Import of unmodified (but trimmed) gcc-2.7.2. The bigger parts of the

non-i386, non-unix, and generatable files have been trimmed, but can easily
be added in later if needed.

gcc-2.7.2.1 will follow shortly, it's a very small delta to this and it's
handy to have both available for reference for such little cost.

The freebsd-specific changes will then be committed, and once the dust has
settled, the bmakefiles will be committed to use this code.

1 files changed, 6602 insertions, 0 deletions

diff --git a/contrib/gcc/c-typeck.c b/contrib/gcc/c-typeck.c
new file mode 100644
index 0000000..e9d6b2a
--- /dev/null
+++ b/contrib/gcc/c-typeck.c
@@ -0,0 +1,6602 @@
+/* Build expressions with type checking for C compiler.
+   Copyright (C) 1987, 88, 91, 92, 93, 94, 1995 Free Software Foundation, Inc.
+
+This file is part of GNU CC.
+
+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.  */
+
+
+/* This file is part of the C front end.
+   It contains routines to build C expressions given their operands,
+   including computing the types of the result, C-specific error checks,
+   and some optimization.
+
+   There are also routines to build RETURN_STMT nodes and CASE_STMT nodes,
+   and to process initializations in declarations (since they work
+   like a strange sort of assignment).  */
+
+#include "config.h"
+#include <stdio.h>
+#include "tree.h"
+#include "c-tree.h"
+#include "flags.h"
+#include "output.h"
+
+/* Nonzero if we've already printed a "missing braces around initializer"
+   message within this initializer.  */
+static int missing_braces_mentioned;
+
+extern char *index ();
+extern char *rindex ();
+
+static tree quality_type		PROTO((tree, tree));
+static int comp_target_types		PROTO((tree, tree));
+static int function_types_compatible_p	PROTO((tree, tree));
+static int type_lists_compatible_p	PROTO((tree, tree));
+static int self_promoting_type_p	PROTO((tree));
+static tree decl_constant_value		PROTO((tree));
+static tree lookup_field		PROTO((tree, tree, tree *));
+static tree convert_arguments		PROTO((tree, tree, tree, tree));
+static tree pointer_int_sum		PROTO((enum tree_code, tree, tree));
+static tree pointer_diff		PROTO((tree, tree));
+static tree unary_complex_lvalue	PROTO((enum tree_code, tree));
+static void pedantic_lvalue_warning	PROTO((enum tree_code));
+static tree internal_build_compound_expr PROTO((tree, int));
+static tree convert_for_assignment	PROTO((tree, tree, char *, tree,
+					       tree, int));
+static void warn_for_assignment		PROTO((char *, char *, tree, int));
+static tree valid_compound_expr_initializer PROTO((tree, tree));
+static void push_string			PROTO((char *));
+static void push_member_name		PROTO((tree));
+static void push_array_bounds		PROTO((int));
+static int spelling_length		PROTO((void));
+static char *print_spelling		PROTO((char *));
+static char *get_spelling		PROTO((char *));
+static void warning_init		PROTO((char *, char *,
+					       char *));
+static tree digest_init			PROTO((tree, tree, int, int));
+static void check_init_type_bitfields	PROTO((tree));
+static void output_init_element		PROTO((tree, tree, tree, int));
+static void output_pending_init_elements PROTO((int));
+
+/* Do `exp = require_complete_type (exp);' to make sure exp
+   does not have an incomplete type.  (That includes void types.)  */
+
+tree
+require_complete_type (value)
+     tree value;
+{
+  tree type = TREE_TYPE (value);
+
+  /* First, detect a valid value with a complete type.  */
+  if (TYPE_SIZE (type) != 0
+      && type != void_type_node)
+    return value;
+
+  incomplete_type_error (value, type);
+  return error_mark_node;
+}
+
+/* Print an error message for invalid use of an incomplete type.
+   VALUE is the expression that was used (or 0 if that isn't known)
+   and TYPE is the type that was invalid.  */
+
+void
+incomplete_type_error (value, type)
+     tree value;
+     tree type;
+{
+  char *errmsg;
+
+  /* Avoid duplicate error message.  */
+  if (TREE_CODE (type) == ERROR_MARK)
+    return;
+
+  if (value != 0 && (TREE_CODE (value) == VAR_DECL
+		     || TREE_CODE (value) == PARM_DECL))
+    error ("`%s' has an incomplete type",
+	   IDENTIFIER_POINTER (DECL_NAME (value)));
+  else
+    {
+    retry:
+      /* We must print an error message.  Be clever about what it says.  */
+
+      switch (TREE_CODE (type))
+	{
+	case RECORD_TYPE:
+	  errmsg = "invalid use of undefined type `struct %s'";
+	  break;
+
+	case UNION_TYPE:
+	  errmsg = "invalid use of undefined type `union %s'";
+	  break;
+
+	case ENUMERAL_TYPE:
+	  errmsg = "invalid use of undefined type `enum %s'";
+	  break;
+
+	case VOID_TYPE:
+	  error ("invalid use of void expression");
+	  return;
+
+	case ARRAY_TYPE:
+	  if (TYPE_DOMAIN (type))
+	    {
+	      type = TREE_TYPE (type);
+	      goto retry;
+	    }
+	  error ("invalid use of array with unspecified bounds");
+	  return;
+
+	default:
+	  abort ();
+	}
+
+      if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
+	error (errmsg, IDENTIFIER_POINTER (TYPE_NAME (type)));
+      else
+	/* If this type has a typedef-name, the TYPE_NAME is a TYPE_DECL.  */
+	error ("invalid use of incomplete typedef `%s'",
+	       IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type))));
+    }
+}
+
+/* Return a variant of TYPE which has all the type qualifiers of LIKE
+   as well as those of TYPE.  */
+
+static tree
+qualify_type (type, like)
+     tree type, like;
+{
+  int constflag = TYPE_READONLY (type) || TYPE_READONLY (like);
+  int volflag = TYPE_VOLATILE (type) || TYPE_VOLATILE (like);
+  return c_build_type_variant (type, constflag, volflag);
+}
+
+/* Return the common type of two types.
+   We assume that comptypes has already been done and returned 1;
+   if that isn't so, this may crash.  In particular, we assume that qualifiers
+   match.
+
+   This is the type for the result of most arithmetic operations
+   if the operands have the given two types.  */
+
+tree
+common_type (t1, t2)
+     tree t1, t2;
+{
+  register enum tree_code code1;
+  register enum tree_code code2;
+  tree attributes;
+
+  /* Save time if the two types are the same.  */
+
+  if (t1 == t2) return t1;
+
+  /* If one type is nonsense, use the other.  */
+  if (t1 == error_mark_node)
+    return t2;
+  if (t2 == error_mark_node)
+    return t1;
+
+  /* Merge the attributes */
+
+  { register tree a1, a2;
+    a1 = TYPE_ATTRIBUTES (t1);
+    a2 = TYPE_ATTRIBUTES (t2);
+
+    /* Either one unset?  Take the set one.  */
+
+    if (!(attributes = a1))
+       attributes = a2;
+
+    /* One that completely contains the other?  Take it.  */
+
+    else if (a2 && !attribute_list_contained (a1, a2))
+       if (attribute_list_contained (a2, a1))
+	  attributes = a2;
+       else
+	{
+	  /* Pick the longest list, and hang on the other list.  */
+	  /* ??? For the moment we punt on the issue of attrs with args.  */
+	
+	  if (list_length (a1) < list_length (a2))
+	     attributes = a2, a2 = a1;
+
+	  for (; a2; a2 = TREE_CHAIN (a2))
+	    if (lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
+				  attributes) == NULL_TREE)
+	      {
+		a1 = copy_node (a2);
+		TREE_CHAIN (a1) = attributes;
+		attributes = a1;
+	      }
+	}
+  }
+
+  /* Treat an enum type as the unsigned integer type of the same width.  */
+
+  if (TREE_CODE (t1) == ENUMERAL_TYPE)
+    t1 = type_for_size (TYPE_PRECISION (t1), 1);
+  if (TREE_CODE (t2) == ENUMERAL_TYPE)
+    t2 = type_for_size (TYPE_PRECISION (t2), 1);
+
+  code1 = TREE_CODE (t1);
+  code2 = TREE_CODE (t2);
+
+  /* If one type is complex, form the common type of the non-complex
+     components, then make that complex.  Use T1 or T2 if it is the
+     required type.  */
+  if (code1 == COMPLEX_TYPE || code2 == COMPLEX_TYPE)
+    {
+      tree subtype1 = code1 == COMPLEX_TYPE ? TREE_TYPE (t1) : t1;
+      tree subtype2 = code2 == COMPLEX_TYPE ? TREE_TYPE (t2) : t2;
+      tree subtype = common_type (subtype1, subtype2);
+
+      if (code1 == COMPLEX_TYPE && TREE_TYPE (t1) == subtype)
+	return build_type_attribute_variant (t1, attributes);
+      else if (code2 == COMPLEX_TYPE && TREE_TYPE (t2) == subtype)
+	return build_type_attribute_variant (t2, attributes);
+      else
+	return build_type_attribute_variant (build_complex_type (subtype),
+					     attributes);
+    }
+
+  switch (code1)
+    {
+    case INTEGER_TYPE:
+    case REAL_TYPE:
+      /* If only one is real, use it as the result.  */
+
+      if (code1 == REAL_TYPE && code2 != REAL_TYPE)
+	return build_type_attribute_variant (t1, attributes);
+
+      if (code2 == REAL_TYPE && code1 != REAL_TYPE)
+	return build_type_attribute_variant (t2, attributes);
+
+      /* Both real or both integers; use the one with greater precision.  */
+
+      if (TYPE_PRECISION (t1) > TYPE_PRECISION (t2))
+	return build_type_attribute_variant (t1, attributes);
+      else if (TYPE_PRECISION (t2) > TYPE_PRECISION (t1))
+	return build_type_attribute_variant (t2, attributes);
+
+      /* Same precision.  Prefer longs to ints even when same size.  */
+
+      if (TYPE_MAIN_VARIANT (t1) == long_unsigned_type_node
+	  || TYPE_MAIN_VARIANT (t2) == long_unsigned_type_node)
+	return build_type_attribute_variant (long_unsigned_type_node,
+					     attributes);
+
+      if (TYPE_MAIN_VARIANT (t1) == long_integer_type_node
+	  || TYPE_MAIN_VARIANT (t2) == long_integer_type_node)
+	{
+	  /* But preserve unsignedness from the other type,
+	     since long cannot hold all the values of an unsigned int.  */
+	  if (TREE_UNSIGNED (t1) || TREE_UNSIGNED (t2))
+	     t1 = long_unsigned_type_node;
+	  else
+	     t1 = long_integer_type_node;
+	  return build_type_attribute_variant (t1, attributes);
+	}
+
+      /* Otherwise prefer the unsigned one.  */
+
+      if (TREE_UNSIGNED (t1))
+	return build_type_attribute_variant (t1, attributes);
+      else
+	return build_type_attribute_variant (t2, attributes);
+
+    case POINTER_TYPE:
+      /* For two pointers, do this recursively on the target type,
+	 and combine the qualifiers of the two types' targets.  */
+      /* This code was turned off; I don't know why.
+	 But ANSI C specifies doing this with the qualifiers.
+	 So I turned it on again.  */
+      {
+	tree target = common_type (TYPE_MAIN_VARIANT (TREE_TYPE (t1)),
+				   TYPE_MAIN_VARIANT (TREE_TYPE (t2)));
+	int constp
+	  = TYPE_READONLY (TREE_TYPE (t1)) || TYPE_READONLY (TREE_TYPE (t2));
+	int volatilep
+	  = TYPE_VOLATILE (TREE_TYPE (t1)) || TYPE_VOLATILE (TREE_TYPE (t2));
+	t1 = build_pointer_type (c_build_type_variant (target, constp,
+				 volatilep));
+	return build_type_attribute_variant (t1, attributes);
+      }
+#if 0
+      t1 = build_pointer_type (common_type (TREE_TYPE (t1), TREE_TYPE (t2)));
+      return build_type_attribute_variant (t1, attributes);
+#endif
+
+    case ARRAY_TYPE:
+      {
+	tree elt = common_type (TREE_TYPE (t1), TREE_TYPE (t2));
+	/* Save space: see if the result is identical to one of the args.  */
+	if (elt == TREE_TYPE (t1) && TYPE_DOMAIN (t1))
+	  return build_type_attribute_variant (t1, attributes);
+	if (elt == TREE_TYPE (t2) && TYPE_DOMAIN (t2))
+	  return build_type_attribute_variant (t2, attributes);
+	/* Merge the element types, and have a size if either arg has one.  */
+	t1 = build_array_type (elt, TYPE_DOMAIN (TYPE_DOMAIN (t1) ? t1 : t2));
+	return build_type_attribute_variant (t1, attributes);
+      }
+
+    case FUNCTION_TYPE:
+      /* Function types: prefer the one that specified arg types.
+	 If both do, merge the arg types.  Also merge the return types.  */
+      {
+	tree valtype = common_type (TREE_TYPE (t1), TREE_TYPE (t2));
+	tree p1 = TYPE_ARG_TYPES (t1);
+	tree p2 = TYPE_ARG_TYPES (t2);
+	int len;
+	tree newargs, n;
+	int i;
+
+	/* Save space: see if the result is identical to one of the args.  */
+	if (valtype == TREE_TYPE (t1) && ! TYPE_ARG_TYPES (t2))
+	  return build_type_attribute_variant (t1, attributes);
+	if (valtype == TREE_TYPE (t2) && ! TYPE_ARG_TYPES (t1))
+	  return build_type_attribute_variant (t2, attributes);
+
+	/* Simple way if one arg fails to specify argument types.  */
+	if (TYPE_ARG_TYPES (t1) == 0)
+	 {
+	   t1 = build_function_type (valtype, TYPE_ARG_TYPES (t2));
+	   return build_type_attribute_variant (t1, attributes);
+	 }
+	if (TYPE_ARG_TYPES (t2) == 0)
+	 {
+	   t1 = build_function_type (valtype, TYPE_ARG_TYPES (t1));
+	   return build_type_attribute_variant (t1, attributes);
+	 }
+
+	/* If both args specify argument types, we must merge the two
+	   lists, argument by argument.  */
+
+	len = list_length (p1);
+	newargs = 0;
+
+	for (i = 0; i < len; i++)
+	  newargs = tree_cons (NULL_TREE, NULL_TREE, newargs);
+
+	n = newargs;
+
+	for (; p1;
+	     p1 = TREE_CHAIN (p1), p2 = TREE_CHAIN (p2), n = TREE_CHAIN (n))
+	  {
+	    /* A null type means arg type is not specified.
+	       Take whatever the other function type has.  */
+	    if (TREE_VALUE (p1) == 0)
+	      {
+		TREE_VALUE (n) = TREE_VALUE (p2);
+		goto parm_done;
+	      }
+	    if (TREE_VALUE (p2) == 0)
+	      {
+		TREE_VALUE (n) = TREE_VALUE (p1);
+		goto parm_done;
+	      }
+	      
+	    /* Given  wait (union {union wait *u; int *i} *)
+	       and  wait (union wait *),
+	       prefer  union wait *  as type of parm.  */
+	    if (TREE_CODE (TREE_VALUE (p1)) == UNION_TYPE
+		&& TREE_VALUE (p1) != TREE_VALUE (p2))
+	      {
+		tree memb;
+		for (memb = TYPE_FIELDS (TREE_VALUE (p1));
+		     memb; memb = TREE_CHAIN (memb))
+		  if (comptypes (TREE_TYPE (memb), TREE_VALUE (p2)))
+		    {
+		      TREE_VALUE (n) = TREE_VALUE (p2);
+		      if (pedantic)
+			pedwarn ("function types not truly compatible in ANSI C");
+		      goto parm_done;
+		    }
+	      }
+	    if (TREE_CODE (TREE_VALUE (p2)) == UNION_TYPE
+		&& TREE_VALUE (p2) != TREE_VALUE (p1))
+	      {
+		tree memb;
+		for (memb = TYPE_FIELDS (TREE_VALUE (p2));
+		     memb; memb = TREE_CHAIN (memb))
+		  if (comptypes (TREE_TYPE (memb), TREE_VALUE (p1)))
+		    {
+		      TREE_VALUE (n) = TREE_VALUE (p1);
+		      if (pedantic)
+			pedwarn ("function types not truly compatible in ANSI C");
+		      goto parm_done;
+		    }
+	      }
+	    TREE_VALUE (n) = common_type (TREE_VALUE (p1), TREE_VALUE (p2));
+	  parm_done: ;
+	  }
+
+	t1 = build_function_type (valtype, newargs);
+	/* ... falls through ... */
+      }
+
+    default:
+      return build_type_attribute_variant (t1, attributes);
+    }
+
+}
+
+/* Return 1 if TYPE1 and TYPE2 are compatible types for assignment
+   or various other operations.  Return 2 if they are compatible
+   but a warning may be needed if you use them together.  */
+
+int
+comptypes (type1, type2)
+     tree type1, type2;
+{
+  register tree t1 = type1;
+  register tree t2 = type2;
+  int attrval, val;
+
+  /* Suppress errors caused by previously reported errors.  */
+
+  if (t1 == t2 || TREE_CODE (t1) == ERROR_MARK || TREE_CODE (t2) == ERROR_MARK)
+    return 1;
+
+  /* Treat an enum type as the integer type of the same width and 
+     signedness.  */
+
+  if (TREE_CODE (t1) == ENUMERAL_TYPE)
+    t1 = type_for_size (TYPE_PRECISION (t1), TREE_UNSIGNED (t1));
+  if (TREE_CODE (t2) == ENUMERAL_TYPE)
+    t2 = type_for_size (TYPE_PRECISION (t2), TREE_UNSIGNED (t2));
+
+  if (t1 == t2)
+    return 1;
+
+  /* Different classes of types can't be compatible.  */
+
+  if (TREE_CODE (t1) != TREE_CODE (t2)) return 0;
+
+  /* Qualifiers must match.  */
+
+  if (TYPE_READONLY (t1) != TYPE_READONLY (t2))
+    return 0;
+  if (TYPE_VOLATILE (t1) != TYPE_VOLATILE (t2))
+    return 0;
+
+  /* Allow for two different type nodes which have essentially the same
+     definition.  Note that we already checked for equality of the type
+     type qualifiers (just above).  */
+
+  if (TYPE_MAIN_VARIANT (t1) == TYPE_MAIN_VARIANT (t2))
+    return 1;
+
+#ifndef COMP_TYPE_ATTRIBUTES
+#define COMP_TYPE_ATTRIBUTES(t1,t2)	1
+#endif
+
+  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
+  if (! (attrval = COMP_TYPE_ATTRIBUTES (t1, t2)))
+     return 0;
+
+  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
+  val = 0;
+
+  switch (TREE_CODE (t1))
+    {
+    case POINTER_TYPE:
+      val = (TREE_TYPE (t1) == TREE_TYPE (t2)
+	      ? 1 : comptypes (TREE_TYPE (t1), TREE_TYPE (t2)));
+      break;
+
+    case FUNCTION_TYPE:
+      val = function_types_compatible_p (t1, t2);
+      break;
+
+    case ARRAY_TYPE:
+      {
+	tree d1 = TYPE_DOMAIN (t1);
+	tree d2 = TYPE_DOMAIN (t2);
+	val = 1;
+
+	/* Target types must match incl. qualifiers.  */
+	if (TREE_TYPE (t1) != TREE_TYPE (t2)
+	    && 0 == (val = comptypes (TREE_TYPE (t1), TREE_TYPE (t2))))
+	  return 0;
+
+	/* Sizes must match unless one is missing or variable.  */
+	if (d1 == 0 || d2 == 0 || d1 == d2
+	    || TREE_CODE (TYPE_MIN_VALUE (d1)) != INTEGER_CST
+	    || TREE_CODE (TYPE_MIN_VALUE (d2)) != INTEGER_CST
+	    || TREE_CODE (TYPE_MAX_VALUE (d1)) != INTEGER_CST
+	    || TREE_CODE (TYPE_MAX_VALUE (d2)) != INTEGER_CST)
+	  break;
+
+	if (! ((TREE_INT_CST_LOW (TYPE_MIN_VALUE (d1))
+		  == TREE_INT_CST_LOW (TYPE_MIN_VALUE (d2)))
+		 && (TREE_INT_CST_HIGH (TYPE_MIN_VALUE (d1))
+		     == TREE_INT_CST_HIGH (TYPE_MIN_VALUE (d2)))
+		 && (TREE_INT_CST_LOW (TYPE_MAX_VALUE (d1))
+		     == TREE_INT_CST_LOW (TYPE_MAX_VALUE (d2)))
+		 && (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (d1))
+		     == TREE_INT_CST_HIGH (TYPE_MAX_VALUE (d2)))))
+	   val = 0;
+        break;
+      }
+
+    case RECORD_TYPE:
+      if (maybe_objc_comptypes (t1, t2, 0) == 1)
+	val = 1;
+      break;
+    }
+  return attrval == 2 && val == 1 ? 2 : val;
+}
+
+/* Return 1 if TTL and TTR are pointers to types that are equivalent,
+   ignoring their qualifiers.  */
+
+static int
+comp_target_types (ttl, ttr)
+     tree ttl, ttr;
+{
+  int val;
+
+  /* Give maybe_objc_comptypes a crack at letting these types through.  */
+  if (val = maybe_objc_comptypes (ttl, ttr, 1) >= 0)
+    return val;
+
+  val = comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (ttl)),
+		   TYPE_MAIN_VARIANT (TREE_TYPE (ttr)));
+
+  if (val == 2 && pedantic)
+    pedwarn ("types are not quite compatible");
+  return val;
+}
+
+/* Subroutines of `comptypes'.  */
+
+/* Return 1 if two function types F1 and F2 are compatible.
+   If either type specifies no argument types,
+   the other must specify a fixed number of self-promoting arg types.
+   Otherwise, if one type specifies only the number of arguments, 
+   the other must specify that number of self-promoting arg types.
+   Otherwise, the argument types must match.  */
+
+static int
+function_types_compatible_p (f1, f2)
+     tree f1, f2;
+{
+  tree args1, args2;
+  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
+  int val = 1;
+  int val1;
+
+  if (!(TREE_TYPE (f1) == TREE_TYPE (f2)
+	|| (val = comptypes (TREE_TYPE (f1), TREE_TYPE (f2)))))
+    return 0;
+
+  args1 = TYPE_ARG_TYPES (f1);
+  args2 = TYPE_ARG_TYPES (f2);
+
+  /* An unspecified parmlist matches any specified parmlist
+     whose argument types don't need default promotions.  */
+
+  if (args1 == 0)
+    {
+      if (!self_promoting_args_p (args2))
+	return 0;
+      /* If one of these types comes from a non-prototype fn definition,
+	 compare that with the other type's arglist.
+	 If they don't match, ask for a warning (but no error).  */
+      if (TYPE_ACTUAL_ARG_TYPES (f1)
+	  && 1 != type_lists_compatible_p (args2, TYPE_ACTUAL_ARG_TYPES (f1)))
+	val = 2;
+      return val;
+    }
+  if (args2 == 0)
+    {
+      if (!self_promoting_args_p (args1))
+	return 0;
+      if (TYPE_ACTUAL_ARG_TYPES (f2)
+	  && 1 != type_lists_compatible_p (args1, TYPE_ACTUAL_ARG_TYPES (f2)))
+	val = 2;
+      return val;
+    }
+
+  /* Both types have argument lists: compare them and propagate results.  */
+  val1 = type_lists_compatible_p (args1, args2);
+  return val1 != 1 ? val1 : val;
+}
+
+/* Check two lists of types for compatibility,
+   returning 0 for incompatible, 1 for compatible,
+   or 2 for compatible with warning.  */
+
+static int
+type_lists_compatible_p (args1, args2)
+     tree args1, args2;
+{
+  /* 1 if no need for warning yet, 2 if warning cause has been seen.  */
+  int val = 1;
+  int newval = 0;
+
+  while (1)
+    {
+      if (args1 == 0 && args2 == 0)
+	return val;
+      /* If one list is shorter than the other,
+	 they fail to match.  */
+      if (args1 == 0 || args2 == 0)
+	return 0;
+      /* A null pointer instead of a type
+	 means there is supposed to be an argument
+	 but nothing is specified about what type it has.
