expr.c

早期freebsd实现

    abort ();

  if (to_mode == from_mode
      || (from_mode == VOIDmode && CONSTANT_P (from)))
    {
      emit_move_insn (to, from);
      return;
    }

  if (to_real)
    {
#ifdef HAVE_extendsfdf2
      if (HAVE_extendsfdf2 && from_mode == SFmode && to_mode == DFmode)
	{
	  emit_unop_insn (CODE_FOR_extendsfdf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_extendsfxf2
      if (HAVE_extendsfxf2 && from_mode == SFmode && to_mode == XFmode)
	{
	  emit_unop_insn (CODE_FOR_extendsfxf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_extendsftf2
      if (HAVE_extendsftf2 && from_mode == SFmode && to_mode == TFmode)
	{
	  emit_unop_insn (CODE_FOR_extendsftf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_extenddfxf2
      if (HAVE_extenddfxf2 && from_mode == DFmode && to_mode == XFmode)
	{
	  emit_unop_insn (CODE_FOR_extenddfxf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_extenddftf2
      if (HAVE_extenddftf2 && from_mode == DFmode && to_mode == TFmode)
	{
	  emit_unop_insn (CODE_FOR_extenddftf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_truncdfsf2
      if (HAVE_truncdfsf2 && from_mode == DFmode && to_mode == SFmode)
	{
	  emit_unop_insn (CODE_FOR_truncdfsf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_truncxfsf2
      if (HAVE_truncxfsf2 && from_mode == XFmode && to_mode == SFmode)
	{
	  emit_unop_insn (CODE_FOR_truncxfsf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_trunctfsf2
      if (HAVE_trunctfsf2 && from_mode == TFmode && to_mode == SFmode)
	{
	  emit_unop_insn (CODE_FOR_trunctfsf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_truncxfdf2
      if (HAVE_truncxfdf2 && from_mode == XFmode && to_mode == DFmode)
	{
	  emit_unop_insn (CODE_FOR_truncxfdf2, to, from, UNKNOWN);
	  return;
	}
#endif
#ifdef HAVE_trunctfdf2
      if (HAVE_trunctfdf2 && from_mode == TFmode && to_mode == DFmode)
	{
	  emit_unop_insn (CODE_FOR_trunctfdf2, to, from, UNKNOWN);
	  return;
	}
#endif

      libcall = (rtx) 0;
      switch (from_mode)
	{
	case SFmode:
	  switch (to_mode)
	    {
	    case DFmode:
	      libcall = extendsfdf2_libfunc;
	      break;

	    case XFmode:
	      libcall = extendsfxf2_libfunc;
	      break;

	    case TFmode:
	      libcall = extendsftf2_libfunc;
	      break;
	    }
	  break;

	case DFmode:
	  switch (to_mode)
	    {
	    case SFmode:
	      libcall = truncdfsf2_libfunc;
	      break;

	    case XFmode:
	      libcall = extenddfxf2_libfunc;
	      break;

	    case TFmode:
	      libcall = extenddftf2_libfunc;
	      break;
	    }
	  break;

	case XFmode:
	  switch (to_mode)
	    {
	    case SFmode:
	      libcall = truncxfsf2_libfunc;
	      break;

	    case DFmode:
	      libcall = truncxfdf2_libfunc;
	      break;
	    }
	  break;

	case TFmode:
	  switch (to_mode)
	    {
	    case SFmode:
	      libcall = trunctfsf2_libfunc;
	      break;

	    case DFmode:
	      libcall = trunctfdf2_libfunc;
	      break;
	    }
	  break;
	}

      if (libcall == (rtx) 0)
	/* This conversion is not implemented yet.  */
	abort ();

      emit_library_call (libcall, 1, to_mode, 1, from, from_mode);
      emit_move_insn (to, hard_libcall_value (to_mode));
      return;
    }

  /* Now both modes are integers.  */

  /* Handle expanding beyond a word.  */
  if (GET_MODE_BITSIZE (from_mode) < GET_MODE_BITSIZE (to_mode)
      && GET_MODE_BITSIZE (to_mode) > BITS_PER_WORD)
    {
      rtx insns;
      rtx lowpart;
      rtx fill_value;
      rtx lowfrom;
      int i;
      enum machine_mode lowpart_mode;
      int nwords = CEIL (GET_MODE_SIZE (to_mode), UNITS_PER_WORD);

