gcc/genpeep.cc

   1 /* Generate code from machine description to perform peephole optimizations.
   2    Copyright (C) 1987-2023 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20
  21 #include "bconfig.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.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 static void match_rtx (rtx, struct link *, int);
  50 static void print_path (struct link *);
  51 static void print_code (RTX_CODE);
  52 \f
  53 static void
  54 gen_peephole (md_rtx_info *info)
  55 {
  56   rtx peep = info->def;
  57   int ninsns = XVECLEN (peep, 0);
  58   int i;
  59
  60   n_operands = 0;
  61
  62   printf ("  insn = ins1;\n");
  63
  64   for (i = 0; i < ninsns; i++)
  65     {
  66       if (i > 0)
  67         {
  68           printf ("  do { insn = NEXT_INSN (insn);\n");
  69           printf ("       if (insn == 0) goto L%d; }\n", info->index);
  70           printf ("  while (NOTE_P (insn)\n");
  71           printf ("\t || (NONJUMP_INSN_P (insn)\n");
  72           printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
  73           printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");
  74
  75           printf ("  if (LABEL_P (insn)\n\
  76       || BARRIER_P (insn))\n    goto L%d;\n", info->index);
  77         }
  78
  79       printf ("  pat = PATTERN (insn);\n");
  80
  81       /* Walk the insn's pattern, remembering at all times the path
  82          down to the walking point.  */
  83
  84       match_rtx (XVECEXP (peep, 0, i), NULL, info->index);
  85     }
  86
  87   /* We get this far if the pattern matches.
  88      Now test the extra condition.  */
  89
  90   if (XSTR (peep, 1) && XSTR (peep, 1)[0])
  91     printf ("  if (! (%s)) goto L%d;\n",
  92             XSTR (peep, 1), info->index);
  93
  94   /* If that matches, construct new pattern and put it in the first insn.
  95      This new pattern will never be matched.
  96      It exists only so that insn-extract can get the operands back.
  97      So use a simple regular form: a PARALLEL containing a vector
  98      of all the operands.  */
  99
 100   printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);
 101
 102   /* Record this define_peephole's insn code in the insn,
 103      as if it had been recognized to match this.  */
 104   printf ("  INSN_CODE (ins1) = %d;\n", info->index);
 105
 106   /* Delete the remaining insns.  */
 107   if (ninsns > 1)
 108     printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");
 109
 110   /* See reload1.cc for insertion of NOTE which guarantees that this
 111      cannot be zero.  */
 112   printf ("  return NEXT_INSN (insn);\n");
 113
 114   printf (" L%d:\n\n", info->index);
 115 }
 116 \f
 117 static void
 118 match_rtx (rtx x, struct link *path, int fail_label)
 119 {
 120   RTX_CODE code;
 121   int i;
 122   int len;
 123   const char *fmt;
 124   struct link link;
 125
 126   if (x == 0)
 127     return;
 128
 129
 130   code = GET_CODE (x);
 131
 132   switch (code)
 133     {
 134     case MATCH_OPERAND:
 135       if (XINT (x, 0) > max_opno)
 136         max_opno = XINT (x, 0);
 137       if (XINT (x, 0) >= n_operands)
 138         n_operands = 1 + XINT (x, 0);
 139
 140       printf ("  x = ");
 141       print_path (path);
 142       printf (";\n");
 143
 144       printf ("  operands[%d] = x;\n", XINT (x, 0));
 145       if (XSTR (x, 1) && XSTR (x, 1)[0])
 146         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 147                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 148       return;
 149
 150     case MATCH_DUP:
 151     case MATCH_PAR_DUP:
 152       printf ("  x = ");
 153       print_path (path);
 154       printf (";\n");
 155
 156       printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
 157               XINT (x, 0), fail_label);
 158       return;
 159
 160     case MATCH_OP_DUP:
 161       printf ("  x = ");
 162       print_path (path);
 163       printf (";\n");
 164
