fold-const.c (const_binop): Avoid performing the FP operation at compile-time...

	* fold-const.c (const_binop): Avoid performing the FP operation at
	compile-time, if either operand is NaN and we honor signaling NaNs,
	or if we're dividing by zero and either flag_trapping_math is set
	or the desired mode doesn't support infinities.
	(fold_initializer): New function to fold an expression ignoring any
	potential run-time exceptions or traps.
	* tree.h (fold_initializer): Prototype here.
	* c-typeck.c (build_binary_op): Move to the end of the file so
	that intializer_stack is in scope.  If constructing an initializer,
	i.e. when initializer_stack is not NULL, use fold_initializer to
	fold expressions.
	* simplify-rtx.c (simplify_binary_operation): Likewise, avoid
	performing FP operations at compile-time, if they would raise an
	exception at run-time.

From-SVN: r69533

5 files changed, 801 insertions, 736 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fea6e3b..dfff20c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,20 @@
+2003-07-17  Roger Sayle  <roger@eyesopen.com>
+
+	* fold-const.c (const_binop): Avoid performing the FP operation at
+	compile-time, if either operand is NaN and we honor signaling NaNs,
+	or if we're dividing by zero and either flag_trapping_math is set
+	or the desired mode doesn't support infinities.
+	(fold_initializer): New function to fold an expression ignoring any
+	potential run-time exceptions or traps.
+	* tree.h (fold_initializer): Prototype here.
+	* c-typeck.c (build_binary_op): Move to the end of the file so
+	that intializer_stack is in scope.  If constructing an initializer,
+	i.e. when initializer_stack is not NULL, use fold_initializer to
+	fold expressions.
+	* simplify-rtx.c (simplify_binary_operation): Likewise, avoid
+	performing FP operations at compile-time, if they would raise an
+	exception at run-time.
+
 2003-07-17  Geoffrey Keating  <geoffk@apple.com>
 
 	PR 11498
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 43b5797..c4154de 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -2008,736 +2008,6 @@ parser_build_binary_op (enum tree_code code, tree arg1, tree arg2)
 