      /* Try converting directly if the insn is supported.  */
      if ((code = can_extend_p (to_mode, from_mode, unsignedp))
	  != CODE_FOR_nothing)
	{
	  /* If FROM is a SUBREG, put it into a register.  Do this
	     so that we always generate the same set of insns for
	     better cse'ing; if an intermediate assignment occurred,
	     we won't be doing the operation directly on the SUBREG.  */
	  if (optimize > 0 && GET_CODE (from) == SUBREG)
	    from = force_reg (from_mode, from);
	  emit_unop_insn (code, to, from, equiv_code);
	  return;
	}
      /* Next, try converting via full word.  */
      else if (GET_MODE_BITSIZE (from_mode) < BITS_PER_WORD
	       && ((code = can_extend_p (to_mode, word_mode, unsignedp))
		   != CODE_FOR_nothing))
	{
	  convert_move (gen_lowpart (word_mode, to), from, unsignedp);
	  emit_unop_insn (code, to,
			  gen_lowpart (word_mode, to), equiv_code);
	  return;
	}

      /* No special multiword conversion insn; do it by hand.  */
      start_sequence ();

      /* Get a copy of FROM widened to a word, if necessary.  */
      if (GET_MODE_BITSIZE (from_mode) < BITS_PER_WORD)
	lowpart_mode = word_mode;
      else
	lowpart_mode = from_mode;

      lowfrom = convert_to_mode (lowpart_mode, from, unsignedp);

      lowpart = gen_lowpart (lowpart_mode, to);
      emit_move_insn (lowpart, lowfrom);

      /* Compute the value to put in each remaining word.  */
      if (unsignedp)
	fill_value = const0_rtx;
      else
	{
#ifdef HAVE_slt
	  if (HAVE_slt
	      && insn_operand_mode[(int) CODE_FOR_slt][0] == word_mode
	      && STORE_FLAG_VALUE == -1)
	    {
	      emit_cmp_insn (lowfrom, const0_rtx, NE, NULL_RTX,
			     lowpart_mode, 0, 0);
	      fill_value = gen_reg_rtx (word_mode);
	      emit_insn (gen_slt (fill_value));
	    }
	  else
#endif
	    {
	      fill_value
		= expand_shift (RSHIFT_EXPR, lowpart_mode, lowfrom,
				size_int (GET_MODE_BITSIZE (lowpart_mode) - 1),
				NULL_RTX, 0);
	      fill_value = convert_to_mode (word_mode, fill_value, 1);
	    }
	}

      /* Fill the remaining words.  */
      for (i = GET_MODE_SIZE (lowpart_mode) / UNITS_PER_WORD; i < nwords; i++)
	{
	  int index = (WORDS_BIG_ENDIAN ? nwords - i - 1 : i);
	  rtx subword = operand_subword (to, index, 1, to_mode);

	  if (subword == 0)
	    abort ();

	  if (fill_value != subword)
	    emit_move_insn (subword, fill_value);
	}

      insns = get_insns ();
      end_sequence ();

      emit_no_conflict_block (insns, to, from, NULL_RTX,
			      gen_rtx (equiv_code, to_mode, from));
      return;
    }

  if (GET_MODE_BITSIZE (from_mode) > BITS_PER_WORD)
    {
      convert_move (to, gen_lowpart (word_mode, from), 0);
      return;
    }

  /* Handle pointer conversion */			/* SPEE 900220 */
  if (to_mode == PSImode)
    {
      if (from_mode != SImode)
	from = convert_to_mode (SImode, from, unsignedp);

#ifdef HAVE_truncsipsi
      if (HAVE_truncsipsi)
	{
	  emit_unop_insn (CODE_FOR_truncsipsi, to, from, UNKNOWN);
	  return;
	}
#endif /* HAVE_truncsipsi */
      abort ();
    }

  if (from_mode == PSImode)
    {
      if (to_mode != SImode)
	{
	  from = convert_to_mode (SImode, from, unsignedp);
	  from_mode = SImode;
	}
      else
	{
#ifdef HAVE_extendpsisi
	  if (HAVE_extendpsisi)
	    {
	      emit_unop_insn (CODE_FOR_extendpsisi, to, from, UNKNOWN);
	      return;
	    }
#endif /* HAVE_extendpsisi */
	  abort ();
	}
    }

  /* Now follow all the conversions between integers
     no more than a word long.  */

