The existing software performance tools concentrate on identification of program bottlenecks. Although such identification is important, it may not necessarily be the only source of performance deficiency. This paper presents a performance tool called RCAT that detects a new type of performance deficiency referred to as redundant computation. Redundant computation is the execution of a statement(s) that does not influence the program output. Our experience showed that significant performance improvements might be achieved as a result of elimination or reduction of redundant computations. RCAT helps the programmers to improve their C programs by localizing the potential performance deficiencies.