Inferring Loop Invariants Using Postconditions

One of the obstacles in automatic program proving is to obtain suitable loop invariants. The invariant of a loop is a weakened form of its postcondition (the loop's goal, also known as its contract); the present work takes advantage of this observation by using the postcondition as the basis for invariant inference, using various heuristics such as "uncoupling" which prove useful in many important algorithms. Thanks to these heuristics, the technique is able to infer invariants for a large variety of loop examples. We present the theory behind the technique, its implementation (freely available for download and currently relying on Microsoft Research's Boogie tool), and the results obtained. 1 Overview Many of the important contributions to the advancement of program proving have been, rather than grand new concepts, specific developments and simplifications; they have removed one obstacle after another preventing the large-scale application of proof techniques to ...

• Type: Conference
• Year: 2010
• Where: BIRTHDAY
• Authors: Carlo A. Furia, Bertrand Meyer
• Keywords: Applied Computing, BIRTHDAY 2010, Loop, Loop Invariants, Suitable Loop Invariants