  /* For truncation, usually we can just refer to FROM in a narrower mode.  */
  if (GET_MODE_BITSIZE (to_mode) < GET_MODE_BITSIZE (from_mode)
      && TRULY_NOOP_TRUNCATION (GET_MODE_BITSIZE (to_mode),
				GET_MODE_BITSIZE (from_mode))
      && ((GET_CODE (from) == MEM
	   && ! MEM_VOLATILE_P (from)
	   && direct_load[(int) to_mode]
	   && ! mode_dependent_address_p (XEXP (from, 0)))
	  || GET_CODE (from) == REG
	  || GET_CODE (from) == SUBREG))
    {
      emit_move_insn (to, gen_lowpart (to_mode, from));
      return;
    }

  /* For truncation, usually we can just refer to FROM in a narrower mode.  */
  if (GET_MODE_BITSIZE (to_mode) > GET_MODE_BITSIZE (from_mode))
    {
      /* Convert directly if that works.  */
      if ((code = can_extend_p (to_mode, from_mode, unsignedp))
	  != CODE_FOR_nothing)
	{
	  /* If FROM is a SUBREG, put it into a register.  Do this
	     so that we always generate the same set of insns for
	     better cse'ing; if an intermediate assignment occurred,
	     we won't be doing the operation directly on the SUBREG.  */
	  if (optimize > 0 && GET_CODE (from) == SUBREG)
	    from = force_reg (from_mode, from);
	  emit_unop_insn (code, to, from, equiv_code);
	  return;
	}
      else
	{
	  enum machine_mode intermediate;

	  /* Search for a mode to convert via.  */
	  for (intermediate = from_mode; intermediate != VOIDmode;
	       intermediate = GET_MODE_WIDER_MODE (intermediate))
	    if ((can_extend_p (to_mode, intermediate, unsignedp)
		 != CODE_FOR_nothing)
		&& (can_extend_p (intermediate, from_mode, unsignedp)
		    != CODE_FOR_nothing))
	      {
		convert_move (to, convert_to_mode (intermediate, from,
						   unsignedp), unsignedp);
		return;
	      }

	  /* No suitable intermediate mode.  */
	  abort ();
	}
    }

  /* Support special truncate insns for certain modes.  */ 

  if (from_mode == DImode && to_mode == SImode)
    {
#ifdef HAVE_truncdisi2
      if (HAVE_truncdisi2)
	{
	  emit_unop_insn (CODE_FOR_truncdisi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  if (from_mode == DImode && to_mode == HImode)
    {
#ifdef HAVE_truncdihi2
      if (HAVE_truncdihi2)
	{
	  emit_unop_insn (CODE_FOR_truncdihi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  if (from_mode == DImode && to_mode == QImode)
    {
#ifdef HAVE_truncdiqi2
      if (HAVE_truncdiqi2)
	{
	  emit_unop_insn (CODE_FOR_truncdiqi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  if (from_mode == SImode && to_mode == HImode)
    {
#ifdef HAVE_truncsihi2
      if (HAVE_truncsihi2)
	{
	  emit_unop_insn (CODE_FOR_truncsihi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  if (from_mode == SImode && to_mode == QImode)
    {
#ifdef HAVE_truncsiqi2
      if (HAVE_truncsiqi2)
	{
	  emit_unop_insn (CODE_FOR_truncsiqi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  if (from_mode == HImode && to_mode == QImode)
    {
#ifdef HAVE_trunchiqi2
      if (HAVE_trunchiqi2)
	{
	  emit_unop_insn (CODE_FOR_trunchiqi2, to, from, UNKNOWN);
	  return;
	}
#endif
      convert_move (to, force_reg (from_mode, from), unsignedp);
      return;
    }

  /* Handle truncation of volatile memrefs, and so on;
     the things that couldn't be truncated directly,
     and for which there was no special instruction.  */
  if (GET_MODE_BITSIZE (to_mode) < GET_MODE_BITSIZE (from_mode))
    {
      rtx temp = force_reg (to_mode, gen_lowpart (to_mode, from));
      emit_move_insn (to, temp);
      return;
    }

  /* Mode combination is not recognized.  */
  abort ();
}

/* Return an rtx for a value that would result
   from converting X to mode MODE.
   Both X and MODE may be floating, or both integer.
   UNSIGNEDP is nonzero if X is an unsigned value.
   This can be done by referring to a part of X in place
   or by copying to a new temporary with conversion.