--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gcc/convert.c	Fri Jul 17 14:47:48 2009 +0900
@@ -0,0 +1,892 @@
+/* Utility routines for data type conversion for GCC.
+   Copyright (C) 1987, 1988, 1991, 1992, 1993, 1994, 1995, 1997, 1998,
+   2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
+   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/>.  */
+
+
+/* These routines are somewhat language-independent utility function
+   intended to be called by the language-specific convert () functions.  */
+
+#include "config.h"
+#include "system.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "tree.h"
+#include "flags.h"
+#include "convert.h"
+#include "toplev.h"
+#include "langhooks.h"
+#include "real.h"
+#include "fixed-value.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 (tree type, tree expr)
+{
+  if (TREE_TYPE (expr) == type)
+    return expr;
+
+  /* Propagate overflow to the NULL pointer.  */
+  if (integer_zerop (expr))
+    return force_fit_type_double (type, 0, 0, 0, TREE_OVERFLOW (expr));
+
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      return fold_build1 (NOP_EXPR, type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+      if (TYPE_PRECISION (TREE_TYPE (expr)) != POINTER_SIZE)
+	expr = fold_build1 (NOP_EXPR,
+                            lang_hooks.types.type_for_size (POINTER_SIZE, 0),
+			    expr);
+      return fold_build1 (CONVERT_EXPR, type, expr);
+
+
+    default:
+      error ("cannot convert to a pointer type");
+      return convert_to_pointer (type, integer_zero_node);
+    }
+}
+
+/* Avoid any floating point extensions from EXP.  */
+tree
+strip_float_extensions (tree exp)
+{
+  tree sub, expt, subt;
+
+  /*  For floating point constant look up the narrowest type that can hold
+      it properly and handle it like (type)(narrowest_type)constant.
+      This way we can optimize for instance a=a*2.0 where "a" is float
+      but 2.0 is double constant.  */
+  if (TREE_CODE (exp) == REAL_CST && !DECIMAL_FLOAT_TYPE_P (TREE_TYPE (exp)))
+    {
+      REAL_VALUE_TYPE orig;
+      tree type = NULL;
+
+      orig = TREE_REAL_CST (exp);
+      if (TYPE_PRECISION (TREE_TYPE (exp)) > TYPE_PRECISION (float_type_node)
+	  && exact_real_truncate (TYPE_MODE (float_type_node), &orig))
+	type = float_type_node;
+      else if (TYPE_PRECISION (TREE_TYPE (exp))
+	       > TYPE_PRECISION (double_type_node)
+	       && exact_real_truncate (TYPE_MODE (double_type_node), &orig))
+	type = double_type_node;
+      if (type)
+	return build_real (type, real_value_truncate (TYPE_MODE (type), orig));
+    }
+
+  if (!CONVERT_EXPR_P (exp))
+    return exp;
+
+  sub = TREE_OPERAND (exp, 0);
+  subt = TREE_TYPE (sub);
+  expt = TREE_TYPE (exp);
+
+  if (!FLOAT_TYPE_P (subt))
+    return exp;
+
+  if (DECIMAL_FLOAT_TYPE_P (expt) != DECIMAL_FLOAT_TYPE_P (subt))
+    return exp;
+
+  if (TYPE_PRECISION (subt) > TYPE_PRECISION (expt))
+    return exp;
+
+  return strip_float_extensions (sub);
+}
+
+
+/* Convert EXPR to some floating-point type TYPE.
