[thirdparty/gcc.git] / gcc / convert.c

/* Utility routines for data type conversion for GNU C.
   Copyright (C) 1987, 88, 91-95, 97, 1998 Free Software Foundation, Inc.

This file is part of GNU C.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


/* These routines are somewhat language-independent utility function
   intended to be called by the language-specific convert () functions.  */

#include "config.h"
#include "tree.h"
#include "flags.h"
#include "convert.h"
#include "toplev.h"

/* Convert EXPR to some pointer or reference type TYPE.

   EXPR must be pointer, reference, integer, enumeral, or literal zero;
   in other cases error is called.  */

tree
convert_to_pointer (type, expr)
     tree type, expr;
{
  if (integer_zerop (expr))
    {
      expr = build_int_2 (0, 0);
      TREE_TYPE (expr) = type;
      return expr;
    }

  switch (TREE_CODE (TREE_TYPE (expr)))
    {
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      return build1 (NOP_EXPR, type, expr);

    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case CHAR_TYPE:
      if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
	return build1 (CONVERT_EXPR, type, expr);

      return
	convert_to_pointer (type,
			    convert (type_for_size (POINTER_SIZE, 0), expr));

    default:
      error ("cannot convert to a pointer type");
      return convert_to_pointer (type, integer_zero_node);
    }
}

/* Convert EXPR to some floating-point type TYPE.

   EXPR must be float, integer, or enumeral;
   in other cases error is called.  */

tree
convert_to_real (type, expr)
     tree type, expr;
{
  switch (TREE_CODE (TREE_TYPE (expr)))
    {
    case REAL_TYPE:
      return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
		     type, expr);

    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case CHAR_TYPE:
      return build1 (FLOAT_EXPR, type, expr);

    case COMPLEX_TYPE:
      return convert (type,
		      fold (build1 (REALPART_EXPR,
				    TREE_TYPE (TREE_TYPE (expr)), expr)));

    case POINTER_TYPE:
    case REFERENCE_TYPE:
      error ("pointer value used where a floating point value was expected");
      return convert_to_real (type, integer_zero_node);

    default:
      error ("aggregate value used where a float was expected");
      return convert_to_real (type, integer_zero_node);
    }
}

/* Convert EXPR to some integer (or enum) type TYPE.

   EXPR must be pointer, integer, discrete (enum, char, or bool), or float;
   in other cases error is called.

   The result of this is always supposed to be a newly created tree node
   not in use in any existing structure.  */

tree
convert_to_integer (type, expr)
     tree type, expr;
{
  enum tree_code ex_form = TREE_CODE (expr);
  tree intype = TREE_TYPE (expr);
  int inprec = TYPE_PRECISION (intype);
  int outprec = TYPE_PRECISION (type);

  switch (TREE_CODE (intype))
    {
    case POINTER_TYPE:
    case REFERENCE_TYPE:
      if (integer_zerop (expr))
	expr = integer_zero_node;
      else
	expr = fold (build1 (CONVERT_EXPR,
			     type_for_size (POINTER_SIZE, 0), expr));

      return convert_to_integer (type, expr);

    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case CHAR_TYPE:
      /* If this is a logical operation, which just returns 0 or 1, we can
	 change the type of the expression.  For some logical operations,
	 we must also change the types of the operands to maintain type
	 correctness.  */

      if (TREE_CODE_CLASS (ex_form) == '<')
	{
	  TREE_TYPE (expr) = type;
	  return expr;
	}

      else if (ex_form == TRUTH_AND_EXPR || ex_form == TRUTH_ANDIF_EXPR
	       || ex_form == TRUTH_OR_EXPR || ex_form == TRUTH_ORIF_EXPR
	       || ex_form == TRUTH_XOR_EXPR)
	{
	  TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
	  TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1));
	  TREE_TYPE (expr) = type;
	  return expr;
	}

      else if (ex_form == TRUTH_NOT_EXPR)
	{
	  TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
	  TREE_TYPE (expr) = type;
	  return expr;
	}

