i386.c

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     make the problem with not enough registers even worse.  */
#ifdef INSN_SCHEDULING
  if (level > 1)
    flag_schedule_insns = 0;
#endif
}

/* Sign-extend a 16-bit constant */

struct rtx_def *
i386_sext16_if_const (op)
     struct rtx_def *op;
{
  if (GET_CODE (op) == CONST_INT)
    {
      HOST_WIDE_INT val = INTVAL (op);
      HOST_WIDE_INT sext_val;
      if (val & 0x8000)
	sext_val = val | ~0xffff;
      else
	sext_val = val & 0xffff;
      if (sext_val != val)
	op = GEN_INT (sext_val);
    }
  return op;
}

/* Return nonzero if the rtx is aligned */

static int
i386_aligned_reg_p (regno)
     int regno;
{
  return (regno == STACK_POINTER_REGNUM
	  || (! flag_omit_frame_pointer && regno == FRAME_POINTER_REGNUM));
}

int
i386_aligned_p (op)
     rtx op;
{
  /* Registers and immediate operands are always "aligned". */
  if (GET_CODE (op) != MEM)
    return 1;

  /* Don't even try to do any aligned optimizations with volatiles. */
  if (MEM_VOLATILE_P (op))
    return 0;

  /* Get address of memory operand. */
  op = XEXP (op, 0);

  switch (GET_CODE (op))
    {
    case CONST_INT:
      if (INTVAL (op) & 3)
	break;
      return 1;

      /* Match "reg + offset" */
    case PLUS:
      if (GET_CODE (XEXP (op, 1)) != CONST_INT)
	break;
      if (INTVAL (XEXP (op, 1)) & 3)
	break;

      op = XEXP (op, 0);
      if (GET_CODE (op) != REG)
	break;

      /* ... fall through ... */

    case REG:
      return i386_aligned_reg_p (REGNO (op));

    default:
      break;
    }

  return 0;
}

/* Return nonzero if INSN looks like it won't compute useful cc bits
   as a side effect.  This information is only a hint. */

int
i386_cc_probably_useless_p (insn)
     rtx insn;
{
  return ! next_cc0_user (insn);
}

/* Return nonzero if IDENTIFIER with arguments ARGS is a valid machine specific
   attribute for DECL.  The attributes in ATTRIBUTES have previously been
   assigned to DECL.  */

int
i386_valid_decl_attribute_p (decl, attributes, identifier, args)
     tree decl ATTRIBUTE_UNUSED;
     tree attributes ATTRIBUTE_UNUSED;
     tree identifier ATTRIBUTE_UNUSED;
     tree args ATTRIBUTE_UNUSED;
{
  return 0;
}

/* Return nonzero if IDENTIFIER with arguments ARGS is a valid machine specific
   attribute for TYPE.  The attributes in ATTRIBUTES have previously been
   assigned to TYPE.  */

int
i386_valid_type_attribute_p (type, attributes, identifier, args)
     tree type;
     tree attributes ATTRIBUTE_UNUSED;
     tree identifier;
     tree args;
{
  if (TREE_CODE (type) != FUNCTION_TYPE
      && TREE_CODE (type) != METHOD_TYPE
      && TREE_CODE (type) != FIELD_DECL
      && TREE_CODE (type) != TYPE_DECL)
    return 0;

  /* Stdcall attribute says callee is responsible for popping arguments
     if they are not variable.  */
  if (is_attribute_p ("stdcall", identifier))
    return (args == NULL_TREE);

  /* Cdecl attribute says the callee is a normal C declaration. */
  if (is_attribute_p ("cdecl", identifier))
    return (args == NULL_TREE);

  /* Regparm attribute specifies how many integer arguments are to be
     passed in registers. */
  if (is_attribute_p ("regparm", identifier))
    {
      tree cst;

      if (! args || TREE_CODE (args) != TREE_LIST
	  || TREE_CHAIN (args) != NULL_TREE
	  || TREE_VALUE (args) == NULL_TREE)
	return 0;

      cst = TREE_VALUE (args);
      if (TREE_CODE (cst) != INTEGER_CST)
	return 0;

      if (TREE_INT_CST_HIGH (cst) != 0
	  || TREE_INT_CST_LOW (cst) < 0
	  || TREE_INT_CST_LOW (cst) > REGPARM_MAX)
	return 0;

      return 1;
    }

  return 0;
}

/* Return 0 if the attributes for two types are incompatible, 1 if they
   are compatible, and 2 if they are nearly compatible (which causes a
   warning to be generated).  */

int
i386_comp_type_attributes (type1, type2)
     tree type1;
     tree type2;
{
  /* Check for mismatch of non-default calling convention. */
  char *rtdstr = TARGET_RTD ? "cdecl" : "stdcall";

  if (TREE_CODE (type1) != FUNCTION_TYPE)
    return 1;

  /* Check for mismatched return types (cdecl vs stdcall).  */
  if (!lookup_attribute (rtdstr, TYPE_ATTRIBUTES (type1))
      != !lookup_attribute (rtdstr, TYPE_ATTRIBUTES (type2)))
    return 0;
  return 1;
}


/* Value is the number of bytes of arguments automatically
   popped when returning from a subroutine call.
   FUNDECL is the declaration node of the function (as a tree),
   FUNTYPE is the data type of the function (as a tree),
   or for a library call it is an identifier node for the subroutine name.
   SIZE is the number of bytes of arguments passed on the stack.

