Quadruples

Unlike expression-tree structured intermediate representations, where every operand can optionally be the root of an expression, quadruple representations are flat. The ``typical'' statement is of the form $a \leftarrow b \oplus c$; the name quadruple comes from the fact that there are four components (a, b, c, $\oplus$) [App98].¹ Obviously an IR expressive enough to represent the entire Java language needs more than a four component operation statement, but we have attempted to retain the atomic simplicity of the quadruple form.