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