gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 1989, 1992, 1997, 1998, 1999, 2000, 2003, 2004,
   3    2007  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 3, 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 COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21
  22 #include "bconfig.h"
  23 #include "system.h"
  24 #include "coretypes.h"
  25 #include "tm.h"
  26 #include "rtl.h"
  27 #include "errors.h"
  28 #include "gensupport.h"
  29
  30
  31 /* While tree-walking an instruction pattern, we keep a chain
  32    of these `struct link's to record how to get down to the
  33    current position.  In each one, POS is the operand number,
  34    and if the operand is a vector VEC is the element number.
  35    VEC is -1 if the operand is not a vector.  */
  36
  37 struct link
  38 {
  39   struct link *next;
  40   int pos;
  41   int vecelt;
  42 };
  43
  44 static int max_opno;
  45
  46 /* Number of operands used in current peephole definition.  */
  47
  48 static int n_operands;
  49
  50 /* Peephole optimizations get insn codes just like insn patterns.
  51    Count them so we know the code of the define_peephole we are handling.  */
  52
  53 static int insn_code_number = 0;
  54
  55 static void gen_peephole (rtx);
  56 static void match_rtx (rtx, struct link *, int);
  57 static void print_path (struct link *);
  58 static void print_code (RTX_CODE);
  59 \f
  60 static void
  61 gen_peephole (rtx peep)
  62 {
  63   int ninsns = XVECLEN (peep, 0);
  64   int i;
  65
  66   n_operands = 0;
  67
  68   printf ("  insn = ins1;\n");
  69
  70   for (i = 0; i < ninsns; i++)
  71     {
  72       if (i > 0)
  73         {
  74           printf ("  do { insn = NEXT_INSN (insn);\n");
  75           printf ("       if (insn == 0) goto L%d; }\n",
  76                   insn_code_number);
  77           printf ("  while (NOTE_P (insn)\n");
  78           printf ("\t || (NONJUMP_INSN_P (insn)\n");
  79           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  80           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  81
  82           printf ("  if (LABEL_P (insn)\n\
  83       || BARRIER_P (insn))\n    goto L%d;\n",
  84                   insn_code_number);
  85         }
  86
  87       printf ("  pat = PATTERN (insn);\n");
  88
  89       /* Walk the insn's pattern, remembering at all times the path
  90          down to the walking point.  */
  91
  92       match_rtx (XVECEXP (peep, 0, i), NULL, insn_code_number);
  93     }
  94
  95   /* We get this far if the pattern matches.
  96      Now test the extra condition.  */
  97
  98   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
  99     printf ("  if (! (%s)) goto L%d;\n",
 100             XSTR (peep, 1), insn_code_number);
 101
 102   /* If that matches, construct new pattern and put it in the first insn.
 103      This new pattern will never be matched.
 104      It exists only so that insn-extract can get the operands back.
 105      So use a simple regular form: a PARALLEL containing a vector
 106      of all the operands.  */
 107
 108   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 109
 110   /* Record this define_peephole's insn code in the insn,
 111      as if it had been recognized to match this.  */
 112   printf ("  INSN_CODE (ins1) = %d;\n",
 113           insn_code_number);
 114
 115   /* Delete the remaining insns.  */
 116   if (ninsns > 1)
 117     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 118
 119   /* See reload1.c for insertion of NOTE which guarantees that this
 120      cannot be zero.  */
 121   printf ("  return NEXT_INSN (insn);\n");
 122
 123   printf (" L%d:\n\n", insn_code_number);
 124 }
 125 \f
 126 static void
 127 match_rtx (rtx x, struct link *path, int fail_label)
 128 {
 129   RTX_CODE code;
 130   int i;
 131   int len;
 132   const char *fmt;
 133   struct link link;
 134
 135   if (x == 0)
 136     return;
 137
 138
 139   code = GET_CODE (x);
 140
 141   switch (code)
 142     {
 143     case MATCH_OPERAND:
 144       if (XINT (x, 0) > max_opno)
 145         max_opno = XINT (x, 0);
 146       if (XINT (x, 0) >= n_operands)
 147         n_operands = 1 + XINT (x, 0);
 148
 149       printf ("  x = ");
 150       print_path (path);
 151       printf (";\n");
