gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992, 1997, 1998,
   3    1999, 2000, 2003, 2004 Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 2, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING.  If not, write to the Free
  19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20 02110-1301, USA.  */
  21
  22
  23 #include "bconfig.h"
  24 #include "system.h"
  25 #include "coretypes.h"
  26 #include "tm.h"
  27 #include "rtl.h"
  28 #include "errors.h"
  29 #include "gensupport.h"
  30
  31
  32 /* While tree-walking an instruction pattern, we keep a chain
  33    of these `struct link's to record how to get down to the
  34    current position.  In each one, POS is the operand number,
  35    and if the operand is a vector VEC is the element number.
  36    VEC is -1 if the operand is not a vector.  */
  37
  38 struct link
  39 {
  40   struct link *next;
  41   int pos;
  42   int vecelt;
  43 };
  44
  45 static int max_opno;
  46
  47 /* Number of operands used in current peephole definition.  */
  48
  49 static int n_operands;
  50
  51 /* Peephole optimizations get insn codes just like insn patterns.
  52    Count them so we know the code of the define_peephole we are handling.  */
  53
  54 static int insn_code_number = 0;
  55
  56 static void gen_peephole (rtx);
  57 static void match_rtx (rtx, struct link *, int);
  58 static void print_path (struct link *);
  59 static void print_code (RTX_CODE);
  60 \f
  61 static void
  62 gen_peephole (rtx peep)
  63 {
  64   int ninsns = XVECLEN (peep, 0);
  65   int i;
  66
  67   n_operands = 0;
  68
  69   printf ("  insn = ins1;\n");
  70
  71   for (i = 0; i < ninsns; i++)
  72     {
  73       if (i > 0)
  74         {
  75           printf ("  do { insn = NEXT_INSN (insn);\n");
  76           printf ("       if (insn == 0) goto L%d; }\n",
  77                   insn_code_number);
  78           printf ("  while (NOTE_P (insn)\n");
  79           printf ("\t || (NONJUMP_INSN_P (insn)\n");
  80           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  81           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  82
  83           printf ("  if (LABEL_P (insn)\n\
  84       || BARRIER_P (insn))\n    goto L%d;\n",
  85                   insn_code_number);
  86         }
  87
  88       printf ("  pat = PATTERN (insn);\n");
  89
  90       /* Walk the insn's pattern, remembering at all times the path
  91          down to the walking point.  */
  92
  93       match_rtx (XVECEXP (peep, 0, i), NULL, insn_code_number);
  94     }
  95
  96   /* We get this far if the pattern matches.
  97      Now test the extra condition.  */
  98
  99   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 100     printf ("  if (! (%s)) goto L%d;\n",
 101             XSTR (peep, 1), insn_code_number);
 102
 103   /* If that matches, construct new pattern and put it in the first insn.
 104      This new pattern will never be matched.
 105      It exists only so that insn-extract can get the operands back.
 106      So use a simple regular form: a PARALLEL containing a vector
 107      of all the operands.  */
 108
 109   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 110
 111   /* Record this define_peephole's insn code in the insn,
 112      as if it had been recognized to match this.  */
 113   printf ("  INSN_CODE (ins1) = %d;\n",
 114           insn_code_number);
 115
 116   /* Delete the remaining insns.  */
 117   if (ninsns > 1)
 118     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 119
 120   /* See reload1.c for insertion of NOTE which guarantees that this
 121      cannot be zero.  */
 122   printf ("  return NEXT_INSN (insn);\n");
 123
 124   printf (" L%d:\n\n", insn_code_number);
 125 }
 126 \f
 127 static void
 128 match_rtx (rtx x, struct link *path, int fail_label)
 129 {
 130   RTX_CODE code;
 131   int i;
 132   int len;
 133   const char *fmt;
 134   struct link link;
 135
 136   if (x == 0)
 137     return;
 138
 139
 140   code = GET_CODE (x);
 141
 142   switch (code)
 143     {
 144     case MATCH_OPERAND:
 145       if (XINT (x, 0) > max_opno)
 146         max_opno = XINT (x, 0);
 147       if (XINT (x, 0) >= n_operands)
 148         n_operands = 1 + XINT (x, 0);
 149
 150       printf ("  x = ");
 151       print_path (path);
 152       printf (";\n");
 153
 154       printf ("  operands[%d] = x;\n", XINT (x, 0));
