+/**
+ * Returns the minimum number of vec4 elements needed to pack a type.
+ *
+ * For simple types, it will return 1 (a single vec4); for matrices, the
+ * number of columns; for array and struct, the sum of the vec4_size of
+ * each of its elements; and for sampler and atomic, zero.
+ *
+ * This method is useful to calculate how much register space is needed to
+ * store a particular type.
+ */
+int
+vec4_visitor::type_size(const struct glsl_type *type)