   On the 80386, the RTD insn may be used to pop them if the number
     of args is fixed, but if the number is variable then the caller
     must pop them all.  RTD can't be used for library calls now
     because the library is compiled with the Unix compiler.
   Use of RTD is a selectable option, since it is incompatible with
   standard Unix calling sequences.  If the option is not selected,
   the caller must always pop the args.

   The attribute stdcall is equivalent to RTD on a per module basis.  */

int
i386_return_pops_args (fundecl, funtype, size)
     tree fundecl;
     tree funtype;
     int size;
{
  int rtd = TARGET_RTD && (!fundecl || TREE_CODE (fundecl) != IDENTIFIER_NODE);

    /* Cdecl functions override -mrtd, and never pop the stack. */
  if (! lookup_attribute ("cdecl", TYPE_ATTRIBUTES (funtype))) {

    /* Stdcall functions will pop the stack if not variable args. */
    if (lookup_attribute ("stdcall", TYPE_ATTRIBUTES (funtype)))
      rtd = 1;

    if (rtd
        && (TYPE_ARG_TYPES (funtype) == NULL_TREE
	    || (TREE_VALUE (tree_last (TYPE_ARG_TYPES (funtype)))
		== void_type_node)))
      return size;
  }

  /* Lose any fake structure return argument.  */
  if (aggregate_value_p (TREE_TYPE (funtype)))
    return GET_MODE_SIZE (Pmode);

    return 0;
}


/* Argument support functions.  */

/* Initialize a variable CUM of type CUMULATIVE_ARGS
   for a call to a function whose data type is FNTYPE.
   For a library call, FNTYPE is 0.  */

void
init_cumulative_args (cum, fntype, libname)
     CUMULATIVE_ARGS *cum;	/* Argument info to initialize */
     tree fntype;		/* tree ptr for function decl */
     rtx libname;		/* SYMBOL_REF of library name or 0 */
{
  static CUMULATIVE_ARGS zero_cum;
  tree param, next_param;

  if (TARGET_DEBUG_ARG)
    {
      fprintf (stderr, "\ninit_cumulative_args (");
      if (fntype)
	fprintf (stderr, "fntype code = %s, ret code = %s",
		 tree_code_name[(int) TREE_CODE (fntype)],
		 tree_code_name[(int) TREE_CODE (TREE_TYPE (fntype))]);
      else
	fprintf (stderr, "no fntype");

      if (libname)
	fprintf (stderr, ", libname = %s", XSTR (libname, 0));
    }

  *cum = zero_cum;

  /* Set up the number of registers to use for passing arguments.  */
  cum->nregs = i386_regparm;
  if (fntype)
    {
      tree attr = lookup_attribute ("regparm", TYPE_ATTRIBUTES (fntype));

      if (attr)
	cum->nregs = TREE_INT_CST_LOW (TREE_VALUE (TREE_VALUE (attr)));
    }

  /* Determine if this function has variable arguments.  This is
     indicated by the last argument being 'void_type_mode' if there
     are no variable arguments.  If there are variable arguments, then
     we won't pass anything in registers */

  if (cum->nregs)
    {
      for (param = (fntype) ? TYPE_ARG_TYPES (fntype) : 0;
	   param != 0; param = next_param)
	{
	  next_param = TREE_CHAIN (param);
	  if (next_param == 0 && TREE_VALUE (param) != void_type_node)
	    cum->nregs = 0;
	}
    }

  if (TARGET_DEBUG_ARG)
    fprintf (stderr, ", nregs=%d )\n", cum->nregs);

  return;
}

/* Update the data in CUM to advance over an argument
   of mode MODE and data type TYPE.
   (TYPE is null for libcalls where that information may not be available.)  */

void
function_arg_advance (cum, mode, type, named)
     CUMULATIVE_ARGS *cum;	/* current arg information */
     enum machine_mode mode;	/* current arg mode */
     tree type;			/* type of the argument or 0 if lib support */
     int named;			/* whether or not the argument was named */
{
  int bytes
    = (mode == BLKmode) ? int_size_in_bytes (type) : GET_MODE_SIZE (mode);
  int words = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;

  if (TARGET_DEBUG_ARG)
    fprintf (stderr,
	     "function_adv (sz=%d, wds=%2d, nregs=%d, mode=%s, named=%d)\n\n",
	     words, cum->words, cum->nregs, GET_MODE_NAME (mode), named);

  cum->words += words;
  cum->nregs -= words;
  cum->regno += words;

  if (cum->nregs <= 0)
    {
      cum->nregs = 0;
      cum->regno = 0;
    }

  return;
}

/* Define where to put the arguments to a function.
   Value is zero to push the argument on the stack,
   or a hard register in which to store the argument.