      /* If we are widening the type, put in an explicit conversion.
	 Similarly if we are not changing the width.  After this, we know
	 we are truncating EXPR.  */

      else if (outprec >= inprec)
	return build1 (NOP_EXPR, type, expr);

      /* If TYPE is an enumeral type or a type with a precision less
	 than the number of bits in its mode, do the conversion to the
	 type corresponding to its mode, then do a nop conversion
	 to TYPE.  */
      else if (TREE_CODE (type) == ENUMERAL_TYPE
	       || outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
	return build1 (NOP_EXPR, type,
		       convert (type_for_mode (TYPE_MODE (type),
					       TREE_UNSIGNED (type)),
				expr));

      /* Here detect when we can distribute the truncation down past some
	 arithmetic.  For example, if adding two longs and converting to an
	 int, we can equally well convert both to ints and then add.
	 For the operations handled here, such truncation distribution
	 is always safe.
	 It is desirable in these cases:
	 1) when truncating down to full-word from a larger size
	 2) when truncating takes no work.
	 3) when at least one operand of the arithmetic has been extended
	 (as by C's default conversions).  In this case we need two conversions
	 if we do the arithmetic as already requested, so we might as well
	 truncate both and then combine.  Perhaps that way we need only one.

	 Note that in general we cannot do the arithmetic in a type
	 shorter than the desired result of conversion, even if the operands
	 are both extended from a shorter type, because they might overflow
	 if combined in that type.  The exceptions to this--the times when
	 two narrow values can be combined in their narrow type even to
	 make a wider result--are handled by "shorten" in build_binary_op.  */

      switch (ex_form)
	{
	case RSHIFT_EXPR:
	  /* We can pass truncation down through right shifting
	     when the shift count is a nonpositive constant.  */
	  if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
	      && tree_int_cst_lt (TREE_OPERAND (expr, 1),
				  convert (TREE_TYPE (TREE_OPERAND (expr, 1)),
					   integer_one_node)))
	    goto trunc1;
	  break;

	case LSHIFT_EXPR:
	  /* We can pass truncation down through left shifting
	     when the shift count is a nonnegative constant.  */
	  if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
	      && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
	      && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
	    {
	      /* If shift count is less than the width of the truncated type,
		 really shift.  */
	      if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
		/* In this case, shifting is like multiplication.  */
		goto trunc1;
	      else
		{
		  /* If it is >= that width, result is zero.
		     Handling this with trunc1 would give the wrong result:
		     (int) ((long long) a << 32) is well defined (as 0)
		     but (int) a << 32 is undefined and would get a
		     warning.  */

		  tree t = convert_to_integer (type, integer_zero_node);

		  /* If the original expression had side-effects, we must
		     preserve it.  */
		  if (TREE_SIDE_EFFECTS (expr))
		    return build (COMPOUND_EXPR, type, expr, t);
		  else
		    return t;
		}
	    }
	  break;

	case MAX_EXPR:
	case MIN_EXPR:
	case MULT_EXPR:
	  {
	    tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
	    tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);

	    /* Don't distribute unless the output precision is at least as big
	       as the actual inputs.  Otherwise, the comparison of the
	       truncated values will be wrong.  */
	    if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
		&& outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
		/* If signedness of arg0 and arg1 don't match,
		   we can't necessarily find a type to compare them in.  */
		&& (TREE_UNSIGNED (TREE_TYPE (arg0))
		    == TREE_UNSIGNED (TREE_TYPE (arg1))))
	      goto trunc1;
	    break;
	  }

	case PLUS_EXPR:
	case MINUS_EXPR:
	case BIT_AND_EXPR:
	case BIT_IOR_EXPR:
	case BIT_XOR_EXPR:
	case BIT_ANDTC_EXPR:
	trunc1:
	  {
	    tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
	    tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);

	    if (outprec >= BITS_PER_WORD
		|| TRULY_NOOP_TRUNCATION (outprec, inprec)
		|| inprec > TYPE_PRECISION (TREE_TYPE (arg0))
		|| inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
	      {
		/* Do the arithmetic in type TYPEX,
		   then convert result to TYPE.  */
		register tree typex = type;

