rtlanal.c

早期freebsd实现

  if (GET_CODE (PATTERN (insn)) == SET)
    {
      rtx dest = SET_DEST (PATTERN (insn));
 
      /* A value is totally replaced if it is the destination or the
	 destination is a SUBREG of REGNO that does not change the number of
	 words in it.  */
     if (GET_CODE (dest) == SUBREG
	  && (((GET_MODE_SIZE (GET_MODE (dest))
		+ UNITS_PER_WORD - 1) / UNITS_PER_WORD)
	      == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
		   + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
	dest = SUBREG_REG (dest);

      if (GET_CODE (dest) != REG)
	return 0;

      regno = REGNO (dest);
      endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
		  : regno + HARD_REGNO_NREGS (regno, GET_MODE (dest)));

      return (test_regno >= regno && test_regno < endregno);
    }
  else if (GET_CODE (PATTERN (insn)) == PARALLEL)
    {
      register int i;

      for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
	{
	  rtx body = XVECEXP (PATTERN (insn), 0, i);

	  if (GET_CODE (body) == SET || GET_CODE (body) == CLOBBER)
	    {
	      rtx dest = SET_DEST (body);

	      if (GET_CODE (dest) == SUBREG
		  && (((GET_MODE_SIZE (GET_MODE (dest))
			+ UNITS_PER_WORD - 1) / UNITS_PER_WORD)
		      == ((GET_MODE_SIZE (GET_MODE (SUBREG_REG (dest)))
			   + UNITS_PER_WORD - 1) / UNITS_PER_WORD)))
		dest = SUBREG_REG (dest);

	      if (GET_CODE (dest) != REG)
		continue;

	      regno = REGNO (dest);
	      endregno = (regno >= FIRST_PSEUDO_REGISTER ? regno + 1
			  : regno + HARD_REGNO_NREGS (regno, GET_MODE (dest)));

	      if (test_regno >= regno && test_regno < endregno)
		return 1;
	    }
	}
    }

  return 0;
}

/* Return the reg-note of kind KIND in insn INSN, if there is one.
   If DATUM is nonzero, look for one whose datum is DATUM.  */

rtx
find_reg_note (insn, kind, datum)
     rtx insn;
     enum reg_note kind;
     rtx datum;
{
  register rtx link;

  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
    if (REG_NOTE_KIND (link) == kind
	&& (datum == 0 || datum == XEXP (link, 0)))
      return link;
  return 0;
}

/* Return the reg-note of kind KIND in insn INSN which applies to register
   number REGNO, if any.  Return 0 if there is no such reg-note.  */

rtx
find_regno_note (insn, kind, regno)
     rtx insn;
     enum reg_note kind;
     int regno;
{
  register rtx link;

  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
    if (REG_NOTE_KIND (link) == kind
	/* Verify that it is a register, so that scratch and MEM won't cause a
	   problem here.  */
	&& GET_CODE (XEXP (link, 0)) == REG
	&& REGNO (XEXP (link, 0)) == regno)
      return link;
  return 0;
}

/* Remove register note NOTE from the REG_NOTES of INSN.  */

void
remove_note (insn, note)
     register rtx note;
     register rtx insn;
{
  register rtx link;

  if (REG_NOTES (insn) == note)
    {
      REG_NOTES (insn) = XEXP (note, 1);
      return;
    }

  for (link = REG_NOTES (insn); link; link = XEXP (link, 1))
    if (XEXP (link, 1) == note)
      {
	XEXP (link, 1) = XEXP (note, 1);
	return;
      }

  abort ();
}

/* Nonzero if X contains any volatile memory references
   UNSPEC_VOLATILE operations or volatile ASM_OPERANDS expressions.  */

int
volatile_refs_p (x)
     rtx x;
{
  register RTX_CODE code;

  code = GET_CODE (x);
  switch (code)
    {
    case LABEL_REF:
    case SYMBOL_REF:
    case CONST_INT:
    case CONST:
    case CONST_DOUBLE:
    case CC0:
    case PC:
    case REG:
    case SCRATCH:
    case CLOBBER:
    case ASM_INPUT:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
      return 0;

    case CALL:
    case UNSPEC_VOLATILE:
 /* case TRAP_IF: This isn't clear yet.  */
      return 1;

    case MEM:
    case ASM_OPERANDS:
      if (MEM_VOLATILE_P (x))
	return 1;
    }

  /* Recursively scan the operands of this expression.  */

  {
    register char *fmt = GET_RTX_FORMAT (code);
    register int i;
    
    for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
      {
	if (fmt[i] == 'e')
	  {
	    if (volatile_refs_p (XEXP (x, i)))
	      return 1;
	  }
	if (fmt[i] == 'E')
	  {
	    register int j;
	    for (j = 0; j < XVECLEN (x, i); j++)
	      if (volatile_refs_p (XVECEXP (x, i, j)))
		return 1;
	  }
      }
  }
  return 0;
}

