gcc/genpeep.c

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987, 89, 92, 97-99, 2000 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 /* While tree-walking an instruction pattern, we keep a chain
  35    of these `struct link's to record how to get down to the
  36    current position.  In each one, POS is the operand number,
  37    and if the operand is a vector VEC is the element number.
  38    VEC is -1 if the operand is not a vector.  */
  39
  40 struct link
  41 {
  42   struct link *next;
  43   int pos;
  44   int vecelt;
  45 };
  46
  47 static int max_opno;
  48
  49 /* Number of operands used in current peephole definition.  */
  50
  51 static int n_operands;
  52
  53 /* Peephole optimizations get insn codes just like insn patterns.
  54    Count them so we know the code of the define_peephole we are handling.  */
  55
  56 static int insn_code_number = 0;
  57
  58 static void gen_peephole PARAMS ((rtx));
  59 static void match_rtx PARAMS ((rtx, struct link *, int));
  60 static void print_path PARAMS ((struct link *));
  61 static void print_code PARAMS ((RTX_CODE));
  62 \f
  63 static void
  64 gen_peephole (peep)
  65      rtx peep;
  66 {
  67   int ninsns = XVECLEN (peep, 0);
  68   int i;
  69
  70   n_operands = 0;
  71
  72   printf ("  insn = ins1;\n");
  73 #if 0
  74   printf ("  want_jump = 0;\n");
  75 #endif
  76
  77   for (i = 0; i < ninsns; i++)
  78     {
  79       if (i > 0)
  80         {
  81           printf ("  do { insn = NEXT_INSN (insn);\n");
  82           printf ("       if (insn == 0) goto L%d; }\n",
  83                   insn_code_number);
  84           printf ("  while (GET_CODE (insn) == NOTE\n");
  85           printf ("\t || (GET_CODE (insn) == INSN\n");
  86           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  87           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  88
  89           printf ("  if (GET_CODE (insn) == CODE_LABEL\n\
  90       || GET_CODE (insn) == BARRIER)\n    goto L%d;\n",
  91                   insn_code_number);
  92         }
  93
  94 #if 0
  95       printf ("  if (GET_CODE (insn) == JUMP_INSN)\n");
  96       printf ("    want_jump = JUMP_LABEL (insn);\n");
  97 #endif
  98
  99       printf ("  pat = PATTERN (insn);\n");
 100
 101       /* Walk the insn's pattern, remembering at all times the path
 102          down to the walking point.  */
 103
 104       match_rtx (XVECEXP (peep, 0, i), NULL_PTR, insn_code_number);
 105     }
 106
 107   /* We get this far if the pattern matches.
 108      Now test the extra condition.  */
 109
 110   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
 111     printf ("  if (! (%s)) goto L%d;\n",
 112             XSTR (peep, 1), insn_code_number);
 113
 114   /* If that matches, construct new pattern and put it in the first insn.
 115      This new pattern will never be matched.
 116      It exists only so that insn-extract can get the operands back.
 117      So use a simple regular form: a PARALLEL containing a vector
 118      of all the operands.  */
 119
 120   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 121
 122 #if 0
 123   printf ("  if (want_jump && GET_CODE (ins1) != JUMP_INSN)\n");
 124   printf ("    {\n");
 125   printf ("      rtx insn2 = emit_jump_insn_before (PATTERN (ins1), ins1);\n");
 126   printf ("      delete_insn (ins1);\n");
 127   printf ("      ins1 = ins2;\n");
 128   printf ("    }\n");
 129 #endif
 130
 131   /* Record this define_peephole's insn code in the insn,
 132      as if it had been recognized to match this.  */
 133   printf ("  INSN_CODE (ins1) = %d;\n",
 134           insn_code_number);
 135
 136   /* Delete the remaining insns.  */
 137   if (ninsns > 1)
 138     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 139
 140   /* See reload1.c for insertion of NOTE which guarantees that this
 141      cannot be zero.  */
 142   printf ("  return NEXT_INSN (insn);\n");
 143
 144   printf (" L%d:\n\n", insn_code_number);
 145 }
 146 \f
 147 static void
 148 match_rtx (x, path, fail_label)
 149      rtx x;
 150      struct link *path;
 151      int fail_label;
 152 {
 153   register RTX_CODE code;
 154   register int i;
 155   register int len;
 156   register const char *fmt;
 157   struct link link;
 158
 159   if (x == 0)
 160     return;
 161
 162
 163   code = GET_CODE (x);
 164
 165   switch (code)
 166     {
 167     case MATCH_OPERAND:
 168       if (XINT (x, 0) > max_opno)
 169         max_opno = XINT (x, 0);
 170       if (XINT (x, 0) >= n_operands)
 171         n_operands = 1 + XINT (x, 0);
 172
 173       printf ("  x = ");
