genpeep.c

/* Generate code from machine description to perform peephole optimizations.
   Copyright (C) 1987, 1989, 1992, 1997, 1998, 1999, 2000, 2003, 2004,
   2007  Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */


#include "bconfig.h"
#include "system.h"
#include "coretypes.h"
#include "tm.h"
#include "rtl.h"
#include "errors.h"
#include "gensupport.h"


/* While tree-walking an instruction pattern, we keep a chain
   of these `struct link's to record how to get down to the
   current position.  In each one, POS is the operand number,
   and if the operand is a vector VEC is the element number.
   VEC is -1 if the operand is not a vector.  */

struct link
{
  struct link *next;
  int pos;
  int vecelt;
};

static int max_opno;

/* Number of operands used in current peephole definition.  */

static int n_operands;

/* Peephole optimizations get insn codes just like insn patterns.
   Count them so we know the code of the define_peephole we are handling.  */

static int insn_code_number = 0;

static void gen_peephole (rtx);
static void match_rtx (rtx, struct link *, int);
static void print_path (struct link *);
static void print_code (RTX_CODE);

static void
gen_peephole (rtx peep)
{
  int ninsns = XVECLEN (peep, 0);
  int i;

  n_operands = 0;

  printf ("  insn = ins1;\n");

  for (i = 0; i < ninsns; i++)
    {
      if (i > 0)
	{
	  printf ("  do { insn = NEXT_INSN (insn);\n");
	  printf ("       if (insn == 0) goto L%d; }\n",
		  insn_code_number);
	  printf ("  while (NOTE_P (insn)\n");
	  printf ("\t || (NONJUMP_INSN_P (insn)\n");
	  printf ("\t     && (GET_CODE (PATTERN (insn)) == USE\n");
	  printf ("\t\t || GET_CODE (PATTERN (insn)) == CLOBBER)));\n");

	  printf ("  if (LABEL_P (insn)\n\
      || BARRIER_P (insn))\n    goto L%d;\n",
		  insn_code_number);
	}

      printf ("  pat = PATTERN (insn);\n");

      /* Walk the insn's pattern, remembering at all times the path
	 down to the walking point.  */

      match_rtx (XVECEXP (peep, 0, i), NULL, insn_code_number);
    }

  /* We get this far if the pattern matches.
     Now test the extra condition.  */

  if (XSTR (peep, 1) && XSTR (peep, 1)[0])
    printf ("  if (! (%s)) goto L%d;\n",
	    XSTR (peep, 1), insn_code_number);

  /* If that matches, construct new pattern and put it in the first insn.
     This new pattern will never be matched.
     It exists only so that insn-extract can get the operands back.
     So use a simple regular form: a PARALLEL containing a vector
     of all the operands.  */

  printf ("  PATTERN (ins1) = gen_rtx_PARALLEL (VOIDmode, gen_rtvec_v (%d, operands));\n", n_operands);

  /* Record this define_peephole's insn code in the insn,
     as if it had been recognized to match this.  */
  printf ("  INSN_CODE (ins1) = %d;\n",
	  insn_code_number);

  /* Delete the remaining insns.  */
  if (ninsns > 1)
    printf ("  delete_for_peephole (NEXT_INSN (ins1), insn);\n");

  /* See reload1.c for insertion of NOTE which guarantees that this
     cannot be zero.  */
  printf ("  return NEXT_INSN (insn);\n");

  printf (" L%d:\n\n", insn_code_number);
}

static void
match_rtx (rtx x, struct link *path, int fail_label)
{
  RTX_CODE code;
  int i;
  int len;
  const char *fmt;
  struct link link;

  if (x == 0)
    return;


  code = GET_CODE (x);

  switch (code)
    {
    case MATCH_OPERAND:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      return;

    case MATCH_DUP:
    case MATCH_PAR_DUP:
      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (!rtx_equal_p (operands[%d], x)) goto L%d;\n",
	      XINT (x, 0), fail_label);
      return;

    case MATCH_OP_DUP:
      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (GET_CODE (operands[%d]) != GET_CODE (x)\n", XINT (x, 0));
      printf ("      || GET_MODE (operands[%d]) != GET_MODE (x)) goto L%d;\n",
	      XINT (x, 0), fail_label);
      printf ("  operands[%d] = x;\n", XINT (x, 0));
      link.next = path;
      link.vecelt = -1;
      for (i = 0; i < XVECLEN (x, 1); i++)
	{
	  link.pos = i;
	  match_rtx (XVECEXP (x, 1, i), &link, fail_label);
	}
      return;

    case MATCH_OPERATOR:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      link.next = path;
      link.vecelt = -1;
      for (i = 0; i < XVECLEN (x, 2); i++)
	{
	  link.pos = i;
	  match_rtx (XVECEXP (x, 2, i), &link, fail_label);
	}
      return;

    case MATCH_PARALLEL:
      if (XINT (x, 0) > max_opno)
	max_opno = XINT (x, 0);
      if (XINT (x, 0) >= n_operands)
	n_operands = 1 + XINT (x, 0);

      printf ("  x = ");
      print_path (path);
      printf (";\n");

      printf ("  if (GET_CODE (x) != PARALLEL) goto L%d;\n", fail_label);
      printf ("  operands[%d] = x;\n", XINT (x, 0));
      if (XSTR (x, 1) && XSTR (x, 1)[0])
	printf ("  if (! %s (x, %smode)) goto L%d;\n",
		XSTR (x, 1), GET_MODE_NAME (GET_MODE (x)), fail_label);
      link.next = path;
      link.pos = 0;
      for (i = 0; i < XVECLEN (x, 2); i++)
	{
	  link.vecelt = i;
	  match_rtx (XVECEXP (x, 2, i), &link, fail_label);
	}
      return;