+
+   EXPR must be float, fixed-point, integer, or enumeral;
+   in other cases error is called.  */
+
+tree
+convert_to_real (tree type, tree expr)
+{
+  enum built_in_function fcode = builtin_mathfn_code (expr);
+  tree itype = TREE_TYPE (expr);
+
+  /* Disable until we figure out how to decide whether the functions are
+     present in runtime.  */
+  /* Convert (float)sqrt((double)x) where x is float into sqrtf(x) */
+  if (optimize
+      && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
+          || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
+    {
+      switch (fcode)
+        {
+#define CASE_MATHFN(FN) case BUILT_IN_##FN: case BUILT_IN_##FN##L:
+	  CASE_MATHFN (COSH)
+	  CASE_MATHFN (EXP)
+	  CASE_MATHFN (EXP10)
+	  CASE_MATHFN (EXP2)
+ 	  CASE_MATHFN (EXPM1)
+	  CASE_MATHFN (GAMMA)
+	  CASE_MATHFN (J0)
+	  CASE_MATHFN (J1)
+	  CASE_MATHFN (LGAMMA)
+	  CASE_MATHFN (POW10)
+	  CASE_MATHFN (SINH)
+	  CASE_MATHFN (TGAMMA)
+	  CASE_MATHFN (Y0)
+	  CASE_MATHFN (Y1)
+	    /* The above functions may set errno differently with float
+	       input or output so this transformation is not safe with
+	       -fmath-errno.  */
+	    if (flag_errno_math)
+	      break;
+	  CASE_MATHFN (ACOS)
+	  CASE_MATHFN (ACOSH)
+	  CASE_MATHFN (ASIN)
+ 	  CASE_MATHFN (ASINH)
+ 	  CASE_MATHFN (ATAN)
+	  CASE_MATHFN (ATANH)
+ 	  CASE_MATHFN (CBRT)
+ 	  CASE_MATHFN (COS)
+ 	  CASE_MATHFN (ERF)
+ 	  CASE_MATHFN (ERFC)
+ 	  CASE_MATHFN (FABS)
+	  CASE_MATHFN (LOG)
+	  CASE_MATHFN (LOG10)
+	  CASE_MATHFN (LOG2)
+ 	  CASE_MATHFN (LOG1P)
+ 	  CASE_MATHFN (LOGB)
+ 	  CASE_MATHFN (SIN)
+	  CASE_MATHFN (SQRT)
+ 	  CASE_MATHFN (TAN)
+ 	  CASE_MATHFN (TANH)
+#undef CASE_MATHFN
+	    {
+	      tree arg0 = strip_float_extensions (CALL_EXPR_ARG (expr, 0));
+	      tree newtype = type;
+
+	      /* We have (outertype)sqrt((innertype)x).  Choose the wider mode from
+		 the both as the safe type for operation.  */
+	      if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (type))
+		newtype = TREE_TYPE (arg0);
+
+	      /* Be careful about integer to fp conversions.
+		 These may overflow still.  */
+	      if (FLOAT_TYPE_P (TREE_TYPE (arg0))
+		  && TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
+		  && (TYPE_MODE (newtype) == TYPE_MODE (double_type_node)
+		      || TYPE_MODE (newtype) == TYPE_MODE (float_type_node)))
+	        {
+		  tree fn = mathfn_built_in (newtype, fcode);
+
+		  if (fn)
+		  {
+		    tree arg = fold (convert_to_real (newtype, arg0));
+		    expr = build_call_expr (fn, 1, arg);
+		    if (newtype == type)
+		      return expr;
+		  }
+		}
+	    }
+	default:
+	  break;
+	}
+    }
+  if (optimize
+      && (((fcode == BUILT_IN_FLOORL
+	   || fcode == BUILT_IN_CEILL
+	   || fcode == BUILT_IN_ROUNDL
+	   || fcode == BUILT_IN_RINTL
+	   || fcode == BUILT_IN_TRUNCL
+	   || fcode == BUILT_IN_NEARBYINTL)
+	  && (TYPE_MODE (type) == TYPE_MODE (double_type_node)
+	      || TYPE_MODE (type) == TYPE_MODE (float_type_node)))