 174       print_path (path);
 175       printf (";\n");
 176
 177       printf ("  operands[%d] = x;\n", XINT (x, 0));
 178       if (XSTR (x, 1) && XSTR (x, 1)[0])
 179         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 180                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 181       return;
 182
 183     case MATCH_DUP:
 184     case MATCH_PAR_DUP:
 185       printf ("  x = ");
 186       print_path (path);
 187       printf (";\n");
 188
 189       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 190               XINT (x, 0), fail_label);
 191       return;
 192
 193     case MATCH_OP_DUP:
 194       printf ("  x = ");
 195       print_path (path);
 196       printf (";\n");
 197
 198       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 199       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 200               XINT (x, 0), fail_label);
 201       printf ("  operands[%d] = x;\n", XINT (x, 0));
 202       link.next = path;
 203       link.vecelt = -1;
 204       for (i = 0; i < XVECLEN (x, 1); i++)
 205         {
 206           link.pos = i;
 207           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 208         }
 209       return;
 210
 211     case MATCH_OPERATOR:
 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 ("  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.vecelt = -1;
 227       for (i = 0; i < XVECLEN (x, 2); i++)
 228         {
 229           link.pos = i;
 230           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 231         }
 232       return;
 233
 234     case MATCH_PARALLEL:
 235       if (XINT (x, 0) > max_opno)
 236         max_opno = XINT (x, 0);
 237       if (XINT (x, 0) >= n_operands)
 238         n_operands = 1 + XINT (x, 0);
 239
 240       printf ("  x = ");
 241       print_path (path);
 242       printf (";\n");
 243
 244       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 245       printf ("  operands[%d] = x;\n", XINT (x, 0));
 246       if (XSTR (x, 1) && XSTR (x, 1)[0])
 247         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 248                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 249       link.next = path;
 250       link.pos = 0;
 251       for (i = 0; i < XVECLEN (x, 2); i++)
 252         {
 253           link.vecelt = i;
 254           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 255         }
 256       return;
 257
 258     case ADDRESS:
 259       match_rtx (XEXP (x, 0), path, fail_label);
 260       return;
 261
 262     default:
 263       break;
 264     }
 265
 266   printf ("  x = ");
 267   print_path (path);
 268   printf (";\n");
 269
 270   printf ("  if (GET_CODE (x) != ");
 271   print_code (code);
 272   printf (") goto L%d;\n", fail_label);
 273
 274   if (GET_MODE (x) != VOIDmode)
 275     {
 276       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 277               GET_MODE_NAME (GET_MODE (x)), fail_label);
 278     }
 279
 280   link.next = path;
 281   link.vecelt = -1;
 282   fmt = GET_RTX_FORMAT (code);
 283   len = GET_RTX_LENGTH (code);
 284   for (i = 0; i < len; i++)
 285     {
 286       link.pos = i;
 287       if (fmt[i] == 'e' || fmt[i] == 'u')
 288         match_rtx (XEXP (x, i), &link, fail_label);
 289       else if (fmt[i] == 'E')
 290         {
 291           int j;
 292           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 293                   i, XVECLEN (x, i), fail_label);
 294           for (j = 0; j < XVECLEN (x, i); j++)
 295             {
 296               link.vecelt = j;
 297               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 298             }
 299         }
 300       else if (fmt[i] == 'i')
 301         {
 302           /* Make sure that at run time `x' is the RTX we want to test.  */
 303           if (i != 0)
 304             {
 305               printf ("  x = ");
 306               print_path (path);
 307               printf (";\n");
 308             }
 309
 310           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 311                   i, XINT (x, i), fail_label);
 312         }
 313       else if (fmt[i] == 'w')
 314         {
 315           /* Make sure that at run time `x' is the RTX we want to test.  */
 316           if (i != 0)
 317             {
 318               printf ("  x = ");
 319               print_path (path);
 320               printf (";\n");
 321             }
 322
 323           printf ("  if (XWINT (x, %d) != ", i);
 324           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 325           printf (") goto L%d;\n", fail_label);
 326         }
