  Global Value Numbering(GVN) is a method for detecting redundant computations
in programs. Here, we introduce the problem of Global Value Numbering in its
original form, as conceived by Kildall(1973), and present an algorithm which is
a simpler variant of Kildall's. The algorithm uses the concept of value
expression - an abstraction of a set of expressions - enabling a representation
of the equivalence information which is compact and simple to manipulate.