   return result;
 }
-
-/* Build a binary-operation expression without default conversions.
-   CODE is the kind of expression to build.
-   This function differs from `build' in several ways:
-   the data type of the result is computed and recorded in it,
-   warnings are generated if arg data types are invalid,
-   special handling for addition and subtraction of pointers is known,
-   and some optimization is done (operations on narrow ints
-   are done in the narrower type when that gives the same result).
-   Constant folding is also done before the result is returned.
-
-   Note that the operands will never have enumeral types, or function
-   or array types, because either they will have the default conversions
-   performed or they have both just been converted to some other type in which
-   the arithmetic is to be done.  */
-
-tree
-build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
-		 int convert_p)
-{
-  tree type0, type1;
-  enum tree_code code0, code1;
-  tree op0, op1;
-
-  /* Expression code to give to the expression when it is built.
-     Normally this is CODE, which is what the caller asked for,
-     but in some special cases we change it.  */
-  enum tree_code resultcode = code;
-
-  /* Data type in which the computation is to be performed.
-     In the simplest cases this is the common type of the arguments.  */
-  tree result_type = NULL;
-
-  /* Nonzero means operands have already been type-converted
-     in whatever way is necessary.
-     Zero means they need to be converted to RESULT_TYPE.  */
-  int converted = 0;
-
-  /* Nonzero means create the expression with this type, rather than
-     RESULT_TYPE.  */
-  tree build_type = 0;
-
-  /* Nonzero means after finally constructing the expression
-     convert it to this type.  */
-  tree final_type = 0;
-
-  /* Nonzero if this is an operation like MIN or MAX which can
-     safely be computed in short if both args are promoted shorts.
-     Also implies COMMON.
-     -1 indicates a bitwise operation; this makes a difference
-     in the exact conditions for when it is safe to do the operation
-     in a narrower mode.  */
-  int shorten = 0;
-
-  /* Nonzero if this is a comparison operation;
-     if both args are promoted shorts, compare the original shorts.
-     Also implies COMMON.  */
-  int short_compare = 0;
-
-  /* Nonzero if this is a right-shift operation, which can be computed on the
-     original short and then promoted if the operand is a promoted short.  */
-  int short_shift = 0;
-
-  /* Nonzero means set RESULT_TYPE to the common type of the args.  */
-  int common = 0;
-
-  if (convert_p)
-    {
-      op0 = default_conversion (orig_op0);
-      op1 = default_conversion (orig_op1);
-    }
-  else
-    {
-      op0 = orig_op0;
-      op1 = orig_op1;
-    }
-
-  type0 = TREE_TYPE (op0);
-  type1 = TREE_TYPE (op1);
-
-  /* The expression codes of the data types of the arguments tell us
-     whether the arguments are integers, floating, pointers, etc.  */
-  code0 = TREE_CODE (type0);
-  code1 = TREE_CODE (type1);
-
-  /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
-  STRIP_TYPE_NOPS (op0);
-  STRIP_TYPE_NOPS (op1);
-
-  /* If an error was already reported for one of the arguments,
-     avoid reporting another error.  */
-
-  if (code0 == ERROR_MARK || code1 == ERROR_MARK)
-    return error_mark_node;
-
-  switch (code)
-    {
-    case PLUS_EXPR:
-      /* Handle the pointer + int case.  */
-      if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	return pointer_int_sum (PLUS_EXPR, op0, op1);
-      else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
-	return pointer_int_sum (PLUS_EXPR, op1, op0);
-      else
-	common = 1;
-      break;
-
-    case MINUS_EXPR:
-      /* Subtraction of two similar pointers.
-	 We must subtract them as integers, then divide by object size.  */
-      if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
-	  && comp_target_types (type0, type1, 1))
-	return pointer_diff (op0, op1);
-      /* Handle pointer minus int.  Just like pointer plus int.  */
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	return pointer_int_sum (MINUS_EXPR, op0, op1);
-      else
-	common = 1;
-      break;
-
-    case MULT_EXPR:
-      common = 1;
-      break;
-
-    case TRUNC_DIV_EXPR:
-    case CEIL_DIV_EXPR:
-    case FLOOR_DIV_EXPR:
-    case ROUND_DIV_EXPR:
-    case EXACT_DIV_EXPR:
-      /* Floating point division by zero is a legitimate way to obtain
-	 infinities and NaNs.  */
-      if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
-	warning ("division by zero");
-
-      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
-	   || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
-	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	      || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
-	{
-	  if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
-	    resultcode = RDIV_EXPR;
-	  else
-	    /* Although it would be tempting to shorten always here, that
-	       loses on some targets, since the modulo instruction is
-	       undefined if the quotient can't be represented in the
-	       computation mode.  We shorten only if unsigned or if
-	       dividing by something we know != -1.  */
-	    shorten = (TREE_UNSIGNED (TREE_TYPE (orig_op0))
-		       || (TREE_CODE (op1) == INTEGER_CST
-			   && ! integer_all_onesp (op1)));
-	  common = 1;
-	}
-      break;
-
-    case BIT_AND_EXPR:
-    case BIT_ANDTC_EXPR:
-    case BIT_IOR_EXPR:
-    case BIT_XOR_EXPR:
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
-	shorten = -1;
-      else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
-	common = 1;
-      break;
-
-    case TRUNC_MOD_EXPR:
-    case FLOOR_MOD_EXPR:
-      if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
-	warning ("division by zero");
-
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  /* Although it would be tempting to shorten always here, that loses
-	     on some targets, since the modulo instruction is undefined if the
-	     quotient can't be represented in the computation mode.  We shorten
-	     only if unsigned or if dividing by something we know != -1.  */
-	  shorten = (TREE_UNSIGNED (TREE_TYPE (orig_op0))
-		     || (TREE_CODE (op1) == INTEGER_CST
-			 && ! integer_all_onesp (op1)));
-	  common = 1;
-	}
-      break;
-
-    case TRUTH_ANDIF_EXPR:
-    case TRUTH_ORIF_EXPR:
-    case TRUTH_AND_EXPR:
-    case TRUTH_OR_EXPR:
-    case TRUTH_XOR_EXPR:
-      if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
-	   || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
-	  && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
-	      || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
-	{
-	  /* Result of these operations is always an int,
-	     but that does not mean the operands should be
-	     converted to ints!  */
-	  result_type = integer_type_node;
-	  op0 = c_common_truthvalue_conversion (op0);
-	  op1 = c_common_truthvalue_conversion (op1);
-	  converted = 1;
-	}
-      break;
-
-      /* Shift operations: result has same type as first operand;
-	 always convert second operand to int.
-	 Also set SHORT_SHIFT if shifting rightward.  */
-
-    case RSHIFT_EXPR:
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
-	    {
-	      if (tree_int_cst_sgn (op1) < 0)
-		warning ("right shift count is negative");
-	      else
-		{
-		  if (! integer_zerop (op1))
-		    short_shift = 1;
-
-		  if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
-		    warning ("right shift count >= width of type");
-		}
-	    }
-
-	  /* Use the type of the value to be shifted.  */
-	  result_type = type0;
-	  /* Convert the shift-count to an integer, regardless of size
-	     of value being shifted.  */
-	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
-	    op1 = convert (integer_type_node, op1);
-	  /* Avoid converting op1 to result_type later.  */
-	  converted = 1;
-	}
-      break;
-
-    case LSHIFT_EXPR:
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
-	    {
-	      if (tree_int_cst_sgn (op1) < 0)
-		warning ("left shift count is negative");
-
-	      else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
-		warning ("left shift count >= width of type");
-	    }
-
-	  /* Use the type of the value to be shifted.  */
-	  result_type = type0;
-	  /* Convert the shift-count to an integer, regardless of size
-	     of value being shifted.  */
-	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
-	    op1 = convert (integer_type_node, op1);
-	  /* Avoid converting op1 to result_type later.  */
-	  converted = 1;
-	}
-      break;
-
-    case RROTATE_EXPR:
-    case LROTATE_EXPR:
-      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
-	    {
-	      if (tree_int_cst_sgn (op1) < 0)
-		warning ("shift count is negative");
-	      else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
-		warning ("shift count >= width of type");
-	    }
-
-	  /* Use the type of the value to be shifted.  */
-	  result_type = type0;
-	  /* Convert the shift-count to an integer, regardless of size
-	     of value being shifted.  */
-	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
-	    op1 = convert (integer_type_node, op1);
-	  /* Avoid converting op1 to result_type later.  */
-	  converted = 1;
-	}
-      break;
-
-    case EQ_EXPR:
-    case NE_EXPR:
-      if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
-	warning ("comparing floating point with == or != is unsafe");
-      /* Result of comparison is always int,
-	 but don't convert the args to int!  */
-      build_type = integer_type_node;
-      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
-	   || code0 == COMPLEX_TYPE
-	   || code0 == VECTOR_TYPE)
-	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
-	      || code1 == COMPLEX_TYPE
-	      || code1 == VECTOR_TYPE))
-	short_compare = 1;
-      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
-	{
-	  tree tt0 = TREE_TYPE (type0);
-	  tree tt1 = TREE_TYPE (type1);
-	  /* Anything compares with void *.  void * compares with anything.
-	     Otherwise, the targets must be compatible
-	     and both must be object or both incomplete.  */
-	  if (comp_target_types (type0, type1, 1))
-	    result_type = common_type (type0, type1);
-	  else if (VOID_TYPE_P (tt0))
-	    {
-	      /* op0 != orig_op0 detects the case of something
-		 whose value is 0 but which isn't a valid null ptr const.  */
-	      if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
-		  && TREE_CODE (tt1) == FUNCTION_TYPE)
-		pedwarn ("ISO C forbids comparison of `void *' with function pointer");
-	    }
-	  else if (VOID_TYPE_P (tt1))
-	    {
-	      if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
-		  && TREE_CODE (tt0) == FUNCTION_TYPE)
-		pedwarn ("ISO C forbids comparison of `void *' with function pointer");
-	    }
-	  else
-	    pedwarn ("comparison of distinct pointer types lacks a cast");
-
-	  if (result_type == NULL_TREE)
-	    result_type = ptr_type_node;
-	}
-      else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
-	       && integer_zerop (op1))
-	result_type = type0;
-      else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
-	       && integer_zerop (op0))
-	result_type = type1;
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  result_type = type0;
-	  pedwarn ("comparison between pointer and integer");
-	}
-      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
-	{
-	  result_type = type1;
-	  pedwarn ("comparison between pointer and integer");
-	}
-      break;
-
-    case MAX_EXPR:
-    case MIN_EXPR:
-      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
-	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
-	shorten = 1;
-      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
-	{
-	  if (comp_target_types (type0, type1, 1))
-	    {
-	      result_type = common_type (type0, type1);
-	      if (pedantic
-		  && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
-		pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
-	    }
-	  else
-	    {
-	      result_type = ptr_type_node;
-	      pedwarn ("comparison of distinct pointer types lacks a cast");
-	    }
-	}
-      break;
-
-    case LE_EXPR:
-    case GE_EXPR:
-    case LT_EXPR:
-    case GT_EXPR:
-      build_type = integer_type_node;
-      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
-	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
-	short_compare = 1;
-      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
-	{
-	  if (comp_target_types (type0, type1, 1))
-	    {
-	      result_type = common_type (type0, type1);
-	      if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
-		  != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
-		pedwarn ("comparison of complete and incomplete pointers");
-	      else if (pedantic
-		       && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
-		pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
-	    }
-	  else
-	    {
-	      result_type = ptr_type_node;
-	      pedwarn ("comparison of distinct pointer types lacks a cast");
-	    }
-	}
-      else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
-	       && integer_zerop (op1))
-	{
-	  result_type = type0;
-	  if (pedantic || extra_warnings)
-	    pedwarn ("ordered comparison of pointer with integer zero");
-	}
-      else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
-	       && integer_zerop (op0))
-	{
-	  result_type = type1;
-	  if (pedantic)
-	    pedwarn ("ordered comparison of pointer with integer zero");
-	}
-      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
-	{
-	  result_type = type0;
-	  pedwarn ("comparison between pointer and integer");
-	}
-      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
-	{
-	  result_type = type1;
-	  pedwarn ("comparison between pointer and integer");
-	}
-      break;
-
-    case UNORDERED_EXPR:
-    case ORDERED_EXPR:
-    case UNLT_EXPR:
-    case UNLE_EXPR:
-    case UNGT_EXPR:
-    case UNGE_EXPR:
-    case UNEQ_EXPR:
-      build_type = integer_type_node;
-      if (code0 != REAL_TYPE || code1 != REAL_TYPE)
-	{
-	  error ("unordered comparison on non-floating point argument");
-	  return error_mark_node;
-	}
-      common = 1;
-      break;
-
-    default:
-      break;
-    }
-
-  if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
-       || code0 == VECTOR_TYPE)
-      &&
-      (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
-       || code1 == VECTOR_TYPE))
-    {
-      int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
-
-      if (shorten || common || short_compare)
-	result_type = common_type (type0, type1);
-
-      /* For certain operations (which identify themselves by shorten != 0)
-	 if both args were extended from the same smaller type,
-	 do the arithmetic in that type and then extend.
-
-	 shorten !=0 and !=1 indicates a bitwise operation.
-	 For them, this optimization is safe only if
-	 both args are zero-extended or both are sign-extended.
-	 Otherwise, we might change the result.
-	 Eg, (short)-1 | (unsigned short)-1 is (int)-1
-	 but calculated in (unsigned short) it would be (unsigned short)-1.  */
-
-      if (shorten && none_complex)
-	{
-	  int unsigned0, unsigned1;
-	  tree arg0 = get_narrower (op0, &unsigned0);
-	  tree arg1 = get_narrower (op1, &unsigned1);
-	  /* UNS is 1 if the operation to be done is an unsigned one.  */
-	  int uns = TREE_UNSIGNED (result_type);
-	  tree type;
-
-	  final_type = result_type;
-
-	  /* Handle the case that OP0 (or OP1) does not *contain* a conversion
-	     but it *requires* conversion to FINAL_TYPE.  */
-
-	  if ((TYPE_PRECISION (TREE_TYPE (op0))
-	       == TYPE_PRECISION (TREE_TYPE (arg0)))
-	      && TREE_TYPE (op0) != final_type)
-	    unsigned0 = TREE_UNSIGNED (TREE_TYPE (op0));
-	  if ((TYPE_PRECISION (TREE_TYPE (op1))
-	       == TYPE_PRECISION (TREE_TYPE (arg1)))
-	      && TREE_TYPE (op1) != final_type)
-	    unsigned1 = TREE_UNSIGNED (TREE_TYPE (op1));
-
-	  /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
-
-	  /* For bitwise operations, signedness of nominal type
-	     does not matter.  Consider only how operands were extended.  */
-	  if (shorten == -1)
-	    uns = unsigned0;
-
-	  /* Note that in all three cases below we refrain from optimizing
-	     an unsigned operation on sign-extended args.
-	     That would not be valid.  */
-
-	  /* Both args variable: if both extended in same way
-	     from same width, do it in that width.
-	     Do it unsigned if args were zero-extended.  */
-	  if ((TYPE_PRECISION (TREE_TYPE (arg0))
-	       < TYPE_PRECISION (result_type))
-	      && (TYPE_PRECISION (TREE_TYPE (arg1))
-		  == TYPE_PRECISION (TREE_TYPE (arg0)))
-	      && unsigned0 == unsigned1
-	      && (unsigned0 || !uns))
-	    result_type
-	      = c_common_signed_or_unsigned_type
-	      (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
-	  else if (TREE_CODE (arg0) == INTEGER_CST
-		   && (unsigned1 || !uns)
-		   && (TYPE_PRECISION (TREE_TYPE (arg1))
-		       < TYPE_PRECISION (result_type))
-		   && (type
-		       = c_common_signed_or_unsigned_type (unsigned1,
-							   TREE_TYPE (arg1)),
-		       int_fits_type_p (arg0, type)))
-	    result_type = type;
-	  else if (TREE_CODE (arg1) == INTEGER_CST
-		   && (unsigned0 || !uns)
-		   && (TYPE_PRECISION (TREE_TYPE (arg0))
-		       < TYPE_PRECISION (result_type))
-		   && (type
-		       = c_common_signed_or_unsigned_type (unsigned0,
-							   TREE_TYPE (arg0)),
-		       int_fits_type_p (arg1, type)))
-	    result_type = type;
-	}
-
-      /* Shifts can be shortened if shifting right.  */
-
-      if (short_shift)
-	{
-	  int unsigned_arg;
-	  tree arg0 = get_narrower (op0, &unsigned_arg);
-
-	  final_type = result_type;
-
-	  if (arg0 == op0 && final_type == TREE_TYPE (op0))
-	    unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0));
-
-	  if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
-	      /* We can shorten only if the shift count is less than the
-		 number of bits in the smaller type size.  */
-	      && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
-	      /* We cannot drop an unsigned shift after sign-extension.  */
-	      && (!TREE_UNSIGNED (final_type) || unsigned_arg))
-	    {
-	      /* Do an unsigned shift if the operand was zero-extended.  */
-	      result_type
-		= c_common_signed_or_unsigned_type (unsigned_arg,
-						    TREE_TYPE (arg0));
-	      /* Convert value-to-be-shifted to that type.  */
-	      if (TREE_TYPE (op0) != result_type)
-		op0 = convert (result_type, op0);
-	      converted = 1;
-	    }
-	}
-
-      /* Comparison operations are shortened too but differently.
-	 They identify themselves by setting short_compare = 1.  */
-
-      if (short_compare)
-	{
-	  /* Don't write &op0, etc., because that would prevent op0
-	     from being kept in a register.
-	     Instead, make copies of the our local variables and
-	     pass the copies by reference, then copy them back afterward.  */
-	  tree xop0 = op0, xop1 = op1, xresult_type = result_type;
-	  enum tree_code xresultcode = resultcode;
-	  tree val
-	    = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
-
-	  if (val != 0)
-	    return val;
-
-	  op0 = xop0, op1 = xop1;
-	  converted = 1;
-	  resultcode = xresultcode;
-
-	  if (warn_sign_compare && skip_evaluation == 0)
-	    {
-	      int op0_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op0));
-	      int op1_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op1));
-	      int unsignedp0, unsignedp1;
-	      tree primop0 = get_narrower (op0, &unsignedp0);
-	      tree primop1 = get_narrower (op1, &unsignedp1);
-
-	      xop0 = orig_op0;
-	      xop1 = orig_op1;
-	      STRIP_TYPE_NOPS (xop0);
-	      STRIP_TYPE_NOPS (xop1);
-
-	      /* Give warnings for comparisons between signed and unsigned
-		 quantities that may fail.
-
-		 Do the checking based on the original operand trees, so that
-		 casts will be considered, but default promotions won't be.
-
-		 Do not warn if the comparison is being done in a signed type,
-		 since the signed type will only be chosen if it can represent
-		 all the values of the unsigned type.  */
-	      if (! TREE_UNSIGNED (result_type))
-		/* OK */;
-              /* Do not warn if both operands are the same signedness.  */
-              else if (op0_signed == op1_signed)
-                /* OK */;
-	      else
-		{
-		  tree sop, uop;
-
-		  if (op0_signed)
-		    sop = xop0, uop = xop1;
-		  else
-		    sop = xop1, uop = xop0;
-
-		  /* Do not warn if the signed quantity is an
-		     unsuffixed integer literal (or some static
-		     constant expression involving such literals or a
-		     conditional expression involving such literals)
-		     and it is non-negative.  */
-		  if (c_tree_expr_nonnegative_p (sop))
-		    /* OK */;
-		  /* Do not warn if the comparison is an equality operation,
-		     the unsigned quantity is an integral constant, and it
-		     would fit in the result if the result were signed.  */
-		  else if (TREE_CODE (uop) == INTEGER_CST
-			   && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
-			   && int_fits_type_p
-			   (uop, c_common_signed_type (result_type)))
-		    /* OK */;
-		  /* Do not warn if the unsigned quantity is an enumeration
-		     constant and its maximum value would fit in the result
-		     if the result were signed.  */
-		  else if (TREE_CODE (uop) == INTEGER_CST
-			   && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
-			   && int_fits_type_p
-			   (TYPE_MAX_VALUE (TREE_TYPE(uop)),
-			    c_common_signed_type (result_type)))
-		    /* OK */;
-		  else
-		    warning ("comparison between signed and unsigned");
-		}
-
-	      /* Warn if two unsigned values are being compared in a size
-		 larger than their original size, and one (and only one) is the
-		 result of a `~' operator.  This comparison will always fail.
-
-		 Also warn if one operand is a constant, and the constant
-		 does not have all bits set that are set in the ~ operand
-		 when it is extended.  */
-
-	      if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
-		  != (TREE_CODE (primop1) == BIT_NOT_EXPR))
-		{
-		  if (TREE_CODE (primop0) == BIT_NOT_EXPR)
-		    primop0 = get_narrower (TREE_OPERAND (primop0, 0),
-					    &unsignedp0);
-		  else
-		    primop1 = get_narrower (TREE_OPERAND (primop1, 0),
-					    &unsignedp1);
-
-		  if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
-		    {
-		      tree primop;
-		      HOST_WIDE_INT constant, mask;
-		      int unsignedp, bits;
-
-		      if (host_integerp (primop0, 0))
-			{
-			  primop = primop1;
-			  unsignedp = unsignedp1;
-			  constant = tree_low_cst (primop0, 0);
-			}
-		      else
-			{
-			  primop = primop0;
-			  unsignedp = unsignedp0;
-			  constant = tree_low_cst (primop1, 0);
-			}
-
-		      bits = TYPE_PRECISION (TREE_TYPE (primop));
-		      if (bits < TYPE_PRECISION (result_type)
-			  && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
-			{
-			  mask = (~ (HOST_WIDE_INT) 0) << bits;
-			  if ((mask & constant) != mask)
-			    warning ("comparison of promoted ~unsigned with constant");
-			}
-		    }
-		  else if (unsignedp0 && unsignedp1
-			   && (TYPE_PRECISION (TREE_TYPE (primop0))
-			       < TYPE_PRECISION (result_type))
-			   && (TYPE_PRECISION (TREE_TYPE (primop1))
-			       < TYPE_PRECISION (result_type)))
-		    warning ("comparison of promoted ~unsigned with unsigned");
-		}
-	    }
-	}
-    }
-
-  /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
-     If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
-     Then the expression will be built.
-     It will be given type FINAL_TYPE if that is nonzero;
-     otherwise, it will be given type RESULT_TYPE.  */
-
-  if (!result_type)
-    {
-      binary_op_error (code);
-      return error_mark_node;
-    }
-
-  if (! converted)
-    {
-      if (TREE_TYPE (op0) != result_type)
-	op0 = convert (result_type, op0);
-      if (TREE_TYPE (op1) != result_type)
-	op1 = convert (result_type, op1);
-    }
-
-  if (build_type == NULL_TREE)
-    build_type = result_type;
-
-  {
-    tree result = build (resultcode, build_type, op0, op1);
-    tree folded;
-
-    folded = fold (result);
-    if (folded == result)
-      TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
-    if (final_type != 0)
-      return convert (final_type, folded);
-    return folded;
-  }
-}
 