   MODE is the argument's machine mode.
   TYPE is the data type of the argument (as a tree).
    This is null for libcalls where that information may
    not be available.
   CUM is a variable of type CUMULATIVE_ARGS which gives info about
    the preceding args and about the function being called.
   NAMED is nonzero if this argument is a named parameter
    (otherwise it is an extra parameter matching an ellipsis).  */

struct rtx_def *
function_arg (cum, mode, type, named)
     CUMULATIVE_ARGS *cum;	/* current arg information */
     enum machine_mode mode;	/* current arg mode */
     tree type;			/* type of the argument or 0 if lib support */
     int named;			/* != 0 for normal args, == 0 for ... args */
{
  rtx ret   = NULL_RTX;
  int bytes
    = (mode == BLKmode) ? int_size_in_bytes (type) : GET_MODE_SIZE (mode);
  int words = (bytes + UNITS_PER_WORD - 1) / UNITS_PER_WORD;

  switch (mode)
    {
      /* For now, pass fp/complex values on the stack. */
    default:
      break;

    case BLKmode:
    case DImode:
    case SImode:
    case HImode:
    case QImode:
      if (words <= cum->nregs)
	ret = gen_rtx_REG (mode, cum->regno);
      break;
    }

  if (TARGET_DEBUG_ARG)
    {
      fprintf (stderr,
	       "function_arg (size=%d, wds=%2d, nregs=%d, mode=%4s, named=%d",
	       words, cum->words, cum->nregs, GET_MODE_NAME (mode), named);

      if (ret)
	fprintf (stderr, ", reg=%%e%s", reg_names[ REGNO(ret) ]);
      else
	fprintf (stderr, ", stack");

      fprintf (stderr, " )\n");
    }

  return ret;
}

/* For an arg passed partly in registers and partly in memory,
   this is the number of registers used.
   For args passed entirely in registers or entirely in memory, zero.  */

int
function_arg_partial_nregs (cum, mode, type, named)
     CUMULATIVE_ARGS *cum ATTRIBUTE_UNUSED;	/* current arg information */
     enum machine_mode mode ATTRIBUTE_UNUSED;	/* current arg mode */
     tree type ATTRIBUTE_UNUSED;		/* type of the argument or 0 if lib support */
     int named ATTRIBUTE_UNUSED;		/* != 0 for normal args, == 0 for ... args */
{
  return 0;
}

char *
singlemove_string (operands)
     rtx *operands;
{
  rtx x;
  if (GET_CODE (operands[0]) == MEM
      && GET_CODE (x = XEXP (operands[0], 0)) == PRE_DEC)
    {
      if (XEXP (x, 0) != stack_pointer_rtx)
	abort ();
      return "push%L1 %1";
    }
  else if (GET_CODE (operands[1]) == CONST_DOUBLE)
    return output_move_const_single (operands);
  else if (GET_CODE (operands[0]) == REG || GET_CODE (operands[1]) == REG)
    return AS2 (mov%L0,%1,%0);
  else if (CONSTANT_P (operands[1]))
    return AS2 (mov%L0,%1,%0);
  else
    {
      output_asm_insn ("push%L1 %1", operands);
      return "pop%L0 %0";
    }
}

/* Output an insn to add the constant N to the register X.  */

static void
asm_add (n, x)
     int n;
     rtx x;
{
  rtx xops[2];
  xops[0] = x;

  if (n == -1)
    output_asm_insn (AS1 (dec%L0,%0), xops);
  else if (n == 1)
    output_asm_insn (AS1 (inc%L0,%0), xops);
  else if (n < 0 || n == 128)
    {
      xops[1] = GEN_INT (-n);
      output_asm_insn (AS2 (sub%L0,%1,%0), xops);
    }
  else if (n > 0)
    {
      xops[1] = GEN_INT (n);
      output_asm_insn (AS2 (add%L0,%1,%0), xops);
    }
}

/* Output assembler code to perform a doubleword move insn
   with operands OPERANDS.  */

char *
output_move_double (operands)
     rtx *operands;
{
  enum {REGOP, OFFSOP, MEMOP, PUSHOP, POPOP, CNSTOP, RNDOP } optype0, optype1;
  rtx latehalf[2];
  rtx middlehalf[2];
  rtx xops[2];
  int dest_overlapped_low = 0;
  int size = GET_MODE_SIZE (GET_MODE (operands[0]));

  middlehalf[0] = 0;
  middlehalf[1] = 0;

  /* First classify both operands.  */

  if (REG_P (operands[0]))
    optype0 = REGOP;
  else if (offsettable_memref_p (operands[0]))
    optype0 = OFFSOP;
  else if (GET_CODE (XEXP (operands[0], 0)) == POST_INC)
    optype0 = POPOP;
  else if (GET_CODE (XEXP (operands[0], 0)) == PRE_DEC)
    optype0 = PUSHOP;
  else if (GET_CODE (operands[0]) == MEM)
    optype0 = MEMOP;
  else