+	  || ((fcode == BUILT_IN_FLOOR
+	       || fcode == BUILT_IN_CEIL
+	       || fcode == BUILT_IN_ROUND
+	       || fcode == BUILT_IN_RINT
+	       || fcode == BUILT_IN_TRUNC
+	       || fcode == BUILT_IN_NEARBYINT)
+	      && (TYPE_MODE (type) == TYPE_MODE (float_type_node)))))
+    {
+      tree fn = mathfn_built_in (type, fcode);
+
+      if (fn)
+	{
+	  tree arg = strip_float_extensions (CALL_EXPR_ARG (expr, 0));
+
+	  /* Make sure (type)arg0 is an extension, otherwise we could end up
+	     changing (float)floor(double d) into floorf((float)d), which is
+	     incorrect because (float)d uses round-to-nearest and can round
+	     up to the next integer.  */
+	  if (TYPE_PRECISION (type) >= TYPE_PRECISION (TREE_TYPE (arg)))
+	    return build_call_expr (fn, 1, fold (convert_to_real (type, arg)));
+	}
+    }
+
+  /* Propagate the cast into the operation.  */
+  if (itype != type && FLOAT_TYPE_P (type))
+    switch (TREE_CODE (expr))
+      {
+	/* Convert (float)-x into -(float)x.  This is safe for
+	   round-to-nearest rounding mode.  */
+	case ABS_EXPR:
+	case NEGATE_EXPR:
+	  if (!flag_rounding_math
+	      && TYPE_PRECISION (type) < TYPE_PRECISION (TREE_TYPE (expr)))
+	    return build1 (TREE_CODE (expr), type,
+			   fold (convert_to_real (type,
+						  TREE_OPERAND (expr, 0))));
+	  break;
+	/* Convert (outertype)((innertype0)a+(innertype1)b)
+	   into ((newtype)a+(newtype)b) where newtype
+	   is the widest mode from all of these.  */
+	case PLUS_EXPR:
+	case MINUS_EXPR:
+	case MULT_EXPR:
+	case RDIV_EXPR:
+	   {
+	     tree arg0 = strip_float_extensions (TREE_OPERAND (expr, 0));
+	     tree arg1 = strip_float_extensions (TREE_OPERAND (expr, 1));
+
+	     if (FLOAT_TYPE_P (TREE_TYPE (arg0))
+		 && FLOAT_TYPE_P (TREE_TYPE (arg1))
+		 && DECIMAL_FLOAT_TYPE_P (itype) == DECIMAL_FLOAT_TYPE_P (type))
+	       {
+		  tree newtype = type;
+
+		  if (TYPE_MODE (TREE_TYPE (arg0)) == SDmode
+		      || TYPE_MODE (TREE_TYPE (arg1)) == SDmode
+		      || TYPE_MODE (type) == SDmode)
+		    newtype = dfloat32_type_node;
+		  if (TYPE_MODE (TREE_TYPE (arg0)) == DDmode
+		      || TYPE_MODE (TREE_TYPE (arg1)) == DDmode
+		      || TYPE_MODE (type) == DDmode)
+		    newtype = dfloat64_type_node;
+		  if (TYPE_MODE (TREE_TYPE (arg0)) == TDmode
+		      || TYPE_MODE (TREE_TYPE (arg1)) == TDmode
+		      || TYPE_MODE (type) == TDmode)
+                    newtype = dfloat128_type_node;
+		  if (newtype == dfloat32_type_node
+		      || newtype == dfloat64_type_node
+		      || newtype == dfloat128_type_node)
+		    {
+		      expr = build2 (TREE_CODE (expr), newtype,
+				     fold (convert_to_real (newtype, arg0)),
+				     fold (convert_to_real (newtype, arg1)));
+		      if (newtype == type)
+			return expr;
+		      break;
+		    }
+
+		  if (TYPE_PRECISION (TREE_TYPE (arg0)) > TYPE_PRECISION (newtype))
+		    newtype = TREE_TYPE (arg0);
+		  if (TYPE_PRECISION (TREE_TYPE (arg1)) > TYPE_PRECISION (newtype))
+		    newtype = TREE_TYPE (arg1);
