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, 59 Temple Place - Suite 330,
  19 Boston, MA 02111-1307, USA.  */
  20
  21
  22 #include <stdio.h>
  23 #include "hconfig.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 extern void free ();
  34 extern rtx read_rtx ();
  35
  36 /* While tree-walking an instruction pattern, we keep a chain
  37    of these `struct link's to record how to get down to the
  38    current position.  In each one, POS is the operand number,
  39    and if the operand is a vector VEC is the element number.
  40    VEC is -1 if the operand is not a vector.  */
  41
  42 struct link
  43 {
  44   struct link *next;
  45   int pos;
  46   int vecelt;
  47 };
  48
  49 char *xmalloc ();
  50 static void match_rtx ();
  51 static void gen_exp ();
  52 static void fatal ();
  53 void fancy_abort ();
  54
  55 static int max_opno;
  56
  57 /* Number of operands used in current peephole definition.  */
  58
  59 static int n_operands;
  60
  61 /* Peephole optimizations get insn codes just like insn patterns.
  62    Count them so we know the code of the define_peephole we are handling.  */
  63
  64 static int insn_code_number = 0;
  65
  66 static void print_path ();
  67 static void print_code ();
  68 \f
  69 static void
  70 gen_peephole (peep)
  71      rtx peep;
  72 {
  73   int ninsns = XVECLEN (peep, 0);
  74   int i;
  75
  76   n_operands = 0;
  77
  78   printf ("  insn = ins1;\n");
  79 #if 0
  80   printf ("  want_jump = 0;\n");
  81 #endif
  82
  83   for (i = 0; i < ninsns; i++)
  84     {
  85       if (i > 0)
  86         {
  87           printf ("  do { insn = NEXT_INSN (insn);\n");
  88           printf ("       if (insn == 0) goto L%d; }\n",
  89                   insn_code_number);
  90           printf ("  while (GET_CODE (insn) == NOTE\n");
  91           printf ("\t || (GET_CODE (insn) == INSN\n");
  92           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  93           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  94
  95           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  96       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  97                   insn_code_number);
  98         }
  99
 100 #if 0
 101       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
 102       printf ("    want_jump = JUMP_LABEL (insn);\n");
 103 #endif
 104
 105       printf ("  pat = PATTERN (insn);\n");
 106
 107       /* Walk the insn's pattern, remembering at all times the path
 108          down to the walking point.  */
 109
 110       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 111     }
 112
 113   /* We get this far if the pattern matches.
 114      Now test the extra condition.  */
 115
 116   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 117     printf ("  if (! (%s)) goto L%d;\n",
 118             XSTR (peep, 1), insn_code_number);
 119
 120   /* If that matches, construct new pattern and put it in the first insn.
 121      This new pattern will never be matched.
 122      It exists only so that insn-extract can get the operands back.
 123      So use a simple regular form: a PARALLEL containing a vector
 124      of all the operands.  */
 125
 126   printf ("  PATTERN (ins1) = gen_rtx (PARALLEL, VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 127
 128 #if 0
 129   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 130   printf ("    {\n");
 131   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 132   printf ("      delete_insn (ins1);\n");
 133   printf ("      ins1 = ins2;\n");
 134   printf ("    }\n");
 135 #endif
 136
 137   /* Record this define_peephole's insn code in the insn,
 138      as if it had been recognized to match this.  */
 139   printf ("  INSN_CODE (ins1) = %d;\n",
 140           insn_code_number);
 141
 142   /* Delete the remaining insns.  */
 143   if (ninsns > 1)
 144     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 145
 146   /* See reload1.c for insertion of NOTE which guarantees that this
 147      cannot be zero.  */
 148   printf ("  return NEXT_INSN (insn);\n");
 149
 150   printf (" L%d:\n\n", insn_code_number);
 151 }
 152 \f
 153 static void
 154 match_rtx (x, path, fail_label)
 155      rtx x;
 156      struct link *path;
 157      int fail_label;
 158 {
 159   register RTX_CODE code;
 160   register int i;
 161   register int len;
 162   register char *fmt;
 163   struct link link;
 164
 165   if (x == 0)
 166     return;
 167
 168
 169   code = GET_CODE (x);
 170
 171   switch (code)
 172     {
 173     case MATCH_OPERAND:
 174       if (XINT (x, 0) > max_opno)
 175         max_opno = XINT (x, 0);
 176       if (XINT (x, 0) >= n_operands)
 177         n_operands = 1 + XINT (x, 0);
 178
 179       printf ("  x = ");
 180       print_path (path);
 181       printf (";\n");