 165       printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
 166       printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
 167               XINT (x, 0), fail_label);
 168       printf ("  operands[%d] = x;\n", XINT (x, 0));
 169       link.next = path;
 170       link.vecelt = -1;
 171       for (i = 0; i < XVECLEN (x, 1); i++)
 172         {
 173           link.pos = i;
 174           match_rtx (XVECEXP (x, 1, i), &link, fail_label);
 175         }
 176       return;
 177
 178     case MATCH_OPERATOR:
 179       if (XINT (x, 0) > max_opno)
 180         max_opno = XINT (x, 0);
 181       if (XINT (x, 0) >= n_operands)
 182         n_operands = 1 + XINT (x, 0);
 183
 184       printf ("  x = ");
 185       print_path (path);
 186       printf (";\n");
 187
 188       printf ("  operands[%d] = x;\n", XINT (x, 0));
 189       if (XSTR (x, 1) && XSTR (x, 1)[0])
 190         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 191                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 192       link.next = path;
 193       link.vecelt = -1;
 194       for (i = 0; i < XVECLEN (x, 2); i++)
 195         {
 196           link.pos = i;
 197           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 198         }
 199       return;
 200
 201     case MATCH_PARALLEL:
 202       if (XINT (x, 0) > max_opno)
 203         max_opno = XINT (x, 0);
 204       if (XINT (x, 0) >= n_operands)
 205         n_operands = 1 + XINT (x, 0);
 206
 207       printf ("  x = ");
 208       print_path (path);
 209       printf (";\n");
 210
 211       printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
 212       printf ("  operands[%d] = x;\n", XINT (x, 0));
 213       if (XSTR (x, 1) && XSTR (x, 1)[0])
 214         printf ("  if (! %s (x, %smode)) goto L%d;\n",
 215                 XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
 216       link.next = path;
 217       link.pos = 0;
 218       for (i = 0; i < XVECLEN (x, 2); i++)
 219         {
 220           link.vecelt = i;
 221           match_rtx (XVECEXP (x, 2, i), &link, fail_label);
 222         }
 223       return;
 224
 225     default:
 226       break;
 227     }
 228
 229   printf ("  x = ");
 230   print_path (path);
 231   printf (";\n");
 232
 233   printf ("  if (GET_CODE (x) != ");
 234   print_code (code);
 235   printf (") goto L%d;\n", fail_label);
 236
 237   if (GET_MODE (x) != VOIDmode)
 238     {
 239       printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
 240               GET_MODE_NAME (GET_MODE (x)), fail_label);
 241     }
 242
 243   link.next = path;
 244   link.vecelt = -1;
 245   fmt = GET_RTX_FORMAT (code);
 246   len = GET_RTX_LENGTH (code);
 247   for (i = 0; i < len; i++)
 248     {
 249       link.pos = i;
 250       if (fmt[i] == 'e' || fmt[i] == 'u')
 251         match_rtx (XEXP (x, i), &link, fail_label);
 252       else if (fmt[i] == 'E')
 253         {
 254           int j;
 255           printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
 256                   i, XVECLEN (x, i), fail_label);
 257           for (j = 0; j < XVECLEN (x, i); j++)
 258             {
 259               link.vecelt = j;
 260               match_rtx (XVECEXP (x, i, j), &link, fail_label);
 261             }
 262         }
 263       else if (fmt[i] == 'i')
 264         {
 265           /* Make sure that at run time `x' is the RTX we want to test.  */
 266           if (i != 0)
 267             {
 268               printf ("  x = ");
 269               print_path (path);
 270               printf (";\n");
 271             }
 272
 273           printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
 274                   i, XINT (x, i), fail_label);
 275         }
 276       else if (fmt[i] == 'r')
 277         {
 278           gcc_assert (i == 0);
 279           printf ("  if (REGNO (x) != %d) goto L%d;\n",
 280                   REGNO (x), fail_label);
 281         }
 282       else if (fmt[i] == 'w')
 283         {