/* Similar to above, except that it also rejects register pre- and post-
   incrementing.  */

int
side_effects_p (x)
     rtx x;
{
  register RTX_CODE code;

  code = GET_CODE (x);
  switch (code)
    {
    case LABEL_REF:
    case SYMBOL_REF:
    case CONST_INT:
    case CONST:
    case CONST_DOUBLE:
    case CC0:
    case PC:
    case REG:
    case SCRATCH:
    case ASM_INPUT:
    case ADDR_VEC:
    case ADDR_DIFF_VEC:
      return 0;

    case CLOBBER:
      /* Reject CLOBBER with a non-VOID mode.  These are made by combine.c
	 when some combination can't be done.  If we see one, don't think
	 that we can simplify the expression.  */
      return (GET_MODE (x) != VOIDmode);

    case PRE_INC:
    case PRE_DEC:
    case POST_INC:
    case POST_DEC:
    case CALL:
    case UNSPEC_VOLATILE:
 /* case TRAP_IF: This isn't clear yet.  */
      return 1;

    case MEM:
    case ASM_OPERANDS:
      if (MEM_VOLATILE_P (x))
	return 1;
    }

  /* Recursively scan the operands of this expression.  */

  {
    register char *fmt = GET_RTX_FORMAT (code);
    register int i;
    
    for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
      {
	if (fmt[i] == 'e')
	  {
	    if (side_effects_p (XEXP (x, i)))
	      return 1;
	  }
	if (fmt[i] == 'E')
	  {
	    register int j;
	    for (j = 0; j < XVECLEN (x, i); j++)
	      if (side_effects_p (XVECEXP (x, i, j)))
		return 1;
	  }
      }
  }
  return 0;
}

/* Return nonzero if evaluating rtx X might cause a trap.  */

int
may_trap_p (x)
     rtx x;
{
  int i;
  enum rtx_code code;
  char *fmt;

  if (x == 0)
    return 0;
  code = GET_CODE (x);
  switch (code)
    {
      /* Handle these cases quickly.  */
    case CONST_INT:
    case CONST_DOUBLE:
    case SYMBOL_REF:
    case LABEL_REF:
    case CONST:
    case PC:
    case CC0:
    case REG:
    case SCRATCH:
      return 0;

      /* Conditional trap can trap!  */
    case UNSPEC_VOLATILE:
    case TRAP_IF:
      return 1;

      /* Memory ref can trap unless it's a static var or a stack slot.  */
    case MEM:
      return rtx_addr_can_trap_p (XEXP (x, 0));

      /* Division by a non-constant might trap.  */
    case DIV:
    case MOD:
    case UDIV:
    case UMOD:
      if (! CONSTANT_P (XEXP (x, 1)))
	return 1;
      /* This was const0_rtx, but by not using that,
	 we can link this file into other programs.  */
      if (GET_CODE (XEXP (x, 1)) == CONST_INT && INTVAL (XEXP (x, 1)) == 0)
	return 1;
    default:
      /* Any floating arithmetic may trap.  */
      if (GET_MODE_CLASS (GET_MODE (x)) == MODE_FLOAT)
	return 1;
    }

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	{
	  if (may_trap_p (XEXP (x, i)))
	    return 1;
	}
      else if (fmt[i] == 'E')
	{
	  register int j;
	  for (j = 0; j < XVECLEN (x, i); j++)
	    if (may_trap_p (XVECEXP (x, i, j)))
	      return 1;
	}
    }
  return 0;
}

/* Return nonzero if X contains a comparison that is not either EQ or NE,
   i.e., an inequality.  */

int
inequality_comparisons_p (x)
     rtx x;
{
  register char *fmt;
  register int len, i;
  register enum rtx_code code = GET_CODE (x);

  switch (code)
    {
    case REG:
    case SCRATCH:
    case PC:
    case CC0:
    case CONST_INT:
    case CONST_DOUBLE:
    case CONST:
    case LABEL_REF:
    case SYMBOL_REF:
      return 0;

    case LT:
    case LTU:
    case GT:
    case GTU:
    case LE:
    case LEU:
    case GE:
    case GEU:
      return 1;
    }

  len = GET_RTX_LENGTH (code);
  fmt = GET_RTX_FORMAT (code);

  for (i = 0; i < len; i++)
    {
      if (fmt[i] == 'e')
	{
	  if (inequality_comparisons_p (XEXP (x, i)))
	    return 1;
	}
      else if (fmt[i] == 'E')
	{
	  register int j;
	  for (j = XVECLEN (x, i) - 1; j >= 0; j--)
	    if (inequality_comparisons_p (XVECEXP (x, i, j)))
	      return 1;
	}
    }
	    
  return 0;
}

/* Replace any occurrence of FROM in X with TO.