 182
 183       printf ("  operands[%d] = x;\n", XINT (x, 0));
 184       if (XSTR (x, 1) && XSTR (x, 1)[0])
 185         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 186                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 187       return;
 188
 189     case MATCH_DUP:
 190     case MATCH_PAR_DUP:
 191       printf ("  x = ");
 192       print_path (path);
 193       printf (";\n");
 194
 195       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 196               XINT (x, 0), fail_label);
 197       return;
 198
 199     case MATCH_OP_DUP:
 200       printf ("  x = ");
 201       print_path (path);
 202       printf (";\n");
 203
 204       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 205       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 206               XINT (x, 0), fail_label);
 207       printf ("  operands[%d] = x;\n", XINT (x, 0));
 208       link.next = path;
 209       link.vecelt = -1;
 210       for (i = 0; i < XVECLEN (x, 1); i++)
 211         {
 212           link.pos = i;
 213           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 214         }
 215       return;
 216
 217     case MATCH_OPERATOR:
 218       if (XINT (x, 0) > max_opno)
 219         max_opno = XINT (x, 0);
 220       if (XINT (x, 0) >= n_operands)
 221         n_operands = 1 + XINT (x, 0);
 222
 223       printf ("  x = ");
 224       print_path (path);
 225       printf (";\n");
 226
 227       printf ("  operands[%d] = x;\n", XINT (x, 0));
 228       if (XSTR (x, 1) && XSTR (x, 1)[0])
 229         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 230                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 231       link.next = path;
 232       link.vecelt = -1;
 233       for (i = 0; i < XVECLEN (x, 2); i++)
 234         {
 235           link.pos = i;
 236           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 237         }
 238       return;
 239
 240     case MATCH_PARALLEL:
 241       if (XINT (x, 0) > max_opno)
 242         max_opno = XINT (x, 0);
 243       if (XINT (x, 0) >= n_operands)
 244         n_operands = 1 + XINT (x, 0);
 245
 246       printf ("  x = ");
 247       print_path (path);
 248       printf (";\n");
 249
 250       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 251       printf ("  operands[%d] = x;\n", XINT (x, 0));
 252       if (XSTR (x, 1) && XSTR (x, 1)[0])
 253         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 254                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 255       link.next = path;
 256       link.pos = 0;
 257       for (i = 0; i < XVECLEN (x, 2); i++)
 258         {
 259           link.vecelt = i;
 260           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 261         }
 262       return;
 263
 264     case ADDRESS:
 265       match_rtx (XEXP (x, 0), path, fail_label);
 266       return;
 267     }
 268
 269   printf ("  x = ");
 270   print_path (path);
 271   printf (";\n");
 272
 273   printf ("  if (GET_CODE (x) != ");
 274   print_code (code);
 275   printf (") goto L%d;\n", fail_label);
 276
 277   if (GET_MODE (x) != VOIDmode)
 278     {
 279       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 280               GET_MODE_NAME (GET_MODE (x)), fail_label);
 281     }
 282
 283   link.next = path;
 284   link.vecelt = -1;
 285   fmt = GET_RTX_FORMAT (code);
 286   len = GET_RTX_LENGTH (code);
 287   for (i = 0; i < len; i++)
 288     {
 289       link.pos = i;
 290       if (fmt[i] == 'e' || fmt[i] == 'u')
 291         match_rtx (XEXP (x, i), &link, fail_label);
 292       else if (fmt[i] == 'E')
 293         {
 294           int j;
 295           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 296                   i, XVECLEN (x, i), fail_label);
 297           for (j = 0; j < XVECLEN (x, i); j++)
 298             {
 299               link.vecelt = j;
 300               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 301             }
 302         }
 303       else if (fmt[i] == 'i')
 304         {
 305           /* Make sure that at run time `x' is the RTX we want to test.  */
 306           if (i != 0)
 307             {
 308               printf ("  x = ");
 309               print_path (path);
 310               printf (";\n");
 311             }
 312
 313           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 314                   i, XINT (x, i), fail_label);
 315         }
 316       else if (fmt[i] == 'w')
 317         {
 318           /* Make sure that at run time `x' is the RTX we want to test.  */
 319           if (i != 0)
 320             {
 321               printf ("  x = ");
 322               print_path (path);
 323               printf (";\n");
 324             }
 325
 326 #if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_INT