 
 /* Return true if `t' is known to be non-negative.  */
@@ -7201,3 +6471,736 @@ c_finish_case (void)
   splay_tree_delete (cs->cases);
   free (cs);
 }
+
+/* Build a binary-operation expression without default conversions.
+   CODE is the kind of expression to build.
+   This function differs from `build' in several ways:
+   the data type of the result is computed and recorded in it,
+   warnings are generated if arg data types are invalid,
+   special handling for addition and subtraction of pointers is known,
+   and some optimization is done (operations on narrow ints
+   are done in the narrower type when that gives the same result).
+   Constant folding is also done before the result is returned.
+
+   Note that the operands will never have enumeral types, or function
+   or array types, because either they will have the default conversions
+   performed or they have both just been converted to some other type in which
+   the arithmetic is to be done.  */
+
+tree
+build_binary_op (enum tree_code code, tree orig_op0, tree orig_op1,
+		 int convert_p)
+{
+  tree type0, type1;
+  enum tree_code code0, code1;
+  tree op0, op1;
+
+  /* Expression code to give to the expression when it is built.
+     Normally this is CODE, which is what the caller asked for,
+     but in some special cases we change it.  */
+  enum tree_code resultcode = code;
+
+  /* Data type in which the computation is to be performed.
+     In the simplest cases this is the common type of the arguments.  */
+  tree result_type = NULL;
+
+  /* Nonzero means operands have already been type-converted
+     in whatever way is necessary.
+     Zero means they need to be converted to RESULT_TYPE.  */
+  int converted = 0;
+
+  /* Nonzero means create the expression with this type, rather than
+     RESULT_TYPE.  */
+  tree build_type = 0;
+
+  /* Nonzero means after finally constructing the expression
+     convert it to this type.  */
+  tree final_type = 0;
+
+  /* Nonzero if this is an operation like MIN or MAX which can
+     safely be computed in short if both args are promoted shorts.
+     Also implies COMMON.
+     -1 indicates a bitwise operation; this makes a difference
+     in the exact conditions for when it is safe to do the operation
+     in a narrower mode.  */
+  int shorten = 0;
+
+  /* Nonzero if this is a comparison operation;
+     if both args are promoted shorts, compare the original shorts.
+     Also implies COMMON.  */
+  int short_compare = 0;
+
+  /* Nonzero if this is a right-shift operation, which can be computed on the
+     original short and then promoted if the operand is a promoted short.  */
+  int short_shift = 0;
+
+  /* Nonzero means set RESULT_TYPE to the common type of the args.  */
+  int common = 0;
+
+  if (convert_p)
+    {
+      op0 = default_conversion (orig_op0);
+      op1 = default_conversion (orig_op1);
+    }
+  else
+    {
+      op0 = orig_op0;
+      op1 = orig_op1;
+    }
+
+  type0 = TREE_TYPE (op0);
+  type1 = TREE_TYPE (op1);
+
+  /* The expression codes of the data types of the arguments tell us
+     whether the arguments are integers, floating, pointers, etc.  */
+  code0 = TREE_CODE (type0);
+  code1 = TREE_CODE (type1);
+
+  /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
+  STRIP_TYPE_NOPS (op0);
+  STRIP_TYPE_NOPS (op1);
+
+  /* If an error was already reported for one of the arguments,
+     avoid reporting another error.  */
+
+  if (code0 == ERROR_MARK || code1 == ERROR_MARK)
+    return error_mark_node;
+
+  switch (code)
+    {
+    case PLUS_EXPR:
+      /* Handle the pointer + int case.  */
+      if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+	return pointer_int_sum (PLUS_EXPR, op0, op1);
+      else if (code1 == POINTER_TYPE && code0 == INTEGER_TYPE)
+	return pointer_int_sum (PLUS_EXPR, op1, op0);
+      else
+	common = 1;
+      break;
+
+    case MINUS_EXPR:
+      /* Subtraction of two similar pointers.
+	 We must subtract them as integers, then divide by object size.  */
+      if (code0 == POINTER_TYPE && code1 == POINTER_TYPE
+	  && comp_target_types (type0, type1, 1))
+	return pointer_diff (op0, op1);
+      /* Handle pointer minus int.  Just like pointer plus int.  */
+      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+	return pointer_int_sum (MINUS_EXPR, op0, op1);
+      else
+	common = 1;
+      break;
+
+    case MULT_EXPR:
+      common = 1;
+      break;
+
+    case TRUNC_DIV_EXPR:
+    case CEIL_DIV_EXPR:
+    case FLOOR_DIV_EXPR:
+    case ROUND_DIV_EXPR:
+    case EXACT_DIV_EXPR:
+      /* Floating point division by zero is a legitimate way to obtain
+	 infinities and NaNs.  */
+      if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
+	warning ("division by zero");
+
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
+	   || code0 == COMPLEX_TYPE || code0 == VECTOR_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
+	      || code1 == COMPLEX_TYPE || code1 == VECTOR_TYPE))
+	{
+	  if (!(code0 == INTEGER_TYPE && code1 == INTEGER_TYPE))
+	    resultcode = RDIV_EXPR;
+	  else
+	    /* Although it would be tempting to shorten always here, that
+	       loses on some targets, since the modulo instruction is
+	       undefined if the quotient can't be represented in the
+	       computation mode.  We shorten only if unsigned or if
+	       dividing by something we know != -1.  */
+	    shorten = (TREE_UNSIGNED (TREE_TYPE (orig_op0))
+		       || (TREE_CODE (op1) == INTEGER_CST
+			   && ! integer_all_onesp (op1)));
+	  common = 1;
+	}
+      break;
+
+    case BIT_AND_EXPR:
+    case BIT_ANDTC_EXPR:
+    case BIT_IOR_EXPR:
+    case BIT_XOR_EXPR:
+      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+	shorten = -1;
+      else if (code0 == VECTOR_TYPE && code1 == VECTOR_TYPE)
+	common = 1;
+      break;
+
+    case TRUNC_MOD_EXPR:
+    case FLOOR_MOD_EXPR:
+      if (warn_div_by_zero && skip_evaluation == 0 && integer_zerop (op1))
+	warning ("division by zero");
+
+      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  /* Although it would be tempting to shorten always here, that loses
+	     on some targets, since the modulo instruction is undefined if the
+	     quotient can't be represented in the computation mode.  We shorten
+	     only if unsigned or if dividing by something we know != -1.  */
+	  shorten = (TREE_UNSIGNED (TREE_TYPE (orig_op0))
+		     || (TREE_CODE (op1) == INTEGER_CST
+			 && ! integer_all_onesp (op1)));
+	  common = 1;
+	}
+      break;
+
+    case TRUTH_ANDIF_EXPR:
+    case TRUTH_ORIF_EXPR:
+    case TRUTH_AND_EXPR:
+    case TRUTH_OR_EXPR:
+    case TRUTH_XOR_EXPR:
+      if ((code0 == INTEGER_TYPE || code0 == POINTER_TYPE
+	   || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == POINTER_TYPE
+	      || code1 == REAL_TYPE || code1 == COMPLEX_TYPE))
+	{
+	  /* Result of these operations is always an int,
+	     but that does not mean the operands should be
+	     converted to ints!  */
+	  result_type = integer_type_node;
+	  op0 = c_common_truthvalue_conversion (op0);
+	  op1 = c_common_truthvalue_conversion (op1);
+	  converted = 1;
+	}
+      break;
+
+      /* Shift operations: result has same type as first operand;
+	 always convert second operand to int.
+	 Also set SHORT_SHIFT if shifting rightward.  */
+
+    case RSHIFT_EXPR:
+      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("right shift count is negative");
+	      else
+		{
+		  if (! integer_zerop (op1))
+		    short_shift = 1;
+
+		  if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
+		    warning ("right shift count >= width of type");
+		}
+	    }
+
+	  /* Use the type of the value to be shifted.  */
+	  result_type = type0;
+	  /* Convert the shift-count to an integer, regardless of size
+	     of value being shifted.  */
+	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
+	    op1 = convert (integer_type_node, op1);
+	  /* Avoid converting op1 to result_type later.  */
+	  converted = 1;
+	}
+      break;
+
+    case LSHIFT_EXPR:
+      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("left shift count is negative");
+
+	      else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
+		warning ("left shift count >= width of type");
+	    }
+
+	  /* Use the type of the value to be shifted.  */