+	 So match anything that self-promotes.  */
+      if (TREE_VALUE (args1) == 0)
+	{
+	  if (! self_promoting_type_p (TREE_VALUE (args2)))
+	    return 0;
+	}
+      else if (TREE_VALUE (args2) == 0)
+	{
+	  if (! self_promoting_type_p (TREE_VALUE (args1)))
+	    return 0;
+	}
+      else if (! (newval = comptypes (TREE_VALUE (args1), TREE_VALUE (args2))))
+	{
+	  /* Allow  wait (union {union wait *u; int *i} *)
+	     and  wait (union wait *)  to be compatible.  */
+	  if (TREE_CODE (TREE_VALUE (args1)) == UNION_TYPE
+	      && (TYPE_NAME (TREE_VALUE (args1)) == 0
+		  || TYPE_TRANSPARENT_UNION (TREE_VALUE (args1)))
+	      && TREE_CODE (TYPE_SIZE (TREE_VALUE (args1))) == INTEGER_CST
+	      && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args1)),
+				     TYPE_SIZE (TREE_VALUE (args2))))
+	    {
+	      tree memb;
+	      for (memb = TYPE_FIELDS (TREE_VALUE (args1));
+		   memb; memb = TREE_CHAIN (memb))
+		if (comptypes (TREE_TYPE (memb), TREE_VALUE (args2)))
+		  break;
+	      if (memb == 0)
+		return 0;
+	    }
+	  else if (TREE_CODE (TREE_VALUE (args2)) == UNION_TYPE
+		   && (TYPE_NAME (TREE_VALUE (args2)) == 0
+		       || TYPE_TRANSPARENT_UNION (TREE_VALUE (args2)))
+		   && TREE_CODE (TYPE_SIZE (TREE_VALUE (args2))) == INTEGER_CST
+		   && tree_int_cst_equal (TYPE_SIZE (TREE_VALUE (args2)),
+					  TYPE_SIZE (TREE_VALUE (args1))))
+	    {
+	      tree memb;
+	      for (memb = TYPE_FIELDS (TREE_VALUE (args2));
+		   memb; memb = TREE_CHAIN (memb))
+		if (comptypes (TREE_TYPE (memb), TREE_VALUE (args1)))
+		  break;
+	      if (memb == 0)
+		return 0;
+	    }
+	  else
+	    return 0;
+	}
+
+      /* comptypes said ok, but record if it said to warn.  */
+      if (newval > val)
+	val = newval;
+
+      args1 = TREE_CHAIN (args1);
+      args2 = TREE_CHAIN (args2);
+    }
+}
+
+/* Return 1 if PARMS specifies a fixed number of parameters
+   and none of their types is affected by default promotions.  */
+
+int
+self_promoting_args_p (parms)
+     tree parms;
+{
+  register tree t;
+  for (t = parms; t; t = TREE_CHAIN (t))
+    {
+      register tree type = TREE_VALUE (t);
+
+      if (TREE_CHAIN (t) == 0 && type != void_type_node)
+	return 0;
+
+      if (type == 0)
+	return 0;
+
+      if (TYPE_MAIN_VARIANT (type) == float_type_node)
+	return 0;
+
+      if (C_PROMOTING_INTEGER_TYPE_P (type))
+	return 0;
+    }
+  return 1;
+}
+
+/* Return 1 if TYPE is not affected by default promotions.  */
+
+static int
+self_promoting_type_p (type)
+     tree type;
+{
+  if (TYPE_MAIN_VARIANT (type) == float_type_node)
+    return 0;
+
+  if (C_PROMOTING_INTEGER_TYPE_P (type))
+    return 0;
+
+  return 1;
+}
+
+/* Return an unsigned type the same as TYPE in other respects.  */
+
+tree
+unsigned_type (type)
+     tree type;
+{
+  tree type1 = TYPE_MAIN_VARIANT (type);
+  if (type1 == signed_char_type_node || type1 == char_type_node)
+    return unsigned_char_type_node;
+  if (type1 == integer_type_node)
+    return unsigned_type_node;
+  if (type1 == short_integer_type_node)
+    return short_unsigned_type_node;
+  if (type1 == long_integer_type_node)
+    return long_unsigned_type_node;
+  if (type1 == long_long_integer_type_node)
+    return long_long_unsigned_type_node;
+  if (type1 == intDI_type_node)
+    return unsigned_intDI_type_node;
+  if (type1 == intSI_type_node)
+    return unsigned_intSI_type_node;
+  if (type1 == intHI_type_node)
+    return unsigned_intHI_type_node;
+  if (type1 == intQI_type_node)
+    return unsigned_intQI_type_node;
+  return type;
+}
+
+/* Return a signed type the same as TYPE in other respects.  */
+
+tree
+signed_type (type)
+     tree type;
+{
+  tree type1 = TYPE_MAIN_VARIANT (type);
+  if (type1 == unsigned_char_type_node || type1 == char_type_node)
+    return signed_char_type_node;
+  if (type1 == unsigned_type_node)
+    return integer_type_node;
+  if (type1 == short_unsigned_type_node)
+    return short_integer_type_node;
+  if (type1 == long_unsigned_type_node)
+    return long_integer_type_node;
+  if (type1 == long_long_unsigned_type_node)
+    return long_long_integer_type_node;
+  if (type1 == unsigned_intDI_type_node)
+    return intDI_type_node;
+  if (type1 == unsigned_intSI_type_node)
+    return intSI_type_node;
+  if (type1 == unsigned_intHI_type_node)
+    return intHI_type_node;
+  if (type1 == unsigned_intQI_type_node)
+    return intQI_type_node;
+  return type;
+}
+
+/* Return a type the same as TYPE except unsigned or
+   signed according to UNSIGNEDP.  */
+
+tree
+signed_or_unsigned_type (unsignedp, type)
+     int unsignedp;
+     tree type;
+{
+  if (! INTEGRAL_TYPE_P (type))
+    return type;
+  if (TYPE_PRECISION (type) == TYPE_PRECISION (signed_char_type_node))
+    return unsignedp ? unsigned_char_type_node : signed_char_type_node;
+  if (TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)) 
+    return unsignedp ? unsigned_type_node : integer_type_node;
+  if (TYPE_PRECISION (type) == TYPE_PRECISION (short_integer_type_node)) 
+    return unsignedp ? short_unsigned_type_node : short_integer_type_node;
+  if (TYPE_PRECISION (type) == TYPE_PRECISION (long_integer_type_node)) 
+    return unsignedp ? long_unsigned_type_node : long_integer_type_node;
+  if (TYPE_PRECISION (type) == TYPE_PRECISION (long_long_integer_type_node)) 
+    return (unsignedp ? long_long_unsigned_type_node
+	    : long_long_integer_type_node);
+  return type;
+}
+
+/* Compute the value of the `sizeof' operator.  */
+
+tree
+c_sizeof (type)
+     tree type;
+{
+  enum tree_code code = TREE_CODE (type);
+  tree t;
+
+  if (code == FUNCTION_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("sizeof applied to a function type");
+      return size_int (1);
+    }
+  if (code == VOID_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("sizeof applied to a void type");
+      return size_int (1);
+    }
+  if (code == ERROR_MARK)
+    return size_int (1);
+  if (TYPE_SIZE (type) == 0)
+    {
+      error ("sizeof applied to an incomplete type");
+      return size_int (0);
+    }
+
+  /* Convert in case a char is more than one unit.  */
+  t = size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
+		  size_int (TYPE_PRECISION (char_type_node)));
+  /* size_binop does not put the constant in range, so do it now.  */
+  if (TREE_CODE (t) == INTEGER_CST && force_fit_type (t, 0))
+    TREE_CONSTANT_OVERFLOW (t) = TREE_OVERFLOW (t) = 1;
+  return t;
+}
+
+tree
+c_sizeof_nowarn (type)
+     tree type;
+{
+  enum tree_code code = TREE_CODE (type);
+  tree t;
+
+  if (code == FUNCTION_TYPE
+      || code == VOID_TYPE
+      || code == ERROR_MARK)
+    return size_int (1);
+  if (TYPE_SIZE (type) == 0)
+    return size_int (0);
+
+  /* Convert in case a char is more than one unit.  */
+  t = size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
+		  size_int (TYPE_PRECISION (char_type_node)));
+  force_fit_type (t, 0);
+  return t;
+}
+
+/* Compute the size to increment a pointer by.  */
+
+tree
+c_size_in_bytes (type)
+     tree type;
+{
+  enum tree_code code = TREE_CODE (type);
+  tree t;
+
+  if (code == FUNCTION_TYPE)
+    return size_int (1);
+  if (code == VOID_TYPE)
+    return size_int (1);
+  if (code == ERROR_MARK)
+    return size_int (1);
+  if (TYPE_SIZE (type) == 0)
+    {
+      error ("arithmetic on pointer to an incomplete type");
+      return size_int (1);
+    }
+
+  /* Convert in case a char is more than one unit.  */
+  t = size_binop (CEIL_DIV_EXPR, TYPE_SIZE (type), 
+		     size_int (BITS_PER_UNIT));
+  force_fit_type (t, 0);
+  return t;
+}
+
+/* Implement the __alignof keyword: Return the minimum required
+   alignment of TYPE, measured in bytes.  */
+
+tree
+c_alignof (type)
+     tree type;
+{
+  enum tree_code code = TREE_CODE (type);
+
+  if (code == FUNCTION_TYPE)
+    return size_int (FUNCTION_BOUNDARY / BITS_PER_UNIT);
+
+  if (code == VOID_TYPE || code == ERROR_MARK)
+    return size_int (1);
+
+  return size_int (TYPE_ALIGN (type) / BITS_PER_UNIT);
+}
+
+/* Implement the __alignof keyword: Return the minimum required
+   alignment of EXPR, measured in bytes.  For VAR_DECL's and
+   FIELD_DECL's return DECL_ALIGN (which can be set from an
+   "aligned" __attribute__ specification).  */
+
+tree
+c_alignof_expr (expr)
+     tree expr;
+{
+  if (TREE_CODE (expr) == VAR_DECL)
+    return size_int (DECL_ALIGN (expr) / BITS_PER_UNIT);
+ 
+  if (TREE_CODE (expr) == COMPONENT_REF
+      && DECL_BIT_FIELD (TREE_OPERAND (expr, 1)))
+    {
+      error ("`__alignof' applied to a bit-field");
+      return size_int (1);
+    }
+  else if (TREE_CODE (expr) == COMPONENT_REF
+      && TREE_CODE (TREE_OPERAND (expr, 1)) == FIELD_DECL)
+    return size_int (DECL_ALIGN (TREE_OPERAND (expr, 1)) / BITS_PER_UNIT);
+ 
+  if (TREE_CODE (expr) == INDIRECT_REF)
+    {
+      tree t = TREE_OPERAND (expr, 0);
+      tree best = t;
+      int bestalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
+ 
+      while (TREE_CODE (t) == NOP_EXPR
+	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (t, 0))) == POINTER_TYPE)
+	{
+	  int thisalign;
+
+	  t = TREE_OPERAND (t, 0);
+	  thisalign = TYPE_ALIGN (TREE_TYPE (TREE_TYPE (t)));
+	  if (thisalign > bestalign)
+	    best = t, bestalign = thisalign;
+	}
+      return c_alignof (TREE_TYPE (TREE_TYPE (best)));
+    }
+  else
+    return c_alignof (TREE_TYPE (expr));
+}
+/* Return either DECL or its known constant value (if it has one).  */
+
+static tree
+decl_constant_value (decl)
+     tree decl;
+{
+  if (! TREE_PUBLIC (decl)
+      /* Don't change a variable array bound or initial value to a constant
+	 in a place where a variable is invalid.  */
+      && current_function_decl != 0
+      && ! pedantic
+      && ! TREE_THIS_VOLATILE (decl)
+      && TREE_READONLY (decl) && ! ITERATOR_P (decl)
+      && DECL_INITIAL (decl) != 0
+      && TREE_CODE (DECL_INITIAL (decl)) != ERROR_MARK
+      /* This is invalid if initial value is not constant.
+	 If it has either a function call, a memory reference,
+	 or a variable, then re-evaluating it could give different results.  */
+      && TREE_CONSTANT (DECL_INITIAL (decl))
+      /* Check for cases where this is sub-optimal, even though valid.  */
+      && TREE_CODE (DECL_INITIAL (decl)) != CONSTRUCTOR
+      && DECL_MODE (decl) != BLKmode)
+    return DECL_INITIAL (decl);
+  return decl;
+}
+
+/* Perform default promotions for C data used in expressions.
+   Arrays and functions are converted to pointers;
+   enumeral types or short or char, to int.
+   In addition, manifest constants symbols are replaced by their values.  */
+
+tree
+default_conversion (exp)
+     tree exp;
+{
+  register tree type = TREE_TYPE (exp);
+  register enum tree_code code = TREE_CODE (type);
+
+  /* Constants can be used directly unless they're not loadable.  */
+  if (TREE_CODE (exp) == CONST_DECL)
+    exp = DECL_INITIAL (exp);
+
+  /* Replace a nonvolatile const static variable with its value unless
+     it is an array, in which case we must be sure that taking the
+     address of the array produces consistent results.  */
+  else if (optimize && TREE_CODE (exp) == VAR_DECL && code != ARRAY_TYPE)
+    {
+      exp = decl_constant_value (exp);
+      type = TREE_TYPE (exp);
+    }
+
+  /* Strip NON_LVALUE_EXPRs and no-op conversions, since we aren't using as
+     an lvalue.  */
+  /* Do not use STRIP_NOPS here!  It will remove conversions from pointer
+     to integer and cause infinite recursion.  */
+  while (TREE_CODE (exp) == NON_LVALUE_EXPR
+	 || (TREE_CODE (exp) == NOP_EXPR
+	     && TREE_TYPE (TREE_OPERAND (exp, 0)) == TREE_TYPE (exp)))
+    exp = TREE_OPERAND (exp, 0);
+
+  /* Normally convert enums to int,
+     but convert wide enums to something wider.  */
+  if (code == ENUMERAL_TYPE)
+    {
+      type = type_for_size (MAX (TYPE_PRECISION (type),
+				 TYPE_PRECISION (integer_type_node)),
+			    ((flag_traditional
+			      || TYPE_PRECISION (type) >= TYPE_PRECISION (integer_type_node))
+			     && TREE_UNSIGNED (type)));
+      return convert (type, exp);
+    }
+
+  if (C_PROMOTING_INTEGER_TYPE_P (type))
+    {
+      /* Traditionally, unsignedness is preserved in default promotions.
+         Also preserve unsignedness if not really getting any wider.  */
+      if (TREE_UNSIGNED (type)
+	  && (flag_traditional
+	      || TYPE_PRECISION (type) == TYPE_PRECISION (integer_type_node)))
+	return convert (unsigned_type_node, exp);
+      return convert (integer_type_node, exp);
+    }
+  if (flag_traditional && !flag_allow_single_precision
+      && TYPE_MAIN_VARIANT (type) == float_type_node)
+    return convert (double_type_node, exp);
+  if (code == VOID_TYPE)
+    {
+      error ("void value not ignored as it ought to be");
+      return error_mark_node;
+    }
+  if (code == FUNCTION_TYPE)
+    {
+      return build_unary_op (ADDR_EXPR, exp, 0);
+    }
+  if (code == ARRAY_TYPE)
+    {
+      register tree adr;
+      tree restype = TREE_TYPE (type);
+      tree ptrtype;
+      int constp = 0;
+      int volatilep = 0;
+
+      if (TREE_CODE_CLASS (TREE_CODE (exp)) == 'r'
+	  || TREE_CODE_CLASS (TREE_CODE (exp)) == 'd')
+	{
+	  constp = TREE_READONLY (exp);
+	  volatilep = TREE_THIS_VOLATILE (exp);
+	}
+
+      if (TYPE_READONLY (type) || TYPE_VOLATILE (type)
+	  || constp || volatilep)
+	restype = c_build_type_variant (restype,
+					TYPE_READONLY (type) || constp,
+					TYPE_VOLATILE (type) || volatilep);
+
+      if (TREE_CODE (exp) == INDIRECT_REF)
+	return convert (TYPE_POINTER_TO (restype),
+			TREE_OPERAND (exp, 0));
+
+      if (TREE_CODE (exp) == COMPOUND_EXPR)
+	{
+	  tree op1 = default_conversion (TREE_OPERAND (exp, 1));
+	  return build (COMPOUND_EXPR, TREE_TYPE (op1),
+			TREE_OPERAND (exp, 0), op1);
+	}
+
+      if (!lvalue_p (exp)
+	  && ! (TREE_CODE (exp) == CONSTRUCTOR && TREE_STATIC (exp)))
+	{
+	  error ("invalid use of non-lvalue array");
+	  return error_mark_node;
+	}
+
+      ptrtype = build_pointer_type (restype);
+
+      if (TREE_CODE (exp) == VAR_DECL)
+	{
+	  /* ??? This is not really quite correct
+	     in that the type of the operand of ADDR_EXPR
+	     is not the target type of the type of the ADDR_EXPR itself.
+	     Question is, can this lossage be avoided?  */
+	  adr = build1 (ADDR_EXPR, ptrtype, exp);
+	  if (mark_addressable (exp) == 0)
+	    return error_mark_node;
+	  TREE_CONSTANT (adr) = staticp (exp);
+	  TREE_SIDE_EFFECTS (adr) = 0;   /* Default would be, same as EXP.  */
+	  return adr;
+	}
+      /* This way is better for a COMPONENT_REF since it can
+	 simplify the offset for a component.  */
+      adr = build_unary_op (ADDR_EXPR, exp, 1);
+      return convert (ptrtype, adr);
+    }
+  return exp;
+}
+
+/* Look up component name in the structure type definition.
+
+   If this component name is found indirectly within an anonymous union,
+   store in *INDIRECT the component which directly contains
+   that anonymous union.  Otherwise, set *INDIRECT to 0.  */
+     
+static tree
+lookup_field (type, component, indirect)
+     tree type, component;
+     tree *indirect;
+{
+  tree field;
+
+  /* If TYPE_LANG_SPECIFIC is set, then it is a sorted array of pointers
+     to the field elements.  Use a binary search on this array to quickly
+     find the element.  Otherwise, do a linear search.  TYPE_LANG_SPECIFIC
+     will always be set for structures which have many elements.  */
+
+  if (TYPE_LANG_SPECIFIC (type))
+    {
+      int bot, top, half;
+      tree *field_array = &TYPE_LANG_SPECIFIC (type)->elts[0];
+
+      field = TYPE_FIELDS (type);
+      bot = 0;
+      top = TYPE_LANG_SPECIFIC (type)->len;
+      while (top - bot > 1)
+	{
+	  half = (top - bot + 1) >> 1;
+	  field = field_array[bot+half];
+
+	  if (DECL_NAME (field) == NULL_TREE)
+	    {
+	      /* Step through all anon unions in linear fashion.  */
+	      while (DECL_NAME (field_array[bot]) == NULL_TREE)
+		{
+		  tree anon, junk;
+
+		  field = field_array[bot++];
+		  anon = lookup_field (TREE_TYPE (field), component, &junk);
+		  if (anon != NULL_TREE)
+		    {
+		      *indirect = field;
+		      return anon;
+		    }
+		}
+
+	      /* Entire record is only anon unions.  */
+	      if (bot > top)
+		return NULL_TREE;
+
+	      /* Restart the binary search, with new lower bound.  */
+	      continue;
+	    }
+
+	  if (DECL_NAME (field) == component)
+	    break;
+	  if (DECL_NAME (field) < component)
+	    bot += half;
+	  else
+	    top = bot + half;
+	}
+
+      if (DECL_NAME (field_array[bot]) == component)
+	field = field_array[bot];
+      else if (DECL_NAME (field) != component)
+	field = 0;
+    }
+  else
+    {
+      for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
+	{
+	  if (DECL_NAME (field) == NULL_TREE)
+	    {
+	      tree junk;
+	      tree anon = lookup_field (TREE_TYPE (field), component, &junk);
+	      if (anon != NULL_TREE)
+		{
+		  *indirect = field;
+		  return anon;
+		}
+	    }
+
+	  if (DECL_NAME (field) == component)
+	    break;
+	}
+    }
+
+  *indirect = NULL_TREE;
+  return field;
+}
+
+/* Make an expression to refer to the COMPONENT field of
+   structure or union value DATUM.  COMPONENT is an IDENTIFIER_NODE.  */
+
+tree
+build_component_ref (datum, component)
+     tree datum, component;
+{
+  register tree type = TREE_TYPE (datum);
+  register enum tree_code code = TREE_CODE (type);
+  register tree field = NULL;
+  register tree ref;
+
+  /* If DATUM is a COMPOUND_EXPR or COND_EXPR, move our reference inside it
+     unless we are not to support things not strictly ANSI.  */
+  switch (TREE_CODE (datum))
+    {
+    case COMPOUND_EXPR:
+      {
+	tree value = build_component_ref (TREE_OPERAND (datum, 1), component);
+	return build (COMPOUND_EXPR, TREE_TYPE (value),
+		      TREE_OPERAND (datum, 0), value);
+      }
+    case COND_EXPR:
+      return build_conditional_expr
+	(TREE_OPERAND (datum, 0),
+	 build_component_ref (TREE_OPERAND (datum, 1), component),
+	 build_component_ref (TREE_OPERAND (datum, 2), component));
+    }
+
+  /* See if there is a field or component with name COMPONENT.  */
+
+  if (code == RECORD_TYPE || code == UNION_TYPE)
+    {
+      tree indirect = 0;
+
+      if (TYPE_SIZE (type) == 0)
+	{
+	  incomplete_type_error (NULL_TREE, type);
+	  return error_mark_node;
+	}
+
+      field = lookup_field (type, component, &indirect);
+
+      if (!field)
+	{
+	  error (code == RECORD_TYPE
+		 ? "structure has no member named `%s'"
+		 : "union has no member named `%s'",
+		 IDENTIFIER_POINTER (component));
+	  return error_mark_node;
+	}
+      if (TREE_TYPE (field) == error_mark_node)
+	return error_mark_node;
+
+      /* If FIELD was found buried within an anonymous union,
+	 make one COMPONENT_REF to get that anonymous union,
+	 then fall thru to make a second COMPONENT_REF to get FIELD.  */
+      if (indirect != 0)
+	{
+	  ref = build (COMPONENT_REF, TREE_TYPE (indirect), datum, indirect);
+	  if (TREE_READONLY (datum) || TREE_READONLY (indirect))
+	    TREE_READONLY (ref) = 1;
+	  if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (indirect))
+	    TREE_THIS_VOLATILE (ref) = 1;
+	  datum = ref;
+	}
+
+      ref = build (COMPONENT_REF, TREE_TYPE (field), datum, field);
+
+      if (TREE_READONLY (datum) || TREE_READONLY (field))
+	TREE_READONLY (ref) = 1;
+      if (TREE_THIS_VOLATILE (datum) || TREE_THIS_VOLATILE (field))
+	TREE_THIS_VOLATILE (ref) = 1;
+
+      return ref;
+    }
+  else if (code != ERROR_MARK)
+    error ("request for member `%s' in something not a structure or union",
+	    IDENTIFIER_POINTER (component));
+
+  return error_mark_node;
+}
+
+/* Given an expression PTR for a pointer, return an expression
+   for the value pointed to.
+   ERRORSTRING is the name of the operator to appear in error messages.  */
+
+tree
+build_indirect_ref (ptr, errorstring)
+     tree ptr;
+     char *errorstring;
+{
+  register tree pointer = default_conversion (ptr);
+  register tree type = TREE_TYPE (pointer);
+
+  if (TREE_CODE (type) == POINTER_TYPE)
+    {
+      if (TREE_CODE (pointer) == ADDR_EXPR
+	  && !flag_volatile
+	  && (TREE_TYPE (TREE_OPERAND (pointer, 0))
+	      == TREE_TYPE (type)))
+	return TREE_OPERAND (pointer, 0);
+      else
+	{
+	  tree t = TREE_TYPE (type);
+	  register tree ref = build1 (INDIRECT_REF,
+				      TYPE_MAIN_VARIANT (t), pointer);
+
+	  if (TYPE_SIZE (t) == 0 && TREE_CODE (t) != ARRAY_TYPE)
+	    {
+	      error ("dereferencing pointer to incomplete type");
+	      return error_mark_node;
+	    }
+	  if (TREE_CODE (t) == VOID_TYPE)
+	    warning ("dereferencing `void *' pointer");
+
+	  /* We *must* set TREE_READONLY when dereferencing a pointer to const,
+	     so that we get the proper error message if the result is used
+	     to assign to.  Also, &* is supposed to be a no-op.
+	     And ANSI C seems to specify that the type of the result
+	     should be the const type.  */
+	  /* A de-reference of a pointer to const is not a const.  It is valid
+	     to change it via some other pointer.  */
+	  TREE_READONLY (ref) = TYPE_READONLY (t);
+	  TREE_SIDE_EFFECTS (ref)
+	    = TYPE_VOLATILE (t) || TREE_SIDE_EFFECTS (pointer) || flag_volatile;
+	  TREE_THIS_VOLATILE (ref) = TYPE_VOLATILE (t);
+	  return ref;
+	}
+    }
+  else if (TREE_CODE (pointer) != ERROR_MARK)
+    error ("invalid type argument of `%s'", errorstring);
+  return error_mark_node;
+}
+
+/* This handles expressions of the form "a[i]", which denotes
+   an array reference.
+
+   This is logically equivalent in C to *(a+i), but we may do it differently.
+   If A is a variable or a member, we generate a primitive ARRAY_REF.
+   This avoids forcing the array out of registers, and can work on
+   arrays that are not lvalues (for example, members of structures returned
+   by functions).  */
+
+tree
+build_array_ref (array, index)
+     tree array, index;
+{
+  if (index == 0)
+    {
+      error ("subscript missing in array reference");
+      return error_mark_node;
+    }
+
+  if (TREE_TYPE (array) == error_mark_node
+      || TREE_TYPE (index) == error_mark_node)
+    return error_mark_node;
+
+  if (TREE_CODE (TREE_TYPE (array)) == ARRAY_TYPE
+      && TREE_CODE (array) != INDIRECT_REF)
+    {
+      tree rval, type;
+
+      /* Subscripting with type char is likely to lose
+	 on a machine where chars are signed.
+	 So warn on any machine, but optionally.
+	 Don't warn for unsigned char since that type is safe.
+	 Don't warn for signed char because anyone who uses that
+	 must have done so deliberately.  */
+      if (warn_char_subscripts
+	  && TYPE_MAIN_VARIANT (TREE_TYPE (index)) == char_type_node)
+	warning ("array subscript has type `char'");
+
+      /* Apply default promotions *after* noticing character types.  */
+      index = default_conversion (index);
+
+      /* Require integer *after* promotion, for sake of enums.  */
+      if (TREE_CODE (TREE_TYPE (index)) != INTEGER_TYPE)
+	{
+	  error ("array subscript is not an integer");
+	  return error_mark_node;
+	}
+
+      /* An array that is indexed by a non-constant
+	 cannot be stored in a register; we must be able to do
+	 address arithmetic on its address.
+	 Likewise an array of elements of variable size.  */
+      if (TREE_CODE (index) != INTEGER_CST
+	  || (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array))) != 0
+	      && TREE_CODE (TYPE_SIZE (TREE_TYPE (TREE_TYPE (array)))) != INTEGER_CST))
+	{
+	  if (mark_addressable (array) == 0)
+	    return error_mark_node;
+	}
+      /* An array that is indexed by a constant value which is not within
+	 the array bounds cannot be stored in a register either; because we
+	 would get a crash in store_bit_field/extract_bit_field when trying
+	 to access a non-existent part of the register.  */
+      if (TREE_CODE (index) == INTEGER_CST
+	  && TYPE_VALUES (TREE_TYPE (array))
+	  && ! int_fits_type_p (index, TYPE_VALUES (TREE_TYPE (array))))
+	{
+	  if (mark_addressable (array) == 0)
+	    return error_mark_node;
+	}
+
+      if (pedantic && !lvalue_p (array))
+	{
+	  if (DECL_REGISTER (array))
+	    pedwarn ("ANSI C forbids subscripting `register' array");
+	  else
+	    pedwarn ("ANSI C forbids subscripting non-lvalue array");
+	}
+
+      if (pedantic)
+	{
+	  tree foo = array;
+	  while (TREE_CODE (foo) == COMPONENT_REF)
+	    foo = TREE_OPERAND (foo, 0);
+	  if (TREE_CODE (foo) == VAR_DECL && DECL_REGISTER (foo))
+	    pedwarn ("ANSI C forbids subscripting non-lvalue array");
+	}
+
+      type = TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (array)));
+      rval = build (ARRAY_REF, type, array, index);
+      /* Array ref is const/volatile if the array elements are
+         or if the array is.  */
+      TREE_READONLY (rval)
+	|= (TYPE_READONLY (TREE_TYPE (TREE_TYPE (array)))
+	    | TREE_READONLY (array));
+      TREE_SIDE_EFFECTS (rval)
+	|= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
+	    | TREE_SIDE_EFFECTS (array));
+      TREE_THIS_VOLATILE (rval)
+	|= (TYPE_VOLATILE (TREE_TYPE (TREE_TYPE (array)))
+	    /* This was added by rms on 16 Nov 91.
+	       It fixes  vol struct foo *a;  a->elts[1] 
+	       in an inline function.
+	       Hope it doesn't break something else.  */
+	    | TREE_THIS_VOLATILE (array));
+      return require_complete_type (fold (rval));
+    }
+
+  {
+    tree ar = default_conversion (array);
+    tree ind = default_conversion (index);
+
+    /* Put the integer in IND to simplify error checking.  */
+    if (TREE_CODE (TREE_TYPE (ar)) == INTEGER_TYPE)
+      {
+	tree temp = ar;
+	ar = ind;
+	ind = temp;
+      }
+
+    if (ar == error_mark_node)
+      return ar;
+
+    if (TREE_CODE (TREE_TYPE (ar)) != POINTER_TYPE)
+      {
+	error ("subscripted value is neither array nor pointer");
+	return error_mark_node;
+      }
+    if (TREE_CODE (TREE_TYPE (ind)) != INTEGER_TYPE)
+      {
+	error ("array subscript is not an integer");
+	return error_mark_node;
+      }
+
+    return build_indirect_ref (build_binary_op (PLUS_EXPR, ar, ind, 0),
+			       "array indexing");
+  }
+}
+
+/* Build a function call to function FUNCTION with parameters PARAMS.
+   PARAMS is a list--a chain of TREE_LIST nodes--in which the
+   TREE_VALUE of each node is a parameter-expression.