+		  /* Sometimes this transformation is safe (cannot
+		     change results through affecting double rounding
+		     cases) and sometimes it is not.  If NEWTYPE is
+		     wider than TYPE, e.g. (float)((long double)double
+		     + (long double)double) converted to
+		     (float)(double + double), the transformation is
+		     unsafe regardless of the details of the types
+		     involved; double rounding can arise if the result
+		     of NEWTYPE arithmetic is a NEWTYPE value half way
+		     between two representable TYPE values but the
+		     exact value is sufficiently different (in the
+		     right direction) for this difference to be
+		     visible in ITYPE arithmetic.  If NEWTYPE is the
+		     same as TYPE, however, the transformation may be
+		     safe depending on the types involved: it is safe
+		     if the ITYPE has strictly more than twice as many
+		     mantissa bits as TYPE, can represent infinities
+		     and NaNs if the TYPE can, and has sufficient
+		     exponent range for the product or ratio of two
+		     values representable in the TYPE to be within the
+		     range of normal values of ITYPE.  */
+		  if (TYPE_PRECISION (newtype) < TYPE_PRECISION (itype)
+		      && (flag_unsafe_math_optimizations
+			  || (TYPE_PRECISION (newtype) == TYPE_PRECISION (type)
+			      && real_can_shorten_arithmetic (TYPE_MODE (itype),
+							      TYPE_MODE (type)))))
+		    {
+		      expr = build2 (TREE_CODE (expr), newtype,
+				     fold (convert_to_real (newtype, arg0)),
+				     fold (convert_to_real (newtype, arg1)));
+		      if (newtype == type)
+			return expr;
+		    }
+	       }
+	   }
+	  break;
+	default:
+	  break;
+      }
+
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case REAL_TYPE:
+      /* Ignore the conversion if we don't need to store intermediate
+	 results and neither type is a decimal float.  */
+      return build1 ((flag_float_store
+		     || DECIMAL_FLOAT_TYPE_P (type)
+		     || DECIMAL_FLOAT_TYPE_P (itype))
+		     ? CONVERT_EXPR : NOP_EXPR, type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+      return build1 (FLOAT_EXPR, type, expr);
+
+    case FIXED_POINT_TYPE:
+      return build1 (FIXED_CONVERT_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), float,
+   fixed-point or vector; 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 (tree type, tree expr)
+{
+  enum tree_code ex_form = TREE_CODE (expr);
+  tree intype = TREE_TYPE (expr);
+  unsigned int inprec = TYPE_PRECISION (intype);
+  unsigned int outprec = TYPE_PRECISION (type);
+
+  /* An INTEGER_TYPE cannot be incomplete, but an ENUMERAL_TYPE can
+     be.  Consider `enum E = { a, b = (enum E) 3 };'.  */
+  if (!COMPLETE_TYPE_P (type))
+    {
+      error ("conversion to incomplete type");
+      return error_mark_node;
+    }
+
+  /* Convert e.g. (long)round(d) -> lround(d).  */
+  /* If we're converting to char, we may encounter differing behavior
+     between converting from double->char vs double->long->char.