 155       if (XSTR (x, 1) && XSTR (x, 1)[0])
 156         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 157                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 158       return;
 159
 160     case MATCH_DUP:
 161     case MATCH_PAR_DUP:
 162       printf ("  x = ");
 163       print_path (path);
 164       printf (";\n");
 165
 166       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 167               XINT (x, 0), fail_label);
 168       return;
 169
 170     case MATCH_OP_DUP:
 171       printf ("  x = ");
 172       print_path (path);
 173       printf (";\n");
 174
 175       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 176       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 177               XINT (x, 0), fail_label);
 178       printf ("  operands[%d] = x;\n", XINT (x, 0));
 179       link.next = path;
 180       link.vecelt = -1;
 181       for (i = 0; i < XVECLEN (x, 1); i++)
 182         {
 183           link.pos = i;
 184           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 185         }
 186       return;
 187
 188     case MATCH_OPERATOR:
 189       if (XINT (x, 0) > max_opno)
 190         max_opno = XINT (x, 0);
 191       if (XINT (x, 0) >= n_operands)
 192         n_operands = 1 + XINT (x, 0);
 193
 194       printf ("  x = ");
 195       print_path (path);
 196       printf (";\n");
 197
 198       printf ("  operands[%d] = x;\n", XINT (x, 0));
 199       if (XSTR (x, 1) && XSTR (x, 1)[0])
 200         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 201                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 202       link.next = path;
 203       link.vecelt = -1;
 204       for (i = 0; i < XVECLEN (x, 2); i++)
 205         {
 206           link.pos = i;
 207           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 208         }
 209       return;
 210
 211     case MATCH_PARALLEL:
 212       if (XINT (x, 0) > max_opno)
 213         max_opno = XINT (x, 0);
 214       if (XINT (x, 0) >= n_operands)
 215         n_operands = 1 + XINT (x, 0);
 216
 217       printf ("  x = ");
 218       print_path (path);
 219       printf (";\n");
 220
 221       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 222       printf ("  operands[%d] = x;\n", XINT (x, 0));
 223       if (XSTR (x, 1) && XSTR (x, 1)[0])
 224         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 225                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 226       link.next = path;
 227       link.pos = 0;
 228       for (i = 0; i < XVECLEN (x, 2); i++)
 229         {
 230           link.vecelt = i;
 231           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 232         }
 233       return;
 234
 235     case ADDRESS:
 236       match_rtx (XEXP (x, 0), path, fail_label);
 237       return;
 238
 239     default:
 240       break;
 241     }
 242
 243   printf ("  x = ");
 244   print_path (path);
 245   printf (";\n");
 246
 247   printf ("  if (GET_CODE (x) != ");
 248   print_code (code);
 249   printf (") goto L%d;\n", fail_label);
 250
 251   if (GET_MODE (x) != VOIDmode)
 252     {
 253       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 254               GET_MODE_NAME (GET_MODE (x)), fail_label);
 255     }
 256
 257   link.next = path;
 258   link.vecelt = -1;
 259   fmt = GET_RTX_FORMAT (code);
 260   len = GET_RTX_LENGTH (code);
 261   for (i = 0; i < len; i++)
 262     {
 263       link.pos = i;
 264       if (fmt[i] == 'e' || fmt[i] == 'u')
 265         match_rtx (XEXP (x, i), &link, fail_label);
 266       else if (fmt[i] == 'E')
 267         {
 268           int j;
 269           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 270                   i, XVECLEN (x, i), fail_label);
 271           for (j = 0; j < XVECLEN (x, i); j++)
 272             {
 273               link.vecelt = j;
 274               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 275             }
 276         }
 277       else if (fmt[i] == 'i')
 278         {
 279           /* Make sure that at run time `x' is the RTX we want to test.  */
 280           if (i != 0)
 281             {
 282               printf ("  x = ");
 283               print_path (path);
 284               printf (";\n");
 285             }
 286
 287           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 288                   i, XINT (x, i), fail_label);