+   FUNCTION's data type may be a function type or a pointer-to-function.  */
+
+tree
+build_function_call (function, params)
+     tree function, params;
+{
+  register tree fntype, fundecl = 0;
+  register tree coerced_params;
+  tree name = NULL_TREE, assembler_name = NULL_TREE;
+
+  /* Strip NON_LVALUE_EXPRs, etc., since we aren't using as an lvalue.  */
+  STRIP_TYPE_NOPS (function);
+
+  /* Convert anything with function type to a pointer-to-function.  */
+  if (TREE_CODE (function) == FUNCTION_DECL)
+    {
+      name = DECL_NAME (function);
+      assembler_name = DECL_ASSEMBLER_NAME (function);
+
+      /* Differs from default_conversion by not setting TREE_ADDRESSABLE
+	 (because calling an inline function does not mean the function
+	 needs to be separately compiled).  */
+      fntype = build_type_variant (TREE_TYPE (function),
+				   TREE_READONLY (function),
+				   TREE_THIS_VOLATILE (function));
+      fundecl = function;
+      function = build1 (ADDR_EXPR, build_pointer_type (fntype), function);
+    }
+  else
+    function = default_conversion (function);
+
+  fntype = TREE_TYPE (function);
+
+  if (TREE_CODE (fntype) == ERROR_MARK)
+    return error_mark_node;
+
+  if (!(TREE_CODE (fntype) == POINTER_TYPE
+	&& TREE_CODE (TREE_TYPE (fntype)) == FUNCTION_TYPE))
+    {
+      error ("called object is not a function");
+      return error_mark_node;
+    }
+
+  /* fntype now gets the type of function pointed to.  */
+  fntype = TREE_TYPE (fntype);
+
+  /* Convert the parameters to the types declared in the
+     function prototype, or apply default promotions.  */
+
+  coerced_params
+    = convert_arguments (TYPE_ARG_TYPES (fntype), params, name, fundecl);
+
+  /* Check for errors in format strings.  */
+
+  if (warn_format && (name || assembler_name))
+    check_function_format (name, assembler_name, coerced_params);
+
+  /* Recognize certain built-in functions so we can make tree-codes
+     other than CALL_EXPR.  We do this when it enables fold-const.c
+     to do something useful.  */
+
+  if (TREE_CODE (function) == ADDR_EXPR
+      && TREE_CODE (TREE_OPERAND (function, 0)) == FUNCTION_DECL
+      && DECL_BUILT_IN (TREE_OPERAND (function, 0)))
+    switch (DECL_FUNCTION_CODE (TREE_OPERAND (function, 0)))
+      {
+      case BUILT_IN_ABS:
+      case BUILT_IN_LABS:
+      case BUILT_IN_FABS:
+	if (coerced_params == 0)
+	  return integer_zero_node;
+	return build_unary_op (ABS_EXPR, TREE_VALUE (coerced_params), 0);
+      }
+
+  {
+    register tree result
+      = build (CALL_EXPR, TREE_TYPE (fntype),
+	       function, coerced_params, NULL_TREE);
+
+    TREE_SIDE_EFFECTS (result) = 1;
+    if (TREE_TYPE (result) == void_type_node)
+      return result;
+    return require_complete_type (result);
+  }
+}
+
+/* Convert the argument expressions in the list VALUES
+   to the types in the list TYPELIST.  The result is a list of converted
+   argument expressions.
+
+   If TYPELIST is exhausted, or when an element has NULL as its type,
+   perform the default conversions.
+
+   PARMLIST is the chain of parm decls for the function being called.
+   It may be 0, if that info is not available.
+   It is used only for generating error messages.
+
+   NAME is an IDENTIFIER_NODE or 0.  It is used only for error messages.
+
+   This is also where warnings about wrong number of args are generated.
+
+   Both VALUES and the returned value are chains of TREE_LIST nodes
+   with the elements of the list in the TREE_VALUE slots of those nodes.  */
+
+static tree
+convert_arguments (typelist, values, name, fundecl)
+     tree typelist, values, name, fundecl;
+{
+  register tree typetail, valtail;
+  register tree result = NULL;
+  int parmnum;
+
+  /* Scan the given expressions and types, producing individual
+     converted arguments and pushing them on RESULT in reverse order.  */
+
+  for (valtail = values, typetail = typelist, parmnum = 0;
+       valtail;
+       valtail = TREE_CHAIN (valtail), parmnum++)
+    {
+      register tree type = typetail ? TREE_VALUE (typetail) : 0;
+      register tree val = TREE_VALUE (valtail);
+
+      if (type == void_type_node)
+	{
+	  if (name)
+	    error ("too many arguments to function `%s'",
+		   IDENTIFIER_POINTER (name));
+	  else
+	    error ("too many arguments to function");
+	  break;
+	}
+
+      /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+      /* Do not use STRIP_NOPS here!  We do not want an enumerator with value 0
+	 to convert automatically to a pointer.  */
+      if (TREE_CODE (val) == NON_LVALUE_EXPR)
+	val = TREE_OPERAND (val, 0);
+
+      if (TREE_CODE (TREE_TYPE (val)) == ARRAY_TYPE
+	  || TREE_CODE (TREE_TYPE (val)) == FUNCTION_TYPE)
+	val = default_conversion (val);
+
+      val = require_complete_type (val);
+
+      if (type != 0)
+	{
+	  /* Formal parm type is specified by a function prototype.  */
+	  tree parmval;
+
+	  if (TYPE_SIZE (type) == 0)
+	    {
+	      error ("type of formal parameter %d is incomplete", parmnum + 1);
+	      parmval = val;
+	    }
+	  else
+	    {
+	      /* Optionally warn about conversions that
+		 differ from the default conversions.  */
+	      if (warn_conversion)
+		{
+		  int formal_prec = TYPE_PRECISION (type);
+
+		  if (INTEGRAL_TYPE_P (type)
+		      && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
+		    warn_for_assignment ("%s as integer rather than floating due to prototype", (char *) 0, name, parmnum + 1);
+		  else if (TREE_CODE (type) == COMPLEX_TYPE
+			   && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
+		    warn_for_assignment ("%s as complex rather than floating due to prototype", (char *) 0, name, parmnum + 1);
+		  else if (TREE_CODE (type) == REAL_TYPE
+			   && INTEGRAL_TYPE_P (TREE_TYPE (val)))
+		    warn_for_assignment ("%s as floating rather than integer due to prototype", (char *) 0, name, parmnum + 1);
+		  else if (TREE_CODE (type) == REAL_TYPE
+			   && TREE_CODE (TREE_TYPE (val)) == COMPLEX_TYPE)
+		    warn_for_assignment ("%s as floating rather than complex due to prototype", (char *) 0, name, parmnum + 1);
+		  /* ??? At some point, messages should be written about
+		     conversions between complex types, but that's too messy
+		     to do now.  */
+		  else if (TREE_CODE (type) == REAL_TYPE
+			   && TREE_CODE (TREE_TYPE (val)) == REAL_TYPE)
+		    {
+		      /* Warn if any argument is passed as `float',
+			 since without a prototype it would be `double'.  */
+		      if (formal_prec == TYPE_PRECISION (float_type_node))
+			warn_for_assignment ("%s as `float' rather than `double' due to prototype", (char *) 0, name, parmnum + 1);
+		    }
+		  /* Detect integer changing in width or signedness.  */
+		  else if (INTEGRAL_TYPE_P (type)
+			   && INTEGRAL_TYPE_P (TREE_TYPE (val)))
+		    {
+		      tree would_have_been = default_conversion (val);
+		      tree type1 = TREE_TYPE (would_have_been);
+
+		      if (TREE_CODE (type) == ENUMERAL_TYPE
+			  && type == TREE_TYPE (val))
+			/* No warning if function asks for enum
+			   and the actual arg is that enum type.  */
+			;
+		      else if (formal_prec != TYPE_PRECISION (type1))
+			warn_for_assignment ("%s with different width due to prototype", (char *) 0, name, parmnum + 1);
+		      else if (TREE_UNSIGNED (type) == TREE_UNSIGNED (type1))
+			;
+		      /* Don't complain if the formal parameter type
+			 is an enum, because we can't tell now whether
+			 the value was an enum--even the same enum.  */
+		      else if (TREE_CODE (type) == ENUMERAL_TYPE)
+			;
+		      else if (TREE_CODE (val) == INTEGER_CST
+			       && int_fits_type_p (val, type))
+			/* Change in signedness doesn't matter
+			   if a constant value is unaffected.  */
+			;
+		      /* Likewise for a constant in a NOP_EXPR.  */
+		      else if (TREE_CODE (val) == NOP_EXPR
+			       && TREE_CODE (TREE_OPERAND (val, 0)) == INTEGER_CST
+			       && int_fits_type_p (TREE_OPERAND (val, 0), type))
+			;
+#if 0 /* We never get such tree structure here.  */
+		      else if (TREE_CODE (TREE_TYPE (val)) == ENUMERAL_TYPE
+			       && int_fits_type_p (TYPE_MIN_VALUE (TREE_TYPE (val)), type)
+			       && int_fits_type_p (TYPE_MAX_VALUE (TREE_TYPE (val)), type))
+			/* Change in signedness doesn't matter
+			   if an enum value is unaffected.  */
+			;
+#endif
+		      /* If the value is extended from a narrower
+			 unsigned type, it doesn't matter whether we
+			 pass it as signed or unsigned; the value
+			 certainly is the same either way.  */
+		      else if (TYPE_PRECISION (TREE_TYPE (val)) < TYPE_PRECISION (type)
+			       && TREE_UNSIGNED (TREE_TYPE (val)))
+			;
+		      else if (TREE_UNSIGNED (type))
+			warn_for_assignment ("%s as unsigned due to prototype", (char *) 0, name, parmnum + 1);
+		      else
+			warn_for_assignment ("%s as signed due to prototype", (char *) 0, name, parmnum + 1);
+		    }
+		}
+
+	      parmval = convert_for_assignment (type, val, 
+					        (char *)0, /* arg passing  */
+						fundecl, name, parmnum + 1);
+	      
+#ifdef PROMOTE_PROTOTYPES
+	      if ((TREE_CODE (type) == INTEGER_TYPE
+		   || TREE_CODE (type) == ENUMERAL_TYPE)
+		  && (TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node)))
+		parmval = default_conversion (parmval);
+#endif
+	    }
+	  result = tree_cons (NULL_TREE, parmval, result);
+	}
+      else if (TREE_CODE (TREE_TYPE (val)) == REAL_TYPE
+               && (TYPE_PRECISION (TREE_TYPE (val))
+	           < TYPE_PRECISION (double_type_node)))
+	/* Convert `float' to `double'.  */
+	result = tree_cons (NULL_TREE, convert (double_type_node, val), result);
+      else
+	/* Convert `short' and `char' to full-size `int'.  */
+	result = tree_cons (NULL_TREE, default_conversion (val), result);
+
+      if (typetail)
+	typetail = TREE_CHAIN (typetail);
+    }
+
+  if (typetail != 0 && TREE_VALUE (typetail) != void_type_node)
+    {
+      if (name)
+	error ("too few arguments to function `%s'",
+	       IDENTIFIER_POINTER (name));
+      else
+	error ("too few arguments to function");
+    }
+
+  return nreverse (result);
+}
+
+/* This is the entry point used by the parser
+   for binary operators in the input.
+   In addition to constructing the expression,
+   we check for operands that were written with other binary operators
+   in a way that is likely to confuse the user.  */
+
+tree
+parser_build_binary_op (code, arg1, arg2)
+     enum tree_code code;
+     tree arg1, arg2;
+{
+  tree result = build_binary_op (code, arg1, arg2, 1);
+
+  char class;
+  char class1 = TREE_CODE_CLASS (TREE_CODE (arg1));
+  char class2 = TREE_CODE_CLASS (TREE_CODE (arg2));
+  enum tree_code code1 = ERROR_MARK;
+  enum tree_code code2 = ERROR_MARK;
+
+  if (class1 == 'e' || class1 == '1'
+      || class1 == '2' || class1 == '<')
+    code1 = C_EXP_ORIGINAL_CODE (arg1);
+  if (class2 == 'e' || class2 == '1'
+      || class2 == '2' || class2 == '<')
+    code2 = C_EXP_ORIGINAL_CODE (arg2);
+
+  /* Check for cases such as x+y<<z which users are likely
+     to misinterpret.  If parens are used, C_EXP_ORIGINAL_CODE
+     is cleared to prevent these warnings.  */
+  if (warn_parentheses)
+    {
+      if (code == LSHIFT_EXPR || code == RSHIFT_EXPR)
+	{
+	  if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
+	      || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
+	    warning ("suggest parentheses around + or - inside shift");
+	}
+
+      if (code == TRUTH_ORIF_EXPR)
+	{
+	  if (code1 == TRUTH_ANDIF_EXPR
+	      || code2 == TRUTH_ANDIF_EXPR)
+	    warning ("suggest parentheses around && within ||");
+	}
+
+      if (code == BIT_IOR_EXPR)
+	{
+	  if (code1 == BIT_AND_EXPR || code1 == BIT_XOR_EXPR
+	      || code1 == PLUS_EXPR || code1 == MINUS_EXPR
+	      || code2 == BIT_AND_EXPR || code2 == BIT_XOR_EXPR
+	      || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
+	    warning ("suggest parentheses around arithmetic in operand of |");
+	  /* Check cases like x|y==z */
+	  if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
+	    warning ("suggest parentheses around comparison in operand of |");
+	}
+
+      if (code == BIT_XOR_EXPR)
+	{
+	  if (code1 == BIT_AND_EXPR
+	      || code1 == PLUS_EXPR || code1 == MINUS_EXPR
+	      || code2 == BIT_AND_EXPR
+	      || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
+	    warning ("suggest parentheses around arithmetic in operand of ^");
+	  /* Check cases like x^y==z */
+	  if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
+	    warning ("suggest parentheses around comparison in operand of ^");
+	}
+
+      if (code == BIT_AND_EXPR)
+	{
+	  if (code1 == PLUS_EXPR || code1 == MINUS_EXPR
+	      || code2 == PLUS_EXPR || code2 == MINUS_EXPR)
+	    warning ("suggest parentheses around + or - in operand of &");
+	  /* Check cases like x&y==z */
+	  if (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<')
+	    warning ("suggest parentheses around comparison in operand of &");
+	}
+    }
+
+  /* Similarly, check for cases like 1<=i<=10 that are probably errors.  */
+  if (TREE_CODE_CLASS (code) == '<' && extra_warnings
+      && (TREE_CODE_CLASS (code1) == '<' || TREE_CODE_CLASS (code2) == '<'))
+    warning ("comparisons like X<=Y<=Z do not have their mathematical meaning");
+
+  unsigned_conversion_warning (result, arg1);
+  unsigned_conversion_warning (result, arg2);
+  overflow_warning (result);
+
+  class = TREE_CODE_CLASS (TREE_CODE (result));
+
+  /* Record the code that was specified in the source,
+     for the sake of warnings about confusing nesting.  */
+  if (class == 'e' || class == '1'
+      || class == '2' || class == '<')
+    C_SET_EXP_ORIGINAL_CODE (result, code);
+  else
+    {
+      int flag = TREE_CONSTANT (result);
+      /* We used to use NOP_EXPR rather than NON_LVALUE_EXPR
+	 so that convert_for_assignment wouldn't strip it.
+	 That way, we got warnings for things like p = (1 - 1).
+	 But it turns out we should not get those warnings.  */
+      result = build1 (NON_LVALUE_EXPR, TREE_TYPE (result), result);
+      C_SET_EXP_ORIGINAL_CODE (result, code);
+      TREE_CONSTANT (result) = flag;
+    }
+
+  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 (code, orig_op0, orig_op1, convert_p)
+     enum tree_code code;
+     tree orig_op0, orig_op1;
+     int convert_p;
+{
+  tree type0, type1;
+  register 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.  */
+  register 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.  */
+  register 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))
+	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:
+      if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE
+	   || code0 == COMPLEX_TYPE)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
+	      || code1 == COMPLEX_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
+			     && (TREE_INT_CST_LOW (op1) != -1
+				 || TREE_INT_CST_HIGH (op1) != -1)));
+	    }
+	  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;
+      /* If one operand is a constant, and the other is a short type
+	 that has been converted to an int,
+	 really do the work in the short type and then convert the
+	 result to int.  If we are lucky, the constant will be 0 or 1
+	 in the short type, making the entire operation go away.  */
+      if (TREE_CODE (op0) == INTEGER_CST
+	  && TREE_CODE (op1) == NOP_EXPR
+	  && TYPE_PRECISION (type1) > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op1, 0)))
+	  && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op1, 0))))
+	{
+	  final_type = result_type;
+	  op1 = TREE_OPERAND (op1, 0);
+	  result_type = TREE_TYPE (op1);
+	}
+      if (TREE_CODE (op1) == INTEGER_CST
+	  && TREE_CODE (op0) == NOP_EXPR
+	  && TYPE_PRECISION (type0) > TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op0, 0)))
+	  && TREE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op0, 0))))
+	{
+	  final_type = result_type;
+	  op0 = TREE_OPERAND (op0, 0);
+	  result_type = TREE_TYPE (op0);
+	}
+      break;
+
+    case TRUNC_MOD_EXPR:
+    case FLOOR_MOD_EXPR:
+      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
+			 && (TREE_INT_CST_LOW (op1) != -1
+			     || TREE_INT_CST_HIGH (op1) != -1)));
+	  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 = truthvalue_conversion (op0);
+	  op1 = 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)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("right shift count is negative");
+	      else
+		{
+		  if (TREE_INT_CST_LOW (op1) | TREE_INT_CST_HIGH (op1))
+		    short_shift = 1;
+		  if (TREE_INT_CST_HIGH (op1) != 0
+		      || ((unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (op1)
+			  >= TYPE_PRECISION (type0)))
+		    warning ("right shift count >= width of type");
+		}
+	    }
+	  /* Use the type of the value to be shifted.
+	     This is what most traditional C compilers do.  */
+	  result_type = type0;
+	  /* Unless traditional, convert the shift-count to an integer,
+	     regardless of size of value being shifted.  */
+	  if (! flag_traditional)
+	    {
+	      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)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("left shift count is negative");
+	      else if (TREE_INT_CST_HIGH (op1) != 0
+		       || ((unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (op1)
+			   >= TYPE_PRECISION (type0)))
+		warning ("left shift count >= width of type");
+	    }
+	  /* Use the type of the value to be shifted.
+	     This is what most traditional C compilers do.  */
+	  result_type = type0;
+	  /* Unless traditional, convert the shift-count to an integer,
+	     regardless of size of value being shifted.  */
+	  if (! flag_traditional)
+	    {
+	      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)
+	    {
+	      if (tree_int_cst_sgn (op1) < 0)
+		warning ("shift count is negative");
+	      else if (TREE_INT_CST_HIGH (op1) != 0
+		       || ((unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (op1)
+			   >= TYPE_PRECISION (type0)))
+		warning ("shift count >= width of type");
+	    }
+	  /* Use the type of the value to be shifted.
+	     This is what most traditional C compilers do.  */
+	  result_type = type0;
+	  /* Unless traditional, convert the shift-count to an integer,
+	     regardless of size of value being shifted.  */
+	  if (! flag_traditional)
+	    {
+	      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:
+      /* 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)
+	  && (code1 == INTEGER_TYPE || code1 == REAL_TYPE
+	      || code1 == COMPLEX_TYPE))
+	short_compare = 1;
+      else if (code0 == POINTER_TYPE && code1 == POINTER_TYPE)
+	{
+	  register tree tt0 = TREE_TYPE (type0);
+	  register 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))
+	    result_type = common_type (type0, type1);
+	  else if (TYPE_MAIN_VARIANT (tt0) == void_type_node)
+	    {
+	      /* 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 ("ANSI C forbids comparison of `void *' with function pointer");
+	    }
+	  else if (TYPE_MAIN_VARIANT (tt1) == void_type_node)
+	    {
+	      if (pedantic && (!integer_zerop (op1) || op1 != orig_op1)
+		  && TREE_CODE (tt0) == FUNCTION_TYPE)
+		pedwarn ("ANSI 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;
+	  if (! flag_traditional)
+	    pedwarn ("comparison between pointer and integer");
+	}
+      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+	{
+	  result_type = type1;
+	  if (! flag_traditional)
+	    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))
+	    {
+	      result_type = common_type (type0, type1);
+	      if (pedantic 
+		  && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
+		pedwarn ("ANSI 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))
+	    {
+	      result_type = common_type (type0, type1);
+	      if ((TYPE_SIZE (TREE_TYPE (type0)) != 0)
+		  != (TYPE_SIZE (TREE_TYPE (type1)) != 0))
+		pedwarn ("comparison of complete and incomplete pointers");
+	      else if (pedantic 
+		       && TREE_CODE (TREE_TYPE (type0)) == FUNCTION_TYPE)
+		pedwarn ("ANSI 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;
+	  if (! flag_traditional)
+	    pedwarn ("comparison between pointer and integer");
+	}
+      else if (code0 == INTEGER_TYPE && code1 == POINTER_TYPE)
+	{
+	  result_type = type1;
+	  if (! flag_traditional)
+	    pedwarn ("comparison between pointer and integer");
+	}
+      break;
+    }
+
+  if ((code0 == INTEGER_TYPE || code0 == REAL_TYPE || code0 == COMPLEX_TYPE)
+      &&
+      (code1 == INTEGER_TYPE || code1 == REAL_TYPE || code1 == COMPLEX_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
+	      = 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 = 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 = 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.  */
+	      && TREE_INT_CST_HIGH (op1) == 0
+	      && TYPE_PRECISION (TREE_TYPE (arg0)) > TREE_INT_CST_LOW (op1)
+	      /* If arg is sign-extended and then unsigned-shifted,
+		 we can simulate this with a signed shift in arg's type
+		 only if the extended result is at least twice as wide
+		 as the arg.  Otherwise, the shift could use up all the
+		 ones made by sign-extension and bring in zeros.
+		 We can't optimize that case at all, but in most machines
+		 it never happens because available widths are 2**N.  */
+	      && (!TREE_UNSIGNED (final_type)
+		  || unsigned_arg
+		  || 2 * TYPE_PRECISION (TREE_TYPE (arg0)) <= TYPE_PRECISION (result_type)))
+	    {
+	      /* Do an unsigned shift if the operand was zero-extended.  */
+	      result_type
+		= 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 (extra_warnings)
+	    {
+	      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);
+
+	      /* Avoid spurious warnings for comparison with enumerators.  */
+ 
+	      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 unsigned.  */
+              else if (op0_signed == op1_signed)
+                /* OK */;
+	      /* Do not warn if the signed quantity is an unsuffixed
+		 integer literal (or some static constant expression
+		 involving such literals) and it is non-negative.  */
+	      else if ((op0_signed && TREE_CODE (xop0) == INTEGER_CST
+			&& tree_int_cst_sgn (xop0) >= 0)
+		       || (op1_signed && TREE_CODE (xop1) == INTEGER_CST
+			   && tree_int_cst_sgn (xop1) >= 0))
+		/* OK */;
+	      /* Do not warn if the comparison is an equality operation,
+                 the unsigned quantity is an integral constant and it does
+                 not use the most significant bit of result_type.  */
+	      else if ((resultcode == EQ_EXPR || resultcode == NE_EXPR)
+		       && ((op0_signed && TREE_CODE (xop1) == INTEGER_CST
+			    && int_fits_type_p (xop1, signed_type (result_type))
+			   || (op1_signed && TREE_CODE (xop0) == INTEGER_CST
+			       && int_fits_type_p (xop0, 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 (TREE_CODE (primop0) == INTEGER_CST
+		      || TREE_CODE (primop1) == INTEGER_CST)
+		    {
+		      tree primop;
+		      long constant, mask;
+		      int unsignedp, bits;
+
+		      if (TREE_CODE (primop0) == INTEGER_CST)
+			{
+			  primop = primop1;
+			  unsignedp = unsignedp1;
+			  constant = TREE_INT_CST_LOW (primop0);
+			}
+		      else
+			{
+			  primop = primop0;
+			  unsignedp = unsignedp0;
+			  constant = TREE_INT_CST_LOW (primop1);
+			}
+
+		      bits = TYPE_PRECISION (TREE_TYPE (primop));
+		      if (bits < TYPE_PRECISION (result_type)
+			  && bits < HOST_BITS_PER_LONG && unsignedp)
+			{
+			  mask = (~0L) << 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;
+
+  {
+    register tree result = build (resultcode, build_type, op0, op1);
+    register 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 a tree for the sum or difference (RESULTCODE says which)
+   of pointer PTROP and integer INTOP.  */
+
+static tree
+pointer_int_sum (resultcode, ptrop, intop)
+     enum tree_code resultcode;
+     register tree ptrop, intop;
+{
+  tree size_exp;
+
+  register tree result;
+  register tree folded;
+
+  /* The result is a pointer of the same type that is being added.  */
+
+  register tree result_type = TREE_TYPE (ptrop);
+
+  if (TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer of type `void *' used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else if (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE)
+    {
+      if (pedantic || warn_pointer_arith)
+	pedwarn ("pointer to a function used in arithmetic");
+      size_exp = integer_one_node;
+    }
+  else
+    size_exp = c_size_in_bytes (TREE_TYPE (result_type));
+
+  /* If what we are about to multiply by the size of the elements
+     contains a constant term, apply distributive law
+     and multiply that constant term separately.
+     This helps produce common subexpressions.  */
+
+  if ((TREE_CODE (intop) == PLUS_EXPR || TREE_CODE (intop) == MINUS_EXPR)
+      && ! TREE_CONSTANT (intop)
+      && TREE_CONSTANT (TREE_OPERAND (intop, 1))
+      && TREE_CONSTANT (size_exp)
+      /* If the constant comes from pointer subtraction,
+	 skip this optimization--it would cause an error.  */
+      && TREE_CODE (TREE_TYPE (TREE_OPERAND (intop, 0))) == INTEGER_TYPE
+      /* If the constant is unsigned, and smaller than the pointer size,
+	 then we must skip this optimization.  This is because it could cause
+	 an overflow error if the constant is negative but INTOP is not.  */
+      && (! TREE_UNSIGNED (TREE_TYPE (intop))
+	  || (TYPE_PRECISION (TREE_TYPE (intop))
+	      == TYPE_PRECISION (TREE_TYPE (ptrop)))))
+    {
+      enum tree_code subcode = resultcode;
+      tree int_type = TREE_TYPE (intop);
+      if (TREE_CODE (intop) == MINUS_EXPR)
+	subcode = (subcode == PLUS_EXPR ? MINUS_EXPR : PLUS_EXPR);
+      /* Convert both subexpression types to the type of intop,
+	 because weird cases involving pointer arithmetic
+	 can result in a sum or difference with different type args.  */
+      ptrop = build_binary_op (subcode, ptrop,
+			       convert (int_type, TREE_OPERAND (intop, 1)), 1);
+      intop = convert (int_type, TREE_OPERAND (intop, 0));
+    }
+
+  /* Convert the integer argument to a type the same size as a pointer
+     so the multiply won't overflow spuriously.  */
+
+  if (TYPE_PRECISION (TREE_TYPE (intop)) != POINTER_SIZE)
+    intop = convert (type_for_size (POINTER_SIZE, 0), intop);
+
+  /* Replace the integer argument with a suitable product by the object size.
+     Do this multiplication as signed, then convert to the appropriate
+     pointer type (actually unsigned integral).  */
+
+  intop = convert (result_type,
+		   build_binary_op (MULT_EXPR, intop,
+				    convert (TREE_TYPE (intop), size_exp), 1));
+
+  /* Create the sum or difference.  */
+
+  result = build (resultcode, result_type, ptrop, intop);
+
+  folded = fold (result);
+  if (folded == result)
+    TREE_CONSTANT (folded) = TREE_CONSTANT (ptrop) & TREE_CONSTANT (intop);
+  return folded;
+}
+
+/* Return a tree for the difference of pointers OP0 and OP1.
