gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 89, 92, 97, 98, 1999 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 #include "errors.h"
  27
  28 static struct obstack obstack;
  29 struct obstack *rtl_obstack = &obstack;
  30
  31 #define obstack_chunk_alloc xmalloc
  32 #define obstack_chunk_free free
  33
  34 /* Define this so we can link with print-rtl.o to get debug_rtx function.  */
  35 char **insn_name_ptr = 0;
  36
  37 /* While tree-walking an instruction pattern, we keep a chain
  38    of these `struct link's to record how to get down to the
  39    current position.  In each one, POS is the operand number,
  40    and if the operand is a vector VEC is the element number.
  41    VEC is -1 if the operand is not a vector.  */
  42
  43 struct link
  44 {
  45   struct link *next;
  46   int pos;
  47   int vecelt;
  48 };
  49
  50 static int max_opno;
  51
  52 /* Number of operands used in current peephole definition.  */
  53
  54 static int n_operands;
  55
  56 /* Peephole optimizations get insn codes just like insn patterns.
  57    Count them so we know the code of the define_peephole we are handling.  */
  58
  59 static int insn_code_number = 0;
  60
  61 static void gen_peephole PROTO((rtx));
  62 static void match_rtx PROTO((rtx, struct link *, int));
  63 static void print_path PROTO((struct link *));
  64 static void print_code PROTO((RTX_CODE));
  65 \f
  66 static void
  67 gen_peephole (peep)
  68      rtx peep;
  69 {
  70   int ninsns = XVECLEN (peep, 0);
  71   int i;
  72
  73   n_operands = 0;
  74
  75   printf ("  insn = ins1;\n");
  76 #if 0
  77   printf ("  want_jump = 0;\n");
  78 #endif
  79
  80   for (i = 0; i < ninsns; i++)
  81     {
  82       if (i > 0)
  83         {
  84           printf ("  do { insn = NEXT_INSN (insn);\n");
  85           printf ("       if (insn == 0) goto L%d; }\n",
  86                   insn_code_number);
  87           printf ("  while (GET_CODE (insn) == NOTE\n");
  88           printf ("\t || (GET_CODE (insn) == INSN\n");
  89           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  90           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  91
  92           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  93       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  94                   insn_code_number);
  95         }
  96
  97 #if 0
  98       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
  99       printf ("    want_jump = JUMP_LABEL (insn);\n");
 100 #endif
 101
 102       printf ("  pat = PATTERN (insn);\n");
 103
 104       /* Walk the insn's pattern, remembering at all times the path
 105          down to the walking point.  */
 106
 107       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 108     }
 109
 110   /* We get this far if the pattern matches.
 111      Now test the extra condition.  */
 112
 113   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 114     printf ("  if (! (%s)) goto L%d;\n",
 115             XSTR (peep, 1), insn_code_number);
 116
 117   /* If that matches, construct new pattern and put it in the first insn.