		/* Can't do arithmetic in enumeral types
		   so use an integer type that will hold the values.  */
		if (TREE_CODE (typex) == ENUMERAL_TYPE)
		  typex = type_for_size (TYPE_PRECISION (typex),
					 TREE_UNSIGNED (typex));

		/* But now perhaps TYPEX is as wide as INPREC.
		   In that case, do nothing special here.
		   (Otherwise would recurse infinitely in convert.  */
		if (TYPE_PRECISION (typex) != inprec)
		  {
		    /* Don't do unsigned arithmetic where signed was wanted,
		       or vice versa.
		       Exception: if either of the original operands were
		       unsigned then can safely do the work as unsigned.
		       And we may need to do it as unsigned
		       if we truncate to the original size.  */
		    typex = ((TREE_UNSIGNED (TREE_TYPE (expr))
			      || TREE_UNSIGNED (TREE_TYPE (arg0))
			      || TREE_UNSIGNED (TREE_TYPE (arg1)))
			     ? unsigned_type (typex) : signed_type (typex));
		    return convert (type,
				    fold (build (ex_form, typex,
						 convert (typex, arg0),
						 convert (typex, arg1),
						 0)));
		  }
	      }
	  }
	  break;

	case NEGATE_EXPR:
	case BIT_NOT_EXPR:
	  /* This is not correct for ABS_EXPR,
	     since we must test the sign before truncation.  */
	  {
	    register tree typex = type;

	    /* Can't do arithmetic in enumeral types
	       so use an integer type that will hold the values.  */
	    if (TREE_CODE (typex) == ENUMERAL_TYPE)
	      typex = type_for_size (TYPE_PRECISION (typex),
				     TREE_UNSIGNED (typex));

	    /* But now perhaps TYPEX is as wide as INPREC.
	       In that case, do nothing special here.
	       (Otherwise would recurse infinitely in convert.  */
	    if (TYPE_PRECISION (typex) != inprec)
	      {
		/* Don't do unsigned arithmetic where signed was wanted,
		   or vice versa.  */
		typex = (TREE_UNSIGNED (TREE_TYPE (expr))
			 ? unsigned_type (typex) : signed_type (typex));
		return convert (type,
				fold (build1 (ex_form, typex,
					      convert (typex,
						       TREE_OPERAND (expr, 0)))));
	      }
	  }

	case NOP_EXPR:
	  /* If truncating after truncating, might as well do all at once.
	     If truncating after extending, we may get rid of wasted work.  */
	  return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));

	case COND_EXPR:
	  /* It is sometimes worthwhile to push the narrowing down through
	     the conditional and never loses.  */
	  return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0),
			      convert (type, TREE_OPERAND (expr, 1)), 
			      convert (type, TREE_OPERAND (expr, 2))));

	default:
	  break;
	}

      return build1 (NOP_EXPR, type, expr);

    case REAL_TYPE:
      return build1 (FIX_TRUNC_EXPR, type, expr);

    case COMPLEX_TYPE:
      return convert (type,
		      fold (build1 (REALPART_EXPR,
				    TREE_TYPE (TREE_TYPE (expr)), expr)));

    default:
      error ("aggregate value used where an integer was expected");
      return convert (type, integer_zero_node);
    }
}