+   The resulting tree has type int.  */
+
+static tree
+pointer_diff (op0, op1)
+     register tree op0, op1;
+{
+  register tree result, folded;
+  tree restype = ptrdiff_type_node;
+
+  tree target_type = TREE_TYPE (TREE_TYPE (op0));
+
+  if (pedantic || warn_pointer_arith)
+    {
+      if (TREE_CODE (target_type) == VOID_TYPE)
+	pedwarn ("pointer of type `void *' used in subtraction");
+      if (TREE_CODE (target_type) == FUNCTION_TYPE)
+	pedwarn ("pointer to a function used in subtraction");
+    }
+
+  /* First do the subtraction as integers;
+     then drop through to build the divide operator.  */
+
+  op0 = build_binary_op (MINUS_EXPR, convert (restype, op0),
+			 convert (restype, op1), 1);
+  /* This generates an error if op1 is pointer to incomplete type.  */
+  if (TYPE_SIZE (TREE_TYPE (TREE_TYPE (op1))) == 0)
+    error ("arithmetic on pointer to an incomplete type");
+
+  /* This generates an error if op0 is pointer to incomplete type.  */
+  op1 = c_size_in_bytes (target_type);
+
+  /* Divide by the size, in easiest possible way.  */
+
+  result = build (EXACT_DIV_EXPR, restype, op0, convert (restype, op1));
+
+  folded = fold (result);
+  if (folded == result)
+    TREE_CONSTANT (folded) = TREE_CONSTANT (op0) & TREE_CONSTANT (op1);
+  return folded;
+}
+
+/* Construct and perhaps optimize a tree representation
+   for a unary operation.  CODE, a tree_code, specifies the operation
+   and XARG is the operand.  NOCONVERT nonzero suppresses
+   the default promotions (such as from short to int).  */
+
+tree
+build_unary_op (code, xarg, noconvert)
+     enum tree_code code;
+     tree xarg;
+     int noconvert;
+{
+  /* No default_conversion here.  It causes trouble for ADDR_EXPR.  */
+  register tree arg = xarg;
+  register tree argtype = 0;
+  register enum tree_code typecode = TREE_CODE (TREE_TYPE (arg));
+  char *errstring = NULL;
+  tree val;
+
+  if (typecode == ERROR_MARK)
+    return error_mark_node;
+  if (typecode == ENUMERAL_TYPE)
+    typecode = INTEGER_TYPE;
+
+  switch (code)
+    {
+    case CONVERT_EXPR:
+      /* This is used for unary plus, because a CONVERT_EXPR
+	 is enough to prevent anybody from looking inside for
+	 associativity, but won't generate any code.  */
+      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
+	    || typecode == COMPLEX_TYPE))
+        errstring = "wrong type argument to unary plus";
+      else if (!noconvert)
+	arg = default_conversion (arg);
+      break;
+
+    case NEGATE_EXPR:
+      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
+	    || typecode == COMPLEX_TYPE))
+        errstring = "wrong type argument to unary minus";
+      else if (!noconvert)
+	arg = default_conversion (arg);
+      break;
+
+    case BIT_NOT_EXPR:
+      if (typecode == COMPLEX_TYPE)
+	{
+	  code = CONJ_EXPR;
+	  if (!noconvert)
+	    arg = default_conversion (arg);
+	}
+      else if (typecode != INTEGER_TYPE)
+        errstring = "wrong type argument to bit-complement";
+      else if (!noconvert)
+	arg = default_conversion (arg);
+      break;
+
+    case ABS_EXPR:
+      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
+	    || typecode == COMPLEX_TYPE))
+        errstring = "wrong type argument to abs";
+      else if (!noconvert)
+	arg = default_conversion (arg);
+      break;
+
+    case CONJ_EXPR:
+      /* Conjugating a real value is a no-op, but allow it anyway.  */
+      if (!(typecode == INTEGER_TYPE || typecode == REAL_TYPE
+	    || typecode == COMPLEX_TYPE))
+	errstring = "wrong type argument to conjugation";
+      else if (!noconvert)
+	arg = default_conversion (arg);
+      break;
+
+    case TRUTH_NOT_EXPR:
+      if (typecode != INTEGER_TYPE
+	  && typecode != REAL_TYPE && typecode != POINTER_TYPE
+	  && typecode != COMPLEX_TYPE
+	  /* These will convert to a pointer.  */
+	  && typecode != ARRAY_TYPE && typecode != FUNCTION_TYPE)
+	{
+	  errstring = "wrong type argument to unary exclamation mark";
+	  break;
+	}
+      arg = truthvalue_conversion (arg);
+      return invert_truthvalue (arg);
+
+    case NOP_EXPR:
+      break;
+
+    case REALPART_EXPR:
+      if (TREE_CODE (arg) == COMPLEX_CST)
+	return TREE_REALPART (arg);
+      else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
+	return fold (build1 (REALPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
+      else
+	return arg;
+
+    case IMAGPART_EXPR:
+      if (TREE_CODE (arg) == COMPLEX_CST)
+	return TREE_IMAGPART (arg);
+      else if (TREE_CODE (TREE_TYPE (arg)) == COMPLEX_TYPE)
+	return fold (build1 (IMAGPART_EXPR, TREE_TYPE (TREE_TYPE (arg)), arg));
+      else
+	return convert (TREE_TYPE (arg), integer_zero_node);
+      
+    case PREINCREMENT_EXPR:
+    case POSTINCREMENT_EXPR:
+    case PREDECREMENT_EXPR:
+    case POSTDECREMENT_EXPR:
+      /* Handle complex lvalues (when permitted)
+	 by reduction to simpler cases.  */
+
+      val = unary_complex_lvalue (code, arg);
+      if (val != 0)
+	return val;
+
+      /* Increment or decrement the real part of the value,
+	 and don't change the imaginary part.  */
+      if (typecode == COMPLEX_TYPE)
+	{
+	  tree real, imag;
+
+	  arg = stabilize_reference (arg);
+	  real = build_unary_op (REALPART_EXPR, arg, 1);
+	  imag = build_unary_op (IMAGPART_EXPR, arg, 1);
+	  return build (COMPLEX_EXPR, TREE_TYPE (arg),
+			build_unary_op (code, real, 1), imag);
+	}
+
+      /* Report invalid types.  */
+
+      if (typecode != POINTER_TYPE
+	  && typecode != INTEGER_TYPE && typecode != REAL_TYPE)
+	{
+	  if (code == PREINCREMENT_EXPR || code == POSTINCREMENT_EXPR)
+	    errstring ="wrong type argument to increment";
+	  else
+	    errstring ="wrong type argument to decrement";
+	  break;
+	}
+
+      {
+	register tree inc;
+	tree result_type = TREE_TYPE (arg);
+
+	arg = get_unwidened (arg, 0);
+	argtype = TREE_TYPE (arg);
+
+	/* Compute the increment.  */
+
+	if (typecode == POINTER_TYPE)
+	  {
+	    /* If pointer target is an undefined struct,
+	       we just cannot know how to do the arithmetic.  */
+	    if (TYPE_SIZE (TREE_TYPE (result_type)) == 0)
+	      error ("%s of pointer to unknown structure",
+		       ((code == PREINCREMENT_EXPR
+			 || code == POSTINCREMENT_EXPR)
+			? "increment" : "decrement"));
+	    else if ((pedantic || warn_pointer_arith)
+		     && (TREE_CODE (TREE_TYPE (result_type)) == FUNCTION_TYPE
+			 || TREE_CODE (TREE_TYPE (result_type)) == VOID_TYPE))
+	      pedwarn ("wrong type argument to %s",
+		       ((code == PREINCREMENT_EXPR
+			 || code == POSTINCREMENT_EXPR)
+			? "increment" : "decrement"));
+	    inc = c_size_in_bytes (TREE_TYPE (result_type));
+	  }
+	else
+	  inc = integer_one_node;
+
+	inc = convert (argtype, inc);
+
+	/* Handle incrementing a cast-expression.  */
+
+	while (1)
+	  switch (TREE_CODE (arg))
+	    {
+	    case NOP_EXPR:
+	    case CONVERT_EXPR:
+	    case FLOAT_EXPR:
+	    case FIX_TRUNC_EXPR:
+	    case FIX_FLOOR_EXPR:
+	    case FIX_ROUND_EXPR:
+	    case FIX_CEIL_EXPR:
+	      pedantic_lvalue_warning (CONVERT_EXPR);
+	      /* If the real type has the same machine representation
+		 as the type it is cast to, we can make better output
+		 by adding directly to the inside of the cast.  */
+	      if ((TREE_CODE (TREE_TYPE (arg))
+		   == TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 0))))
+		  && (TYPE_MODE (TREE_TYPE (arg))
+		      == TYPE_MODE (TREE_TYPE (TREE_OPERAND (arg, 0)))))
+		arg = TREE_OPERAND (arg, 0);
+	      else
+		{
+		  tree incremented, modify, value;
+		  arg = stabilize_reference (arg);
+		  if (code == PREINCREMENT_EXPR || code == PREDECREMENT_EXPR)
+		    value = arg;
+		  else
+		    value = save_expr (arg);
+		  incremented = build (((code == PREINCREMENT_EXPR
+					 || code == POSTINCREMENT_EXPR)
+					? PLUS_EXPR : MINUS_EXPR),
+				       argtype, value, inc);
+		  TREE_SIDE_EFFECTS (incremented) = 1;
+		  modify = build_modify_expr (arg, NOP_EXPR, incremented);
+		  value = build (COMPOUND_EXPR, TREE_TYPE (arg), modify, value);
+		  TREE_USED (value) = 1;
+		  return value;
+		}
+	      break;
+
+	    default:
+	      goto give_up;
+	    }
+      give_up:
+
+	/* Complain about anything else that is not a true lvalue.  */
+	if (!lvalue_or_else (arg, ((code == PREINCREMENT_EXPR
+				    || code == POSTINCREMENT_EXPR)
+				   ? "increment" : "decrement")))
+	  return error_mark_node;
+
+	/* Report a read-only lvalue.  */
+	if (TREE_READONLY (arg))
+	  readonly_warning (arg, 
+			    ((code == PREINCREMENT_EXPR
+			      || code == POSTINCREMENT_EXPR)
+			     ? "increment" : "decrement"));
+
+	val = build (code, TREE_TYPE (arg), arg, inc);
+	TREE_SIDE_EFFECTS (val) = 1;
+	val = convert (result_type, val);
+	if (TREE_CODE (val) != code)
+	  TREE_NO_UNUSED_WARNING (val) = 1;
+	return val;
+      }
+
+    case ADDR_EXPR:
+      /* Note that this operation never does default_conversion
+	 regardless of NOCONVERT.  */
+
+      /* Let &* cancel out to simplify resulting code.  */
+      if (TREE_CODE (arg) == INDIRECT_REF)
+	{
+	  /* Don't let this be an lvalue.  */
+	  if (lvalue_p (TREE_OPERAND (arg, 0)))
+	    return non_lvalue (TREE_OPERAND (arg, 0));
+	  return TREE_OPERAND (arg, 0);
+	}
+
+      /* For &x[y], return x+y */
+      if (TREE_CODE (arg) == ARRAY_REF)
+	{
+	  if (mark_addressable (TREE_OPERAND (arg, 0)) == 0)
+	    return error_mark_node;
+	  return build_binary_op (PLUS_EXPR, TREE_OPERAND (arg, 0),
+				  TREE_OPERAND (arg, 1), 1);
+	}
+
+      /* Handle complex lvalues (when permitted)
+	 by reduction to simpler cases.  */
+      val = unary_complex_lvalue (code, arg);
+      if (val != 0)
+	return val;
+
+#if 0 /* Turned off because inconsistent;
+	 float f; *&(int)f = 3.4 stores in int format
+	 whereas (int)f = 3.4 stores in float format.  */
+      /* Address of a cast is just a cast of the address
+	 of the operand of the cast.  */
+      switch (TREE_CODE (arg))
+	{
+	case NOP_EXPR:
+	case CONVERT_EXPR:
+	case FLOAT_EXPR:
+	case FIX_TRUNC_EXPR:
+	case FIX_FLOOR_EXPR:
+	case FIX_ROUND_EXPR:
+	case FIX_CEIL_EXPR:
+	  if (pedantic)
+	    pedwarn ("ANSI C forbids the address of a cast expression");
+	  return convert (build_pointer_type (TREE_TYPE (arg)),
+			  build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0),
+					  0));
+	}
+#endif
+
+      /* Allow the address of a constructor if all the elements
+	 are constant.  */
+      if (TREE_CODE (arg) == CONSTRUCTOR && TREE_CONSTANT (arg))
+	;
+      /* Anything not already handled and not a true memory reference
+	 is an error.  */
+      else if (typecode != FUNCTION_TYPE && !lvalue_or_else (arg, "unary `&'"))
+	return error_mark_node;
+
+      /* Ordinary case; arg is a COMPONENT_REF or a decl.  */
+      argtype = TREE_TYPE (arg);
+      /* If the lvalue is const or volatile,
+	 merge that into the type that the address will point to.  */
+      if (TREE_CODE_CLASS (TREE_CODE (arg)) == 'd'
+	  || TREE_CODE_CLASS (TREE_CODE (arg)) == 'r')
+	{
+	  if (TREE_READONLY (arg) || TREE_THIS_VOLATILE (arg))
+	    argtype = c_build_type_variant (argtype,
+					    TREE_READONLY (arg),
+					    TREE_THIS_VOLATILE (arg));
+	}
+
+      argtype = build_pointer_type (argtype);
+
+      if (mark_addressable (arg) == 0)
+	return error_mark_node;
+
+      {
+	tree addr;
+
+	if (TREE_CODE (arg) == COMPONENT_REF)
+	  {
+	    tree field = TREE_OPERAND (arg, 1);
+
+	    addr = build_unary_op (ADDR_EXPR, TREE_OPERAND (arg, 0), 0);
+
+	    if (DECL_BIT_FIELD (field))
+	      {
+		error ("attempt to take address of bit-field structure member `%s'",
+		       IDENTIFIER_POINTER (DECL_NAME (field)));
+		return error_mark_node;
+	      }
+
+	    addr = convert (argtype, addr);
+
+	    if (! integer_zerop (DECL_FIELD_BITPOS (field)))
+	      {
+		tree offset
+		  = size_binop (EASY_DIV_EXPR, DECL_FIELD_BITPOS (field),
+				size_int (BITS_PER_UNIT));
+		int flag = TREE_CONSTANT (addr);
+		addr = fold (build (PLUS_EXPR, argtype,
+				    addr, convert (argtype, offset)));
+		TREE_CONSTANT (addr) = flag;
+	      }
+	  }
+	else
+	  addr = build1 (code, argtype, arg);
+
+	/* Address of a static or external variable or
+	   file-scope function counts as a constant.  */
+	if (staticp (arg)
+	    && ! (TREE_CODE (arg) == FUNCTION_DECL
+		  && DECL_CONTEXT (arg) != 0))
+	  TREE_CONSTANT (addr) = 1;
+	return addr;
+      }
+    }
+
+  if (!errstring)
+    {
+      if (argtype == 0)
+	argtype = TREE_TYPE (arg);
+      return fold (build1 (code, argtype, arg));
+    }
+
+  error (errstring);
+  return error_mark_node;
+}
+
+#if 0
+/* If CONVERSIONS is a conversion expression or a nested sequence of such,
+   convert ARG with the same conversions in the same order
+   and return the result.  */
+
+static tree
+convert_sequence (conversions, arg)
+     tree conversions;
+     tree arg;
+{
+  switch (TREE_CODE (conversions))
+    {
+    case NOP_EXPR:
+    case CONVERT_EXPR:
+    case FLOAT_EXPR:
+    case FIX_TRUNC_EXPR:
+    case FIX_FLOOR_EXPR:
+    case FIX_ROUND_EXPR:
+    case FIX_CEIL_EXPR:
+      return convert (TREE_TYPE (conversions),
+		      convert_sequence (TREE_OPERAND (conversions, 0),
+					arg));
+
+    default:
+      return arg;
+    }
+}
+#endif /* 0 */
+
+/* Return nonzero if REF is an lvalue valid for this language.
+   Lvalues can be assigned, unless their type has TYPE_READONLY.
+   Lvalues can have their address taken, unless they have DECL_REGISTER.  */
+
+int
+lvalue_p (ref)
+     tree ref;
+{
+  register enum tree_code code = TREE_CODE (ref);
+
+  switch (code)
+    {
+    case REALPART_EXPR:
+    case IMAGPART_EXPR:
+    case COMPONENT_REF:
+      return lvalue_p (TREE_OPERAND (ref, 0));
+
+    case STRING_CST:
+      return 1;
+
+    case INDIRECT_REF:
+    case ARRAY_REF:
+    case VAR_DECL:
+    case PARM_DECL:
+    case RESULT_DECL:
+    case ERROR_MARK:
+      if (TREE_CODE (TREE_TYPE (ref)) != FUNCTION_TYPE
+	  && TREE_CODE (TREE_TYPE (ref)) != METHOD_TYPE)
+	return 1;
+      break;
+    }
+  return 0;
+}
+
+/* Return nonzero if REF is an lvalue valid for this language;
+   otherwise, print an error message and return zero.  */
+
+int
+lvalue_or_else (ref, string)
+     tree ref;
+     char *string;
+{
+  int win = lvalue_p (ref);
+  if (! win)
+    error ("invalid lvalue in %s", string);
+  return win;
+}
+
+/* Apply unary lvalue-demanding operator CODE to the expression ARG
+   for certain kinds of expressions which are not really lvalues
+   but which we can accept as lvalues.
+
+   If ARG is not a kind of expression we can handle, return zero.  */
+   
+static tree
+unary_complex_lvalue (code, arg)
+     enum tree_code code;
+     tree arg;
+{
+  /* Handle (a, b) used as an "lvalue".  */
+  if (TREE_CODE (arg) == COMPOUND_EXPR)
+    {
+      tree real_result = build_unary_op (code, TREE_OPERAND (arg, 1), 0);
+      pedantic_lvalue_warning (COMPOUND_EXPR);
+      return build (COMPOUND_EXPR, TREE_TYPE (real_result),
+		    TREE_OPERAND (arg, 0), real_result);
+    }
+
+  /* Handle (a ? b : c) used as an "lvalue".  */
+  if (TREE_CODE (arg) == COND_EXPR)
+    {
+      pedantic_lvalue_warning (COND_EXPR);
+      return (build_conditional_expr
+	      (TREE_OPERAND (arg, 0),
+	       build_unary_op (code, TREE_OPERAND (arg, 1), 0),
+	       build_unary_op (code, TREE_OPERAND (arg, 2), 0)));
+    }
+
+  return 0;
+}
+
+/* If pedantic, warn about improper lvalue.   CODE is either COND_EXPR
+   COMPOUND_EXPR, or CONVERT_EXPR (for casts).  */
+
+static void
+pedantic_lvalue_warning (code)
+     enum tree_code code;
+{
+  if (pedantic)
+    pedwarn ("ANSI C forbids use of %s expressions as lvalues",
+	     code == COND_EXPR ? "conditional"
+	     : code == COMPOUND_EXPR ? "compound" : "cast");
+}
+
+/* Warn about storing in something that is `const'.  */
+
+void
+readonly_warning (arg, string)
+     tree arg;
+     char *string;
+{
+  char buf[80];
+  strcpy (buf, string);
+
+  /* Forbid assignments to iterators.  */
+  if (TREE_CODE (arg) == VAR_DECL && ITERATOR_P (arg))
+    {
+      strcat (buf, " of iterator `%s'");
+      pedwarn (buf, IDENTIFIER_POINTER (DECL_NAME (arg)));
+    }
+
+  if (TREE_CODE (arg) == COMPONENT_REF)
+    {
+      if (TYPE_READONLY (TREE_TYPE (TREE_OPERAND (arg, 0))))
+	readonly_warning (TREE_OPERAND (arg, 0), string);
+      else
+	{
+	  strcat (buf, " of read-only member `%s'");
+	  pedwarn (buf, IDENTIFIER_POINTER (DECL_NAME (TREE_OPERAND (arg, 1))));
+	}
+    }
+  else if (TREE_CODE (arg) == VAR_DECL)
+    {
+      strcat (buf, " of read-only variable `%s'");
+      pedwarn (buf, IDENTIFIER_POINTER (DECL_NAME (arg)));
+    }
+  else
+    {
+      pedwarn ("%s of read-only location", buf);
+    }
+}
+
+/* Mark EXP saying that we need to be able to take the
+   address of it; it should not be allocated in a register.
+   Value is 1 if successful.  */
+
+int
+mark_addressable (exp)
+     tree exp;
+{
+  register tree x = exp;
+  while (1)
+    switch (TREE_CODE (x))
+      {
+      case ADDR_EXPR:
+      case COMPONENT_REF:
+      case ARRAY_REF:
+      case REALPART_EXPR:
+      case IMAGPART_EXPR:
+	x = TREE_OPERAND (x, 0);
+	break;
+
+      case CONSTRUCTOR:
+	TREE_ADDRESSABLE (x) = 1;
+	return 1;
+
+      case VAR_DECL:
+      case CONST_DECL:
+      case PARM_DECL:
+      case RESULT_DECL:
+	if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x)
+	    && DECL_NONLOCAL (x))
+	  {
+	    if (TREE_PUBLIC (x))
+	      {
+		error ("global register variable `%s' used in nested function",
+		       IDENTIFIER_POINTER (DECL_NAME (x)));
+		return 0;
+	      }
+	    pedwarn ("register variable `%s' used in nested function",
+		     IDENTIFIER_POINTER (DECL_NAME (x)));
+	  }
+	else if (DECL_REGISTER (x) && !TREE_ADDRESSABLE (x))
+	  {
+	    if (TREE_PUBLIC (x))
+	      {
+		error ("address of global register variable `%s' requested",
+		       IDENTIFIER_POINTER (DECL_NAME (x)));
+		return 0;
+	      }
+
+	    /* If we are making this addressable due to its having
+	       volatile components, give a different error message.  Also
+	       handle the case of an unnamed parameter by not trying
+	       to give the name.  */
+
+	    else if (C_TYPE_FIELDS_VOLATILE (TREE_TYPE (x)))
+	      {
+		error ("cannot put object with volatile field into register");
+		return 0;
+	      }
+
+	    pedwarn ("address of register variable `%s' requested",
+		     IDENTIFIER_POINTER (DECL_NAME (x)));
+	  }
+	put_var_into_stack (x);
+
+	/* drops in */
+      case FUNCTION_DECL:
+	TREE_ADDRESSABLE (x) = 1;
+#if 0  /* poplevel deals with this now.  */
+	if (DECL_CONTEXT (x) == 0)
+	  TREE_ADDRESSABLE (DECL_ASSEMBLER_NAME (x)) = 1;
+#endif
+
+      default:
+	return 1;
+    }
+}
+
+/* Build and return a conditional expression IFEXP ? OP1 : OP2.  */
+
+tree
+build_conditional_expr (ifexp, op1, op2)
+     tree ifexp, op1, op2;
+{
+  register tree type1;
+  register tree type2;
+  register enum tree_code code1;
+  register enum tree_code code2;
+  register tree result_type = NULL;
+  tree orig_op1 = op1, orig_op2 = op2;
+
+  /* If second operand is omitted, it is the same as the first one;
+     make sure it is calculated only once.  */
+  if (op1 == 0)
+    {
+      if (pedantic)
+	pedwarn ("ANSI C forbids omitting the middle term of a ?: expression");
+      ifexp = op1 = save_expr (ifexp);
+    }
+
+  ifexp = truthvalue_conversion (default_conversion (ifexp));
+
+#if 0 /* Produces wrong result if within sizeof.  */
+  /* Don't promote the operands separately if they promote
+     the same way.  Return the unpromoted type and let the combined
+     value get promoted if necessary.  */
+
+  if (TREE_TYPE (op1) == TREE_TYPE (op2)
+      && TREE_CODE (TREE_TYPE (op1)) != ARRAY_TYPE
+      && TREE_CODE (TREE_TYPE (op1)) != ENUMERAL_TYPE
+      && TREE_CODE (TREE_TYPE (op1)) != FUNCTION_TYPE)
+    {
+      if (TREE_CODE (ifexp) == INTEGER_CST)
+	return pedantic_non_lvalue (integer_zerop (ifexp) ? op2 : op1);
+
+      return fold (build (COND_EXPR, TREE_TYPE (op1), ifexp, op1, op2));
+    }
+#endif
+
+  /* Promote both alternatives.  */
+
+  if (TREE_CODE (TREE_TYPE (op1)) != VOID_TYPE)
+    op1 = default_conversion (op1);
+  if (TREE_CODE (TREE_TYPE (op2)) != VOID_TYPE)
+    op2 = default_conversion (op2);
+
+  if (TREE_CODE (ifexp) == ERROR_MARK
+      || TREE_CODE (TREE_TYPE (op1)) == ERROR_MARK
+      || TREE_CODE (TREE_TYPE (op2)) == ERROR_MARK)
+    return error_mark_node;
+
+  type1 = TREE_TYPE (op1);
+  code1 = TREE_CODE (type1);
+  type2 = TREE_TYPE (op2);
+  code2 = TREE_CODE (type2);
+      
+  /* Quickly detect the usual case where op1 and op2 have the same type
+     after promotion.  */
+  if (TYPE_MAIN_VARIANT (type1) == TYPE_MAIN_VARIANT (type2))
+    {
+      if (type1 == type2)
+	result_type = type1;
+      else
+	result_type = TYPE_MAIN_VARIANT (type1);
+    }
+  else if ((code1 == INTEGER_TYPE || code1 == REAL_TYPE)
+           && (code2 == INTEGER_TYPE || code2 == REAL_TYPE))
+    {
+      result_type = common_type (type1, type2);
+    }
+  else if (code1 == VOID_TYPE || code2 == VOID_TYPE)
+    {
+      if (pedantic && (code1 != VOID_TYPE || code2 != VOID_TYPE))
+	pedwarn ("ANSI C forbids conditional expr with only one void side");
+      result_type = void_type_node;
+    }
+  else if (code1 == POINTER_TYPE && code2 == POINTER_TYPE)
+    {
+      if (comp_target_types (type1, type2))
+	result_type = common_type (type1, type2);
+      else if (integer_zerop (op1) && TREE_TYPE (type1) == void_type_node
+	       && TREE_CODE (orig_op1) != NOP_EXPR)
+	result_type = qualify_type (type2, type1);
+      else if (integer_zerop (op2) && TREE_TYPE (type2) == void_type_node
+	       && TREE_CODE (orig_op2) != NOP_EXPR)
+	result_type = qualify_type (type1, type2);
+      else if (TYPE_MAIN_VARIANT (TREE_TYPE (type1)) == void_type_node)
+	{
+	  if (pedantic && TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
+	    pedwarn ("ANSI C forbids conditional expr between `void *' and function pointer");
+	  result_type = qualify_type (type1, type2);
+	}
+      else if (TYPE_MAIN_VARIANT (TREE_TYPE (type2)) == void_type_node)
+	{
+	  if (pedantic && TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
+	    pedwarn ("ANSI C forbids conditional expr between `void *' and function pointer");
+	  result_type = qualify_type (type2, type1);
+	}
+      else
+	{
+	  pedwarn ("pointer type mismatch in conditional expression");
+	  result_type = build_pointer_type (void_type_node);
+	}
+    }
+  else if (code1 == POINTER_TYPE && code2 == INTEGER_TYPE)
+    {
+      if (! integer_zerop (op2))
+	pedwarn ("pointer/integer type mismatch in conditional expression");
+      else
+	{
+	  op2 = null_pointer_node;
+#if 0  /* The spec seems to say this is permitted.  */
+	  if (pedantic && TREE_CODE (type1) == FUNCTION_TYPE)
+	    pedwarn ("ANSI C forbids conditional expr between 0 and function pointer");
+#endif
+	}
+      result_type = type1;
+    }
+  else if (code2 == POINTER_TYPE && code1 == INTEGER_TYPE)
+    {
+      if (!integer_zerop (op1))
+	pedwarn ("pointer/integer type mismatch in conditional expression");
+      else
+	{
+	  op1 = null_pointer_node;
+#if 0  /* The spec seems to say this is permitted.  */
+	  if (pedantic && TREE_CODE (type2) == FUNCTION_TYPE)
+	    pedwarn ("ANSI C forbids conditional expr between 0 and function pointer");
+#endif
+	}
+      result_type = type2;
+    }
+
+  if (!result_type)
+    {
+      if (flag_cond_mismatch)
+	result_type = void_type_node;
+      else
+	{
+	  error ("type mismatch in conditional expression");
+	  return error_mark_node;
+	}
+    }
+
+  /* Merge const and volatile flags of the incoming types.  */
+  result_type
+    = build_type_variant (result_type,
+			  TREE_READONLY (op1) || TREE_READONLY (op2),
+			  TREE_THIS_VOLATILE (op1) || TREE_THIS_VOLATILE (op2));
+
+  if (result_type != TREE_TYPE (op1))
+    op1 = convert_and_check (result_type, op1);
+  if (result_type != TREE_TYPE (op2))
+    op2 = convert_and_check (result_type, op2);
+    
+#if 0
+  if (code1 == RECORD_TYPE || code1 == UNION_TYPE)
+    {
+      result_type = TREE_TYPE (op1);
+      if (TREE_CONSTANT (ifexp))
+	return pedantic_non_lvalue (integer_zerop (ifexp) ? op2 : op1);
+
+      if (TYPE_MODE (result_type) == BLKmode)
+	{
+	  register tree tempvar
+	    = build_decl (VAR_DECL, NULL_TREE, result_type);
+	  register tree xop1 = build_modify_expr (tempvar, op1);
+	  register tree xop2 = build_modify_expr (tempvar, op2);
+	  register tree result = fold (build (COND_EXPR, result_type,
+					      ifexp, xop1, xop2));
+
+	  layout_decl (tempvar, TYPE_ALIGN (result_type));
+	  /* No way to handle variable-sized objects here.
