+ /**
+ * Determine if an r-value has the value zero
+ *
+ * The base implementation of this function always returns \c false. The
+ * \c ir_constant class over-rides this function to return \c true \b only
+ * for vector and scalar types that have all elements set to the value
+ * zero (or \c false for booleans).
+ *
+ * \sa ir_constant::has_value, ir_rvalue::is_one, ir_rvalue::is_negative_one
+ */
+ virtual bool is_zero() const;
+
+ /**
+ * Determine if an r-value has the value one
+ *
+ * The base implementation of this function always returns \c false. The
+ * \c ir_constant class over-rides this function to return \c true \b only
+ * for vector and scalar types that have all elements set to the value
+ * one (or \c true for booleans).
+ *
+ * \sa ir_constant::has_value, ir_rvalue::is_zero, ir_rvalue::is_negative_one
+ */
+ virtual bool is_one() const;
+
+ /**
+ * Determine if an r-value has the value negative one
+ *
+ * The base implementation of this function always returns \c false. The
+ * \c ir_constant class over-rides this function to return \c true \b only
+ * for vector and scalar types that have all elements set to the value
+ * negative one. For boolean times, the result is always \c false.
+ *
+ * \sa ir_constant::has_value, ir_rvalue::is_zero, ir_rvalue::is_one
+ */
+ virtual bool is_negative_one() const;
+