/* Convert EXPR to the complex type TYPE in the usual ways.  */

tree
convert_to_complex (type, expr)
     tree type, expr;
{
  tree subtype = TREE_TYPE (type);
  
  switch (TREE_CODE (TREE_TYPE (expr)))
    {
    case REAL_TYPE:
    case INTEGER_TYPE:
    case ENUMERAL_TYPE:
    case BOOLEAN_TYPE:
    case CHAR_TYPE:
      return build (COMPLEX_EXPR, type, convert (subtype, expr),
		    convert (subtype, integer_zero_node));

    case COMPLEX_TYPE:
      {
	tree elt_type = TREE_TYPE (TREE_TYPE (expr));

	if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
	  return expr;
	else if (TREE_CODE (expr) == COMPLEX_EXPR)
	  return fold (build (COMPLEX_EXPR,
			      type,
			      convert (subtype, TREE_OPERAND (expr, 0)),
			      convert (subtype, TREE_OPERAND (expr, 1))));
	else
	  {
	    expr = save_expr (expr);
	    return
	      fold (build (COMPLEX_EXPR,
			   type, convert (subtype,
					  fold (build1 (REALPART_EXPR,
							TREE_TYPE (TREE_TYPE (expr)),
							expr))),
			   convert (subtype,
				    fold (build1 (IMAGPART_EXPR,
						  TREE_TYPE (TREE_TYPE (expr)),
						  expr)))));
	  }
      }

    case POINTER_TYPE:
    case REFERENCE_TYPE:
      error ("pointer value used where a complex was expected");
      return convert_to_complex (type, integer_zero_node);