+	     I fear that the entire handling of BLKmode conditional exprs
+	     needs to be redone.  */
+	  if (TREE_CODE (DECL_SIZE (tempvar)) != INTEGER_CST)
+	    abort ();
+	  DECL_RTL (tempvar)
+	    = assign_stack_local (DECL_MODE (tempvar),
+				  (TREE_INT_CST_LOW (DECL_SIZE (tempvar))
+				   + BITS_PER_UNIT - 1)
+				  / BITS_PER_UNIT,
+				  0);
+
+	  TREE_SIDE_EFFECTS (result)
+	    = TREE_SIDE_EFFECTS (ifexp) | TREE_SIDE_EFFECTS (op1)
+	      | TREE_SIDE_EFFECTS (op2);
+	  return build (COMPOUND_EXPR, result_type, result, tempvar);
+	}
+    }
+#endif /* 0 */
+    
+  if (TREE_CODE (ifexp) == INTEGER_CST)
+    return pedantic_non_lvalue (integer_zerop (ifexp) ? op2 : op1);
+
+  return fold (build (COND_EXPR, result_type, ifexp, op1, op2));
+}
+
+/* Given a list of expressions, return a compound expression
+   that performs them all and returns the value of the last of them.  */
+
+tree
+build_compound_expr (list)
+     tree list;
+{
+  return internal_build_compound_expr (list, TRUE);
+}
+
+static tree
+internal_build_compound_expr (list, first_p)
+     tree list;
+     int first_p;
+{
+  register tree rest;
+
+  if (TREE_CHAIN (list) == 0)
+    {
+#if 0 /* If something inside inhibited lvalueness, we should not override.  */
+      /* Consider (x, y+0), which is not an lvalue since y+0 is not.  */
+
+      /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+      if (TREE_CODE (list) == NON_LVALUE_EXPR)
+	list = TREE_OPERAND (list, 0);
+#endif
+
+      /* Don't let (0, 0) be null pointer constant.  */
+      if (!first_p && integer_zerop (TREE_VALUE (list)))
+	return non_lvalue (TREE_VALUE (list));
+      return TREE_VALUE (list);
+    }
+
+  if (TREE_CHAIN (list) != 0 && TREE_CHAIN (TREE_CHAIN (list)) == 0)
+    {
+      /* Convert arrays to pointers when there really is a comma operator.  */
+      if (TREE_CODE (TREE_TYPE (TREE_VALUE (TREE_CHAIN (list)))) == ARRAY_TYPE)
+	TREE_VALUE (TREE_CHAIN (list))
+	  = default_conversion (TREE_VALUE (TREE_CHAIN (list)));
+    }
+
+  rest = internal_build_compound_expr (TREE_CHAIN (list), FALSE);
+
+  if (! TREE_SIDE_EFFECTS (TREE_VALUE (list)))
+    {
+      /* The left-hand operand of a comma expression is like an expression
+         statement: with -W or -Wunused, we should warn if it doesn't have
+	 any side-effects, unless it was explicitly cast to (void).  */
+      if ((extra_warnings || warn_unused)
+           && ! (TREE_CODE (TREE_VALUE (list)) == CONVERT_EXPR
+                && TREE_TYPE (TREE_VALUE (list)) == void_type_node))
+        warning ("left-hand operand of comma expression has no effect");
+
+      /* When pedantic, a compound expression can be neither an lvalue
+         nor an integer constant expression.  */
+      if (! pedantic)
+        return rest;
+    }
+
+  /* With -Wunused, we should also warn if the left-hand operand does have
+     side-effects, but computes a value which is not used.  For example, in
+     `foo() + bar(), baz()' the result of the `+' operator is not used,
+     so we should issue a warning.  */
+  else if (warn_unused)
+    warn_if_unused_value (TREE_VALUE (list));
+
+  return build (COMPOUND_EXPR, TREE_TYPE (rest), TREE_VALUE (list), rest);
+}
+
+/* Build an expression representing a cast to type TYPE of expression EXPR.  */
+
+tree
+build_c_cast (type, expr)
+     register tree type;
+     tree expr;
+{
+  register tree value = expr;
+  
+  if (type == error_mark_node || expr == error_mark_node)
+    return error_mark_node;
+  type = TYPE_MAIN_VARIANT (type);
+
+#if 0
+  /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+  if (TREE_CODE (value) == NON_LVALUE_EXPR)
+    value = TREE_OPERAND (value, 0);
+#endif
+
+  if (TREE_CODE (type) == ARRAY_TYPE)
+    {
+      error ("cast specifies array type");
+      return error_mark_node;
+    }
+
+  if (TREE_CODE (type) == FUNCTION_TYPE)
+    {
+      error ("cast specifies function type");
+      return error_mark_node;
+    }
+
+  if (type == TREE_TYPE (value))
+    {
+      if (pedantic)
+	{
+	  if (TREE_CODE (type) == RECORD_TYPE
+	      || TREE_CODE (type) == UNION_TYPE)
+	    pedwarn ("ANSI C forbids casting nonscalar to the same type");
+	}
+    }
+  else if (TREE_CODE (type) == UNION_TYPE)
+    {
+      tree field;
+      if (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
+	  || TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE)
+	value = default_conversion (value);
+
+      for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
+	if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (field)),
+		       TYPE_MAIN_VARIANT (TREE_TYPE (value))))
+	  break;
+
+      if (field)
+	{
+	  char *name;
+	  tree t;
+
+	  if (pedantic)
+	    pedwarn ("ANSI C forbids casts to union type");
+	  if (TYPE_NAME (type) != 0)
+	    {
+	      if (TREE_CODE (TYPE_NAME (type)) == IDENTIFIER_NODE)
+		name = IDENTIFIER_POINTER (TYPE_NAME (type));
+	      else
+		name = IDENTIFIER_POINTER (DECL_NAME (TYPE_NAME (type)));
+	    }
+	  else
+	    name = "";
+	  t = digest_init (type, build (CONSTRUCTOR, type, NULL_TREE,
+					build_tree_list (field, value)),
+			   0, 0);
+	  TREE_CONSTANT (t) = TREE_CONSTANT (value);
+	  return t;
+	}
+      error ("cast to union type from type not present in union");
+      return error_mark_node;
+    }
+  else
+    {
+      tree otype, ovalue;
+
+      /* If casting to void, avoid the error that would come
+	 from default_conversion in the case of a non-lvalue array.  */
+      if (type == void_type_node)
+	return build1 (CONVERT_EXPR, type, value);
+
+      /* Convert functions and arrays to pointers,
+	 but don't convert any other types.  */
+      if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
+	  || TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE)
+	value = default_conversion (value);
+      otype = TREE_TYPE (value);
+
+      /* Optionally warn about potentially worrisome casts.  */
+
+      if (warn_cast_qual
+	  && TREE_CODE (type) == POINTER_TYPE
+	  && TREE_CODE (otype) == POINTER_TYPE)
+	{
+	  if (TYPE_VOLATILE (TREE_TYPE (otype))
+	      && ! TYPE_VOLATILE (TREE_TYPE (type)))
+	    pedwarn ("cast discards `volatile' from pointer target type");
+	  if (TYPE_READONLY (TREE_TYPE (otype))
+	      && ! TYPE_READONLY (TREE_TYPE (type)))
+	    pedwarn ("cast discards `const' from pointer target type");
+	}
+
+      /* Warn about possible alignment problems.  */
+      if (STRICT_ALIGNMENT && warn_cast_align
+	  && TREE_CODE (type) == POINTER_TYPE
+	  && TREE_CODE (otype) == POINTER_TYPE
+	  && TREE_CODE (TREE_TYPE (otype)) != VOID_TYPE
+	  && TREE_CODE (TREE_TYPE (otype)) != FUNCTION_TYPE
+	  && TYPE_ALIGN (TREE_TYPE (type)) > TYPE_ALIGN (TREE_TYPE (otype)))
+	warning ("cast increases required alignment of target type");
+
+      if (TREE_CODE (type) == INTEGER_TYPE
+	  && TREE_CODE (otype) == POINTER_TYPE
+	  && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
+	  && !TREE_CONSTANT (value))
+	warning ("cast from pointer to integer of different size");
+
+      if (warn_bad_function_cast
+	  && TREE_CODE (value) == CALL_EXPR
+	  && TREE_CODE (type) != TREE_CODE (otype))
+	warning ("cast does not match function type");
+
+      if (TREE_CODE (type) == POINTER_TYPE
+	  && TREE_CODE (otype) == INTEGER_TYPE
+	  && TYPE_PRECISION (type) != TYPE_PRECISION (otype)
+#if 0
+	  /* Don't warn about converting 0 to pointer,
+	     provided the 0 was explicit--not cast or made by folding.  */
+	  && !(TREE_CODE (value) == INTEGER_CST && integer_zerop (value))
+#endif
+	  /* Don't warn about converting any constant.  */
+	  && !TREE_CONSTANT (value))
+	warning ("cast to pointer from integer of different size");
+
+      ovalue = value;
+      value = convert (type, value);
+
+      /* Ignore any integer overflow caused by the cast.  */
+      if (TREE_CODE (value) == INTEGER_CST)
+	{
+	  TREE_OVERFLOW (value) = TREE_OVERFLOW (ovalue);
+	  TREE_CONSTANT_OVERFLOW (value) = TREE_CONSTANT_OVERFLOW (ovalue);
+	}
+    }
+
+  /* Pedantically, don't ley (void *) (FOO *) 0 be a null pointer constant.  */
+  if (pedantic && TREE_CODE (value) == INTEGER_CST
+      && TREE_CODE (expr) == INTEGER_CST
+      && TREE_CODE (TREE_TYPE (expr)) != INTEGER_TYPE)
+    value = non_lvalue (value);
+
+  /* If pedantic, don't let a cast be an lvalue.  */
+  if (value == expr && pedantic)
+    value = non_lvalue (value);
+
+  return value;
+}
+
+/* Build an assignment expression of lvalue LHS from value RHS.
+   MODIFYCODE is the code for a binary operator that we use
+   to combine the old value of LHS with RHS to get the new value.
+   Or else MODIFYCODE is NOP_EXPR meaning do a simple assignment.  */
+
+tree
+build_modify_expr (lhs, modifycode, rhs)
+     tree lhs, rhs;
+     enum tree_code modifycode;
+{
+  register tree result;
+  tree newrhs;
+  tree lhstype = TREE_TYPE (lhs);
+  tree olhstype = lhstype;
+
+  /* Types that aren't fully specified cannot be used in assignments.  */
+  lhs = require_complete_type (lhs);
+
+  /* Avoid duplicate error messages from operands that had errors.  */
+  if (TREE_CODE (lhs) == ERROR_MARK || TREE_CODE (rhs) == ERROR_MARK)
+    return error_mark_node;
+
+  /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+  /* Do not use STRIP_NOPS here.  We do not want an enumerator
+     whose value is 0 to count as a null pointer constant.  */
+  if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
+    rhs = TREE_OPERAND (rhs, 0);
+
+  newrhs = rhs;
+
+  /* Handle control structure constructs used as "lvalues".  */
+
+  switch (TREE_CODE (lhs))
+    {
+      /* Handle (a, b) used as an "lvalue".  */
+    case COMPOUND_EXPR:
+      pedantic_lvalue_warning (COMPOUND_EXPR);
+      newrhs = build_modify_expr (TREE_OPERAND (lhs, 1),
+				  modifycode, rhs);
+      if (TREE_CODE (newrhs) == ERROR_MARK)
+	return error_mark_node;
+      return build (COMPOUND_EXPR, lhstype,
+		    TREE_OPERAND (lhs, 0), newrhs);
+ 
+      /* Handle (a ? b : c) used as an "lvalue".  */
+    case COND_EXPR:
+      pedantic_lvalue_warning (COND_EXPR);
+      rhs = save_expr (rhs);
+      {
+	/* Produce (a ? (b = rhs) : (c = rhs))
+	   except that the RHS goes through a save-expr
+	   so the code to compute it is only emitted once.  */
+	tree cond
+	  = build_conditional_expr (TREE_OPERAND (lhs, 0),
+				    build_modify_expr (TREE_OPERAND (lhs, 1),
+						       modifycode, rhs),
+				    build_modify_expr (TREE_OPERAND (lhs, 2),
+						       modifycode, rhs));
+	if (TREE_CODE (cond) == ERROR_MARK)
+	  return cond;
+	/* Make sure the code to compute the rhs comes out
+	   before the split.  */
+	return build (COMPOUND_EXPR, TREE_TYPE (lhs),
+		      /* But cast it to void to avoid an "unused" error.  */
+		      convert (void_type_node, rhs), cond);
+      }
+    }
+
+  /* If a binary op has been requested, combine the old LHS value with the RHS
+     producing the value we should actually store into the LHS.  */
+
+  if (modifycode != NOP_EXPR)
+    {
+      lhs = stabilize_reference (lhs);
+      newrhs = build_binary_op (modifycode, lhs, rhs, 1);
+    }
+
+  /* Handle a cast used as an "lvalue".
+     We have already performed any binary operator using the value as cast.
+     Now convert the result to the cast type of the lhs,
+     and then true type of the lhs and store it there;
+     then convert result back to the cast type to be the value
+     of the assignment.  */
+
+  switch (TREE_CODE (lhs))
+    {
+    case NOP_EXPR:
+    case CONVERT_EXPR:
+    case FLOAT_EXPR:
+    case FIX_TRUNC_EXPR:
+    case FIX_FLOOR_EXPR:
+    case FIX_ROUND_EXPR:
+    case FIX_CEIL_EXPR:
+      if (TREE_CODE (TREE_TYPE (newrhs)) == ARRAY_TYPE
+	  || TREE_CODE (TREE_TYPE (newrhs)) == FUNCTION_TYPE)
+	newrhs = default_conversion (newrhs);
+      {
+	tree inner_lhs = TREE_OPERAND (lhs, 0);
+	tree result;
+	result = build_modify_expr (inner_lhs, NOP_EXPR,
+				    convert (TREE_TYPE (inner_lhs),
+					     convert (lhstype, newrhs)));
+	if (TREE_CODE (result) == ERROR_MARK)
+	  return result;
+	pedantic_lvalue_warning (CONVERT_EXPR);
+	return convert (TREE_TYPE (lhs), result);
+      }
+    }
+
+  /* Now we have handled acceptable kinds of LHS that are not truly lvalues.
+     Reject anything strange now.  */
+
+  if (!lvalue_or_else (lhs, "assignment"))
+    return error_mark_node;
+
+  /* Warn about storing in something that is `const'.  */
+
+  if (TREE_READONLY (lhs) || TYPE_READONLY (lhstype)
+      || ((TREE_CODE (lhstype) == RECORD_TYPE
+	   || TREE_CODE (lhstype) == UNION_TYPE)
+	  && C_TYPE_FIELDS_READONLY (lhstype)))
+    readonly_warning (lhs, "assignment");
+
+  /* If storing into a structure or union member,
+     it has probably been given type `int'.
+     Compute the type that would go with
+     the actual amount of storage the member occupies.  */
+
+  if (TREE_CODE (lhs) == COMPONENT_REF
+      && (TREE_CODE (lhstype) == INTEGER_TYPE
+	  || TREE_CODE (lhstype) == REAL_TYPE
+	  || TREE_CODE (lhstype) == ENUMERAL_TYPE))
+    lhstype = TREE_TYPE (get_unwidened (lhs, 0));
+
+  /* If storing in a field that is in actuality a short or narrower than one,
+     we must store in the field in its actual type.  */
+
+  if (lhstype != TREE_TYPE (lhs))
+    {
+      lhs = copy_node (lhs);
+      TREE_TYPE (lhs) = lhstype;
+    }
+
+  /* Convert new value to destination type.  */
+
+  newrhs = convert_for_assignment (lhstype, newrhs, "assignment",
+				   NULL_TREE, NULL_TREE, 0);
+  if (TREE_CODE (newrhs) == ERROR_MARK)
+    return error_mark_node;
+
+  result = build (MODIFY_EXPR, lhstype, lhs, newrhs);
+  TREE_SIDE_EFFECTS (result) = 1;
+
+  /* If we got the LHS in a different type for storing in,
+     convert the result back to the nominal type of LHS
+     so that the value we return always has the same type
+     as the LHS argument.  */
+
+  if (olhstype == TREE_TYPE (result))
+    return result;
+  return convert_for_assignment (olhstype, result, "assignment",
+				 NULL_TREE, NULL_TREE, 0);
+}
+
+/* Convert value RHS to type TYPE as preparation for an assignment
+   to an lvalue of type TYPE.
+   The real work of conversion is done by `convert'.
+   The purpose of this function is to generate error messages
+   for assignments that are not allowed in C.
+   ERRTYPE is a string to use in error messages:
+   "assignment", "return", etc.  If it is null, this is parameter passing
+   for a function call (and different error messages are output).  Otherwise,
+   it may be a name stored in the spelling stack and interpreted by
+   get_spelling.
+
+   FUNNAME is the name of the function being called,
+   as an IDENTIFIER_NODE, or null.
+   PARMNUM is the number of the argument, for printing in error messages.  */
+
+static tree
+convert_for_assignment (type, rhs, errtype, fundecl, funname, parmnum)
+     tree type, rhs;
+     char *errtype;
+     tree fundecl, funname;
+     int parmnum;
+{
+  register enum tree_code codel = TREE_CODE (type);
+  register tree rhstype;
+  register enum tree_code coder;
+
+  /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+  /* Do not use STRIP_NOPS here.  We do not want an enumerator
+     whose value is 0 to count as a null pointer constant.  */
+  if (TREE_CODE (rhs) == NON_LVALUE_EXPR)
+    rhs = TREE_OPERAND (rhs, 0);
+
+  if (TREE_CODE (TREE_TYPE (rhs)) == ARRAY_TYPE
+      || TREE_CODE (TREE_TYPE (rhs)) == FUNCTION_TYPE)
+    rhs = default_conversion (rhs);
+  else if (optimize && TREE_CODE (rhs) == VAR_DECL)
+    rhs = decl_constant_value (rhs);
+
+  rhstype = TREE_TYPE (rhs);
+  coder = TREE_CODE (rhstype);
+
+  if (coder == ERROR_MARK)
+    return error_mark_node;
+
+  if (TYPE_MAIN_VARIANT (type) == TYPE_MAIN_VARIANT (rhstype))
+    {
+      overflow_warning (rhs);
+      /* Check for Objective-C protocols.  This will issue a warning if
+	 there are protocol violations.  No need to use the return value.  */
+      maybe_objc_comptypes (type, rhstype, 0);
+      return rhs;
+    }
+
+  if (coder == VOID_TYPE)
+    {
+      error ("void value not ignored as it ought to be");
+      return error_mark_node;
+    }
+  /* Arithmetic types all interconvert, and enum is treated like int.  */
+  if ((codel == INTEGER_TYPE || codel == REAL_TYPE || codel == ENUMERAL_TYPE
+       || codel == COMPLEX_TYPE)
+      && (coder == INTEGER_TYPE || coder == REAL_TYPE || coder == ENUMERAL_TYPE
+	  || coder == COMPLEX_TYPE))
+    return convert_and_check (type, rhs);
+
+  /* Conversion to a union from its member types.  */
+  else if (codel == UNION_TYPE)
+    {
+      tree memb_types;
+
+      for (memb_types = TYPE_FIELDS (type); memb_types;
+	   memb_types = TREE_CHAIN (memb_types))
+	{
+	  if (comptypes (TREE_TYPE (memb_types), TREE_TYPE (rhs)))
+	    {
+	      if (pedantic
+		  && !(fundecl != 0 && DECL_IN_SYSTEM_HEADER (fundecl)))
+		pedwarn ("ANSI C prohibits argument conversion to union type");
+	      return build1 (NOP_EXPR, type, rhs);
+	    }
+
+	  else if (coder == POINTER_TYPE
+		   && TREE_CODE (TREE_TYPE (memb_types)) == POINTER_TYPE)
+	    {
+	      tree memb_type = TREE_TYPE (memb_types);
+	      register tree ttl = TREE_TYPE (memb_type);
+	      register tree ttr = TREE_TYPE (rhstype);
+
+	      /* Any non-function converts to a [const][volatile] void *
+		 and vice versa; otherwise, targets must be the same.
+		 Meanwhile, the lhs target must have all the qualifiers of
+		 the rhs.  */
+	      if (TYPE_MAIN_VARIANT (ttl) == void_type_node
+		  || TYPE_MAIN_VARIANT (ttr) == void_type_node
+		  || comp_target_types (memb_type, rhstype))
+		{
+		  /* Const and volatile mean something different for function
+		     types, so the usual warnings are not appropriate.  */
+		  if (TREE_CODE (ttr) != FUNCTION_TYPE
+		      || TREE_CODE (ttl) != FUNCTION_TYPE)
+		    {
+		      if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr))
+			warn_for_assignment ("%s discards `const' from pointer target type",
+					     get_spelling (errtype), funname,
+					     parmnum);
+		      if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr))
+			warn_for_assignment ("%s discards `volatile' from pointer target type",
+					     get_spelling (errtype), funname,
+					     parmnum);
+		    }
+		  else
+		    {
+		      /* Because const and volatile on functions are
+			 restrictions that say the function will not do
+			 certain things, it is okay to use a const or volatile
+			 function where an ordinary one is wanted, but not
+			 vice-versa.  */
+		      if (TYPE_READONLY (ttl) && ! TYPE_READONLY (ttr))
+			warn_for_assignment ("%s makes `const *' function pointer from non-const",
+					     get_spelling (errtype), funname,
+					     parmnum);
+		      if (TYPE_VOLATILE (ttl) && ! TYPE_VOLATILE (ttr))
+			warn_for_assignment ("%s makes `volatile *' function pointer from non-volatile",
+					     get_spelling (errtype), funname,
+					     parmnum);
+		    }
+
+		  if (pedantic
+		      && !(fundecl != 0 && DECL_IN_SYSTEM_HEADER (fundecl)))
+		    pedwarn ("ANSI C prohibits argument conversion to union type");
+		  return build1 (NOP_EXPR, type, rhs);
+		}
+	    }
+
+	  /* Can convert integer zero to any pointer type.  */
+	  else if (TREE_CODE (TREE_TYPE (memb_types)) == POINTER_TYPE
+		   && (integer_zerop (rhs)
+		       || (TREE_CODE (rhs) == NOP_EXPR
+			   && integer_zerop (TREE_OPERAND (rhs, 0)))))
+	    return build1 (NOP_EXPR, type, null_pointer_node);
+	}
+    }
+
+  /* Conversions among pointers */
+  else if (codel == POINTER_TYPE && coder == POINTER_TYPE)
+    {
+      register tree ttl = TREE_TYPE (type);
+      register tree ttr = TREE_TYPE (rhstype);
+
+      /* Any non-function converts to a [const][volatile] void *
+	 and vice versa; otherwise, targets must be the same.
+	 Meanwhile, the lhs target must have all the qualifiers of the rhs.  */
+      if (TYPE_MAIN_VARIANT (ttl) == void_type_node
+	  || TYPE_MAIN_VARIANT (ttr) == void_type_node
+	  || comp_target_types (type, rhstype)
+	  || (unsigned_type (TYPE_MAIN_VARIANT (ttl))
+	      == unsigned_type (TYPE_MAIN_VARIANT (ttr))))
+	{
+	  if (pedantic
+	      && ((TYPE_MAIN_VARIANT (ttl) == void_type_node
+		   && TREE_CODE (ttr) == FUNCTION_TYPE)
+		  ||
+		  (TYPE_MAIN_VARIANT (ttr) == void_type_node
+		   /* Check TREE_CODE to catch cases like (void *) (char *) 0
+		      which are not ANSI null ptr constants.  */
+		   && (!integer_zerop (rhs) || TREE_CODE (rhs) == NOP_EXPR)
+		   && TREE_CODE (ttl) == FUNCTION_TYPE)))
+	    warn_for_assignment ("ANSI forbids %s between function pointer and `void *'",
+				 get_spelling (errtype), funname, parmnum);
+	  /* Const and volatile mean something different for function types,
+	     so the usual warnings are not appropriate.  */
+	  else if (TREE_CODE (ttr) != FUNCTION_TYPE
+		   && TREE_CODE (ttl) != FUNCTION_TYPE)
+	    {
+	      if (! TYPE_READONLY (ttl) && TYPE_READONLY (ttr))
+		warn_for_assignment ("%s discards `const' from pointer target type",
+				     get_spelling (errtype), funname, parmnum);
+	      else if (! TYPE_VOLATILE (ttl) && TYPE_VOLATILE (ttr))
+		warn_for_assignment ("%s discards `volatile' from pointer target type",
+				     get_spelling (errtype), funname, parmnum);
+	      /* If this is not a case of ignoring a mismatch in signedness,
+		 no warning.  */
+	      else if (TYPE_MAIN_VARIANT (ttl) == void_type_node
+		       || TYPE_MAIN_VARIANT (ttr) == void_type_node
+		       || comp_target_types (type, rhstype))
+		;
+	      /* If there is a mismatch, do warn.  */
+	      else if (pedantic)
+		warn_for_assignment ("pointer targets in %s differ in signedness",
+				     get_spelling (errtype), funname, parmnum);
+	    }
+	  else if (TREE_CODE (ttl) == FUNCTION_TYPE
+		   && TREE_CODE (ttr) == FUNCTION_TYPE)
+	    {
+	      /* Because const and volatile on functions are restrictions
+		 that say the function will not do certain things,
+		 it is okay to use a const or volatile function
+		 where an ordinary one is wanted, but not vice-versa.  */
+	      if (TYPE_READONLY (ttl) && ! TYPE_READONLY (ttr))
+		warn_for_assignment ("%s makes `const *' function pointer from non-const",
+				     get_spelling (errtype), funname, parmnum);
+	      if (TYPE_VOLATILE (ttl) && ! TYPE_VOLATILE (ttr))
+		warn_for_assignment ("%s makes `volatile *' function pointer from non-volatile",
+				     get_spelling (errtype), funname, parmnum);
+	    }
+	}
+      else
+	warn_for_assignment ("%s from incompatible pointer type",
+			     get_spelling (errtype), funname, parmnum);
+      return convert (type, rhs);
+    }
+  else if (codel == POINTER_TYPE && coder == INTEGER_TYPE)
+    {
+      /* An explicit constant 0 can convert to a pointer,
+	 or one that results from arithmetic, even including
+	 a cast to integer type.  */
+      if (! (TREE_CODE (rhs) == INTEGER_CST && integer_zerop (rhs))
+	  &&
+	  ! (TREE_CODE (rhs) == NOP_EXPR
+	     && TREE_CODE (TREE_TYPE (rhs)) == INTEGER_TYPE
+	     && TREE_CODE (TREE_OPERAND (rhs, 0)) == INTEGER_CST
+	     && integer_zerop (TREE_OPERAND (rhs, 0))))
+	{
+	  warn_for_assignment ("%s makes pointer from integer without a cast",
+			       get_spelling (errtype), funname, parmnum);
+	  return convert (type, rhs);
+	}
+      return null_pointer_node;
+    }
+  else if (codel == INTEGER_TYPE && coder == POINTER_TYPE)
+    {
+      warn_for_assignment ("%s makes integer from pointer without a cast",
+			   get_spelling (errtype), funname, parmnum);
+      return convert (type, rhs);
+    }
+
+  if (!errtype)
+    {
+      if (funname)
+ 	{
+ 	  tree selector = maybe_building_objc_message_expr ();
+ 
+ 	  if (selector && parmnum > 2)
+ 	    error ("incompatible type for argument %d of `%s'",
+		   parmnum - 2, IDENTIFIER_POINTER (selector));
+ 	  else
+	    error ("incompatible type for argument %d of `%s'",
+		   parmnum, IDENTIFIER_POINTER (funname));
+	}
+      else
+	error ("incompatible type for argument %d of indirect function call",
+	       parmnum);
+    }
+  else
+    error ("incompatible types in %s", get_spelling (errtype));
+
+  return error_mark_node;
+}
+
+/* Print a warning using MSG.
