+/* Implement the __alignof keyword: Return the minimum required
+ alignment of E, measured in bytes. For VAR_DECL's and
+ FIELD_DECL's return DECL_ALIGN (which can be set from an
+ "aligned" __attribute__ specification). */
+
+static tree
+cxx_alignof_expr (tree e)
+{
+ tree t;
+
+ if (e == error_mark_node)
+ return error_mark_node;
+
+ if (processing_template_decl)
+ {
+ e = build_min (ALIGNOF_EXPR, size_type_node, e);
+ TREE_SIDE_EFFECTS (e) = 0;
+ TREE_READONLY (e) = 1;
+
+ return e;
+ }
+
+ if (TREE_CODE (e) == VAR_DECL)
+ t = size_int (DECL_ALIGN_UNIT (e));
+ else if (TREE_CODE (e) == COMPONENT_REF
+ && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL
+ && DECL_C_BIT_FIELD (TREE_OPERAND (e, 1)))
+ {
+ error ("invalid application of %<__alignof%> to a bit-field");
+ t = size_one_node;
+ }
+ else if (TREE_CODE (e) == COMPONENT_REF
+ && TREE_CODE (TREE_OPERAND (e, 1)) == FIELD_DECL)
+ t = size_int (DECL_ALIGN_UNIT (TREE_OPERAND (e, 1)));
+ else if (is_overloaded_fn (e))
+ {
+ pedwarn ("ISO C++ forbids applying %<__alignof%> to an expression of "
+ "function type");
+ t = size_one_node;
+ }
+ else if (type_unknown_p (e))
+ {
+ cxx_incomplete_type_error (e, TREE_TYPE (e));
+ t = size_one_node;
+ }
+ else
+ return cxx_sizeof_or_alignof_type (TREE_TYPE (e), ALIGNOF_EXPR, true);
+
+ return fold_convert (size_type_node, t);
+}
+
+/* Process a sizeof or alignof expression E with code OP where the operand
+ is an expression. */
+
+tree
+cxx_sizeof_or_alignof_expr (tree e, enum tree_code op)
+{
+ if (op == SIZEOF_EXPR)
+ return cxx_sizeof_expr (e);
+ else
+ return cxx_alignof_expr (e);
+}