    default:
      error ("aggregate value used where a complex was expected");
      return convert_to_complex (type, integer_zero_node);
    }
}
Commit	Line	Data
76e616db	1	/* Utility routines for data type conversion for GNU C.
f5963e61	2	Copyright (C) 1987, 88, 91-95, 97, 1998 Free Software Foundation, Inc.
76e616db BK	3
	4	This file is part of GNU C.
	5
	6	GNU CC is free software; you can redistribute it and/or modify
	7	it under the terms of the GNU General Public License as published by
	8	the Free Software Foundation; either version 2, or (at your option)
	9	any later version.
	10
	11	GNU CC is distributed in the hope that it will be useful,
	12	but WITHOUT ANY WARRANTY; without even the implied warranty of
	13	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	14	GNU General Public License for more details.
	15
	16	You should have received a copy of the GNU General Public License
	17	along with GNU CC; see the file COPYING. If not, write to
940d9d63 RK	18	the Free Software Foundation, 59 Temple Place - Suite 330,
940d9d63 RK	19	Boston, MA 02111-1307, USA. */
76e616db BK	20
	21
	22	/* These routines are somewhat language-independent utility function
0f41302f	23	intended to be called by the language-specific convert () functions. */
76e616db BK	24
	25	#include "config.h"
	26	#include "tree.h"
	27	#include "flags.h"
	28	#include "convert.h"
10f0ad3d	29	#include "toplev.h"
76e616db	30
98c76e3c	31	/* Convert EXPR to some pointer or reference type TYPE.
76e616db	32
98c76e3c	33	EXPR must be pointer, reference, integer, enumeral, or literal zero;
0f41302f	34	in other cases error is called. */
76e616db BK	35
	36	tree
	37	convert_to_pointer (type, expr)
	38	tree type, expr;
	39	{
76e616db BK	40	if (integer_zerop (expr))
76e616db BK	41	{
76e616db BK	42	expr = build_int_2 (0, 0);
	43	TREE_TYPE (expr) = type;
	44	return expr;
	45	}
	46
f5963e61	47	switch (TREE_CODE (TREE_TYPE (expr)))
76e616db	48	{
f5963e61 JL	49	case POINTER_TYPE:
	50	case REFERENCE_TYPE:
	51	return build1 (NOP_EXPR, type, expr);
	52
	53	case INTEGER_TYPE:
	54	case ENUMERAL_TYPE:
	55	case BOOLEAN_TYPE:
	56	case CHAR_TYPE:
	57	if (TYPE_PRECISION (TREE_TYPE (expr)) == POINTER_SIZE)
76e616db	58	return build1 (CONVERT_EXPR, type, expr);
76e616db	59
f5963e61 JL	60	return
	61	convert_to_pointer (type,
	62	convert (type_for_size (POINTER_SIZE, 0), expr));
76e616db	63
f5963e61 JL	64	default:
	65	error ("cannot convert to a pointer type");
	66	return convert_to_pointer (type, integer_zero_node);
	67	}
76e616db BK	68	}
	69
	70	/* Convert EXPR to some floating-point type TYPE.
	71
	72	EXPR must be float, integer, or enumeral;
0f41302f	73	in other cases error is called. */
76e616db BK	74
	75	tree
	76	convert_to_real (type, expr)
	77	tree type, expr;
	78	{
f5963e61 JL	79	switch (TREE_CODE (TREE_TYPE (expr)))
	80	{
	81	case REAL_TYPE:
	82	return build1 (flag_float_store ? CONVERT_EXPR : NOP_EXPR,
	83	type, expr);
	84
	85	case INTEGER_TYPE:
	86	case ENUMERAL_TYPE:
	87	case BOOLEAN_TYPE:
	88	case CHAR_TYPE:
	89	return build1 (FLOAT_EXPR, type, expr);
	90
	91	case COMPLEX_TYPE:
	92	return convert (type,
	93	fold (build1 (REALPART_EXPR,
	94	TREE_TYPE (TREE_TYPE (expr)), expr)));
	95
	96	case POINTER_TYPE:
	97	case REFERENCE_TYPE:
	98	error ("pointer value used where a floating point value was expected");
	99	return convert_to_real (type, integer_zero_node);
	100
	101	default:
	102	error ("aggregate value used where a float was expected");
	103	return convert_to_real (type, integer_zero_node);
	104	}
76e616db BK	105	}
	106
	107	/* Convert EXPR to some integer (or enum) type TYPE.
	108
	109	EXPR must be pointer, integer, discrete (enum, char, or bool), or float;
	110	in other cases error is called.
	111
	112	The result of this is always supposed to be a newly created tree node