+	  result_type = type0;
+	  /* Convert the shift-count to an integer, regardless of size
+	     of value being shifted.  */
+	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
+	    op1 = convert (integer_type_node, op1);
+	  /* Avoid converting op1 to result_type later.  */
+	  converted = 1;
+	}
+      break;
+
+    case RROTATE_EXPR:
+    case LROTATE_EXPR:
+      if (code0 == INTEGER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  if (TREE_CODE (op1) == INTEGER_CST && skip_evaluation == 0)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("shift count is negative");
+	      else if (compare_tree_int (op1, TYPE_PRECISION (type0)) >= 0)
+		warning ("shift count >= width of type");
+	    }
+
+	  /* Use the type of the value to be shifted.  */
+	  result_type = type0;
+	  /* Convert the shift-count to an integer, regardless of size
+	     of value being shifted.  */
+	  if (TYPE_MAIN_VARIANT (TREE_TYPE (op1)) != integer_type_node)
+	    op1 = convert (integer_type_node, op1);
+	  /* Avoid converting op1 to result_type later.  */
+	  converted = 1;
+	}
+      break;
+
+    case EQ_EXPR:
+    case NE_EXPR:
+      if (warn_float_equal && (code0 == REAL_TYPE || code1 == REAL_TYPE))
+	warning ("comparing floating point with == or != is unsafe");
+      /* Result of comparison is always int,
+	 but don't convert the args to int!  */
+      build_type = integer_type_node;
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
+	   || code0 == COMPLEX_TYPE
+	   || code0 == VECTOR_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
+	      || code1 == COMPLEX_TYPE
+	      || code1 == VECTOR_TYPE))
+	short_compare = 1;
+      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
+	{
+	  tree tt0 = TREE_TYPE (type0);
+	  tree tt1 = TREE_TYPE (type1);
+	  /* Anything compares with void *.  void * compares with anything.
+	     Otherwise, the targets must be compatible
+	     and both must be object or both incomplete.  */
+	  if (comp_target_types (type0, type1, 1))
+	    result_type = common_type (type0, type1);
+	  else if (VOID_TYPE_P (tt0))
+	    {
+	      /* op0 != orig_op0 detects the case of something
+		 whose value is 0 but which isn't a valid null ptr const.  */
+	      if (pedantic && (!integer_zerop (op0) || op0 != orig_op0)
+		  && TREE_CODE (tt1) == FUNCTION_TYPE)
+		pedwarn ("ISO C forbids comparison of `void *' with function pointer");
+	    }
+	  else if (VOID_TYPE_P (tt1))
+	    {
+	      if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
+		  && TREE_CODE (tt0) == FUNCTION_TYPE)
+		pedwarn ("ISO C forbids comparison of `void *' with function pointer");
+	    }
+	  else
+	    pedwarn ("comparison of distinct pointer types lacks a cast");
+
+	  if (result_type == NULL_TREE)
+	    result_type = ptr_type_node;
+	}
+      else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
+	       && integer_zerop (op1))
+	result_type = type0;
+      else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
+	       && integer_zerop (op0))
+	result_type = type1;
+      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  result_type = type0;
+	  pedwarn ("comparison between pointer and integer");
+	}
+      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+	{
+	  result_type = type1;
+	  pedwarn ("comparison between pointer and integer");
+	}
+      break;
+
+    case MAX_EXPR:
+    case MIN_EXPR:
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
+	shorten = 1;
+      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
+	{
+	  if (comp_target_types (type0, type1, 1))
+	    {
+	      result_type = common_type (type0, type1);
+	      if (pedantic
+		  && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
+		pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
+	    }
+	  else
+	    {
+	      result_type = ptr_type_node;
+	      pedwarn ("comparison of distinct pointer types lacks a cast");
+	    }
+	}
+      break;
+
+    case LE_EXPR:
+    case GE_EXPR:
+    case LT_EXPR:
+    case GT_EXPR:
+      build_type = integer_type_node;
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE))
+	short_compare = 1;
+      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
+	{
+	  if (comp_target_types (type0, type1, 1))
+	    {
+	      result_type = common_type (type0, type1);
+	      if (!COMPLETE_TYPE_P (TREE_TYPE (type0))
+		  != !COMPLETE_TYPE_P (TREE_TYPE (type1)))
+		pedwarn ("comparison of complete and incomplete pointers");
+	      else if (pedantic
+		       && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
+		pedwarn ("ISO C forbids ordered comparisons of pointers to functions");
+	    }
+	  else
+	    {
+	      result_type = ptr_type_node;
+	      pedwarn ("comparison of distinct pointer types lacks a cast");
+	    }
+	}
+      else if (code0 == POINTER_TYPE && TREE_CODE (op1) == INTEGER_CST
+	       && integer_zerop (op1))
+	{
+	  result_type = type0;
+	  if (pedantic || extra_warnings)
+	    pedwarn ("ordered comparison of pointer with integer zero");
+	}
+      else if (code1 == POINTER_TYPE && TREE_CODE (op0) == INTEGER_CST
+	       && integer_zerop (op0))
+	{
+	  result_type = type1;
+	  if (pedantic)
+	    pedwarn ("ordered comparison of pointer with integer zero");
+	}
+      else if (code0 == POINTER_TYPE && code1 == INTEGER_TYPE)
+	{
+	  result_type = type0;
+	  pedwarn ("comparison between pointer and integer");
+	}
+      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+	{
+	  result_type = type1;
+	  pedwarn ("comparison between pointer and integer");
+	}
+      break;
+
+    case UNORDERED_EXPR:
+    case ORDERED_EXPR:
+    case UNLT_EXPR:
+    case UNLE_EXPR:
+    case UNGT_EXPR:
+    case UNGE_EXPR:
+    case UNEQ_EXPR:
+      build_type = integer_type_node;
+      if (code0 != REAL_TYPE || code1 != REAL_TYPE)
+	{
+	  error ("unordered comparison on non-floating point argument");
+	  return error_mark_node;
+	}
+      common = 1;
+      break;
+
+    default:
+      break;
+    }
+
+  if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE
+       || code0 == VECTOR_TYPE)
+      &&
+      (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_TYPE
+       || code1 == VECTOR_TYPE))
+    {
+      int none_complex = (code0 != COMPLEX_TYPE && code1 != COMPLEX_TYPE);
+
+      if (shorten || common || short_compare)
+	result_type = common_type (type0, type1);
+
+      /* For certain operations (which identify themselves by shorten != 0)
+	 if both args were extended from the same smaller type,
+	 do the arithmetic in that type and then extend.
+
+	 shorten !=0 and !=1 indicates a bitwise operation.
+	 For them, this optimization is safe only if
+	 both args are zero-extended or both are sign-extended.
+	 Otherwise, we might change the result.
+	 Eg, (short)-1 | (unsigned short)-1 is (int)-1
+	 but calculated in (unsigned short) it would be (unsigned short)-1.  */
+
+      if (shorten && none_complex)
+	{
+	  int unsigned0, unsigned1;
+	  tree arg0 = get_narrower (op0, &unsigned0);
+	  tree arg1 = get_narrower (op1, &unsigned1);
+	  /* UNS is 1 if the operation to be done is an unsigned one.  */
+	  int uns = TREE_UNSIGNED (result_type);
+	  tree type;
+
+	  final_type = result_type;
+
+	  /* Handle the case that OP0 (or OP1) does not *contain* a conversion
+	     but it *requires* conversion to FINAL_TYPE.  */
+
+	  if ((TYPE_PRECISION (TREE_TYPE (op0))
+	       == TYPE_PRECISION (TREE_TYPE (arg0)))
+	      && TREE_TYPE (op0) != final_type)
+	    unsigned0 = TREE_UNSIGNED (TREE_TYPE (op0));
+	  if ((TYPE_PRECISION (TREE_TYPE (op1))
+	       == TYPE_PRECISION (TREE_TYPE (arg1)))
+	      && TREE_TYPE (op1) != final_type)
+	    unsigned1 = TREE_UNSIGNED (TREE_TYPE (op1));
+
+	  /* Now UNSIGNED0 is 1 if ARG0 zero-extends to FINAL_TYPE.  */
+
+	  /* For bitwise operations, signedness of nominal type
+	     does not matter.  Consider only how operands were extended.  */
+	  if (shorten == -1)
+	    uns = unsigned0;
+
+	  /* Note that in all three cases below we refrain from optimizing
+	     an unsigned operation on sign-extended args.
+	     That would not be valid.  */
+
+	  /* Both args variable: if both extended in same way
+	     from same width, do it in that width.
+	     Do it unsigned if args were zero-extended.  */