+     We're in "undefined" territory but we prefer to be conservative,
+     so only proceed in "unsafe" math mode.  */
+  if (optimize
+      && (flag_unsafe_math_optimizations
+	  || (long_integer_type_node
+	      && outprec >= TYPE_PRECISION (long_integer_type_node))))
+    {
+      tree s_expr = strip_float_extensions (expr);
+      tree s_intype = TREE_TYPE (s_expr);
+      const enum built_in_function fcode = builtin_mathfn_code (s_expr);
+      tree fn = 0;
+      
+      switch (fcode)
+        {
+	CASE_FLT_FN (BUILT_IN_CEIL):
+	  /* Only convert in ISO C99 mode.  */
+	  if (!TARGET_C99_FUNCTIONS)
+	    break;
+	  if (outprec < TYPE_PRECISION (long_integer_type_node)
+	      || (outprec == TYPE_PRECISION (long_integer_type_node)
+		  && !TYPE_UNSIGNED (type)))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LCEIL);
+	  else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
+		   && !TYPE_UNSIGNED (type))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LLCEIL);
+	  break;
+
+	CASE_FLT_FN (BUILT_IN_FLOOR):
+	  /* Only convert in ISO C99 mode.  */
+	  if (!TARGET_C99_FUNCTIONS)
+	    break;
+	  if (outprec < TYPE_PRECISION (long_integer_type_node)
+	      || (outprec == TYPE_PRECISION (long_integer_type_node)
+		  && !TYPE_UNSIGNED (type)))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LFLOOR);
+	  else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
+		   && !TYPE_UNSIGNED (type))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LLFLOOR);
+	  break;
+
+	CASE_FLT_FN (BUILT_IN_ROUND):
+	  if (outprec < TYPE_PRECISION (long_integer_type_node)
+	      || (outprec == TYPE_PRECISION (long_integer_type_node)
+		  && !TYPE_UNSIGNED (type)))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LROUND);
+	  else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
+		   && !TYPE_UNSIGNED (type))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LLROUND);
+	  break;
+
+	CASE_FLT_FN (BUILT_IN_NEARBYINT):
+	  /* Only convert nearbyint* if we can ignore math exceptions.  */
+	  if (flag_trapping_math)
+	    break;
+	  /* ... Fall through ...  */
+	CASE_FLT_FN (BUILT_IN_RINT):
+	  if (outprec < TYPE_PRECISION (long_integer_type_node)
+	      || (outprec == TYPE_PRECISION (long_integer_type_node)
+		  && !TYPE_UNSIGNED (type)))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LRINT);
+	  else if (outprec == TYPE_PRECISION (long_long_integer_type_node)
+		   && !TYPE_UNSIGNED (type))
+	    fn = mathfn_built_in (s_intype, BUILT_IN_LLRINT);
+	  break;
+
+	CASE_FLT_FN (BUILT_IN_TRUNC):
+	  return convert_to_integer (type, CALL_EXPR_ARG (s_expr, 0));
+
+	default:
+	  break;
+	}
+      
+      if (fn)
+        {
+	  tree newexpr = build_call_expr (fn, 1, CALL_EXPR_ARG (s_expr, 0));
+	  return convert_to_integer (type, newexpr);
+	}
+    }
+
+  switch (TREE_CODE (intype))
+    {
+    case POINTER_TYPE:
+    case REFERENCE_TYPE:
+      if (integer_zerop (expr))
+	return build_int_cst (type, 0);
+
+      /* Convert to an unsigned integer of the correct width first,
+	 and from there widen/truncate to the required type.  */
+      expr = fold_build1 (CONVERT_EXPR,
+			  lang_hooks.types.type_for_size (POINTER_SIZE, 0),
+			  expr);
+      return fold_convert (type, expr);
+
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case OFFSET_TYPE:
+      /* If this is a logical operation, which just returns 0 or 1, we can
+	 change the type of the expression.  */
+
+      if (TREE_CODE_CLASS (ex_form) == tcc_comparison)
+	{
+	  expr = copy_node (expr);
+	  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)
+	{
+	  enum tree_code code;
+	  tree tem;
+