 289         }
 290       else if (fmt[i] == 'w')
 291         {
 292           /* Make sure that at run time `x' is the RTX we want to test.  */
 293           if (i != 0)
 294             {
 295               printf ("  x = ");
 296               print_path (path);
 297               printf (";\n");
 298             }
 299
 300           printf ("  if (XWINT (x, %d) != ", i);
 301           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 302           printf (") goto L%d;\n", fail_label);
 303         }
 304       else if (fmt[i] == 's')
 305         {
 306           /* Make sure that at run time `x' is the RTX we want to test.  */
 307           if (i != 0)
 308             {
 309               printf ("  x = ");
 310               print_path (path);
 311               printf (";\n");
 312             }
 313
 314           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 315                   i, XSTR (x, i), fail_label);
 316         }
 317     }
 318 }
 319
 320 /* Given a PATH, representing a path down the instruction's
 321    pattern from the root to a certain point, output code to
 322    evaluate to the rtx at that point.  */
 323
 324 static void
 325 print_path (struct link *path)
 326 {
 327   if (path == 0)
 328     printf ("pat");
 329   else if (path->vecelt >= 0)
 330     {
 331       printf ("XVECEXP (");
 332       print_path (path->next);
 333       printf (", %d, %d)", path->pos, path->vecelt);
 334     }
 335   else
 336     {
 337       printf ("XEXP (");
 338       print_path (path->next);
 339       printf (", %d)", path->pos);
 340     }
 341 }
 342 \f
 343 static void
 344 print_code (RTX_CODE code)
 345 {
 346   const char *p1;
 347   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 348     putchar (TOUPPER(*p1));
 349 }
 350
 351 extern int main (int, char **);
 352
 353 int
 354 main (int argc, char **argv)
 355 {
 356   rtx desc;
 357
 358   max_opno = -1;
 359
 360   progname = "genpeep";
 361
 362   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 363     return (FATAL_EXIT_CODE);
 364
 365   printf ("/* Generated automatically by the program `genpeep'\n\
 366 from the machine description file `md'.  */\n\n");
 367
 368   printf ("#include \"config.h\"\n");
 369   printf ("#include \"system.h\"\n");
 370   printf ("#include \"coretypes.h\"\n");
 371   printf ("#include \"tm.h\"\n");
 372   printf ("#include \"insn-config.h\"\n");
 373   printf ("#include \"rtl.h\"\n");
 374   printf ("#include \"tm_p.h\"\n");
 375   printf ("#include \"regs.h\"\n");
 376   printf ("#include \"output.h\"\n");
 377   printf ("#include \"real.h\"\n");
 378   printf ("#include \"recog.h\"\n");
 379   printf ("#include \"except.h\"\n\n");
 380   printf ("#include \"function.h\"\n\n");
 381
 382   printf ("#ifdef HAVE_peephole\n");
 383   printf ("extern rtx peep_operand[];\n\n");
 384   printf ("#define operands peep_operand\n\n");
 385
 386   printf ("rtx\npeephole (rtx ins1)\n{\n");
 387   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 388
 389   /* Early out: no peepholes for insns followed by barriers.  */
 390   printf ("  if (NEXT_INSN (ins1)\n");
 391   printf ("      && BARRIER_P (NEXT_INSN (ins1)))\n");
 392   printf ("    return 0;\n\n");
 393
 394   /* Read the machine description.  */
 395
 396   while (1)
 397     {
 398       int line_no, rtx_number = 0;
 399
 400       desc = read_md_rtx (&line_no, &rtx_number);
 401       if (desc == NULL)
 402         break;
 403
 404        if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 405         {
 406           gen_peephole (desc);
 407           insn_code_number++;
 408         }
 409       if (GET_CODE (desc) == DEFINE_INSN
 410           || GET_CODE (desc) == DEFINE_EXPAND
 411           || GET_CODE (desc) == DEFINE_SPLIT
 412           || GET_CODE (desc) == DEFINE_PEEPHOLE2)
 413         {
 414           insn_code_number++;
 415         }
 416     }
 417
 418   printf ("  return 0;\n}\n\n");
 419
 420   if (max_opno == -1)
 421     max_opno = 1;
 422
 423   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 424   printf ("#endif\n");
 425
 426   fflush (stdout);
 427   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 428 }
 429
 430 /* Define this so we can link with print-rtl.o to get debug_rtx function.  */
 431 const char *
 432 get_insn_name (int code ATTRIBUTE_UNUSED)
 433 {
 434   return NULL;
 435 }