A Synergistic Analysis for Sharing and Groundness which traces Linearity

Accurate variable sharing information is crucial both in the automatic parallelisation and in the optimisation of sequential logic programs. Analysis for possible variable sharing is thus an important topic in logic programming and many analyses have been proposed for inferring dependencies between the variables of a program, for instance, by combining domains and analyses. This paper develops the combined domain theme by explaining how term structure, and in particular linearity, can be represented in a sharing group format. This enables aliasing behaviour to be more precisely captured; groundness information to be more accurately propagated; and in addition, refines the tracking and application of linearity. In practical terms, this permits aliasing and groundness to be inferred to a higher degree of accuracy than in previous proposals and also can speed up the analysis itself. Correctness is formally proven.