+	  if ((TYPE_PRECISION (TREE_TYPE (arg0))
+	       < TYPE_PRECISION (result_type))
+	      && (TYPE_PRECISION (TREE_TYPE (arg1))
+		  == TYPE_PRECISION (TREE_TYPE (arg0)))
+	      && unsigned0 == unsigned1
+	      && (unsigned0 || !uns))
+	    result_type
+	      = c_common_signed_or_unsigned_type
+	      (unsigned0, common_type (TREE_TYPE (arg0), TREE_TYPE (arg1)));
+	  else if (TREE_CODE (arg0) == INTEGER_CST
+		   && (unsigned1 || !uns)
+		   && (TYPE_PRECISION (TREE_TYPE (arg1))
+		       < TYPE_PRECISION (result_type))
+		   && (type
+		       = c_common_signed_or_unsigned_type (unsigned1,
+							   TREE_TYPE (arg1)),
+		       int_fits_type_p (arg0, type)))
+	    result_type = type;
+	  else if (TREE_CODE (arg1) == INTEGER_CST
+		   && (unsigned0 || !uns)
+		   && (TYPE_PRECISION (TREE_TYPE (arg0))
+		       < TYPE_PRECISION (result_type))
+		   && (type
+		       = c_common_signed_or_unsigned_type (unsigned0,
+							   TREE_TYPE (arg0)),
+		       int_fits_type_p (arg1, type)))
+	    result_type = type;
+	}
+
+      /* Shifts can be shortened if shifting right.  */
+
+      if (short_shift)
+	{
+	  int unsigned_arg;
+	  tree arg0 = get_narrower (op0, &unsigned_arg);
+
+	  final_type = result_type;
+
+	  if (arg0 == op0 && final_type == TREE_TYPE (op0))
+	    unsigned_arg = TREE_UNSIGNED (TREE_TYPE (op0));
+
+	  if (TYPE_PRECISION (TREE_TYPE (arg0)) < TYPE_PRECISION (result_type)
+	      /* We can shorten only if the shift count is less than the
+		 number of bits in the smaller type size.  */
+	      && compare_tree_int (op1, TYPE_PRECISION (TREE_TYPE (arg0))) < 0
+	      /* We cannot drop an unsigned shift after sign-extension.  */
+	      && (!TREE_UNSIGNED (final_type) || unsigned_arg))
+	    {
+	      /* Do an unsigned shift if the operand was zero-extended.  */
+	      result_type
+		= c_common_signed_or_unsigned_type (unsigned_arg,
+						    TREE_TYPE (arg0));
+	      /* Convert value-to-be-shifted to that type.  */
+	      if (TREE_TYPE (op0) != result_type)
+		op0 = convert (result_type, op0);
+	      converted = 1;
+	    }
+	}
+
+      /* Comparison operations are shortened too but differently.
+	 They identify themselves by setting short_compare = 1.  */
+
+      if (short_compare)
+	{
+	  /* Don't write &op0, etc., because that would prevent op0
+	     from being kept in a register.
+	     Instead, make copies of the our local variables and
+	     pass the copies by reference, then copy them back afterward.  */
+	  tree xop0 = op0, xop1 = op1, xresult_type = result_type;
+	  enum tree_code xresultcode = resultcode;
+	  tree val
+	    = shorten_compare (&xop0, &xop1, &xresult_type, &xresultcode);
+
+	  if (val != 0)
+	    return val;
+
+	  op0 = xop0, op1 = xop1;
+	  converted = 1;
+	  resultcode = xresultcode;
+
+	  if (warn_sign_compare && skip_evaluation == 0)
+	    {
+	      int op0_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op0));
+	      int op1_signed = ! TREE_UNSIGNED (TREE_TYPE (orig_op1));
+	      int unsignedp0, unsignedp1;
+	      tree primop0 = get_narrower (op0, &unsignedp0);
+	      tree primop1 = get_narrower (op1, &unsignedp1);
+
+	      xop0 = orig_op0;
+	      xop1 = orig_op1;
+	      STRIP_TYPE_NOPS (xop0);
+	      STRIP_TYPE_NOPS (xop1);
+
+	      /* Give warnings for comparisons between signed and unsigned
+		 quantities that may fail.
+
+		 Do the checking based on the original operand trees, so that
+		 casts will be considered, but default promotions won't be.
+
+		 Do not warn if the comparison is being done in a signed type,
+		 since the signed type will only be chosen if it can represent
+		 all the values of the unsigned type.  */
+	      if (! TREE_UNSIGNED (result_type))
+		/* OK */;
+              /* Do not warn if both operands are the same signedness.  */
+              else if (op0_signed == op1_signed)
+                /* OK */;
+	      else
+		{
+		  tree sop, uop;
+
+		  if (op0_signed)
+		    sop = xop0, uop = xop1;
+		  else
+		    sop = xop1, uop = xop0;
+
+		  /* Do not warn if the signed quantity is an
+		     unsuffixed integer literal (or some static
+		     constant expression involving such literals or a
+		     conditional expression involving such literals)
+		     and it is non-negative.  */
+		  if (c_tree_expr_nonnegative_p (sop))
+		    /* OK */;
+		  /* Do not warn if the comparison is an equality operation,
+		     the unsigned quantity is an integral constant, and it
+		     would fit in the result if the result were signed.  */
+		  else if (TREE_CODE (uop) == INTEGER_CST
+			   && (resultcode == EQ_EXPR || resultcode == NE_EXPR)
+			   && int_fits_type_p
+			   (uop, c_common_signed_type (result_type)))
+		    /* OK */;
+		  /* Do not warn if the unsigned quantity is an enumeration
+		     constant and its maximum value would fit in the result
+		     if the result were signed.  */
+		  else if (TREE_CODE (uop) == INTEGER_CST
+			   && TREE_CODE (TREE_TYPE (uop)) == ENUMERAL_TYPE
+			   && int_fits_type_p
+			   (TYPE_MAX_VALUE (TREE_TYPE(uop)),
+			    c_common_signed_type (result_type)))
+		    /* OK */;
+		  else
+		    warning ("comparison between signed and unsigned");
+		}
+
+	      /* Warn if two unsigned values are being compared in a size
+		 larger than their original size, and one (and only one) is the
+		 result of a `~' operator.  This comparison will always fail.
+
+		 Also warn if one operand is a constant, and the constant
+		 does not have all bits set that are set in the ~ operand
+		 when it is extended.  */
+
+	      if ((TREE_CODE (primop0) == BIT_NOT_EXPR)
+		  != (TREE_CODE (primop1) == BIT_NOT_EXPR))
+		{
+		  if (TREE_CODE (primop0) == BIT_NOT_EXPR)
+		    primop0 = get_narrower (TREE_OPERAND (primop0, 0),
+					    &unsignedp0);
+		  else
+		    primop1 = get_narrower (TREE_OPERAND (primop1, 0),
+					    &unsignedp1);
+
+		  if (host_integerp (primop0, 0) || host_integerp (primop1, 0))
+		    {
+		      tree primop;
+		      HOST_WIDE_INT constant, mask;
+		      int unsignedp, bits;
+
+		      if (host_integerp (primop0, 0))
+			{
+			  primop = primop1;
+			  unsignedp = unsignedp1;
+			  constant = tree_low_cst (primop0, 0);
+			}
+		      else
+			{
+			  primop = primop0;
+			  unsignedp = unsignedp0;
+			  constant = tree_low_cst (primop1, 0);
+			}
+
+		      bits = TYPE_PRECISION (TREE_TYPE (primop));
+		      if (bits < TYPE_PRECISION (result_type)
+			  && bits < HOST_BITS_PER_WIDE_INT && unsignedp)
+			{
+			  mask = (~ (HOST_WIDE_INT) 0) << bits;
+			  if ((mask & constant) != mask)
+			    warning ("comparison of promoted ~unsigned with constant");
+			}
+		    }
+		  else if (unsignedp0 && unsignedp1
+			   && (TYPE_PRECISION (TREE_TYPE (primop0))
+			       < TYPE_PRECISION (result_type))
+			   && (TYPE_PRECISION (TREE_TYPE (primop1))
+			       < TYPE_PRECISION (result_type)))
+		    warning ("comparison of promoted ~unsigned with unsigned");
+		}
+	    }
+	}
+    }
+
+  /* At this point, RESULT_TYPE must be nonzero to avoid an error message.
+     If CONVERTED is zero, both args will be converted to type RESULT_TYPE.
+     Then the expression will be built.
+     It will be given type FINAL_TYPE if that is nonzero;
+     otherwise, it will be given type RESULT_TYPE.  */
+
+  if (!result_type)
+    {
+      binary_op_error (code);
+      return error_mark_node;
+    }
+
+  if (! converted)
+    {
+      if (TREE_TYPE (op0) != result_type)
+	op0 = convert (result_type, op0);
+      if (TREE_TYPE (op1) != result_type)
+	op1 = convert (result_type, op1);
+    }
+
+  if (build_type == NULL_TREE)
+    build_type = result_type;
+
+  {
+    tree result = build (resultcode, build_type, op0, op1);
+    tree folded;
+
+    /* Treat expressions in initializers specially as they can't trap.  */
+    folded = initializer_stack ? fold_initializer (result)
+			       : fold (result);
+    if (folded == result)
+      TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
+    if (final_type != 0)
+      return convert (final_type, folded);
+    return folded;
+  }
+}
+
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index 95a68bc..32c145e 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -1228,14 +1228,31 @@ const_binop (enum tree_code code, tree arg1, tree arg2, int notrunc)
 