+	  /* If the precision of the EXPR's type is K bits and the
+	     destination mode has more bits, and the sign is changing,
+	     it is not safe to use a NOP_EXPR.  For example, suppose
+	     that EXPR's type is a 3-bit unsigned integer type, the
+	     TYPE is a 3-bit signed integer type, and the machine mode
+	     for the types is 8-bit QImode.  In that case, the
+	     conversion necessitates an explicit sign-extension.  In
+	     the signed-to-unsigned case the high-order bits have to
+	     be cleared.  */
+	  if (TYPE_UNSIGNED (type) != TYPE_UNSIGNED (TREE_TYPE (expr))
+	      && (TYPE_PRECISION (TREE_TYPE (expr))
+		  != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)))))
+	    code = CONVERT_EXPR;
+	  else
+	    code = NOP_EXPR;
+
+	  tem = fold_unary (code, type, expr);
+	  if (tem)
+	    return tem;
+
+	  tem = build1 (code, type, expr);
+	  TREE_NO_WARNING (tem) = 1;
+	  return tem;
+	}
+
+      /* 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 (lang_hooks.types.type_for_mode
+				(TYPE_MODE (type), TYPE_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_sgn (TREE_OPERAND (expr, 1)) <= 0)
+	    goto trunc1;
+	  break;
+
+	case LSHIFT_EXPR:
+	  /* We can pass truncation down through left shifting
+	     when the shift count is a nonnegative constant and
+	     the target type is unsigned.  */
+	  if (TREE_CODE (TREE_OPERAND (expr, 1)) == INTEGER_CST
+	      && tree_int_cst_sgn (TREE_OPERAND (expr, 1)) >= 0
+	      && TYPE_UNSIGNED (type)
+	      && 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 = build_int_cst (type, 0);
+
+		  /* If the original expression had side-effects, we must
+		     preserve it.  */
+		  if (TREE_SIDE_EFFECTS (expr))
+		    return build2 (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.  */
+		&& (TYPE_UNSIGNED (TREE_TYPE (arg0))
+		    == TYPE_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:
+	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.  */
+		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 = lang_hooks.types.type_for_size
+		    (TYPE_PRECISION (typex), TYPE_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 both of the original operands were
+		       unsigned then we can safely do the work as unsigned.
+		       Exception: shift operations take their type solely
+		       from the first argument.
+		       Exception: the LSHIFT_EXPR case above requires that
+		       we perform this operation unsigned lest we produce
+		       signed-overflow undefinedness.
+		       And we may need to do it as unsigned
+		       if we truncate to the original size.  */
+		    if (TYPE_UNSIGNED (TREE_TYPE (expr))
+			|| (TYPE_UNSIGNED (TREE_TYPE (arg0))
+			    && (TYPE_UNSIGNED (TREE_TYPE (arg1))
+				|| ex_form == LSHIFT_EXPR
+				|| ex_form == RSHIFT_EXPR
+				|| ex_form == LROTATE_EXPR
+				|| ex_form == RROTATE_EXPR))
+			|| ex_form == LSHIFT_EXPR
+			/* If we have !flag_wrapv, and either ARG0 or
+			   ARG1 is of a signed type, we have to do
+			   PLUS_EXPR or MINUS_EXPR in an unsigned
+			   type.  Otherwise, we would introduce
+			   signed-overflow undefinedness.  */
+			|| ((!TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg0))
+			     || !TYPE_OVERFLOW_WRAPS (TREE_TYPE (arg1)))
+			    && (ex_form == PLUS_EXPR
+				|| ex_form == MINUS_EXPR)))
+		      typex = unsigned_type_for (typex);
+		    else
+		      typex = signed_type_for (typex);
+		    return convert (type,
+				    fold_build2 (ex_form, typex,
+						 convert (typex, arg0),
+						 convert (typex, arg1)));
+		  }
+	      }
+	  }
+	  break;
+
+	case NEGATE_EXPR:
+	case BIT_NOT_EXPR:
+	  /* This is not correct for ABS_EXPR,