	113	not in use in any existing structure. */
	114
	115	tree
	116	convert_to_integer (type, expr)
	117	tree type, expr;
	118	{
f5963e61 JL	119	enum tree_code ex_form = TREE_CODE (expr);
	120	tree intype = TREE_TYPE (expr);
	121	int inprec = TYPE_PRECISION (intype);
	122	int outprec = TYPE_PRECISION (type);
76e616db	123
f5963e61	124	switch (TREE_CODE (intype))
76e616db	125	{
f5963e61 JL	126	case POINTER_TYPE:
f5963e61 JL	127	case REFERENCE_TYPE:
76e616db BK	128	if (integer_zerop (expr))
	129	expr = integer_zero_node;
	130	else
	131	expr = fold (build1 (CONVERT_EXPR,
	132	type_for_size (POINTER_SIZE, 0), expr));
76e616db	133
f5963e61	134	return convert_to_integer (type, expr);
76e616db	135
f5963e61 JL	136	case INTEGER_TYPE:
	137	case ENUMERAL_TYPE:
	138	case BOOLEAN_TYPE:
	139	case CHAR_TYPE:
	140	/* If this is a logical operation, which just returns 0 or 1, we can
	141	change the type of the expression. For some logical operations,
	142	we must also change the types of the operands to maintain type
c9529354	143	correctness. */
76e616db	144
c9529354	145	if (TREE_CODE_CLASS (ex_form) == '<')
76e616db BK	146	{
	147	TREE_TYPE (expr) = type;
	148	return expr;
	149	}
f5963e61	150
c9529354 RK	151	else if (ex_form == TRUTH_AND_EXPR \|\| ex_form == TRUTH_ANDIF_EXPR
	152	\|\| ex_form == TRUTH_OR_EXPR \|\| ex_form == TRUTH_ORIF_EXPR
	153	\|\| ex_form == TRUTH_XOR_EXPR)
	154	{
	155	TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
	156	TREE_OPERAND (expr, 1) = convert (type, TREE_OPERAND (expr, 1));
	157	TREE_TYPE (expr) = type;
	158	return expr;
	159	}
f5963e61	160
c9529354 RK	161	else if (ex_form == TRUTH_NOT_EXPR)
	162	{
	163	TREE_OPERAND (expr, 0) = convert (type, TREE_OPERAND (expr, 0));
	164	TREE_TYPE (expr) = type;
	165	return expr;
	166	}
f5963e61 JL	167
	168	/* If we are widening the type, put in an explicit conversion.
	169	Similarly if we are not changing the width. After this, we know
	170	we are truncating EXPR. */
	171
76e616db BK	172	else if (outprec >= inprec)
	173	return build1 (NOP_EXPR, type, expr);
	174
1c013b45 RK	175	/* If TYPE is an enumeral type or a type with a precision less
	176	than the number of bits in its mode, do the conversion to the
	177	type corresponding to its mode, then do a nop conversion
	178	to TYPE. */
	179	else if (TREE_CODE (type) == ENUMERAL_TYPE
	180	\|\| outprec != GET_MODE_BITSIZE (TYPE_MODE (type)))
	181	return build1 (NOP_EXPR, type,
	182	convert (type_for_mode (TYPE_MODE (type),
	183	TREE_UNSIGNED (type)),
	184	expr));
	185
ab29fdfc RK	186	/* Here detect when we can distribute the truncation down past some
	187	arithmetic. For example, if adding two longs and converting to an
	188	int, we can equally well convert both to ints and then add.
	189	For the operations handled here, such truncation distribution
	190	is always safe.
	191	It is desirable in these cases:
	192	1) when truncating down to full-word from a larger size
	193	2) when truncating takes no work.
	194	3) when at least one operand of the arithmetic has been extended
	195	(as by C's default conversions). In this case we need two conversions
	196	if we do the arithmetic as already requested, so we might as well
	197	truncate both and then combine. Perhaps that way we need only one.
	198
	199	Note that in general we cannot do the arithmetic in a type
	200	shorter than the desired result of conversion, even if the operands
	201	are both extended from a shorter type, because they might overflow
	202	if combined in that type. The exceptions to this--the times when
	203	two narrow values can be combined in their narrow type even to
	204	make a wider result--are handled by "shorten" in build_binary_op. */
76e616db BK	205
	206	switch (ex_form)
	207	{
	208	case RSHIFT_EXPR:
	209	/* We can pass truncation down through right shifting