   Note that copying is not done so X must not be shared unless all copies
   are to be modified.  */

rtx
replace_rtx (x, from, to)
     rtx x, from, to;
{
  register int i, j;
  register char *fmt;

  if (x == from)
    return to;

  /* Allow this function to make replacements in EXPR_LISTs.  */
  if (x == 0)
    return 0;

  fmt = GET_RTX_FORMAT (GET_CODE (x));
  for (i = GET_RTX_LENGTH (GET_CODE (x)) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	XEXP (x, i) = replace_rtx (XEXP (x, i), from, to);
      else if (fmt[i] == 'E')
	for (j = XVECLEN (x, i) - 1; j >= 0; j--)
	  XVECEXP (x, i, j) = replace_rtx (XVECEXP (x, i, j), from, to);
    }

  return x;
}  

/* Throughout the rtx X, replace many registers according to REG_MAP.
   Return the replacement for X (which may be X with altered contents).
   REG_MAP[R] is the replacement for register R, or 0 for don't replace.
   NREGS is the length of REG_MAP; regs >= NREGS are not mapped.  

   We only support REG_MAP entries of REG or SUBREG.  Also, hard registers
   should not be mapped to pseudos or vice versa since validate_change
   is not called.

   If REPLACE_DEST is 1, replacements are also done in destinations;
   otherwise, only sources are replaced.  */

rtx
replace_regs (x, reg_map, nregs, replace_dest)
     rtx x;
     rtx *reg_map;
     int nregs;
     int replace_dest;
{
  register enum rtx_code code;
  register int i;
  register char *fmt;

  if (x == 0)
    return x;

  code = GET_CODE (x);
  switch (code)
    {
    case SCRATCH:
    case PC:
    case CC0:
    case CONST_INT:
    case CONST_DOUBLE:
    case CONST:
    case SYMBOL_REF:
    case LABEL_REF:
      return x;

    case REG:
      /* Verify that the register has an entry before trying to access it.  */
      if (REGNO (x) < nregs && reg_map[REGNO (x)] != 0)
	return reg_map[REGNO (x)];
      return x;

    case SUBREG:
      /* Prevent making nested SUBREGs.  */
      if (GET_CODE (SUBREG_REG (x)) == REG && REGNO (SUBREG_REG (x)) < nregs
	  && reg_map[REGNO (SUBREG_REG (x))] != 0
	  && GET_CODE (reg_map[REGNO (SUBREG_REG (x))]) == SUBREG)
	{
	  rtx map_val = reg_map[REGNO (SUBREG_REG (x))];
	  rtx map_inner = SUBREG_REG (map_val);

	  if (GET_MODE (x) == GET_MODE (map_inner))
	    return map_inner;
	  else
	    {
	      /* We cannot call gen_rtx here since we may be linked with
		 genattrtab.c.  */
	      /* Let's try clobbering the incoming SUBREG and see
		 if this is really safe.  */
	      SUBREG_REG (x) = map_inner;
	      SUBREG_WORD (x) += SUBREG_WORD (map_val);
	      return x;
#if 0
	      rtx new = rtx_alloc (SUBREG);
	      PUT_MODE (new, GET_MODE (x));
	      SUBREG_REG (new) = map_inner;
	      SUBREG_WORD (new) = SUBREG_WORD (x) + SUBREG_WORD (map_val);
#endif
	    }
	}
      break;

    case SET:
      if (replace_dest)
	SET_DEST (x) = replace_regs (SET_DEST (x), reg_map, nregs, 0);

      else if (GET_CODE (SET_DEST (x)) == MEM
	       || GET_CODE (SET_DEST (x)) == STRICT_LOW_PART)
	/* Even if we are not to replace destinations, replace register if it
	   is CONTAINED in destination (destination is memory or
	   STRICT_LOW_PART).  */
	XEXP (SET_DEST (x), 0) = replace_regs (XEXP (SET_DEST (x), 0),
					       reg_map, nregs, 0);
      else if (GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
	/* Similarly, for ZERO_EXTRACT we replace all operands.  */
	break;

      SET_SRC (x) = replace_regs (SET_SRC (x), reg_map, nregs, 0);
      return x;
    }

  fmt = GET_RTX_FORMAT (code);
  for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
    {
      if (fmt[i] == 'e')
	XEXP (x, i) = replace_regs (XEXP (x, i), reg_map, nregs, replace_dest);
      if (fmt[i] == 'E')
	{
	  register int j;
	  for (j = 0; j < XVECLEN (x, i); j++)
	    XVECEXP (x, i, j) = replace_regs (XVECEXP (x, i, j), reg_map,
					      nregs, replace_dest);
	}
    }
  return x;
}