+	     since we must test the sign before truncation.  */
+	  {
+	    tree typex;
+
+	    /* Don't do unsigned arithmetic where signed was wanted,
+	       or vice versa.  */
+	    if (TYPE_UNSIGNED (TREE_TYPE (expr)))
+	      typex = unsigned_type_for (type);
+	    else
+	      typex = signed_type_for (type);
+	    return convert (type,
+			    fold_build1 (ex_form, typex,
+					 convert (typex,
+						  TREE_OPERAND (expr, 0))));
+	  }
+
+	case NOP_EXPR:
+	  /* Don't introduce a
+	     "can't convert between vector values of different size" error.  */
+	  if (TREE_CODE (TREE_TYPE (TREE_OPERAND (expr, 0))) == VECTOR_TYPE
+	      && (GET_MODE_SIZE (TYPE_MODE (TREE_TYPE (TREE_OPERAND (expr, 0))))
+		  != GET_MODE_SIZE (TYPE_MODE (type))))
+	    break;
+	  /* 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_build3 (COND_EXPR, type, TREE_OPERAND (expr, 0),
+			      convert (type, TREE_OPERAND (expr, 1)),
+			      convert (type, TREE_OPERAND (expr, 2)));
+
+	default:
+	  break;
+	}
+
+      return build1 (CONVERT_EXPR, type, expr);
+
+    case REAL_TYPE:
+      return build1 (FIX_TRUNC_EXPR, type, expr);
+
+    case FIXED_POINT_TYPE:
+      return build1 (FIXED_CONVERT_EXPR, type, expr);
+
+    case COMPLEX_TYPE:
+      return convert (type,
+		      fold_build1 (REALPART_EXPR,
+				   TREE_TYPE (TREE_TYPE (expr)), expr));
+
+    case VECTOR_TYPE:
+      if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
+	{
+	  error ("can't convert between vector values of different size");
+	  return error_mark_node;
+	}
+      return build1 (VIEW_CONVERT_EXPR, type, 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 (tree type, tree expr)
+{
+  tree subtype = TREE_TYPE (type);
+
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case REAL_TYPE:
+    case FIXED_POINT_TYPE:
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+      return build2 (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_build2 (COMPLEX_EXPR, type,
+			      convert (subtype, TREE_OPERAND (expr, 0)),
+			      convert (subtype, TREE_OPERAND (expr, 1)));
+	else
+	  {
+	    expr = save_expr (expr);
+	    return
+	      fold_build2 (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);
+    }
+}
+
+/* Convert EXPR to the vector type TYPE in the usual ways.  */
+
+tree
+convert_to_vector (tree type, tree expr)
+{
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case INTEGER_TYPE:
+    case VECTOR_TYPE:
+      if (!tree_int_cst_equal (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (expr))))
+	{
+	  error ("can't convert between vector values of different size");
+	  return error_mark_node;
+	}
+      return build1 (VIEW_CONVERT_EXPR, type, expr);
+
+    default:
+      error ("can't convert value to a vector");
+      return error_mark_node;
+    }
+}
+
+/* Convert EXPR to some fixed-point type TYPE.
+
+   EXPR must be fixed-point, float, integer, or enumeral;
+   in other cases error is called.  */
+
+tree
+convert_to_fixed (tree type, tree expr)
+{
+  if (integer_zerop (expr))
+    {
+      tree fixed_zero_node = build_fixed (type, FCONST0 (TYPE_MODE (type)));
+      return fixed_zero_node;
+    }
+  else if (integer_onep (expr) && ALL_SCALAR_ACCUM_MODE_P (TYPE_MODE (type)))
+    {
+      tree fixed_one_node = build_fixed (type, FCONST1 (TYPE_MODE (type)));
+      return fixed_one_node;
+    }
+
+  switch (TREE_CODE (TREE_TYPE (expr)))
+    {
+    case FIXED_POINT_TYPE:
+    case INTEGER_TYPE:
+    case ENUMERAL_TYPE:
+    case BOOLEAN_TYPE:
+    case REAL_TYPE:
+      return build1 (FIXED_CONVERT_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 a fixed-point was expected");
+      return error_mark_node;
+    }
+}