+   It gets OPNAME as its one parameter.
+   If OPNAME is null, it is replaced by "passing arg ARGNUM of `FUNCTION'".
+   FUNCTION and ARGNUM are handled specially if we are building an
+   Objective-C selector.  */
+
+static void
+warn_for_assignment (msg, opname, function, argnum)
+     char *msg;
+     char *opname;
+     tree function;
+     int argnum;
+{
+  static char argstring[] = "passing arg %d of `%s'";
+  static char argnofun[] =  "passing arg %d";
+
+  if (opname == 0)
+    {
+      tree selector = maybe_building_objc_message_expr ();
+      
+      if (selector && argnum > 2)
+	{
+	  function = selector;
+	  argnum -= 2;
+	}
+      if (function)
+	{
+	  /* Function name is known; supply it.  */
+	  opname = (char *) alloca (IDENTIFIER_LENGTH (function)
+				    + sizeof (argstring) + 25 /*%d*/ + 1);
+	  sprintf (opname, argstring, argnum, IDENTIFIER_POINTER (function));
+	}
+      else
+	{
+	  /* Function name unknown (call through ptr); just give arg number.  */
+	  opname = (char *) alloca (sizeof (argnofun) + 25 /*%d*/ + 1);
+	  sprintf (opname, argnofun, argnum);
+	}
+    }
+  pedwarn (msg, opname);
+}
+
+/* Return nonzero if VALUE is a valid constant-valued expression
+   for use in initializing a static variable; one that can be an
+   element of a "constant" initializer.
+
+   Return null_pointer_node if the value is absolute;
+   if it is relocatable, return the variable that determines the relocation.
+   We assume that VALUE has been folded as much as possible;
+   therefore, we do not need to check for such things as
+   arithmetic-combinations of integers.  */
+
+tree
+initializer_constant_valid_p (value, endtype)
+     tree value;
+     tree endtype;
+{
+  switch (TREE_CODE (value))
+    {
+    case CONSTRUCTOR:
+      if ((TREE_CODE (TREE_TYPE (value)) == UNION_TYPE
+	   || TREE_CODE (TREE_TYPE (value)) == RECORD_TYPE)
+	  && TREE_CONSTANT (value))
+	return
+	  initializer_constant_valid_p (TREE_VALUE (CONSTRUCTOR_ELTS (value)),
+					endtype);
+	
+      return TREE_STATIC (value) ? null_pointer_node : 0;
+
+    case INTEGER_CST:
+    case REAL_CST:
+    case STRING_CST:
+    case COMPLEX_CST:
+      return null_pointer_node;
+
+    case ADDR_EXPR:
+      return TREE_OPERAND (value, 0);
+
+    case NON_LVALUE_EXPR:
+      return initializer_constant_valid_p (TREE_OPERAND (value, 0), endtype);
+
+    case CONVERT_EXPR:
+    case NOP_EXPR:
+      /* Allow conversions between pointer types.  */
+      if (TREE_CODE (TREE_TYPE (value)) == POINTER_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == POINTER_TYPE)
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0), endtype);
+
+      /* Allow conversions between real types.  */
+      if (TREE_CODE (TREE_TYPE (value)) == REAL_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == REAL_TYPE)
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0), endtype);
+
+      /* Allow length-preserving conversions between integer types.  */
+      if (TREE_CODE (TREE_TYPE (value)) == INTEGER_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == INTEGER_TYPE
+	  && (TYPE_PRECISION (TREE_TYPE (value))
+	      == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (value, 0)))))
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0), endtype);
+
+      /* Allow conversions between other integer types only if
+	 explicit value.  */
+      if (TREE_CODE (TREE_TYPE (value)) == INTEGER_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == INTEGER_TYPE)
+	{
+	  tree inner = initializer_constant_valid_p (TREE_OPERAND (value, 0),
+						     endtype);
+	  if (inner == null_pointer_node)
+	    return null_pointer_node;
+	  return 0;
+	}
+
+      /* Allow (int) &foo provided int is as wide as a pointer.  */
+      if (TREE_CODE (TREE_TYPE (value)) == INTEGER_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == POINTER_TYPE
+	  && (TYPE_PRECISION (TREE_TYPE (value))
+	      >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (value, 0)))))
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0),
+					     endtype);
+
+      /* Likewise conversions from int to pointers.  */
+      if (TREE_CODE (TREE_TYPE (value)) == POINTER_TYPE
+	  && TREE_CODE (TREE_TYPE (TREE_OPERAND (value, 0))) == INTEGER_TYPE
+	  && (TYPE_PRECISION (TREE_TYPE (value))
+	      <= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (value, 0)))))
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0),
+					     endtype);
+
+      /* Allow conversions to union types if the value inside is okay.  */
+      if (TREE_CODE (TREE_TYPE (value)) == UNION_TYPE)
+	return initializer_constant_valid_p (TREE_OPERAND (value, 0),
+					     endtype);
+      return 0;
+
+    case PLUS_EXPR:
+      if (TREE_CODE (endtype) == INTEGER_TYPE
+	  && TYPE_PRECISION (endtype) < POINTER_SIZE)
+	return 0;
+      {
+	tree valid0 = initializer_constant_valid_p (TREE_OPERAND (value, 0),
+						    endtype);
+	tree valid1 = initializer_constant_valid_p (TREE_OPERAND (value, 1),
+						    endtype);
+	/* If either term is absolute, use the other terms relocation.  */
+	if (valid0 == null_pointer_node)
+	  return valid1;
+	if (valid1 == null_pointer_node)
+	  return valid0;
+	return 0;
+      }
+
+    case MINUS_EXPR:
+      if (TREE_CODE (endtype) == INTEGER_TYPE
+	  && TYPE_PRECISION (endtype) < POINTER_SIZE)
+	return 0;
+      {
+	tree valid0 = initializer_constant_valid_p (TREE_OPERAND (value, 0),
+						    endtype);
+	tree valid1 = initializer_constant_valid_p (TREE_OPERAND (value, 1),
+						    endtype);
+	/* Win if second argument is absolute.  */
+	if (valid1 == null_pointer_node)
+	  return valid0;
+	/* Win if both arguments have the same relocation.
+	   Then the value is absolute.  */
+	if (valid0 == valid1)
+	  return null_pointer_node;
+	return 0;
+      }
+    }
+
+  return 0;
+}
+
+/* If VALUE is a compound expr all of whose expressions are constant, then
+   return its value.  Otherwise, return error_mark_node.
+
+   This is for handling COMPOUND_EXPRs as initializer elements
+   which is allowed with a warning when -pedantic is specified.  */
+
+static tree
+valid_compound_expr_initializer (value, endtype)
+     tree value;
+     tree endtype;
+{
+  if (TREE_CODE (value) == COMPOUND_EXPR)
+    {
+      if (valid_compound_expr_initializer (TREE_OPERAND (value, 0), endtype)
+	  == error_mark_node)
+	return error_mark_node;
+      return valid_compound_expr_initializer (TREE_OPERAND (value, 1),
+					      endtype);
+    }
+  else if (! TREE_CONSTANT (value)
+	   && ! initializer_constant_valid_p (value, endtype))
+    return error_mark_node;
+  else
+    return value;
+}
+
+/* Perform appropriate conversions on the initial value of a variable,
+   store it in the declaration DECL,
+   and print any error messages that are appropriate.
+   If the init is invalid, store an ERROR_MARK.  */
+
+void
+store_init_value (decl, init)
+     tree decl, init;
+{
+  register tree value, type;
+
+  /* If variable's type was invalidly declared, just ignore it.  */
+
+  type = TREE_TYPE (decl);
+  if (TREE_CODE (type) == ERROR_MARK)
+    return;
+
+  /* Digest the specified initializer into an expression.  */
+
+  value = digest_init (type, init, TREE_STATIC (decl),
+		       TREE_STATIC (decl) || pedantic);
+
+  /* Store the expression if valid; else report error.  */
+
+#if 0
+  /* Note that this is the only place we can detect the error
+     in a case such as   struct foo bar = (struct foo) { x, y };
+     where there is one initial value which is a constructor expression.  */
+  if (value == error_mark_node)
+    ;
+  else if (TREE_STATIC (decl) && ! TREE_CONSTANT (value))
+    {
+      error ("initializer for static variable is not constant");
+      value = error_mark_node;
+    }
+  else if (TREE_STATIC (decl)
+	   && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
+    {
+      error ("initializer for static variable uses complicated arithmetic");
+      value = error_mark_node;
+    }
+  else
+    {
+      if (pedantic && TREE_CODE (value) == CONSTRUCTOR)
+	{
+	  if (! TREE_CONSTANT (value))
+	    pedwarn ("aggregate initializer is not constant");
+	  else if (! TREE_STATIC (value))
+	    pedwarn ("aggregate initializer uses complicated arithmetic");
+	}
+    }
+#endif
+
+  DECL_INITIAL (decl) = value;
+
+  /* ANSI wants warnings about out-of-range constant initializers.  */
+  STRIP_TYPE_NOPS (value);
+  constant_expression_warning (value);
+}
+
+/* Methods for storing and printing names for error messages.  */
+
+/* Implement a spelling stack that allows components of a name to be pushed
+   and popped.  Each element on the stack is this structure.  */
+
+struct spelling
+{
+  int kind;
+  union
+    {
+      int i;
+      char *s;
+    } u;
+};
+
+#define SPELLING_STRING 1
+#define SPELLING_MEMBER 2
+#define SPELLING_BOUNDS 3
+
+static struct spelling *spelling;	/* Next stack element (unused).  */
+static struct spelling *spelling_base;	/* Spelling stack base.  */
+static int spelling_size;		/* Size of the spelling stack.  */
+
+/* Macros to save and restore the spelling stack around push_... functions.
+   Alternative to SAVE_SPELLING_STACK.  */
+
+#define SPELLING_DEPTH() (spelling - spelling_base)
+#define RESTORE_SPELLING_DEPTH(depth) (spelling = spelling_base + depth)
+
+/* Save and restore the spelling stack around arbitrary C code.  */
+
+#define SAVE_SPELLING_DEPTH(code)		\
+{						\
+  int __depth = SPELLING_DEPTH ();		\
+  code;						\
+  RESTORE_SPELLING_DEPTH (__depth);		\
+}
+
+/* Push an element on the spelling stack with type KIND and assign VALUE
+   to MEMBER.  */
+
+#define PUSH_SPELLING(KIND, VALUE, MEMBER)				\
+{									\
+  int depth = SPELLING_DEPTH ();					\
+									\
+  if (depth >= spelling_size)						\
+    {									\
+      spelling_size += 10;						\
+      if (spelling_base == 0)						\
+	spelling_base							\
+	  = (struct spelling *) xmalloc (spelling_size * sizeof (struct spelling));	\
+      else								\
+        spelling_base							\
+	  = (struct spelling *) xrealloc (spelling_base,		\
+					  spelling_size * sizeof (struct spelling));	\
+      RESTORE_SPELLING_DEPTH (depth);					\
+    }									\
+									\
+  spelling->kind = (KIND);						\
+  spelling->MEMBER = (VALUE);						\
+  spelling++;								\
+}
+
+/* Push STRING on the stack.  Printed literally.  */
+
+static void
+push_string (string)
+     char *string;
+{
+  PUSH_SPELLING (SPELLING_STRING, string, u.s);
+}
+
+/* Push a member name on the stack.  Printed as '.' STRING.  */
+
+static void
+push_member_name (decl)
+     tree decl;
+     
+{
+  char *string
+    = DECL_NAME (decl) ? IDENTIFIER_POINTER (DECL_NAME (decl)) : "<anonymous>";
+  PUSH_SPELLING (SPELLING_MEMBER, string, u.s);
+}
+
+/* Push an array bounds on the stack.  Printed as [BOUNDS].  */
+
+static void
+push_array_bounds (bounds)
+     int bounds;
+{
+  PUSH_SPELLING (SPELLING_BOUNDS, bounds, u.i);
+}
+
+/* Compute the maximum size in bytes of the printed spelling.  */
+
+static int
+spelling_length ()
+{
+  register int size = 0;
+  register struct spelling *p;
+
+  for (p = spelling_base; p < spelling; p++)
+    {
+      if (p->kind == SPELLING_BOUNDS)
+	size += 25;
+      else
+	size += strlen (p->u.s) + 1;
+    }
+
+  return size;
+}
+
+/* Print the spelling to BUFFER and return it.  */
+
+static char *
+print_spelling (buffer)
+     register char *buffer;
+{
+  register char *d = buffer;
+  register char *s;
+  register struct spelling *p;
+
+  for (p = spelling_base; p < spelling; p++)
+    if (p->kind == SPELLING_BOUNDS)
+      {
+	sprintf (d, "[%d]", p->u.i);
+	d += strlen (d);
+      }
+    else
+      {
+	if (p->kind == SPELLING_MEMBER)
+	  *d++ = '.';
+	for (s = p->u.s; *d = *s++; d++)
+	  ;
+      }
+  *d++ = '\0';
+  return buffer;
+}
+
+/* Provide a means to pass component names derived from the spelling stack.  */
+
+char initialization_message;
+
+/* Interpret the spelling of the given ERRTYPE message.  */
+
+static char *
+get_spelling (errtype)
+     char *errtype;
+{
+  static char *buffer;
+  static int size = -1;
+
+  if (errtype == &initialization_message)
+    {
+      /* Avoid counting chars */
+      static char message[] = "initialization of `%s'";
+      register int needed = sizeof (message) + spelling_length () + 1;
+      char *temp;
+
+      if (size < 0)
+	buffer = (char *) xmalloc (size = needed);
+      if (needed > size)
+	buffer = (char *) xrealloc (buffer, size = needed);
+
+      temp = (char *) alloca (needed);
+      sprintf (buffer, message, print_spelling (temp));
+      return buffer;
+    }
+
+  return errtype;
+}
+
+/* Issue an error message for a bad initializer component.
+   FORMAT describes the message.  OFWHAT is the name for the component.
+   LOCAL is a format string for formatting the insertion of the name
+   into the message.
+
+   If OFWHAT is null, the component name is stored on the spelling stack.
+   If the component name is a null string, then LOCAL is omitted entirely.  */
+
+void
+error_init (format, local, ofwhat)
+     char *format, *local, *ofwhat;
+{
+  char *buffer;
+
+  if (ofwhat == 0)
+    ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
+  buffer = (char *) alloca (strlen (local) + strlen (ofwhat) + 2);
+
+  if (*ofwhat)
+    sprintf (buffer, local, ofwhat);
+  else
+    buffer[0] = 0;
+
+  error (format, buffer);
+}
+
+/* Issue a pedantic warning for a bad initializer component.
+   FORMAT describes the message.  OFWHAT is the name for the component.
+   LOCAL is a format string for formatting the insertion of the name
+   into the message.
+
+   If OFWHAT is null, the component name is stored on the spelling stack.
+   If the component name is a null string, then LOCAL is omitted entirely.  */
+
+void
+pedwarn_init (format, local, ofwhat)
+     char *format, *local, *ofwhat;
+{
+  char *buffer;
+
+  if (ofwhat == 0)
+    ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
+  buffer = (char *) alloca (strlen (local) + strlen (ofwhat) + 2);
+
+  if (*ofwhat)
+    sprintf (buffer, local, ofwhat);
+  else
+    buffer[0] = 0;
+
+  pedwarn (format, buffer);
+}
+
+/* Issue a warning for a bad initializer component.
+   FORMAT describes the message.  OFWHAT is the name for the component.
+   LOCAL is a format string for formatting the insertion of the name
+   into the message.
+
+   If OFWHAT is null, the component name is stored on the spelling stack.
+   If the component name is a null string, then LOCAL is omitted entirely.  */
+
+static void
+warning_init (format, local, ofwhat)
+     char *format, *local, *ofwhat;
+{
+  char *buffer;
+
+  if (ofwhat == 0)
+    ofwhat = print_spelling ((char *) alloca (spelling_length () + 1));
+  buffer = (char *) alloca (strlen (local) + strlen (ofwhat) + 2);
+
+  if (*ofwhat)
+    sprintf (buffer, local, ofwhat);
+  else
+    buffer[0] = 0;
+
+  warning (format, buffer);
+}
+
+/* Digest the parser output INIT as an initializer for type TYPE.
+   Return a C expression of type TYPE to represent the initial value.
+
+   The arguments REQUIRE_CONSTANT and CONSTRUCTOR_CONSTANT request errors
+   if non-constant initializers or elements are seen.  CONSTRUCTOR_CONSTANT
+   applies only to elements of constructors.  */
+
+static tree
+digest_init (type, init, require_constant, constructor_constant)
+     tree type, init;
+     int require_constant, constructor_constant;
+{
+  enum tree_code code = TREE_CODE (type);
+  tree inside_init = init;
+
+  if (init == error_mark_node)
+    return init;
+
+  /* Strip NON_LVALUE_EXPRs since we aren't using as an lvalue.  */
+  /* Do not use STRIP_NOPS here.  We do not want an enumerator
+     whose value is 0 to count as a null pointer constant.  */
+  if (TREE_CODE (init) == NON_LVALUE_EXPR)
+    inside_init = TREE_OPERAND (init, 0);
+
+  /* Initialization of an array of chars from a string constant
+     optionally enclosed in braces.  */
+
+  if (code == ARRAY_TYPE)
+    {
+      tree typ1 = TYPE_MAIN_VARIANT (TREE_TYPE (type));
+      if ((typ1 == char_type_node
+	   || typ1 == signed_char_type_node
+	   || typ1 == unsigned_char_type_node
+	   || typ1 == unsigned_wchar_type_node
+	   || typ1 == signed_wchar_type_node)
+	  && ((inside_init && TREE_CODE (inside_init) == STRING_CST)))
+	{
+	  if (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
+			 TYPE_MAIN_VARIANT (type)))
+	    return inside_init;
+
+	  if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
+	       != char_type_node)
+	      && TYPE_PRECISION (typ1) == TYPE_PRECISION (char_type_node))
+	    {
+	      error_init ("char-array%s initialized from wide string",
+			  " `%s'", NULL);
+	      return error_mark_node;
+	    }
+	  if ((TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (inside_init)))
+	       == char_type_node)
+	      && TYPE_PRECISION (typ1) != TYPE_PRECISION (char_type_node))
+	    {
+	      error_init ("int-array%s initialized from non-wide string",
+			  " `%s'", NULL);
+	      return error_mark_node;
+	    }
+
+	  TREE_TYPE (inside_init) = type;
+	  if (TYPE_DOMAIN (type) != 0
+	      && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
+	    {
+	      register int size = TREE_INT_CST_LOW (TYPE_SIZE (type));
+	      size = (size + BITS_PER_UNIT - 1) / BITS_PER_UNIT;
+	      /* Subtract 1 (or sizeof (wchar_t))
+		 because it's ok to ignore the terminating null char
+		 that is counted in the length of the constant.  */
+	      if (size < TREE_STRING_LENGTH (inside_init)
+		  - (TYPE_PRECISION (typ1) != TYPE_PRECISION (char_type_node)
+		     ? TYPE_PRECISION (wchar_type_node) / BITS_PER_UNIT
+		     : 1))
+		pedwarn_init (
+		  "initializer-string for array of chars%s is too long",
+		  " `%s'", NULL);
+	    }
+	  return inside_init;
+	}
+    }
+
+  /* Any type can be initialized
+     from an expression of the same type, optionally with braces.  */
+
+  if (inside_init && TREE_TYPE (inside_init) != 0
+      && (comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (inside_init)),
+		     TYPE_MAIN_VARIANT (type))
+	  || (code == ARRAY_TYPE
+	      && comptypes (TREE_TYPE (inside_init), type))
+	  || (code == POINTER_TYPE
+	      && (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
+		  || TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE)
+	      && comptypes (TREE_TYPE (TREE_TYPE (inside_init)),
+			    TREE_TYPE (type)))))
+    {
+      if (code == POINTER_TYPE
+	  && (TREE_CODE (TREE_TYPE (inside_init)) == ARRAY_TYPE
+	      || TREE_CODE (TREE_TYPE (inside_init)) == FUNCTION_TYPE))
+	inside_init = default_conversion (inside_init);
+      else if (code == ARRAY_TYPE && TREE_CODE (inside_init) != STRING_CST
+	       && TREE_CODE (inside_init) != CONSTRUCTOR)
+	{
+	  error_init ("array%s initialized from non-constant array expression",
+		      " `%s'", NULL);
+	  return error_mark_node;
+	}
+
+      if (optimize && TREE_CODE (inside_init) == VAR_DECL)
+	inside_init = decl_constant_value (inside_init);
+
+      /* Compound expressions can only occur here if -pedantic or
+	 -pedantic-errors is specified.  In the later case, we always want
+	 an error.  In the former case, we simply want a warning.  */
+      if (require_constant && pedantic
+	  && TREE_CODE (inside_init) == COMPOUND_EXPR)
+	{
+	  inside_init
+	    = valid_compound_expr_initializer (inside_init,
+					       TREE_TYPE (inside_init));
+	  if (inside_init == error_mark_node)
+	    error_init ("initializer element%s is not constant",
+			" for `%s'", NULL);
+	  else
+	    pedwarn_init ("initializer element%s is not constant",
+			  " for `%s'", NULL);
+	  if (flag_pedantic_errors)
+	    inside_init = error_mark_node;
+	}
+      else if (require_constant && ! TREE_CONSTANT (inside_init))
+	{
+	  error_init ("initializer element%s is not constant",
+		      " for `%s'", NULL);
+	  inside_init = error_mark_node;
+	}
+      else if (require_constant
+	       && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
+	{
+	  error_init ("initializer element%s is not computable at load time",
+		      " for `%s'", NULL);
+	  inside_init = error_mark_node;
+	}
+
+      return inside_init;
+    }
+
+  /* Handle scalar types, including conversions.  */
+
+  if (code == INTEGER_TYPE || code == REAL_TYPE || code == POINTER_TYPE
+      || code == ENUMERAL_TYPE || code == COMPLEX_TYPE)
+    {
+      /* Note that convert_for_assignment calls default_conversion
+	 for arrays and functions.  We must not call it in the
+	 case where inside_init is a null pointer constant.  */
+      inside_init
+	= convert_for_assignment (type, init, "initialization",
+				  NULL_TREE, NULL_TREE, 0);
+
+      if (require_constant && ! TREE_CONSTANT (inside_init))
+	{
+	  error_init ("initializer element%s is not constant",
+		      " for `%s'", NULL);
+	  inside_init = error_mark_node;
+	}
+      else if (require_constant
+	       && initializer_constant_valid_p (inside_init, TREE_TYPE (inside_init)) == 0)
+	{
+	  error_init ("initializer element%s is not computable at load time",
+		      " for `%s'", NULL);
+	  inside_init = error_mark_node;
+	}
+
+      return inside_init;
+    }
+
+  /* Come here only for records and arrays.  */
+
+  if (TYPE_SIZE (type) && TREE_CODE (TYPE_SIZE (type)) != INTEGER_CST)
+    {
+      error_init ("variable-sized object%s may not be initialized",
+		  " `%s'", NULL);
+      return error_mark_node;
+    }
+
+  /* Traditionally, you can write  struct foo x = 0;
+     and it initializes the first element of x to 0.  */
+  if (flag_traditional)
+    {
+      tree top = 0, prev = 0, otype = type;
+      while (TREE_CODE (type) == RECORD_TYPE
+	     || TREE_CODE (type) == ARRAY_TYPE
+	     || TREE_CODE (type) == QUAL_UNION_TYPE
+	     || TREE_CODE (type) == UNION_TYPE)
+	{
+	  tree temp = build (CONSTRUCTOR, type, NULL_TREE, NULL_TREE);
+	  if (prev == 0)
+	    top = temp;
+	  else
+	    TREE_OPERAND (prev, 1) = build_tree_list (NULL_TREE, temp);
+	  prev = temp;
+	  if (TREE_CODE (type) == ARRAY_TYPE)
+	    type = TREE_TYPE (type);
+	  else if (TYPE_FIELDS (type))
+	    type = TREE_TYPE (TYPE_FIELDS (type));
+	  else
+	    {
+	      error_init ("invalid initializer%s", " for `%s'", NULL);
+	      return error_mark_node;
+	    }
+	}
+
+      if (otype != type)
+	{
+	  TREE_OPERAND (prev, 1)
+	    = build_tree_list (NULL_TREE,
+			       digest_init (type, init, require_constant,
+					    constructor_constant));
+	  return top;
+	}
+      else
+	return error_mark_node;
+    }
+  error_init ("invalid initializer%s", " for `%s'", NULL);
+  return error_mark_node;
+}
+
+/* Handle initializers that use braces.  */
+
+/* Type of object we are accumulating a constructor for.
+   This type is always a RECORD_TYPE, UNION_TYPE or ARRAY_TYPE.  */
+static tree constructor_type;
+
+/* For a RECORD_TYPE or UNION_TYPE, this is the chain of fields
+   left to fill.  */
+static tree constructor_fields;
+
+/* For an ARRAY_TYPE, this is the specified index
+   at which to store the next element we get.
+   This is a special INTEGER_CST node that we modify in place.  */
+static tree constructor_index;
+
+/* For an ARRAY_TYPE, this is the end index of the range
+   to initialize with the next element, or NULL in the ordinary case
+   where the element is used just once.  */
+static tree constructor_range_end;
+
+/* For an ARRAY_TYPE, this is the maximum index.  */
+static tree constructor_max_index;
+
+/* For a RECORD_TYPE, this is the first field not yet written out.  */
+static tree constructor_unfilled_fields;
+
+/* For an ARRAY_TYPE, this is the index of the first element
+   not yet written out.
+   This is a special INTEGER_CST node that we modify in place.  */
+static tree constructor_unfilled_index;
+
+/* In a RECORD_TYPE, the byte index of the next consecutive field.
+   This is so we can generate gaps between fields, when appropriate.
+   This is a special INTEGER_CST node that we modify in place.  */
+static tree constructor_bit_index;
+
+/* If we are saving up the elements rather than allocating them,
+   this is the list of elements so far (in reverse order,
+   most recent first).  */
+static tree constructor_elements;
+
+/* 1 if so far this constructor's elements are all compile-time constants.  */
+static int constructor_constant;
+
+/* 1 if so far this constructor's elements are all valid address constants.  */
+static int constructor_simple;
+
+/* 1 if this constructor is erroneous so far.  */
+static int constructor_erroneous;
+
+/* 1 if have called defer_addressed_constants.  */
+static int constructor_subconstants_deferred;
+
+/* List of pending elements at this constructor level.
+   These are elements encountered out of order
+   which belong at places we haven't reached yet in actually
+   writing the output.  */
+static tree constructor_pending_elts;
+
+/* The SPELLING_DEPTH of this constructor.  */
+static int constructor_depth;
+
+/* 0 if implicitly pushing constructor levels is allowed.  */
+int constructor_no_implicit = 0; /* 0 for C; 1 for some other languages. */
+
+/* 1 if this constructor level was entered implicitly.  */
+static int constructor_implicit;
+
+static int require_constant_value;
+static int require_constant_elements;
+
+/* 1 if it is ok to output this constructor as we read it.