   if (TREE_CODE (arg1) == REAL_CST)
     {
+      enum machine_mode mode;
       REAL_VALUE_TYPE d1;
       REAL_VALUE_TYPE d2;
       REAL_VALUE_TYPE value;
-      tree t;
+      tree t, type;
 
       d1 = TREE_REAL_CST (arg1);
       d2 = TREE_REAL_CST (arg2);
 
+      type = TREE_TYPE (arg1);
+      mode = TYPE_MODE (type);
+
+      /* Don't perform operation if we honor signaling NaNs and
+	 either operand is a NaN.  */
+      if (HONOR_SNANS (mode)
+	  && (REAL_VALUE_ISNAN (d1) || REAL_VALUE_ISNAN (d2)))
+	return NULL_TREE;
+
+      /* Don't perform operation if it would raise a division
+	 by zero exception.  */
+      if (code == RDIV_EXPR
+	  && REAL_VALUES_EQUAL (d2, dconst0)
+	  && (flag_trapping_math || ! MODE_HAS_INFINITIES (mode)))
+	return NULL_TREE;
+
       /* If either operand is a NaN, just return it.  Otherwise, set up
 	 for floating-point trap; we return an overflow.  */
       if (REAL_VALUE_ISNAN (d1))
@@ -1245,9 +1262,7 @@ const_binop (enum tree_code code, tree arg1, tree arg2, int notrunc)
 