	210	when the shift count is a nonpositive constant. */
	211	if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
ab29fdfc RK	212	&& tree_int_cst_lt (TREE_OPERAND (expr, 1),
	213	convert (TREE_TYPE (TREE_OPERAND (expr, 1)),
	214	integer_one_node)))
76e616db BK	215	goto trunc1;
	216	break;
	217
	218	case LSHIFT_EXPR:
	219	/* We can pass truncation down through left shifting
	220	when the shift count is a nonnegative constant. */
	221	if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
ab29fdfc	222	&& tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
76e616db BK	223	&& TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
	224	{
	225	/* If shift count is less than the width of the truncated type,
	226	really shift. */
	227	if (tree_int_cst_lt (TREE_OPERAND (expr, 1), TYPE_SIZE (type)))
	228	/* In this case, shifting is like multiplication. */
	229	goto trunc1;
	230	else
d9a9c5a7 RK	231	{
	232	/* If it is >= that width, result is zero.
	233	Handling this with trunc1 would give the wrong result:
	234	(int) ((long long) a << 32) is well defined (as 0)
	235	but (int) a << 32 is undefined and would get a
	236	warning. */
	237
	238	tree t = convert_to_integer (type, integer_zero_node);
	239
	240	/* If the original expression had side-effects, we must
	241	preserve it. */
	242	if (TREE_SIDE_EFFECTS (expr))
	243	return build (COMPOUND_EXPR, type, expr, t);
	244	else
	245	return t;
	246	}
76e616db BK	247	}
	248	break;
	249
	250	case MAX_EXPR:
	251	case MIN_EXPR:
	252	case MULT_EXPR:
	253	{
	254	tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
	255	tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
	256
	257	/* Don't distribute unless the output precision is at least as big
	258	as the actual inputs. Otherwise, the comparison of the
	259	truncated values will be wrong. */
	260	if (outprec >= TYPE_PRECISION (TREE_TYPE (arg0))
	261	&& outprec >= TYPE_PRECISION (TREE_TYPE (arg1))
	262	/* If signedness of arg0 and arg1 don't match,
	263	we can't necessarily find a type to compare them in. */
	264	&& (TREE_UNSIGNED (TREE_TYPE (arg0))
	265	== TREE_UNSIGNED (TREE_TYPE (arg1))))
	266	goto trunc1;
	267	break;
	268	}
	269
	270	case PLUS_EXPR:
	271	case MINUS_EXPR:
	272	case BIT_AND_EXPR:
	273	case BIT_IOR_EXPR:
	274	case BIT_XOR_EXPR:
	275	case BIT_ANDTC_EXPR:
	276	trunc1:
	277	{
	278	tree arg0 = get_unwidened (TREE_OPERAND (expr, 0), type);
	279	tree arg1 = get_unwidened (TREE_OPERAND (expr, 1), type);
	280
	281	if (outprec >= BITS_PER_WORD
	282	\|\| TRULY_NOOP_TRUNCATION (outprec, inprec)
	283	\|\| inprec > TYPE_PRECISION (TREE_TYPE (arg0))
	284	\|\| inprec > TYPE_PRECISION (TREE_TYPE (arg1)))
	285	{
	286	/* Do the arithmetic in type TYPEX,
	287	then convert result to TYPE. */
	288	register tree typex = type;
	289
	290	/* Can't do arithmetic in enumeral types
	291	so use an integer type that will hold the values. */
	292	if (TREE_CODE (typex) == ENUMERAL_TYPE)
	293	typex = type_for_size (TYPE_PRECISION (typex),
	294	TREE_UNSIGNED (typex));
	295
	296	/* But now perhaps TYPEX is as wide as INPREC.
	297	In that case, do nothing special here.
	298	(Otherwise would recurse infinitely in convert. */
	299	if (TYPE_PRECISION (typex) != inprec)
	300	{
	301	/* Don't do unsigned arithmetic where signed was wanted,
	302	or vice versa.
	303	Exception: if either of the original operands were
	304	unsigned then can safely do the work as unsigned.
	305	And we may need to do it as unsigned
	306	if we truncate to the original size. */
	307	typex = ((TREE_UNSIGNED (TREE_TYPE (expr))
	308	\|\| TREE_UNSIGNED (TREE_TYPE (arg0))
	309	\|\| TREE_UNSIGNED (TREE_TYPE (arg1)))
	310	? unsigned_type (typex) : signed_type (typex));
311	return convert (type,
95e78909 RK	312	fold (build (ex_form, typex,
	313	convert (typex, arg0),
	314	convert (typex, arg1),
	315	0)));