 152
 153       printf ("  operands[%d] = x;\n", XINT (x, 0));
 154       if (XSTR (x, 1) && XSTR (x, 1)[0])
 155         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 156                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 157       return;
 158
 159     case MATCH_DUP:
 160     case MATCH_PAR_DUP:
 161       printf ("  x = ");
 162       print_path (path);
 163       printf (";\n");
 164
 165       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 166               XINT (x, 0), fail_label);
 167       return;
 168
 169     case MATCH_OP_DUP:
 170       printf ("  x = ");
 171       print_path (path);
 172       printf (";\n");
 173
 174       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 175       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 176               XINT (x, 0), fail_label);
 177       printf ("  operands[%d] = x;\n", XINT (x, 0));
 178       link.next = path;
 179       link.vecelt = -1;
 180       for (i = 0; i < XVECLEN (x, 1); i++)
 181         {
 182           link.pos = i;
 183           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 184         }
 185       return;
 186
 187     case MATCH_OPERATOR:
 188       if (XINT (x, 0) > max_opno)
 189         max_opno = XINT (x, 0);
 190       if (XINT (x, 0) >= n_operands)
 191         n_operands = 1 + XINT (x, 0);
 192
 193       printf ("  x = ");
 194       print_path (path);
 195       printf (";\n");
 196
 197       printf ("  operands[%d] = x;\n", XINT (x, 0));
 198       if (XSTR (x, 1) && XSTR (x, 1)[0])
 199         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 200                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 201       link.next = path;
 202       link.vecelt = -1;
 203       for (i = 0; i < XVECLEN (x, 2); i++)
 204         {
 205           link.pos = i;
 206           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 207         }
 208       return;
 209
 210     case MATCH_PARALLEL:
 211       if (XINT (x, 0) > max_opno)
 212         max_opno = XINT (x, 0);
 213       if (XINT (x, 0) >= n_operands)
 214         n_operands = 1 + XINT (x, 0);
 215
 216       printf ("  x = ");
 217       print_path (path);
 218       printf (";\n");
 219
 220       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 221       printf ("  operands[%d] = x;\n", XINT (x, 0));
 222       if (XSTR (x, 1) && XSTR (x, 1)[0])
 223         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 224                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 225       link.next = path;
 226       link.pos = 0;
 227       for (i = 0; i < XVECLEN (x, 2); i++)
 228         {
 229           link.vecelt = i;
 230           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 231         }
 232       return;
 233
 234     case ADDRESS:
 235       match_rtx (XEXP (x, 0), path, fail_label);
 236       return;
 237
 238     default:
 239       break;
 240     }
 241
 242   printf ("  x = ");
 243   print_path (path);
 244   printf (";\n");
 245
 246   printf ("  if (GET_CODE (x) != ");
 247   print_code (code);
 248   printf (") goto L%d;\n", fail_label);
 249
 250   if (GET_MODE (x) != VOIDmode)
 251     {
 252       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 253               GET_MODE_NAME (GET_MODE (x)), fail_label);
 254     }
 255
 256   link.next = path;
 257   link.vecelt = -1;
 258   fmt = GET_RTX_FORMAT (code);
 259   len = GET_RTX_LENGTH (code);
 260   for (i = 0; i < len; i++)
 261     {
 262       link.pos = i;
 263       if (fmt[i] == 'e' || fmt[i] == 'u')
 264         match_rtx (XEXP (x, i), &link, fail_label);
 265       else if (fmt[i] == 'E')
 266         {
 267           int j;
 268           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 269                   i, XVECLEN (x, i), fail_label);
 270           for (j = 0; j < XVECLEN (x, i); j++)
 271             {
 272               link.vecelt = j;
 273               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 274             }
 275         }
 276       else if (fmt[i] == 'i')
 277         {
 278           /* Make sure that at run time `x' is the RTX we want to test.  */
 279           if (i != 0)
 280             {
 281               printf ("  x = ");
 282               print_path (path);