 284           /* Make sure that at run time `x' is the RTX we want to test.  */
 285           if (i != 0)
 286             {
 287               printf ("  x = ");
 288               print_path (path);
 289               printf (";\n");
 290             }
 291
 292           printf ("  if (XWINT (x, %d) != ", i);
 293           printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
 294           printf (") goto L%d;\n", fail_label);
 295         }
 296       else if (fmt[i] == 's')
 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 (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
 307                   i, XSTR (x, i), fail_label);
 308         }
 309       else if (fmt[i] == 'p')
 310         /* Not going to support subregs for legacy define_peeholes.  */
 311         gcc_unreachable ();
 312     }
 313 }
 314
 315 /* Given a PATH, representing a path down the instruction's
 316    pattern from the root to a certain point, output code to
 317    evaluate to the rtx at that point.  */
 318
 319 static void
 320 print_path (struct link *path)
 321 {
 322   if (path == 0)
 323     printf ("pat");
 324   else if (path->vecelt >= 0)
 325     {
 326       printf ("XVECEXP (");
 327       print_path (path->next);
 328       printf (", %d, %d)", path->pos, path->vecelt);
 329     }
 330   else
 331     {
 332       printf ("XEXP (");
 333       print_path (path->next);
 334       printf (", %d)", path->pos);
 335     }
 336 }
 337 \f
 338 static void
 339 print_code (RTX_CODE code)
 340 {
 341   const char *p1;
 342   for (p1 = GET_RTX_NAME (code); *p1; p1++)
 343     putchar (TOUPPER (*p1));
 344 }
 345
 346 extern int main (int, const char **);
 347
 348 int
 349 main (int argc, const char **argv)
 350 {
 351   max_opno = -1;
 352
 353   progname = "genpeep";
 354
 355   if (!init_rtx_reader_args (argc, argv))
 356     return (FATAL_EXIT_CODE);
 357
 358   printf ("/* Generated automatically by the program `genpeep'\n\
 359 from the machine description file `md'.  */\n\n");
 360
 361   printf ("#define IN_TARGET_CODE 1\n");
 362   printf ("#include \"config.h\"\n");
 363   printf ("#include \"system.h\"\n");
 364   printf ("#include \"coretypes.h\"\n");
 365   printf ("#include \"backend.h\"\n");
 366   printf ("#include \"tree.h\"\n");
 367   printf ("#include \"rtl.h\"\n");
 368   printf ("#include \"insn-config.h\"\n");
 369   printf ("#include \"alias.h\"\n");
 370   printf ("#include \"varasm.h\"\n");
 371   printf ("#include \"stor-layout.h\"\n");
 372   printf ("#include \"calls.h\"\n");
 373   printf ("#include \"memmodel.h\"\n");
 374   printf ("#include \"tm_p.h\"\n");
 375   printf ("#include \"regs.h\"\n");
 376   printf ("#include \"output.h\"\n");
 377   printf ("#include \"recog.h\"\n");
 378   printf ("#include \"except.h\"\n");
 379   printf ("#include \"diagnostic-core.h\"\n");
 380   printf ("#include \"flags.h\"\n");
 381   printf ("#include \"tm-constrs.h\"\n\n");
 382
 383   printf ("extern rtx peep_operand[];\n\n");
 384   printf ("#define operands peep_operand\n\n");
 385
 386   printf ("rtx_insn *\npeephole (rtx_insn *ins1)\n{\n");
 387   printf ("  rtx_insn *insn ATTRIBUTE_UNUSED;\n");
 388   printf ("  rtx x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");
 389
 390   /* Early out: no peepholes for insns followed by barriers.  */
 391   printf ("  if (NEXT_INSN (ins1)\n");
 392   printf ("      && BARRIER_P (NEXT_INSN (ins1)))\n");
 393   printf ("    return 0;\n\n");
 394
 395   /* Read the machine description.  */
 396
 397   md_rtx_info info;
 398   while (read_md_rtx (&info))
 399     switch (GET_CODE (info.def))
 400       {
 401       case DEFINE_PEEPHOLE:
 402         gen_peephole (&info);
 403         break;
 404
 405       default:
 406         break;
 407       }
 408
 409   printf ("  return 0;\n}\n\n");
 410
 411   if (max_opno == -1)
 412     max_opno = 1;
 413
 414   printf ("rtx peep_operand[%d];\n", max_opno + 1);
 415
 416   fflush (stdout);
 417   return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
 418 }