+   0 means must accumulate a CONSTRUCTOR expression.  */
+static int constructor_incremental;
+
+/* DECL node for which an initializer is being read.
+   0 means we are reading a constructor expression
+   such as (struct foo) {...}.  */
+static tree constructor_decl;
+
+/* start_init saves the ASMSPEC arg here for really_start_incremental_init.  */
+static char *constructor_asmspec;
+
+/* Nonzero if this is an initializer for a top-level decl.  */
+static int constructor_top_level;
+
+/* When we finish reading a constructor expression
+   (constructor_decl is 0), the CONSTRUCTOR goes here.  */
+static tree constructor_result;
+
+/* This stack has a level for each implicit or explicit level of
+   structuring in the initializer, including the outermost one.  It
+   saves the values of most of the variables above.  */
+
+struct constructor_stack
+{
+  struct constructor_stack *next;
+  tree type;
+  tree fields;
+  tree index;
+  tree range_end;
+  tree max_index;
+  tree unfilled_index;
+  tree unfilled_fields;
+  tree bit_index;
+  tree elements;
+  int offset;
+  tree pending_elts;
+  int depth;
+  /* If nonzero, this value should replace the entire
+     constructor at this level.  */
+  tree replacement_value;
+  char constant;
+  char simple;
+  char implicit;
+  char incremental;
+  char erroneous;
+  char outer;
+};
+
+struct constructor_stack *constructor_stack;
+
+/* This stack records separate initializers that are nested.
+   Nested initializers can't happen in ANSI C, but GNU C allows them
+   in cases like { ... (struct foo) { ... } ... }.  */
+
+struct initializer_stack
+{
+  struct initializer_stack *next;
+  tree decl;
+  char *asmspec;
+  struct constructor_stack *constructor_stack;
+  tree elements;
+  struct spelling *spelling;
+  struct spelling *spelling_base;
+  int spelling_size;
+  char top_level;
+  char incremental;
+  char require_constant_value;
+  char require_constant_elements;
+  char deferred;
+};
+
+struct initializer_stack *initializer_stack;
+
+/* Prepare to parse and output the initializer for variable DECL.  */
+
+void
+start_init (decl, asmspec_tree, top_level)
+     tree decl;
+     tree asmspec_tree;
+     int top_level;
+{
+  char *locus;
+  struct initializer_stack *p
+    = (struct initializer_stack *) xmalloc (sizeof (struct initializer_stack));
+  char *asmspec = 0;
+
+  if (asmspec_tree)
+    asmspec = TREE_STRING_POINTER (asmspec_tree);
+
+  p->decl = constructor_decl;
+  p->asmspec = constructor_asmspec;
+  p->incremental = constructor_incremental;
+  p->require_constant_value = require_constant_value;
+  p->require_constant_elements = require_constant_elements;
+  p->constructor_stack = constructor_stack;
+  p->elements = constructor_elements;
+  p->spelling = spelling;
+  p->spelling_base = spelling_base;
+  p->spelling_size = spelling_size;
+  p->deferred = constructor_subconstants_deferred;
+  p->top_level = constructor_top_level;
+  p->next = initializer_stack;
+  initializer_stack = p;
+
+  constructor_decl = decl;
+  constructor_incremental = top_level;
+  constructor_asmspec = asmspec;
+  constructor_subconstants_deferred = 0;
+  constructor_top_level = top_level;
+
+  if (decl != 0)
+    {
+      require_constant_value = TREE_STATIC (decl);
+      require_constant_elements
+	= ((TREE_STATIC (decl) || pedantic)
+	   /* For a scalar, you can always use any value to initialize,
+	      even within braces.  */
+	   && (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
+	       || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
+	       || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE
+	       || TREE_CODE (TREE_TYPE (decl)) == QUAL_UNION_TYPE));
+      locus = IDENTIFIER_POINTER (DECL_NAME (decl));
+      constructor_incremental |= TREE_STATIC (decl);
+    }
+  else
+    {
+      require_constant_value = 0;
+      require_constant_elements = 0;
+      locus = "(anonymous)";
+    }
+
+  constructor_stack = 0;
+
+  missing_braces_mentioned = 0;
+
+  spelling_base = 0;
+  spelling_size = 0;
+  RESTORE_SPELLING_DEPTH (0);
+
+  if (locus)
+    push_string (locus);
+}
+
+void
+finish_init ()
+{
+  struct initializer_stack *p = initializer_stack;
+
+  /* Output subconstants (string constants, usually)
+     that were referenced within this initializer and saved up.
+     Must do this if and only if we called defer_addressed_constants.  */
+  if (constructor_subconstants_deferred)
+    output_deferred_addressed_constants ();
+
+  /* Free the whole constructor stack of this initializer.  */
+  while (constructor_stack)
+    {
+      struct constructor_stack *q = constructor_stack;
+      constructor_stack = q->next;
+      free (q);
+    }
+
+  /* Pop back to the data of the outer initializer (if any).  */
+  constructor_decl = p->decl;
+  constructor_asmspec = p->asmspec;
+  constructor_incremental = p->incremental;
+  require_constant_value = p->require_constant_value;
+  require_constant_elements = p->require_constant_elements;
+  constructor_stack = p->constructor_stack;
+  constructor_elements = p->elements;
+  spelling = p->spelling;
+  spelling_base = p->spelling_base;
+  spelling_size = p->spelling_size;
+  constructor_subconstants_deferred = p->deferred;
+  constructor_top_level = p->top_level;
+  initializer_stack = p->next;
+  free (p);
+}
+
+/* Call here when we see the initializer is surrounded by braces.
+   This is instead of a call to push_init_level;
+   it is matched by a call to pop_init_level.
+
+   TYPE is the type to initialize, for a constructor expression.
+   For an initializer for a decl, TYPE is zero.  */
+
+void
+really_start_incremental_init (type)
+     tree type;
+{
+  struct constructor_stack *p
+    = (struct constructor_stack *) xmalloc (sizeof (struct constructor_stack));
+
+  if (type == 0)
+    type = TREE_TYPE (constructor_decl);
+
+  /* Turn off constructor_incremental if type is a struct with bitfields.
+     Do this before the first push, so that the corrected value
+     is available in finish_init.  */
+  check_init_type_bitfields (type);
+
+  p->type = constructor_type;
+  p->fields = constructor_fields;
+  p->index = constructor_index;
+  p->range_end = constructor_range_end;
+  p->max_index = constructor_max_index;
+  p->unfilled_index = constructor_unfilled_index;
+  p->unfilled_fields = constructor_unfilled_fields;
+  p->bit_index = constructor_bit_index;
+  p->elements = constructor_elements;
+  p->constant = constructor_constant;
+  p->simple = constructor_simple;
+  p->erroneous = constructor_erroneous;
+  p->pending_elts = constructor_pending_elts;
+  p->depth = constructor_depth;
+  p->replacement_value = 0;
+  p->implicit = 0;
+  p->incremental = constructor_incremental;
+  p->outer = 0;
+  p->next = 0;
+  constructor_stack = p;
+
+  constructor_constant = 1;
+  constructor_simple = 1;
+  constructor_depth = SPELLING_DEPTH ();
+  constructor_elements = 0;
+  constructor_pending_elts = 0;
+  constructor_type = type;
+
+  if (TREE_CODE (constructor_type) == RECORD_TYPE
+      || TREE_CODE (constructor_type) == UNION_TYPE)
+    {
+      constructor_fields = TYPE_FIELDS (constructor_type);
+      /* Skip any nameless bit fields at the beginning.  */
+      while (constructor_fields != 0 && DECL_BIT_FIELD (constructor_fields)
+	     && DECL_NAME (constructor_fields) == 0)
+	constructor_fields = TREE_CHAIN (constructor_fields);
+      constructor_unfilled_fields = constructor_fields;
+      constructor_bit_index = copy_node (integer_zero_node);
+    }
+  else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+    {
+      constructor_range_end = 0;
+      if (TYPE_DOMAIN (constructor_type))
+	{
+	  constructor_max_index
+	    = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
+	  constructor_index
+	    = copy_node (TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
+	}
+      else
+	constructor_index = copy_node (integer_zero_node);
+      constructor_unfilled_index = copy_node (constructor_index);
+    }
+  else
+    {
+      /* Handle the case of int x = {5}; */
+      constructor_fields = constructor_type;
+      constructor_unfilled_fields = constructor_type;
+    }
+
+  if (constructor_incremental)
+    {
+      int momentary = suspend_momentary ();
+      push_obstacks_nochange ();
+      if (TREE_PERMANENT (constructor_decl))
+	end_temporary_allocation ();
+      make_decl_rtl (constructor_decl, constructor_asmspec,
+		     constructor_top_level);
+      assemble_variable (constructor_decl, constructor_top_level, 0, 1);
+      pop_obstacks ();
+      resume_momentary (momentary);
+    }
+
+  if (constructor_incremental)
+    {
+      defer_addressed_constants ();
+      constructor_subconstants_deferred = 1;
+    }
+}
+
+/* Push down into a subobject, for initialization.
+   If this is for an explicit set of braces, IMPLICIT is 0.
+   If it is because the next element belongs at a lower level,
+   IMPLICIT is 1.  */
+
+void
+push_init_level (implicit)
+     int implicit;
+{
+  struct constructor_stack *p;
+
+  /* If we've exhausted any levels that didn't have braces,
+     pop them now.  */
+  while (constructor_stack->implicit)
+    {
+      if ((TREE_CODE (constructor_type) == RECORD_TYPE
+	   || TREE_CODE (constructor_type) == UNION_TYPE)
+	  && constructor_fields == 0)
+	process_init_element (pop_init_level (1));
+      else if (TREE_CODE (constructor_type) == ARRAY_TYPE
+	       && tree_int_cst_lt (constructor_max_index, constructor_index))
+	process_init_element (pop_init_level (1));
+      else
+	break;
+    }
+
+  /* Structure elements may require alignment.  Do this now
+     if necessary for the subaggregate.  */
+  if (constructor_incremental && constructor_type != 0
+      && TREE_CODE (constructor_type) == RECORD_TYPE && constructor_fields)
+    {
+      /* Advance to offset of this element.  */
+      if (! tree_int_cst_equal (constructor_bit_index,
+				DECL_FIELD_BITPOS (constructor_fields)))
+	{
+	  int next = (TREE_INT_CST_LOW
+		      (DECL_FIELD_BITPOS (constructor_fields))
+		      / BITS_PER_UNIT);
+	  int here = (TREE_INT_CST_LOW (constructor_bit_index)
+		      / BITS_PER_UNIT);
+
+	  assemble_zeros (next - here);
+	}
+    }
+
+  p = (struct constructor_stack *) xmalloc (sizeof (struct constructor_stack));
+  p->type = constructor_type;
+  p->fields = constructor_fields;
+  p->index = constructor_index;
+  p->range_end = constructor_range_end;
+  p->max_index = constructor_max_index;
+  p->unfilled_index = constructor_unfilled_index;
+  p->unfilled_fields = constructor_unfilled_fields;
+  p->bit_index = constructor_bit_index;
+  p->elements = constructor_elements;
+  p->constant = constructor_constant;
+  p->simple = constructor_simple;
+  p->erroneous = constructor_erroneous;
+  p->pending_elts = constructor_pending_elts;
+  p->depth = constructor_depth;
+  p->replacement_value = 0;
+  p->implicit = implicit;
+  p->incremental = constructor_incremental;
+  p->outer = 0;
+  p->next = constructor_stack;
+  constructor_stack = p;
+
+  constructor_constant = 1;
+  constructor_simple = 1;
+  constructor_depth = SPELLING_DEPTH ();
+  constructor_elements = 0;
+  constructor_pending_elts = 0;
+
+  /* Don't die if an entire brace-pair level is superfluous
+     in the containing level.  */
+  if (constructor_type == 0)
+    ;
+  else if (TREE_CODE (constructor_type) == RECORD_TYPE
+	   || TREE_CODE (constructor_type) == UNION_TYPE)
+    {
+      /* Don't die if there are extra init elts at the end.  */
+      if (constructor_fields == 0)
+	constructor_type = 0;
+      else
+	{
+	  constructor_type = TREE_TYPE (constructor_fields);
+	  push_member_name (constructor_fields);
+	  constructor_depth++;
+	  if (constructor_fields != constructor_unfilled_fields)
+	    constructor_incremental = 0;
+	}
+    }
+  else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+    {
+      constructor_type = TREE_TYPE (constructor_type);
+      push_array_bounds (TREE_INT_CST_LOW (constructor_index));
+      constructor_depth++;
+      if (! tree_int_cst_equal (constructor_index, constructor_unfilled_index)
+	  || constructor_range_end != 0)
+	constructor_incremental = 0;
+    }
+
+  if (constructor_type == 0)
+    {
+      error_init ("extra brace group at end of initializer%s",
+		  " for `%s'", NULL);
+      constructor_fields = 0;
+      constructor_unfilled_fields = 0;
+      return;
+    }
+
+  /* Turn off constructor_incremental if type is a struct with bitfields.  */
+  check_init_type_bitfields (constructor_type);
+
+  if (implicit && warn_missing_braces && !missing_braces_mentioned)
+    {
+      missing_braces_mentioned = 1;
+      warning_init ("missing braces around initializer%s", " for `%s'", NULL);
+    }
+
+  if (TREE_CODE (constructor_type) == RECORD_TYPE
+	   || TREE_CODE (constructor_type) == UNION_TYPE)
+    {
+      constructor_fields = TYPE_FIELDS (constructor_type);
+      /* Skip any nameless bit fields at the beginning.  */
+      while (constructor_fields != 0 && DECL_BIT_FIELD (constructor_fields)
+	     && DECL_NAME (constructor_fields) == 0)
+	constructor_fields = TREE_CHAIN (constructor_fields);
+      constructor_unfilled_fields = constructor_fields;
+      constructor_bit_index = copy_node (integer_zero_node);
+    }
+  else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+    {
+      constructor_range_end = 0;
+      if (TYPE_DOMAIN (constructor_type))
+	{
+	  constructor_max_index
+	    = TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type));
+	  constructor_index
+	    = copy_node (TYPE_MIN_VALUE (TYPE_DOMAIN (constructor_type)));
+	}
+      else
+	constructor_index = copy_node (integer_zero_node);
+      constructor_unfilled_index = copy_node (constructor_index);
+    }
+  else
+    {
+      warning_init ("braces around scalar initializer%s", " for `%s'", NULL);
+      constructor_fields = constructor_type;
+      constructor_unfilled_fields = constructor_type;
+    }
+}
+
+/* Don't read a struct incrementally if it has any bitfields,
+   because the incremental reading code doesn't know how to
+   handle bitfields yet.  */
+
+static void
+check_init_type_bitfields (type)
+     tree type;
+{
+  if (TREE_CODE (type) == RECORD_TYPE)
+    {
+      tree tail;
+      for (tail = TYPE_FIELDS (type); tail;
+	   tail = TREE_CHAIN (tail))
+	{
+	  if (DECL_BIT_FIELD (tail)
+	      /* This catches cases like `int foo : 8;'.  */
+	      || DECL_MODE (tail) != TYPE_MODE (TREE_TYPE (tail)))
+	    {
+	      constructor_incremental = 0;
+	      break;
+	    }
+
+	  check_init_type_bitfields (TREE_TYPE (tail));
+	}
+    }
+
+  else if (TREE_CODE (type) == ARRAY_TYPE)
+    check_init_type_bitfields (TREE_TYPE (type));
+}
+
+/* At the end of an implicit or explicit brace level, 
+   finish up that level of constructor.
+   If we were outputting the elements as they are read, return 0
+   from inner levels (process_init_element ignores that),
+   but return error_mark_node from the outermost level
+   (that's what we want to put in DECL_INITIAL).
+   Otherwise, return a CONSTRUCTOR expression.  */
+
+tree
+pop_init_level (implicit)
+     int implicit;
+{
+  struct constructor_stack *p;
+  int size = 0;
+  tree constructor = 0;
+
+  if (implicit == 0)
+    {
+      /* When we come to an explicit close brace,
+	 pop any inner levels that didn't have explicit braces.  */
+      while (constructor_stack->implicit)
+	process_init_element (pop_init_level (1));
+    }
+
+  p = constructor_stack;
+
+  if (constructor_type != 0)
+    size = int_size_in_bytes (constructor_type);
+
+  /* Now output all pending elements.  */
+  output_pending_init_elements (1);
+
+#if 0 /* c-parse.in warns about {}.  */
+  /* In ANSI, each brace level must have at least one element.  */
+  if (! implicit && pedantic
+      && (TREE_CODE (constructor_type) == ARRAY_TYPE
+	  ? integer_zerop (constructor_unfilled_index)
+	  : constructor_unfilled_fields == TYPE_FIELDS (constructor_type)))
+    pedwarn_init ("empty braces in initializer%s", " for `%s'", NULL);
+#endif
+
+  /* Pad out the end of the structure.  */
+  
+  if (p->replacement_value)
+    {
+      /* If this closes a superfluous brace pair,
+	 just pass out the element between them.  */
+      constructor = p->replacement_value;
+      /* If this is the top level thing within the initializer,
+	 and it's for a variable, then since we already called
+	 assemble_variable, we must output the value now.  */
+      if (p->next == 0 && constructor_decl != 0
+	  && constructor_incremental)
+	{
+	  constructor = digest_init (constructor_type, constructor,
+				     require_constant_value,
+				     require_constant_elements);
+
+	  /* If initializing an array of unknown size,
+	     determine the size now.  */
+	  if (TREE_CODE (constructor_type) == ARRAY_TYPE
+	      && TYPE_DOMAIN (constructor_type) == 0)
+	    {
+	      int failure;
+	      int momentary_p;
+
+	      push_obstacks_nochange ();
+	      if (TREE_PERMANENT (constructor_type))
+		end_temporary_allocation ();
+
+	      momentary_p = suspend_momentary ();
+
+	      /* We shouldn't have an incomplete array type within
+		 some other type.  */
+	      if (constructor_stack->next)
+		abort ();
+
+	      failure
+		= complete_array_type (constructor_type,
+				       constructor, 0);
+	      if (failure)
+		abort ();
+
+	      size = int_size_in_bytes (constructor_type);
+	      resume_momentary (momentary_p);
+	      pop_obstacks ();
+	    }
+
+	  output_constant (constructor, size);
+	}
+    }
+  else if (constructor_type == 0)
+    ;
+  else if (TREE_CODE (constructor_type) != RECORD_TYPE
+	   && TREE_CODE (constructor_type) != UNION_TYPE
+	   && TREE_CODE (constructor_type) != ARRAY_TYPE
+	   && ! constructor_incremental)
+    {
+      /* A nonincremental scalar initializer--just return
+	 the element, after verifying there is just one.  */
+      if (constructor_elements == 0)
+	{
+	  error_init ("empty scalar initializer%s",
+		      " for `%s'", NULL);
+	  constructor = error_mark_node;
+	}
+      else if (TREE_CHAIN (constructor_elements) != 0)
+	{
+	  error_init ("extra elements in scalar initializer%s",
+		      " for `%s'", NULL);
+	  constructor = TREE_VALUE (constructor_elements);
+	}
+      else
+	constructor = TREE_VALUE (constructor_elements);
+    }
+  else if (! constructor_incremental)
+    {
+      if (constructor_erroneous)
+	constructor = error_mark_node;
+      else
+	{
+	  int momentary = suspend_momentary ();
+
+	  constructor = build (CONSTRUCTOR, constructor_type, NULL_TREE,
+			       nreverse (constructor_elements));
+	  if (constructor_constant)
+	    TREE_CONSTANT (constructor) = 1;
+	  if (constructor_constant && constructor_simple)
+	    TREE_STATIC (constructor) = 1;
+
+	  resume_momentary (momentary);
+	}
+    }
+  else
+    {
+      tree filled;
+      int momentary = suspend_momentary ();
+
+      if (TREE_CODE (constructor_type) == RECORD_TYPE
+	  || TREE_CODE (constructor_type) == UNION_TYPE)
+	{
+	  /* Find the offset of the end of that field.  */
+	  filled = size_binop (CEIL_DIV_EXPR,
+			       constructor_bit_index,
+			       size_int (BITS_PER_UNIT));
+	}
+      else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  /* If initializing an array of unknown size,
+	     determine the size now.  */
+	  if (TREE_CODE (constructor_type) == ARRAY_TYPE
+	      && TYPE_DOMAIN (constructor_type) == 0)
+	    {
+	      tree maxindex
+		= size_binop (MINUS_EXPR,
+			      constructor_unfilled_index,
+			      integer_one_node);
+
+	      push_obstacks_nochange ();
+	      if (TREE_PERMANENT (constructor_type))
+		end_temporary_allocation ();
+	      maxindex = copy_node (maxindex);
+	      TYPE_DOMAIN (constructor_type) = build_index_type (maxindex);
+	      TREE_TYPE (maxindex) = TYPE_DOMAIN (constructor_type);
+
+	      /* TYPE_MAX_VALUE is always one less than the number of elements
+		 in the array, because we start counting at zero.  Therefore,
+		 warn only if the value is less than zero.  */
+	      if (pedantic
+		  && (tree_int_cst_sgn (TYPE_MAX_VALUE (TYPE_DOMAIN (constructor_type)))
+		      < 0))
+		error_with_decl (constructor_decl,
+				 "zero or negative array size `%s'");
+	      layout_type (constructor_type);
+	      size = int_size_in_bytes (constructor_type);
+	      pop_obstacks ();
+	    }
+
+	  filled = size_binop (MULT_EXPR, constructor_unfilled_index,
+			       size_in_bytes (TREE_TYPE (constructor_type)));
+	}
+      else
+	filled = 0;
+
+      if (filled != 0)
+	assemble_zeros (size - TREE_INT_CST_LOW (filled));
+
+      resume_momentary (momentary);
+    }
+
+	  
+  constructor_type = p->type;
+  constructor_fields = p->fields;
+  constructor_index = p->index;
+  constructor_range_end = p->range_end;
+  constructor_max_index = p->max_index;
+  constructor_unfilled_index = p->unfilled_index;
+  constructor_unfilled_fields = p->unfilled_fields;
+  constructor_bit_index = p->bit_index;
+  constructor_elements = p->elements;
+  constructor_constant = p->constant;
+  constructor_simple = p->simple;
+  constructor_erroneous = p->erroneous;
+  constructor_pending_elts = p->pending_elts;
+  constructor_depth = p->depth;
+  constructor_incremental = p->incremental;
+  RESTORE_SPELLING_DEPTH (constructor_depth);
+
+  constructor_stack = p->next;
+  free (p);
+
+  if (constructor == 0)
+    {
+      if (constructor_stack == 0)
+	return error_mark_node;
+      return NULL_TREE;
+    }
+  return constructor;
+}
+
+/* Within an array initializer, specify the next index to be initialized.
+   FIRST is that index.  If LAST is nonzero, then initialize a range
+   of indices, running from FIRST through LAST.  */
+
+void
+set_init_index (first, last)
+     tree first, last;
+{
+  while ((TREE_CODE (first) == NOP_EXPR
+	  || TREE_CODE (first) == CONVERT_EXPR
+	  || TREE_CODE (first) == NON_LVALUE_EXPR)
+	 && (TYPE_MODE (TREE_TYPE (first))
+	     == TYPE_MODE (TREE_TYPE (TREE_OPERAND (first, 0)))))
+    (first) = TREE_OPERAND (first, 0);
+  if (last)
+    while ((TREE_CODE (last) == NOP_EXPR
+	    || TREE_CODE (last) == CONVERT_EXPR
+	    || TREE_CODE (last) == NON_LVALUE_EXPR)
+	   && (TYPE_MODE (TREE_TYPE (last))
+	       == TYPE_MODE (TREE_TYPE (TREE_OPERAND (last, 0)))))
+      (last) = TREE_OPERAND (last, 0);
+
+  if (TREE_CODE (first) != INTEGER_CST)
+    error_init ("nonconstant array index in initializer%s", " for `%s'", NULL);
+  else if (last != 0 && TREE_CODE (last) != INTEGER_CST)
+    error_init ("nonconstant array index in initializer%s", " for `%s'", NULL);
+  else if (tree_int_cst_lt (first, constructor_unfilled_index))
+    error_init ("duplicate array index in initializer%s", " for `%s'", NULL);
+  else
+    {
+      TREE_INT_CST_LOW (constructor_index)
+	= TREE_INT_CST_LOW (first);
+      TREE_INT_CST_HIGH (constructor_index)
+	= TREE_INT_CST_HIGH (first);
+
+      if (last != 0 && tree_int_cst_lt (last, first))
+	error_init ("empty index range in initializer%s", " for `%s'", NULL);
+      else
+	{
+	  if (pedantic)
+	    pedwarn ("ANSI C forbids specifying element to initialize");
+	  constructor_range_end = last;
+	}
+    }
+}
+
+/* Within a struct initializer, specify the next field to be initialized.  */
+
+void
+set_init_label (fieldname)
+     tree fieldname;
+{
+  tree tail;
+  int passed = 0;
+
+  /* Don't die if an entire brace-pair level is superfluous
+     in the containing level.  */
+  if (constructor_type == 0)
+    return;
+
+  for (tail = TYPE_FIELDS (constructor_type); tail;
+       tail = TREE_CHAIN (tail))
+    {
+      if (tail == constructor_unfilled_fields)
+	passed = 1;
+      if (DECL_NAME (tail) == fieldname)
+	break;
+    }
+
+  if (tail == 0)
+    error ("unknown field `%s' specified in initializer",
+	   IDENTIFIER_POINTER (fieldname));
+  else if (!passed)
+    error ("field `%s' already initialized",
+	   IDENTIFIER_POINTER (fieldname));
+  else
+    {
+      constructor_fields = tail;
+      if (pedantic)
+	pedwarn ("ANSI C forbids specifying structure member to initialize");
+    }
+}
+
+/* "Output" the next constructor element.
+   At top level, really output it to assembler code now.
+   Otherwise, collect it in a list from which we will make a CONSTRUCTOR.
+   TYPE is the data type that the containing data type wants here.
+   FIELD is the field (a FIELD_DECL) or the index that this element fills.