76e616db BK	316	}
	317	}
	318	}
	319	break;
	320
	321	case NEGATE_EXPR:
	322	case BIT_NOT_EXPR:
d283912a RS	323	/* This is not correct for ABS_EXPR,
d283912a RS	324	since we must test the sign before truncation. */
76e616db BK	325	{
	326	register tree typex = type;
	327
	328	/* Can't do arithmetic in enumeral types
	329	so use an integer type that will hold the values. */
	330	if (TREE_CODE (typex) == ENUMERAL_TYPE)
	331	typex = type_for_size (TYPE_PRECISION (typex),
	332	TREE_UNSIGNED (typex));
	333
	334	/* But now perhaps TYPEX is as wide as INPREC.
	335	In that case, do nothing special here.
	336	(Otherwise would recurse infinitely in convert. */
	337	if (TYPE_PRECISION (typex) != inprec)
	338	{
	339	/* Don't do unsigned arithmetic where signed was wanted,
	340	or vice versa. */
	341	typex = (TREE_UNSIGNED (TREE_TYPE (expr))
	342	? unsigned_type (typex) : signed_type (typex));
	343	return convert (type,
95e78909 RK	344	fold (build1 (ex_form, typex,
	345	convert (typex,
	346	TREE_OPERAND (expr, 0)))));
76e616db BK	347	}
	348	}
	349
	350	case NOP_EXPR:
	351	/* If truncating after truncating, might as well do all at once.
	352	If truncating after extending, we may get rid of wasted work. */
	353	return convert (type, get_unwidened (TREE_OPERAND (expr, 0), type));
	354
	355	case COND_EXPR:
f5963e61 JL	356	/* It is sometimes worthwhile to push the narrowing down through
	357	the conditional and never loses. */
	358	return fold (build (COND_EXPR, type, TREE_OPERAND (expr, 0),
	359	convert (type, TREE_OPERAND (expr, 1)),
	360	convert (type, TREE_OPERAND (expr, 2))));
76e616db	361
31031edd JL	362	default:
31031edd JL	363	break;
76e616db BK	364	}
	365
	366	return build1 (NOP_EXPR, type, expr);
76e616db	367
f5963e61 JL	368	case REAL_TYPE:
f5963e61 JL	369	return build1 (FIX_TRUNC_EXPR, type, expr);
76e616db	370
f5963e61 JL	371	case COMPLEX_TYPE:
	372	return convert (type,
	373	fold (build1 (REALPART_EXPR,
	374	TREE_TYPE (TREE_TYPE (expr)), expr)));
0b127821	375
f5963e61 JL	376	default:
	377	error ("aggregate value used where an integer was expected");
	378	return convert (type, integer_zero_node);
	379	}
76e616db	380	}
0b127821 RS	381
	382	/* Convert EXPR to the complex type TYPE in the usual ways. */
	383
	384	tree
	385	convert_to_complex (type, expr)
	386	tree type, expr;
	387	{
0b127821 RS	388	tree subtype = TREE_TYPE (type);
0b127821 RS	389
f5963e61	390	switch (TREE_CODE (TREE_TYPE (expr)))
0b127821	391	{
f5963e61 JL	392	case REAL_TYPE:
	393	case INTEGER_TYPE:
	394	case ENUMERAL_TYPE:
	395	case BOOLEAN_TYPE:
	396	case CHAR_TYPE:
	397	return build (COMPLEX_EXPR, type, convert (subtype, expr),
0b127821	398	convert (subtype, integer_zero_node));
0b127821	399
f5963e61 JL	400	case COMPLEX_TYPE:
	401	{
	402	tree elt_type = TREE_TYPE (TREE_TYPE (expr));
	403
	404	if (TYPE_MAIN_VARIANT (elt_type) == TYPE_MAIN_VARIANT (subtype))
	405	return expr;
	406	else if (TREE_CODE (expr) == COMPLEX_EXPR)
0b127821 RS	407	return fold (build (COMPLEX_EXPR,
0b127821 RS	408	type,
f5963e61 JL	409	convert (subtype, TREE_OPERAND (expr, 0)),
	410	convert (subtype, TREE_OPERAND (expr, 1))));
	411	else
	412	{
	413	expr = save_expr (expr);
	414	return
	415	fold (build (COMPLEX_EXPR,
	416	type, convert (subtype,
	417	fold (build1 (REALPART_EXPR,
	418	TREE_TYPE (TREE_TYPE (expr)),
	419	expr))),
	420	convert (subtype,
	421	fold (build1 (IMAGPART_EXPR,
	422	TREE_TYPE (TREE_TYPE (expr)),
	423	expr)))));
	424	}
	425	}
0b127821	426
f5963e61 JL	427	case POINTER_TYPE:
	428	case REFERENCE_TYPE:
	429	error ("pointer value used where a complex was expected");
	430	return convert_to_complex (type, integer_zero_node);
	431
	432	default:
	433	error ("aggregate value used where a complex was expected");
	434	return convert_to_complex (type, integer_zero_node);
	435	}
0b127821	436	}