    case ADDRESS:
      match_rtx (XEXP (x, 0), path, fail_label);
      return;

    default:
      break;
    }

  printf ("  x = ");
  print_path (path);
  printf (";\n");

  printf ("  if (GET_CODE (x) != ");
  print_code (code);
  printf (") goto L%d;\n", fail_label);

  if (GET_MODE (x) != VOIDmode)
    {
      printf ("  if (GET_MODE (x) != %smode) goto L%d;\n",
	      GET_MODE_NAME (GET_MODE (x)), fail_label);
    }

  link.next = path;
  link.vecelt = -1;
  fmt = GET_RTX_FORMAT (code);
  len = GET_RTX_LENGTH (code);
  for (i = 0; i < len; i++)
    {
      link.pos = i;
      if (fmt[i] == 'e' || fmt[i] == 'u')
	match_rtx (XEXP (x, i), &link, fail_label);
      else if (fmt[i] == 'E')
	{
	  int j;
	  printf ("  if (XVECLEN (x, %d) != %d) goto L%d;\n",
		  i, XVECLEN (x, i), fail_label);
	  for (j = 0; j < XVECLEN (x, i); j++)
	    {
	      link.vecelt = j;
	      match_rtx (XVECEXP (x, i, j), &link, fail_label);
	    }
	}
      else if (fmt[i] == 'i')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (XINT (x, %d) != %d) goto L%d;\n",
		  i, XINT (x, i), fail_label);
	}
      else if (fmt[i] == 'w')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (XWINT (x, %d) != ", i);
	  printf (HOST_WIDE_INT_PRINT_DEC, XWINT (x, i));
	  printf (") goto L%d;\n", fail_label);
	}
      else if (fmt[i] == 's')
	{
	  /* Make sure that at run time `x' is the RTX we want to test.  */
	  if (i != 0)
	    {
	      printf ("  x = ");
	      print_path (path);
	      printf (";\n");
	    }

	  printf ("  if (strcmp (XSTR (x, %d), \"%s\")) goto L%d;\n",
		  i, XSTR (x, i), fail_label);
	}
    }
}

/* Given a PATH, representing a path down the instruction's
   pattern from the root to a certain point, output code to
   evaluate to the rtx at that point.  */

static void
print_path (struct link *path)
{
  if (path == 0)
    printf ("pat");
  else if (path->vecelt >= 0)
    {
      printf ("XVECEXP (");
      print_path (path->next);
      printf (", %d, %d)", path->pos, path->vecelt);
    }
  else
    {
      printf ("XEXP (");
      print_path (path->next);
      printf (", %d)", path->pos);
    }
}

static void
print_code (RTX_CODE code)
{
  const char *p1;
  for (p1 = GET_RTX_NAME (code); *p1; p1++)
    putchar (TOUPPER(*p1));
}

extern int main (int, char **);

int
main (int argc, char **argv)
{
  rtx desc;

  max_opno = -1;

  progname = "genpeep";

  if (init_md_reader_args (argc, argv) != SUCCESS_EXIT_CODE)
    return (FATAL_EXIT_CODE);

  printf ("/* Generated automatically by the program `genpeep'\n\
from the machine description file `md'.  */\n\n");

  printf ("#include \"config.h\"\n");
  printf ("#include \"system.h\"\n");
  printf ("#include \"coretypes.h\"\n");
  printf ("#include \"tm.h\"\n");
  printf ("#include \"insn-config.h\"\n");
  printf ("#include \"rtl.h\"\n");
  printf ("#include \"tm_p.h\"\n");
  printf ("#include \"regs.h\"\n");
  printf ("#include \"output.h\"\n");
  printf ("#include \"real.h\"\n");
  printf ("#include \"recog.h\"\n");
  printf ("#include \"except.h\"\n");
  printf ("#include \"function.h\"\n");
  printf ("#include \"toplev.h\"\n");
  printf ("#include \"flags.h\"\n");
  printf ("#include \"tm-constrs.h\"\n\n");

  printf ("#ifdef HAVE_peephole\n");
  printf ("extern rtx peep_operand[];\n\n");
  printf ("#define operands peep_operand\n\n");

  printf ("rtx\npeephole (rtx ins1)\n{\n");
  printf ("  rtx insn ATTRIBUTE_UNUSED, x ATTRIBUTE_UNUSED, pat ATTRIBUTE_UNUSED;\n\n");

  /* Early out: no peepholes for insns followed by barriers.  */
  printf ("  if (NEXT_INSN (ins1)\n");
  printf ("      && BARRIER_P (NEXT_INSN (ins1)))\n");
  printf ("    return 0;\n\n");

  /* Read the machine description.  */

  while (1)
    {
      int line_no, rtx_number = 0;

      desc = read_md_rtx (&line_no, &rtx_number);
      if (desc == NULL)
	break;

       if (GET_CODE (desc) == DEFINE_PEEPHOLE)
	{
	  gen_peephole (desc);
	  insn_code_number++;
	}
      if (GET_CODE (desc) == DEFINE_INSN
	  || GET_CODE (desc) == DEFINE_EXPAND
	  || GET_CODE (desc) == DEFINE_SPLIT
	  || GET_CODE (desc) == DEFINE_PEEPHOLE2)
	{
	  insn_code_number++;
	}
    }

  printf ("  return 0;\n}\n\n");

  if (max_opno == -1)
    max_opno = 1;

  printf ("rtx peep_operand[%d];\n", max_opno + 1);
  printf ("#endif\n");

  fflush (stdout);
  return (ferror (stdout) != 0 ? FATAL_EXIT_CODE : SUCCESS_EXIT_CODE);
}