 118      This new pattern will never be matched.
 119      It exists only so that insn-extract can get the operands back.
 120      So use a simple regular form: a PARALLEL containing a vector
 121      of all the operands.  */
 122
 123   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 124
 125 #if 0
 126   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 127   printf ("    {\n");
 128   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 129   printf ("      delete_insn (ins1);\n");
 130   printf ("      ins1 = ins2;\n");
 131   printf ("    }\n");
 132 #endif
 133
 134   /* Record this define_peephole's insn code in the insn,
 135      as if it had been recognized to match this.  */
 136   printf ("  INSN_CODE (ins1) = %d;\n",
 137           insn_code_number);
 138
 139   /* Delete the remaining insns.  */
 140   if (ninsns > 1)
 141     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 142
 143   /* See reload1.c for insertion of NOTE which guarantees that this
 144      cannot be zero.  */
 145   printf ("  return NEXT_INSN (insn);\n");
 146
 147   printf (" L%d:\n\n", insn_code_number);
 148 }
 149 \f
 150 static void
 151 match_rtx (x, path, fail_label)
 152      rtx x;
 153      struct link *path;
 154      int fail_label;
 155 {
 156   register RTX_CODE code;
 157   register int i;
 158   register int len;
 159   register const char *fmt;
 160   struct link link;
 161
 162   if (x == 0)
 163     return;
 164
 165
 166   code = GET_CODE (x);
 167
 168   switch (code)
 169     {
 170     case MATCH_OPERAND:
 171       if (XINT (x, 0) > max_opno)
 172         max_opno = XINT (x, 0);
 173       if (XINT (x, 0) >= n_operands)
 174         n_operands = 1 + XINT (x, 0);
 175
 176       printf ("  x = ");
 177       print_path (path);
 178       printf (";\n");
 179
 180       printf ("  operands[%d] = x;\n", XINT (x, 0));
 181       if (XSTR (x, 1) && XSTR (x, 1)[0])
 182         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 183                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 184       return;
 185
 186     case MATCH_DUP:
 187     case MATCH_PAR_DUP:
 188       printf ("  x = ");
 189       print_path (path);
 190       printf (";\n");
 191
 192       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 193               XINT (x, 0), fail_label);
 194       return;
 195
 196     case MATCH_OP_DUP:
 197       printf ("  x = ");
 198       print_path (path);
 199       printf (";\n");
 200
 201       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 202       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 203               XINT (x, 0), fail_label);
 204       printf ("  operands[%d] = x;\n", XINT (x, 0));
 205       link.next = path;
 206       link.vecelt = -1;
 207       for (i = 0; i < XVECLEN (x, 1); i++)
 208         {
 209           link.pos = i;
 210           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 211         }
 212       return;
 213
 214     case MATCH_OPERATOR:
 215       if (XINT (x, 0) > max_opno)
 216         max_opno = XINT (x, 0);
 217       if (XINT (x, 0) >= n_operands)
 218         n_operands = 1 + XINT (x, 0);
 219
 220       printf ("  x = ");
 221       print_path (path);
 222       printf (";\n");
 223
 224       printf ("  operands[%d] = x;\n", XINT (x, 0));
 225       if (XSTR (x, 1) && XSTR (x, 1)[0])
 226         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 227                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 228       link.next = path;
 229       link.vecelt = -1;
 230       for (i = 0; i < XVECLEN (x, 2); i++)
 231         {
 232           link.pos = i;
 233           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 234         }
 235       return;
 236
 237     case MATCH_PARALLEL:
 238       if (XINT (x, 0) > max_opno)
 239         max_opno = XINT (x, 0);
 240       if (XINT (x, 0) >= n_operands)
 241         n_operands = 1 + XINT (x, 0);
 242
 243       printf ("  x = ");
 244       print_path (path);
 245       printf (";\n");
 246
 247       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 248       printf ("  operands[%d] = x;\n", XINT (x, 0));
 249       if (XSTR (x, 1) && XSTR (x, 1)[0])
 250         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 251                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 252       link.next = path;
 253       link.pos = 0;
 254       for (i = 0; i < XVECLEN (x, 2); i++)
 255         {
 256           link.vecelt = i;
 257           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 258         }
 259       return;
 260
 261     case ADDRESS:
 262       match_rtx (XEXP (x, 0), path, fail_label);
 263       return;
 264