+
+   PENDING if non-nil means output pending elements that belong
+   right after this element.  (PENDING is normally 1;
+   it is 0 while outputting pending elements, to avoid recursion.)  */
+
+static void
+output_init_element (value, type, field, pending)
+     tree value, type, field;
+     int pending;
+{
+  int duplicate = 0;
+
+  if (TREE_CODE (TREE_TYPE (value)) == FUNCTION_TYPE
+      || (TREE_CODE (TREE_TYPE (value)) == ARRAY_TYPE
+	  && !(TREE_CODE (value) == STRING_CST
+	       && TREE_CODE (type) == ARRAY_TYPE
+	       && TREE_CODE (TREE_TYPE (type)) == INTEGER_TYPE)
+	  && !comptypes (TYPE_MAIN_VARIANT (TREE_TYPE (value)),
+			 TYPE_MAIN_VARIANT (type))))
+    value = default_conversion (value);
+
+  if (value == error_mark_node)
+    constructor_erroneous = 1;
+  else if (!TREE_CONSTANT (value))
+    constructor_constant = 0;
+  else if (initializer_constant_valid_p (value, TREE_TYPE (value)) == 0
+	   || ((TREE_CODE (constructor_type) == RECORD_TYPE
+		|| TREE_CODE (constructor_type) == UNION_TYPE)
+	       && DECL_BIT_FIELD (field) && TREE_CODE (value) != INTEGER_CST))
+    constructor_simple = 0;
+
+  if (require_constant_value && ! TREE_CONSTANT (value))
+    {
+      error_init ("initializer element%s is not constant",
+		  " for `%s'", NULL);
+      value = error_mark_node;
+    }
+  else if (require_constant_elements
+	   && initializer_constant_valid_p (value, TREE_TYPE (value)) == 0)
+    {
+      error_init ("initializer element%s is not computable at load time",
+		  " for `%s'", NULL);
+      value = error_mark_node;
+    }
+
+  /* If this element duplicates one on constructor_pending_elts,
+     print a message and ignore it.  Don't do this when we're
+     processing elements taken off constructor_pending_elts,
+     because we'd always get spurious errors.  */
+  if (pending)
+    {
+      if (TREE_CODE (constructor_type) == RECORD_TYPE
+	  || TREE_CODE (constructor_type) == UNION_TYPE)
+	{
+	  if (purpose_member (field, constructor_pending_elts))
+	    {
+	      error_init ("duplicate initializer%s", " for `%s'", NULL);
+	      duplicate = 1;
+	    }
+	}
+      if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  tree tail;
+	  for (tail = constructor_pending_elts; tail;
+	       tail = TREE_CHAIN (tail))
+	    if (TREE_PURPOSE (tail) != 0
+		&& TREE_CODE (TREE_PURPOSE (tail)) == INTEGER_CST
+		&& tree_int_cst_equal (TREE_PURPOSE (tail), constructor_index))
+	      break;
+
+	  if (tail != 0)
+	    {
+	      error_init ("duplicate initializer%s", " for `%s'", NULL);
+	      duplicate = 1;
+	    }
+	}
+    }
+
+  /* If this element doesn't come next in sequence,
+     put it on constructor_pending_elts.  */
+  if (TREE_CODE (constructor_type) == ARRAY_TYPE
+      && !tree_int_cst_equal (field, constructor_unfilled_index))
+    {
+      if (! duplicate)
+	/* The copy_node is needed in case field is actually
+	   constructor_index, which is modified in place.  */
+	constructor_pending_elts
+	  = tree_cons (copy_node (field),
+		       digest_init (type, value, require_constant_value, 
+				    require_constant_elements),
+		       constructor_pending_elts);
+    }
+  else if (TREE_CODE (constructor_type) == RECORD_TYPE
+	   && field != constructor_unfilled_fields)
+    {
+      /* We do this for records but not for unions.  In a union,
+	 no matter which field is specified, it can be initialized
+	 right away since it starts at the beginning of the union.  */
+      if (!duplicate)
+	constructor_pending_elts
+	  = tree_cons (field,
+		       digest_init (type, value, require_constant_value, 
+				    require_constant_elements),
+		       constructor_pending_elts);
+    }
+  else
+    {
+      /* Otherwise, output this element either to
+	 constructor_elements or to the assembler file.  */
+
+      if (!duplicate)
+	{
+	  if (! constructor_incremental)
+	    {
+	      if (field && TREE_CODE (field) == INTEGER_CST)
+		field = copy_node (field);
+	      constructor_elements
+		= tree_cons (field, digest_init (type, value,
+						 require_constant_value, 
+						 require_constant_elements),
+			     constructor_elements);
+	    }
+	  else
+	    {
+	      /* Structure elements may require alignment.
+		 Do this, if necessary.  */
+	      if (TREE_CODE (constructor_type) == RECORD_TYPE)
+		{
+		  /* Advance to offset of this element.  */
+		  if (! tree_int_cst_equal (constructor_bit_index,
+					    DECL_FIELD_BITPOS (field)))
+		    {
+		      int next = (TREE_INT_CST_LOW (DECL_FIELD_BITPOS (field))
+				  / BITS_PER_UNIT);
+		      int here = (TREE_INT_CST_LOW (constructor_bit_index)
+				  / BITS_PER_UNIT);
+
+		      assemble_zeros (next - here);
+		    }
+		}
+	      output_constant (digest_init (type, value,
+					    require_constant_value,
+					    require_constant_elements),
+			       int_size_in_bytes (type));
+
+	      /* For a record or union,
+		 keep track of end position of last field.  */
+	      if (TREE_CODE (constructor_type) == RECORD_TYPE
+		  || TREE_CODE (constructor_type) == UNION_TYPE)
+		{
+		  tree temp = size_binop (PLUS_EXPR, DECL_FIELD_BITPOS (field),
+					  DECL_SIZE (field));
+		  TREE_INT_CST_LOW (constructor_bit_index)
+		    = TREE_INT_CST_LOW (temp);
+		  TREE_INT_CST_HIGH (constructor_bit_index)
+		    = TREE_INT_CST_HIGH (temp);
+		}
+	    }
+	}
+
+      /* Advance the variable that indicates sequential elements output.  */
+      if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  tree tem = size_binop (PLUS_EXPR, constructor_unfilled_index,
+				 integer_one_node);
+	  TREE_INT_CST_LOW (constructor_unfilled_index)
+	    = TREE_INT_CST_LOW (tem);
+	  TREE_INT_CST_HIGH (constructor_unfilled_index)
+	    = TREE_INT_CST_HIGH (tem);
+	}
+      else if (TREE_CODE (constructor_type) == RECORD_TYPE)
+	constructor_unfilled_fields = TREE_CHAIN (constructor_unfilled_fields);
+      else if (TREE_CODE (constructor_type) == UNION_TYPE)
+	constructor_unfilled_fields = 0;
+
+      /* Now output any pending elements which have become next.  */
+      if (pending)
+	output_pending_init_elements (0);
+    }
+}
+
+/* Output any pending elements which have become next.
+   As we output elements, constructor_unfilled_{fields,index}
+   advances, which may cause other elements to become next;
+   if so, they too are output.
+
+   If ALL is 0, we return when there are
+   no more pending elements to output now.
+
+   If ALL is 1, we output space as necessary so that
+   we can output all the pending elements.  */
+
+static void
+output_pending_init_elements (all)
+     int all;
+{
+  tree tail;
+  tree next;
+
+ retry:
+
+  /* Look thru the whole pending list.
+     If we find an element that should be output now,
+     output it.  Otherwise, set NEXT to the element
+     that comes first among those still pending.  */
+     
+  next = 0;
+  for (tail = constructor_pending_elts; tail;
+       tail = TREE_CHAIN (tail))
+    {
+      if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  if (tree_int_cst_equal (TREE_PURPOSE (tail),
+				  constructor_unfilled_index))
+	    {
+	      output_init_element (TREE_VALUE (tail),
+				   TREE_TYPE (constructor_type),
+				   constructor_unfilled_index, 0);
+	      goto retry;
+	    }
+	  else if (tree_int_cst_lt (TREE_PURPOSE (tail),
+				    constructor_unfilled_index))
+	    ;
+	  else if (next == 0
+		   || tree_int_cst_lt (TREE_PURPOSE (tail), next))
+	    next = TREE_PURPOSE (tail);
+	}
+      else if (TREE_CODE (constructor_type) == RECORD_TYPE
+	       || TREE_CODE (constructor_type) == UNION_TYPE)
+	{
+	  if (TREE_PURPOSE (tail) == constructor_unfilled_fields)
+	    {
+	      output_init_element (TREE_VALUE (tail),
+				   TREE_TYPE (constructor_unfilled_fields),
+				   constructor_unfilled_fields,
+				   0);
+	      goto retry;
+	    }
+	  else if (constructor_unfilled_fields == 0
+		   || tree_int_cst_lt (DECL_FIELD_BITPOS (TREE_PURPOSE (tail)),
+				       DECL_FIELD_BITPOS (constructor_unfilled_fields)))
+	    ;
+	  else if (next == 0
+		   || tree_int_cst_lt (DECL_FIELD_BITPOS (TREE_PURPOSE (tail)),
+				       DECL_FIELD_BITPOS (next)))
+	    next = TREE_PURPOSE (tail);
+	}
+    }
+
+  /* Ordinarily return, but not if we want to output all
+     and there are elements left.  */
+  if (! (all && next != 0))
+    return;
+
+  /* Generate space up to the position of NEXT.  */
+  if (constructor_incremental)
+    {
+      tree filled;
+      tree nextpos_tree = size_int (0);
+
+      if (TREE_CODE (constructor_type) == RECORD_TYPE
+	  || TREE_CODE (constructor_type) == UNION_TYPE)
+	{
+	  /* Find the last field written out, if any.  */
+	  for (tail = TYPE_FIELDS (constructor_type); tail;
+	       tail = TREE_CHAIN (tail))
+	    if (TREE_CHAIN (tail) == constructor_unfilled_fields)
+	      break;
+
+	  if (tail)
+	    /* Find the offset of the end of that field.  */
+	    filled = size_binop (CEIL_DIV_EXPR,
+				 size_binop (PLUS_EXPR,
+					     DECL_FIELD_BITPOS (tail),
+					     DECL_SIZE (tail)),
+				 size_int (BITS_PER_UNIT));
+	  else
+	    filled = size_int (0);
+
+	  nextpos_tree = size_binop (CEIL_DIV_EXPR,
+				     DECL_FIELD_BITPOS (next),
+				     size_int (BITS_PER_UNIT));
+
+	  TREE_INT_CST_HIGH (constructor_bit_index)
+	    = TREE_INT_CST_HIGH (DECL_FIELD_BITPOS (next));
+	  TREE_INT_CST_LOW (constructor_bit_index)
+	    = TREE_INT_CST_LOW (DECL_FIELD_BITPOS (next));
+	  constructor_unfilled_fields = next;
+	}
+      else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  filled = size_binop (MULT_EXPR, constructor_unfilled_index,
+			       size_in_bytes (TREE_TYPE (constructor_type)));
+	  nextpos_tree
+	    = size_binop (MULT_EXPR, next,
+			  size_in_bytes (TREE_TYPE (constructor_type)));
+	  TREE_INT_CST_LOW (constructor_unfilled_index)
+	    = TREE_INT_CST_LOW (next);
+	  TREE_INT_CST_HIGH (constructor_unfilled_index)
+	    = TREE_INT_CST_HIGH (next);
+	}
+      else
+	filled = 0;
+
+      if (filled)
+	{
+	  int nextpos = TREE_INT_CST_LOW (nextpos_tree);
+
+	  assemble_zeros (nextpos - TREE_INT_CST_LOW (filled));
+	}
+    }
+  else
+    {
+      /* If it's not incremental, just skip over the gap,
+	 so that after jumping to retry we will output the next
+	 successive element.  */
+      if (TREE_CODE (constructor_type) == RECORD_TYPE
+	  || TREE_CODE (constructor_type) == UNION_TYPE)
+	constructor_unfilled_fields = next;
+      else if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  TREE_INT_CST_LOW (constructor_unfilled_index)
+	    = TREE_INT_CST_LOW (next);
+	  TREE_INT_CST_HIGH (constructor_unfilled_index)
+	    = TREE_INT_CST_HIGH (next);
+	}
+    }
+
+  goto retry;
+}
+
+/* Add one non-braced element to the current constructor level.
+   This adjusts the current position within the constructor's type.
+   This may also start or terminate implicit levels
+   to handle a partly-braced initializer.
+
+   Once this has found the correct level for the new element,
+   it calls output_init_element.
+
+   Note: if we are incrementally outputting this constructor,
+   this function may be called with a null argument
+   representing a sub-constructor that was already incrementally output.
+   When that happens, we output nothing, but we do the bookkeeping
+   to skip past that element of the current constructor.  */
+
+void
+process_init_element (value)
+     tree value;
+{
+  tree orig_value = value;
+  int string_flag = value != 0 && TREE_CODE (value) == STRING_CST;
+
+  /* Handle superfluous braces around string cst as in
+     char x[] = {"foo"}; */
+  if (string_flag
+      && constructor_type
+      && TREE_CODE (constructor_type) == ARRAY_TYPE
+      && TREE_CODE (TREE_TYPE (constructor_type)) == INTEGER_TYPE
+      && integer_zerop (constructor_unfilled_index))
+    {
+      constructor_stack->replacement_value = value;
+      return;
+    }
+
+  if (constructor_stack->replacement_value != 0)
+    {
+      error_init ("excess elements in struct initializer%s",
+		  " after `%s'", NULL_PTR);
+      return;
+    }
+
+  /* Ignore elements of a brace group if it is entirely superfluous
+     and has already been diagnosed.  */
+  if (constructor_type == 0)
+    return;
+
+  /* If we've exhausted any levels that didn't have braces,
+     pop them now.  */
+  while (constructor_stack->implicit)
+    {
+      if ((TREE_CODE (constructor_type) == RECORD_TYPE
+	   || TREE_CODE (constructor_type) == UNION_TYPE)
+	  && constructor_fields == 0)
+	process_init_element (pop_init_level (1));
+      else if (TREE_CODE (constructor_type) == ARRAY_TYPE
+	       && tree_int_cst_lt (constructor_max_index, constructor_index))
+	process_init_element (pop_init_level (1));
+      else
+	break;
+    }
+
+  while (1)
+    {
+      if (TREE_CODE (constructor_type) == RECORD_TYPE)
+	{
+	  tree fieldtype;
+	  enum tree_code fieldcode;
+
+	  if (constructor_fields == 0)
+	    {
+	      pedwarn_init ("excess elements in struct initializer%s",
+			    " after `%s'", NULL_PTR);
+	      break;
+	    }
+
+	  fieldtype = TREE_TYPE (constructor_fields);
+	  if (fieldtype != error_mark_node)
+	    fieldtype = TYPE_MAIN_VARIANT (fieldtype);
+	  fieldcode = TREE_CODE (fieldtype);
+
+	  /* Accept a string constant to initialize a subarray.  */
+	  if (value != 0
+	      && fieldcode == ARRAY_TYPE
+	      && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
+	      && string_flag)
+	    value = orig_value;
+	  /* Otherwise, if we have come to a subaggregate,
+	     and we don't have an element of its type, push into it.  */
+	  else if (value != 0 && !constructor_no_implicit
+		   && value != error_mark_node
+		   && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != fieldtype
+		   && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
+		       || fieldcode == UNION_TYPE))
+	    {
+	      push_init_level (1);
+	      continue;
+	    }
+
+	  if (value)
+	    {
+	      push_member_name (constructor_fields);
+	      output_init_element (value, fieldtype, constructor_fields, 1);
+	      RESTORE_SPELLING_DEPTH (constructor_depth);
+	    }
+	  else
+	    /* Do the bookkeeping for an element that was
+	       directly output as a constructor.  */
+	    {
+	      /* For a record, keep track of end position of last field.  */
+	      tree temp = size_binop (PLUS_EXPR,
+				      DECL_FIELD_BITPOS (constructor_fields),
+				      DECL_SIZE (constructor_fields));
+	      TREE_INT_CST_LOW (constructor_bit_index)
+		= TREE_INT_CST_LOW (temp);
+	      TREE_INT_CST_HIGH (constructor_bit_index)
+		= TREE_INT_CST_HIGH (temp);
+
+	      constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
+	    }
+
+	  constructor_fields = TREE_CHAIN (constructor_fields);
+	  /* Skip any nameless bit fields at the beginning.  */
+	  while (constructor_fields != 0 && DECL_BIT_FIELD (constructor_fields)
+		 && DECL_NAME (constructor_fields) == 0)
+	    constructor_fields = TREE_CHAIN (constructor_fields);
+	  break;
+	}
+      if (TREE_CODE (constructor_type) == UNION_TYPE)
+	{
+	  tree fieldtype;
+	  enum tree_code fieldcode;
+
+	  if (constructor_fields == 0)
+	    {
+	      pedwarn_init ("excess elements in union initializer%s",
+			    " after `%s'", NULL_PTR);
+	      break;
+	    }
+
+	  fieldtype = TREE_TYPE (constructor_fields);
+	  if (fieldtype != error_mark_node)
+	    fieldtype = TYPE_MAIN_VARIANT (fieldtype);
+	  fieldcode = TREE_CODE (fieldtype);
+
+	  /* Accept a string constant to initialize a subarray.  */
+	  if (value != 0
+	      && fieldcode == ARRAY_TYPE
+	      && TREE_CODE (TREE_TYPE (fieldtype)) == INTEGER_TYPE
+	      && string_flag)
+	    value = orig_value;
+	  /* Otherwise, if we have come to a subaggregate,
+	     and we don't have an element of its type, push into it.  */
+	  else if (value != 0 && !constructor_no_implicit
+		   && value != error_mark_node
+		   && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != fieldtype
+		   && (fieldcode == RECORD_TYPE || fieldcode == ARRAY_TYPE
+		       || fieldcode == UNION_TYPE))
+	    {
+	      push_init_level (1);
+	      continue;
+	    }
+
+	  if (value)
+	    {
+	      push_member_name (constructor_fields);
+	      output_init_element (value, fieldtype, constructor_fields, 1);
+	      RESTORE_SPELLING_DEPTH (constructor_depth);
+	    }
+	  else
+	    /* Do the bookkeeping for an element that was
+	       directly output as a constructor.  */
+	    {
+	      TREE_INT_CST_LOW (constructor_bit_index)
+		= TREE_INT_CST_LOW (DECL_SIZE (constructor_fields));
+	      TREE_INT_CST_HIGH (constructor_bit_index)
+		= TREE_INT_CST_HIGH (DECL_SIZE (constructor_fields));
+
+	      constructor_unfilled_fields = TREE_CHAIN (constructor_fields);
+	    }
+
+	  constructor_fields = 0;
+	  break;
+	}
+      if (TREE_CODE (constructor_type) == ARRAY_TYPE)
+	{
+	  tree elttype = TYPE_MAIN_VARIANT (TREE_TYPE (constructor_type));
+	  enum tree_code eltcode = TREE_CODE (elttype);
+
+	  /* Accept a string constant to initialize a subarray.  */
+	  if (value != 0
+	      && eltcode == ARRAY_TYPE
+	      && TREE_CODE (TREE_TYPE (elttype)) == INTEGER_TYPE
+	      && string_flag)
+	    value = orig_value;
+	  /* Otherwise, if we have come to a subaggregate,
+	     and we don't have an element of its type, push into it.  */
+	  else if (value != 0 && !constructor_no_implicit
+		   && value != error_mark_node
+		   && TYPE_MAIN_VARIANT (TREE_TYPE (value)) != elttype
+		   && (eltcode == RECORD_TYPE || eltcode == ARRAY_TYPE
+		       || eltcode == UNION_TYPE))
+	    {
+	      push_init_level (1);
+	      continue;
+	    }
+
+	  if (constructor_max_index != 0
+	      && tree_int_cst_lt (constructor_max_index, constructor_index))
+	    {
+	      pedwarn_init ("excess elements in array initializer%s",
+			    " after `%s'", NULL_PTR);
+	      break;
+	    }
+
+	  /* In the case of [LO .. HI] = VALUE, only evaluate VALUE once. */
+	  if (constructor_range_end)
+	    value = save_expr (value);
+
+	  /* Now output the actual element.
+	     Ordinarily, output once.
+	     If there is a range, repeat it till we advance past the range.  */
+	  do
+	    {
+	      tree tem;
+
+	      if (value)
+		{
+		  push_array_bounds (TREE_INT_CST_LOW (constructor_index));
+		  output_init_element (value, elttype, constructor_index, 1);
+		  RESTORE_SPELLING_DEPTH (constructor_depth);
+		}
+
+	      tem = size_binop (PLUS_EXPR, constructor_index,
+				integer_one_node);
+	      TREE_INT_CST_LOW (constructor_index)
+		= TREE_INT_CST_LOW (tem);
+	      TREE_INT_CST_HIGH (constructor_index)
+		= TREE_INT_CST_HIGH (tem);
+
+	      if (!value)
+		/* If we are doing the bookkeeping for an element that was
+		   directly output as a constructor,
+		   we must update constructor_unfilled_index.  */
+		{
+		  TREE_INT_CST_LOW (constructor_unfilled_index)
+		    = TREE_INT_CST_LOW (constructor_index);
+		  TREE_INT_CST_HIGH (constructor_unfilled_index)
+		    = TREE_INT_CST_HIGH (constructor_index);
+		}
+	    }
+	  while (! (constructor_range_end == 0
+		    || tree_int_cst_lt (constructor_range_end,
+					constructor_index)));
+
+	  break;
+	}
+
+      /* Handle the sole element allowed in a braced initializer
+	 for a scalar variable.  */
+      if (constructor_fields == 0)
+	{
+	  pedwarn_init ("excess elements in scalar initializer%s",
+			" after `%s'", NULL_PTR);
+	  break;
+	}
+
+      if (value)
+	output_init_element (value, constructor_type, NULL_TREE, 1);
+      constructor_fields = 0;
+      break;
+    }
+
+  /* If the (lexically) previous elments are not now saved,
+     we can discard the storage for them.  */
+  if (constructor_incremental && constructor_pending_elts == 0 && value != 0
+      && constructor_stack == 0)
+    clear_momentary ();
+}
+
+/* Expand an ASM statement with operands, handling output operands
+   that are not variables or INDIRECT_REFS by transforming such
+   cases into cases that expand_asm_operands can handle.
+
+   Arguments are same as for expand_asm_operands.  */
+
+void
+c_expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
+     tree string, outputs, inputs, clobbers;
+     int vol;
+     char *filename;
+     int line;
+{
+  int noutputs = list_length (outputs);
+  register int i;
+  /* o[I] is the place that output number I should be written.  */
+  register tree *o = (tree *) alloca (noutputs * sizeof (tree));
+  register tree tail;
+
+  if (TREE_CODE (string) == ADDR_EXPR)
+    string = TREE_OPERAND (string, 0);
+  if (TREE_CODE (string) != STRING_CST)
+    {
+      error ("asm template is not a string constant");
+      return;
+    }
+
+  /* Record the contents of OUTPUTS before it is modified.  */
+  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
+    o[i] = TREE_VALUE (tail);
+
+  /* Perform default conversions on array and function inputs.  */
+  /* Don't do this for other types--
+     it would screw up operands expected to be in memory.  */
+  for (i = 0, tail = inputs; tail; tail = TREE_CHAIN (tail), i++)
+    if (TREE_CODE (TREE_TYPE (TREE_VALUE (tail))) == ARRAY_TYPE
+	|| TREE_CODE (TREE_TYPE (TREE_VALUE (tail))) == FUNCTION_TYPE)
+      TREE_VALUE (tail) = default_conversion (TREE_VALUE (tail));
+
+  /* Generate the ASM_OPERANDS insn;
+     store into the TREE_VALUEs of OUTPUTS some trees for
+     where the values were actually stored.  */
+  expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line);
+
+  /* Copy all the intermediate outputs into the specified outputs.  */
+  for (i = 0, tail = outputs; tail; tail = TREE_CHAIN (tail), i++)
+    {
+      if (o[i] != TREE_VALUE (tail))
+	{
+	  expand_expr (build_modify_expr (o[i], NOP_EXPR, TREE_VALUE (tail)),
+		       0, VOIDmode, 0);
+	  free_temp_slots ();
+	}
+      /* Detect modification of read-only values.
+	 (Otherwise done by build_modify_expr.)  */
+      else
+	{
+	  tree type = TREE_TYPE (o[i]);
+	  if (TREE_READONLY (o[i])
+	      || TYPE_READONLY (type)
+	      || ((TREE_CODE (type) == RECORD_TYPE
+		   || TREE_CODE (type) == UNION_TYPE)
+		  && C_TYPE_FIELDS_READONLY (type)))
+	    readonly_warning (o[i], "modification by `asm'");
+	}
+    }
+
+  /* Those MODIFY_EXPRs could do autoincrements.  */
+  emit_queue ();
+}
+
+/* Expand a C `return' statement.
+   RETVAL is the expression for what to return,
+   or a null pointer for `return;' with no value.  */
+
+void
+c_expand_return (retval)
+     tree retval;
+{
+  tree valtype = TREE_TYPE (TREE_TYPE (current_function_decl));
+
+  if (TREE_THIS_VOLATILE (current_function_decl))
+    warning ("function declared `noreturn' has a `return' statement");
+
+  if (!retval)
+    {
+      current_function_returns_null = 1;
+      if (warn_return_type && valtype != 0 && TREE_CODE (valtype) != VOID_TYPE)
+	warning ("`return' with no value, in function returning non-void");
+      expand_null_return ();
+    }
+  else if (valtype == 0 || TREE_CODE (valtype) == VOID_TYPE)
+    {
+      current_function_returns_null = 1;
+      if (pedantic || TREE_CODE (TREE_TYPE (retval)) != VOID_TYPE)
+	pedwarn ("`return' with a value, in function returning void");
+      expand_return (retval);
+    }
+  else
+    {
+      tree t = convert_for_assignment (valtype, retval, "return",
+				       NULL_TREE, NULL_TREE, 0);
+      tree res = DECL_RESULT (current_function_decl);
+      tree inner;
+
+      if (t == error_mark_node)
+	return;
+
+      inner = t = convert (TREE_TYPE (res), t);
+
+      /* Strip any conversions, additions, and subtractions, and see if
+	 we are returning the address of a local variable.  Warn if so.  */
+      while (1)
+	{
+	  switch (TREE_CODE (inner))
+	    {
+	    case NOP_EXPR:   case NON_LVALUE_EXPR:  case CONVERT_EXPR:
+	    case PLUS_EXPR:
+	      inner = TREE_OPERAND (inner, 0);
+	      continue;
+
+	    case MINUS_EXPR:
+	      /* If the second operand of the MINUS_EXPR has a pointer
+		 type (or is converted from it), this may be valid, so
+		 don't give a warning.  */
+	      {
+		tree op1 = TREE_OPERAND (inner, 1);
+
+		while (! POINTER_TYPE_P (TREE_TYPE (op1))
+		       && (TREE_CODE (op1) == NOP_EXPR
+			   || TREE_CODE (op1) == NON_LVALUE_EXPR
+			   || TREE_CODE (op1) == CONVERT_EXPR))
+		  op1 = TREE_OPERAND (op1, 0);
+
+		if (POINTER_TYPE_P (TREE_TYPE (op1)))
+		  break;
+
+		inner = TREE_OPERAND (inner, 0);
+		continue;
+	      }
+	      
+	    case ADDR_EXPR:
+	      inner = TREE_OPERAND (inner, 0);
+
+	      while (TREE_CODE_CLASS (TREE_CODE (inner)) == 'r')
+		inner = TREE_OPERAND (inner, 0);
+
+	      if (TREE_CODE (inner) == VAR_DECL
+		  && ! DECL_EXTERNAL (inner)
+		  && ! TREE_STATIC (inner)
+		  && DECL_CONTEXT (inner) == current_function_decl)
+		warning ("function returns address of local variable");
+	      break;
+	    }
+
+	  break;
+	}
+
+      t = build (MODIFY_EXPR, TREE_TYPE (res), res, t);
+      TREE_SIDE_EFFECTS (t) = 1;
+      expand_return (t);
+      current_function_returns_value = 1;
+    }
+}
+
+/* Start a C switch statement, testing expression EXP.
+   Return EXP if it is valid, an error node otherwise.  */
+
+tree
+c_expand_start_case (exp)
+     tree exp;
+{
+  register enum tree_code code = TREE_CODE (TREE_TYPE (exp));
+  tree type = TREE_TYPE (exp);
+
+  if (code != INTEGER_TYPE && code != ENUMERAL_TYPE && code != ERROR_MARK)
+    {
+      error ("switch quantity not an integer");
+      exp = error_mark_node;
+    }
+  else
+    {
+      tree index;
+      type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
+
+      if (warn_traditional
+	  && (type == long_integer_type_node
+	      || type == long_unsigned_type_node))
+	pedwarn ("`long' switch expression not converted to `int' in ANSI C");
+
+      exp = default_conversion (exp);
+      type = TREE_TYPE (exp);
+      index = get_unwidened (exp, NULL_TREE);
+      /* We can't strip a conversion from a signed type to an unsigned,
+	 because if we did, int_fits_type_p would do the wrong thing
+	 when checking case values for being in range,
+	 and it's too hard to do the right thing.  */
+      if (TREE_UNSIGNED (TREE_TYPE (exp))
+	  == TREE_UNSIGNED (TREE_TYPE (index)))
+	exp = index;
+    }
+
+  expand_start_case (1, exp, type, "switch statement");
+
+  return exp;
+}