|| coder == COMPLEX_TYPE))
return convert_and_check (type, rhs);
+ /* Conversion to a transparent union from its member types.
+ This applies only to function arguments. */
+ else if (codel == UNION_TYPE && TYPE_TRANSPARENT_UNION (type) && ! errtype)
+ {
+ tree memb_types;
+ tree marginal_memb_type = 0;
+
+ for (memb_types = TYPE_FIELDS (type); memb_types;
+ memb_types = TREE_CHAIN (memb_types))
+ {
+ tree memb_type = TREE_TYPE (memb_types);
+
+ if (comptypes (TYPE_MAIN_VARIANT (memb_type),
+ TYPE_MAIN_VARIANT (rhstype)))
+ break;
+
+ if (TREE_CODE (memb_type) != POINTER_TYPE)
+ continue;
+
+ if (coder == POINTER_TYPE)
+ {
+ 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))
+ {
+ /* If this type won't generate any warnings, use it. */
+ if ((TREE_CODE (ttr) == FUNCTION_TYPE
+ && TREE_CODE (ttl) == FUNCTION_TYPE)
+ ? ((! TYPE_READONLY (ttl) | TYPE_READONLY (ttr))
+ & (! TYPE_VOLATILE (ttl) | TYPE_VOLATILE (ttr)))
+ : ((TYPE_READONLY (ttl) | ! TYPE_READONLY (ttr))
+ & (TYPE_VOLATILE (ttl) | ! TYPE_VOLATILE (ttr))))
+ break;
+
+ /* Keep looking for a better type, but remember this one. */
+ if (! marginal_memb_type)
+ marginal_memb_type = memb_type;
+ }
+ }
+
+ /* Can convert integer zero to any pointer type. */
+ if (integer_zerop (rhs)
+ || (TREE_CODE (rhs) == NOP_EXPR
+ && integer_zerop (TREE_OPERAND (rhs, 0))))
+ {
+ rhs = null_pointer_node;
+ break;
+ }
+ }
+
+ if (memb_types || marginal_memb_type)
+ {
+ if (! memb_types)
+ {
+ /* We have only a marginally acceptable member type;
+ it needs a warning. */
+ register tree ttl = TREE_TYPE (marginal_memb_type);
+ register tree ttr = TREE_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)
+ {
+ /* 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
+ {
+ 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);
+ }
+ }
+
+ if (pedantic && ! DECL_IN_SYSTEM_HEADER (fundecl))
+ pedwarn ("ANSI C prohibits argument conversion to union type");
+
+ return build1 (NOP_EXPR, type, rhs);
+ }
+ }
+
/* Conversions among pointers */
else if (codel == POINTER_TYPE && coder == POINTER_TYPE)
{