 265     default:
 266       break;
 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           printf ("  if (XWINT (x, %d) != ", i);
 327           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 328           printf (") goto L%d;\n", fail_label);
 329         }
 330       else if (fmt[i] == 's')
 331         {
 332           /* Make sure that at run time `x' is the RTX we want to test.  */
 333           if (i != 0)
 334             {
 335               printf ("  x = ");
 336               print_path (path);
 337               printf (";\n");
 338             }
 339
 340           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 341                   i, XSTR (x, i), fail_label);
 342         }
 343     }
 344 }
 345
 346 /* Given a PATH, representing a path down the instruction's
 347    pattern from the root to a certain point, output code to
 348    evaluate to the rtx at that point.  */
 349
 350 static void
 351 print_path (path)
 352      struct link *path;
 353 {
 354   if (path == 0)
 355     printf ("pat");
 356   else if (path->vecelt >= 0)
 357     {
 358       printf ("XVECEXP (");
 359       print_path (path->next);
 360       printf (", %d, %d)", path->pos, path->vecelt);
 361     }
 362   else
 363     {
 364       printf ("XEXP (");
 365       print_path (path->next);
 366       printf (", %d)", path->pos);
 367     }
 368 }
 369 \f
 370 static void
 371 print_code (code)
 372      RTX_CODE code;
 373 {
 374   register const char *p1;
 375   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 376     {
 377       if (*p1 >= 'a' && *p1 <= 'z')
 378         putchar (*p1 + 'A' - 'a');
 379       else
 380         putchar (*p1);
 381     }
 382 }
 383 \f
 384 PTR
 385 xmalloc (size)
 386   size_t size;
 387 {
 388   register PTR val = (PTR) malloc (size);
 389
 390   if (val == 0)
 391     fatal ("virtual memory exhausted");
 392   return val;
 393 }
 394
 395 PTR
 396 xrealloc (old, size)
 397   PTR old;
 398   size_t size;
 399 {
 400   register PTR ptr;
 401   if (old)
 402     ptr = (PTR) realloc (old, size);
 403   else
 404     ptr = (PTR) malloc (size);
 405   if (!ptr)
 406     fatal ("virtual memory exhausted");
 407   return ptr;
 408 }
 409
 410 int
 411 main (argc, argv)
 412      int argc;
 413      char **argv;
 414 {
 415   rtx desc;
 416   FILE *infile;
 417   register int c;
 418
 419   max_opno = -1;
 420
 421   progname = "genpeep";
 422   obstack_init (rtl_obstack);
 423
 424   if (argc <= 1)
 425     fatal ("No input file name.");
 426
 427   infile = fopen (argv[1], "r");
 428   if (infile == 0)
 429     {
 430       perror (argv[1]);
 431       exit (FATAL_EXIT_CODE);
 432     }
 433
 434   printf ("/* Generated automatically by the program `genpeep'\n\
 435 from the machine description file `md'.  */\n\n");
 436
 437   printf ("#include \"config.h\"\n");
 438   printf ("#include \"system.h\"\n");
 439   printf ("#include \"insn-config.h\"\n");
 440   printf ("#include \"rtl.h\"\n");
 441   printf ("#include \"regs.h\"\n");
 442   printf ("#include \"output.h\"\n");
 443   printf ("#include \"real.h\"\n");
 444   printf ("#include \"recog.h\"\n");
 445   printf ("#include \"except.h\"\n\n");
 446   printf ("#include \"function.h\"\n\n");
 447
 448   printf ("#ifdef HAVE_peephole\n");
 449   printf ("extern rtx peep_operand[];\n\n");
 450   printf ("#define operands peep_operand\n\n");
 451
 452   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 453   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 454
 455   /* Early out: no peepholes for insns followed by barriers.  */
 456   printf ("  if (NEXT_INSN (ins1)\n");
 457   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 458   printf ("    return 0;\n\n");
 459
 460   /* Read the machine description.  */
 461
 462   while (1)
 463     {
 464       c = read_skip_spaces (infile);
 465       if (c == EOF)
 466         break;
 467       ungetc (c, infile);
 468
 469       desc = read_rtx (infile);
 470       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 471         {
 472           gen_peephole (desc);
 473           insn_code_number++;
 474         }
 475       if (GET_CODE (desc) == DEFINE_INSN
 476           || GET_CODE (desc) == DEFINE_EXPAND
 477           || GET_CODE (desc) == DEFINE_SPLIT)
 478         {
 479           insn_code_number++;
 480         }
 481     }
 482
 483   printf ("  return 0;\n}\n\n");
 484
 485   if (max_opno == -1)
 486     max_opno = 1;
 487
 488   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 489   printf ("#endif\n");
 490
 491   fflush (stdout);
 492   exit (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 493   /* NOTREACHED */
 494   return 0;
 495 }