 327           printf ("  if (XWINT (x, %d) != %d) goto L%d;\n",
 328                   i, XWINT (x, i), fail_label);
 329 #else
 330           printf ("  if (XWINT (x, %d) != %ld) goto L%d;\n",
 331                   i, XWINT (x, i), fail_label);
 332 #endif
 333         }
 334       else if (fmt[i] == 's')
 335         {
 336           /* Make sure that at run time `x' is the RTX we want to test.  */
 337           if (i != 0)
 338             {
 339               printf ("  x = ");
 340               print_path (path);
 341               printf (";\n");
 342             }
 343
 344           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 345                   i, XSTR (x, i), fail_label);
 346         }
 347     }
 348 }
 349
 350 /* Given a PATH, representing a path down the instruction's
 351    pattern from the root to a certain point, output code to
 352    evaluate to the rtx at that point.  */
 353
 354 static void
 355 print_path (path)
 356      struct link *path;
 357 {
 358   if (path == 0)
 359     printf ("pat");
 360   else if (path->vecelt >= 0)
 361     {
 362       printf ("XVECEXP (");
 363       print_path (path->next);
 364       printf (", %d, %d)", path->pos, path->vecelt);
 365     }
 366   else
 367     {
 368       printf ("XEXP (");
 369       print_path (path->next);
 370       printf (", %d)", path->pos);
 371     }
 372 }
 373 \f
 374 static void
 375 print_code (code)
 376      RTX_CODE code;
 377 {
 378   register char *p1;
 379   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 380     {
 381       if (*p1 >= 'a' && *p1 <= 'z')
 382         putchar (*p1 + 'A' - 'a');
 383       else
 384         putchar (*p1);
 385     }
 386 }
 387 \f
 388 char *
 389 xmalloc (size)
 390      unsigned size;
 391 {
 392   register char *val = (char *) malloc (size);
 393
 394   if (val == 0)
 395     fatal ("virtual memory exhausted");
 396   return val;
 397 }
 398
 399 char *
 400 xrealloc (ptr, size)
 401      char *ptr;
 402      unsigned size;
 403 {
 404   char *result = (char *) realloc (ptr, size);
 405   if (!result)
 406     fatal ("virtual memory exhausted");
 407   return result;
 408 }
 409
 410 static void
 411 fatal (s, a1, a2)
 412      char *s;
 413 {
 414   fprintf (stderr, "genpeep: ");
 415   fprintf (stderr, s, a1, a2);
 416   fprintf (stderr, "\n");
 417   exit (FATAL_EXIT_CODE);
 418 }
 419
 420 /* More 'friendly' abort that prints the line and file.
 421    config.h can #define abort fancy_abort if you like that sort of thing.  */
 422
 423 void
 424 fancy_abort ()
 425 {
 426   fatal ("Internal gcc abort.");
 427 }
 428 \f
 429 int
 430 main (argc, argv)
 431      int argc;
 432      char **argv;
 433 {
 434   rtx desc;
 435   FILE *infile;
 436   register int c;
 437
 438   max_opno = -1;
 439
 440   obstack_init (rtl_obstack);
 441
 442   if (argc <= 1)
 443     fatal ("No input file name.");
 444
 445   infile = fopen (argv[1], "r");
 446   if (infile == 0)
 447     {
 448       perror (argv[1]);
 449       exit (FATAL_EXIT_CODE);
 450     }
 451
 452   init_rtl ();
 453
 454   printf ("/* Generated automatically by the program `genpeep'\n\
 455 from the machine description file `md'.  */\n\n");
 456
 457   printf ("#include \"config.h\"\n");
 458   printf ("#include \"rtl.h\"\n");
 459   printf ("#include \"regs.h\"\n");
 460   printf ("#include \"output.h\"\n");
 461   printf ("#include \"real.h\"\n\n");
 462
 463   printf ("extern rtx peep_operand[];\n\n");
 464   printf ("#define operands peep_operand\n\n");
 465
 466   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 467   printf ("  rtx insn, x, pat;\n");
 468   printf ("  int i;\n\n");
 469
 470   /* Early out: no peepholes for insns followed by barriers.  */
 471   printf ("  if (NEXT_INSN (ins1)\n");
 472   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 473   printf ("    return 0;\n\n");
 474
 475   /* Read the machine description.  */
 476
 477   while (1)
 478     {
 479       c = read_skip_spaces (infile);
 480       if (c == EOF)
 481         break;
 482       ungetc (c, infile);
 483
 484       desc = read_rtx (infile);
 485       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 486         {
 487           gen_peephole (desc);
 488           insn_code_number++;
 489         }
 490       if (GET_CODE (desc) == DEFINE_INSN
 491           || GET_CODE (desc) == DEFINE_EXPAND
 492           || GET_CODE (desc) == DEFINE_SPLIT)
 493         {
 494           insn_code_number++;
 495         }
 496     }
 497
 498   printf ("  return 0;\n}\n\n");
 499
 500   if (max_opno == -1)
 501     max_opno = 1;
 502
 503   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 504
 505   fflush (stdout);
 506   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 507   /* NOTREACHED */
 508   return 0;
 509 }