       REAL_ARITHMETIC (value, code, d1, d2);
 
-      t = build_real (TREE_TYPE (arg1),
-		      real_value_truncate (TYPE_MODE (TREE_TYPE (arg1)),
-					   value));
+      t = build_real (type, real_value_truncate (mode, value));
 
       TREE_OVERFLOW (t)
 	= (force_fit_type (t, 0)
@@ -7886,6 +7901,31 @@ fold (tree expr)
     } /* switch (code) */
 }
 
+/* Perform constant folding and related simplification of intializer
+   expression EXPR.  This behaves identically to "fold" but ignores
+   potential run-time traps and exceptions that fold must preserve.  */
+
+tree
+fold_initializer (tree expr)
+{
+  int saved_signaling_nans = flag_signaling_nans;
+  int saved_trapping_math = flag_trapping_math;
+  int saved_trapv = flag_trapv;
+  tree result;
+
+  flag_signaling_nans = 0;
+  flag_trapping_math = 0;
+  flag_trapv = 0;
+
+  result = fold (expr);
+
+  flag_signaling_nans = saved_signaling_nans;
+  flag_trapping_math = saved_trapping_math;
+  flag_trapv = saved_trapv;
+
+  return result;
+}
+
 /* Determine if first argument is a multiple of second argument.  Return 0 if
    it is not, or we cannot easily determined it to be.
 
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c
index 3b85767..8568529 100644
--- a/gcc/simplify-rtx.c
+++ b/gcc/simplify-rtx.c
@@ -929,9 +929,13 @@ simplify_binary_operation (enum rtx_code code, enum machine_mode mode,
       f0 = real_value_truncate (mode, f0);
       f1 = real_value_truncate (mode, f1);
 
+      if (HONOR_SNANS (mode)
+	  && (REAL_VALUE_ISNAN (f0) || REAL_VALUE_ISNAN (f1)))
+	return 0;
+
       if (code == DIV
-	  && !MODE_HAS_INFINITIES (mode)
-	  && REAL_VALUES_EQUAL (f1, dconst0))
+	  && REAL_VALUES_EQUAL (f1, dconst0)
+	  && (flag_trapping_math || ! MODE_HAS_INFINITIES (mode)))
 	return 0;
 
       REAL_ARITHMETIC (value, rtx_to_tree_code (code), f0, f1);
diff --git a/gcc/tree.h b/gcc/tree.h
index 04ad1d0..b627a98 100644
--- a/gcc/tree.h
+++ b/gcc/tree.h
@@ -2715,6 +2715,7 @@ extern void using_eh_for_cleanups (void);
    subexpressions are not changed.  */
 
 extern tree fold (tree);
+extern tree fold_initializer (tree);
 extern tree fold_single_bit_test (enum tree_code, tree, tree, tree);
 
 extern int force_fit_type (tree, int);