 283               printf (";\n");
 284             }
 285
 286           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 287                   i, XINT (x, i), fail_label);
 288         }
 289       else if (fmt[i] == 'w')
 290         {
 291           /* Make sure that at run time `x' is the RTX we want to test.  */
 292           if (i != 0)
 293             {
 294               printf ("  x = ");
 295               print_path (path);
 296               printf (";\n");
 297             }
 298
 299           printf ("  if (XWINT (x, %d) != ", i);
 300           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 301           printf (") goto L%d;\n", fail_label);
 302         }
 303       else if (fmt[i] == 's')
 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 (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 314                   i, XSTR (x, i), fail_label);
 315         }
 316     }
 317 }
 318
 319 /* Given a PATH, representing a path down the instruction's
 320    pattern from the root to a certain point, output code to
 321    evaluate to the rtx at that point.  */
 322
 323 static void
 324 print_path (struct link *path)
 325 {
 326   if (path == 0)
 327     printf ("pat");
 328   else if (path->vecelt >= 0)
 329     {
 330       printf ("XVECEXP (");
 331       print_path (path->next);
 332       printf (", %d, %d)", path->pos, path->vecelt);
 333     }
 334   else
 335     {
 336       printf ("XEXP (");
 337       print_path (path->next);
 338       printf (", %d)", path->pos);
 339     }
 340 }
 341 \f
 342 static void
 343 print_code (RTX_CODE code)
 344 {
 345   const char *p1;
 346   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 347     putchar (TOUPPER(*p1));
 348 }
 349
 350 extern int main (int, char **);
 351
 352 int
 353 main (int argc, char **argv)
 354 {
 355   rtx desc;
 356
 357   max_opno = -1;
 358
 359   progname = "genpeep";
 360
 361   if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
 362     return (FATAL_EXIT_CODE);
 363
 364   printf ("/* Generated automatically by the program `genpeep'\n\
 365 from the machine description file `md'.  */\n\n");
 366
 367   printf ("#include \"config.h\"\n");
 368   printf ("#include \"system.h\"\n");
 369   printf ("#include \"coretypes.h\"\n");
 370   printf ("#include \"tm.h\"\n");
 371   printf ("#include \"insn-config.h\"\n");
 372   printf ("#include \"rtl.h\"\n");
 373   printf ("#include \"tm_p.h\"\n");
 374   printf ("#include \"regs.h\"\n");
 375   printf ("#include \"output.h\"\n");
 376   printf ("#include \"real.h\"\n");
 377   printf ("#include \"recog.h\"\n");
 378   printf ("#include \"except.h\"\n");
 379   printf ("#include \"function.h\"\n");
 380   printf ("#include \"toplev.h\"\n");
 381   printf ("#include \"flags.h\"\n");
 382   printf ("#include \"tm-constrs.h\"\n\n");
 383
 384   printf ("#ifdef HAVE_peephole\n");
 385   printf ("extern rtx peep_operand[];\n\n");
 386   printf ("#define operands peep_operand\n\n");
 387
 388   printf ("rtx\npeephole (rtx ins1)\n{\n");
 389   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 390
 391   /* Early out: no peepholes for insns followed by barriers.  */
 392   printf ("  if (NEXT_INSN (ins1)\n");
 393   printf ("      && BARRIER_P (NEXT_INSN (ins1)))\n");
 394   printf ("    return 0;\n\n");
 395
 396   /* Read the machine description.  */
 397
 398   while (1)
 399     {
 400       int line_no, rtx_number = 0;
 401
 402       desc = read_md_rtx (&line_no, &rtx_number);
 403       if (desc == NULL)
 404         break;
 405
 406        if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 407         {
 408           gen_peephole (desc);
 409           insn_code_number++;
 410         }
 411       if (GET_CODE (desc) == DEFINE_INSN
 412           || GET_CODE (desc) == DEFINE_EXPAND
 413           || GET_CODE (desc) == DEFINE_SPLIT
 414           || GET_CODE (desc) == DEFINE_PEEPHOLE2)
 415         {
 416           insn_code_number++;
 417         }
 418     }
 419
 420   printf ("  return 0;\n}\n\n");
 421
 422   if (max_opno == -1)
 423     max_opno = 1;
 424
 425   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 426   printf ("#endif\n");
 427
 428   fflush (stdout);
 429   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 430 }