r");
 441   if (infile == 0)
 442     {
 443       perror (argv[1]);
 444       exit (FATAL_EXIT_CODE);
 445     }
 446
 447   init_rtl ();
 448
 449   printf ("/* Generated automatically by the program `genpeep'\n\
 450 from the machine description file `md'.  */\n\n");
 451
 452   printf ("#include \"config.h\"\n");
 453   printf ("#include \"system.h\"\n");
 454   printf ("#include \"rtl.h\"\n");
 455   printf ("#include \"regs.h\"\n");
 456   printf ("#include \"output.h\"\n");
 457   printf ("#include \"real.h\"\n");
 458   printf ("#include \"except.h\"\n\n");
 459
 460   printf ("extern rtx peep_operand[];\n\n");
 461   printf ("#define operands peep_operand\n\n");
 462
 463   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 464   printf ("  rtx insn, x, pat;\n\n");
 465
 466   /* Early out: no peepholes for insns followed by barriers.  */
 467   printf ("  if (NEXT_INSN (ins1)\n");
 468   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 469   printf ("    return 0;\n\n");
 470
 471   /* Read the machine description.  */
 472
 473   while (1)
 474     {
 475       c = read_skip_spaces (infile);
 476       if (c == EOF)
 477         break;
 478       ungetc (c, infile);
 479
 480       desc = read_rtx (infile);
 481       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 482         {
 483           gen_peephole (desc);
 484           insn_code_number++;
 485         }
 486       if (GET_CODE (desc) == DEFINE_INSN
 487           || GET_CODE (desc) == DEFINE_EXPAND
 488           || GET_CODE (desc) == DEFINE_SPLIT)
 489         {
 490           insn_code_number++;
 491         }
 492     }
 493
 494   printf ("  return 0;\n}\n\n");
 495
 496   if (max_opno == -1)
 497     max_opno = 1;
 498
 499   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 500
 501   fflush (stdout);
 502   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 503   /* NOTREACHED */
 504   return 0;
 505 }