 327       else if (fmt[i] == 's')
 328         {
 329           /* Make sure that at run time `x' is the RTX we want to test.  */
 330           if (i != 0)
 331             {
 332               printf ("  x = ");
 333               print_path (path);
 334               printf (";\n");
 335             }
 336
 337           printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 338                   i, XSTR (x, i), fail_label);
 339         }
 340     }
 341 }
 342
 343 /* Given a PATH, representing a path down the instruction's
 344    pattern from the root to a certain point, output code to
 345    evaluate to the rtx at that point.  */
 346
 347 static void
 348 print_path (path)
 349      struct link *path;
 350 {
 351   if (path == 0)
 352     printf ("pat");
 353   else if (path->vecelt >= 0)
 354     {
 355       printf ("XVECEXP (");
 356       print_path (path->next);
 357       printf (", %d, %d)", path->pos, path->vecelt);
 358     }
 359   else
 360     {
 361       printf ("XEXP (");
 362       print_path (path->next);
 363       printf (", %d)", path->pos);
 364     }
 365 }
 366 \f
 367 static void
 368 print_code (code)
 369      RTX_CODE code;
 370 {
 371   register const char *p1;
 372   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 373     putchar (TOUPPER(*p1));
 374 }
 375 \f
 376 PTR
 377 xmalloc (size)
 378   size_t size;
 379 {
 380   register PTR val = (PTR) malloc (size);
 381
 382   if (val == 0)
 383     fatal ("virtual memory exhausted");
 384   return val;
 385 }
 386
 387 PTR
 388 xrealloc (old, size)
 389   PTR old;
 390   size_t size;
 391 {
 392   register PTR ptr;
 393   if (old)
 394     ptr = (PTR) realloc (old, size);
 395   else
 396     ptr = (PTR) malloc (size);
 397   if (!ptr)
 398     fatal ("virtual memory exhausted");
 399   return ptr;
 400 }
 401
 402 extern int main PARAMS ((int, char **));
 403
 404 int
 405 main (argc, argv)
 406      int argc;
 407      char **argv;
 408 {
 409   rtx desc;
 410   FILE *infile;
 411   register int c;
 412
 413   max_opno = -1;
 414
 415   progname = "genpeep";
 416   obstack_init (rtl_obstack);
 417
 418   if (argc <= 1)
 419     fatal ("No input file name.");
 420
 421   infile = fopen (argv[1], "r");
 422   if (infile == 0)
 423     {
 424       perror (argv[1]);
 425       return (FATAL_EXIT_CODE);
 426     }
 427   read_rtx_filename = argv[1];
 428
 429   printf ("/* Generated automatically by the program `genpeep'\n\
 430 from the machine description file `md'.  */\n\n");
 431
 432   printf ("#include \"config.h\"\n");
 433   printf ("#include \"system.h\"\n");
 434   printf ("#include \"insn-config.h\"\n");
 435   printf ("#include \"rtl.h\"\n");
 436   printf ("#include \"tm_p.h\"\n");
 437   printf ("#include \"regs.h\"\n");
 438   printf ("#include \"output.h\"\n");
 439   printf ("#include \"real.h\"\n");
 440   printf ("#include \"recog.h\"\n");
 441   printf ("#include \"except.h\"\n\n");
 442   printf ("#include \"function.h\"\n\n");
 443
 444   printf ("#ifdef HAVE_peephole\n");
 445   printf ("extern rtx peep_operand[];\n\n");
 446   printf ("#define operands peep_operand\n\n");
 447
 448   printf ("rtx\npeephole (ins1)\n     rtx ins1;\n{\n");
 449   printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 450
 451   /* Early out: no peepholes for insns followed by barriers.  */
 452   printf ("  if (NEXT_INSN (ins1)\n");
 453   printf ("      && GET_CODE (NEXT_INSN (ins1)) == BARRIER)\n");
 454   printf ("    return 0;\n\n");
 455
 456   /* Read the machine description.  */
 457
 458   while (1)
 459     {
 460       c = read_skip_spaces (infile);
 461       if (c == EOF)
 462         break;
 463       ungetc (c, infile);
 464
 465       desc = read_rtx (infile);
 466       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
 467         {
 468           gen_peephole (desc);
 469           insn_code_number++;
 470         }
 471       if (GET_CODE (desc) == DEFINE_INSN
 472           || GET_CODE (desc) == DEFINE_EXPAND
 473           || GET_CODE (desc) == DEFINE_SPLIT)
 474         {
 475           insn_code_number++;
 476         }
 477     }
 478
 479   printf ("  return 0;\n}\n\n");
 480
 481   if (max_opno == -1)
 482     max_opno = 1;
 483
 484   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 485   printf ("#endif\n");
 486
 487   fflush (stdout);
 488   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 489 }
 490
 491 /* Define this so we can link with print-rtl.o to get debug_rtx function.  */
 492 const char *
 493 get_insn_name (code)
 494      int code ATTRIBUTE_UNUSED;
 495 {
 496   return NULL;
 497 }