Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!mcgill-vision!bloom-beacon!eru!luth!sunic!mcsun!prlbcom!kulcs!gerda
From: gerda@kulcs.uucp (Gerda Janssens)
Newsgroups: comp.lang.prolog
Subject: Re : incrementing values
Message-ID: <1833@kulcs.kulcs.uucp>
Date: 6 Feb 90 09:15:06 GMT
Reply-To: gerda@kulcs.UUCP ()
Organization: Katholieke Universiteit Leuven, Dept. Computer Science
Lines: 13


The efficiency of 'X1 is X0 + 1' can substantially be increased
if at compile time we known that it is actually destructive assignment
and that we can safely reuse the memory cel of X0 for X1.
This kind of information can be derived by doing global analysis of the 
PROLOG program.  At our department a framework for abstract interpretation
has been developed and one of the applications is concerned with detecting
opportunities for compile time garbage collection, as is required for the 
example at hand.

A. Mulkers, W. Winsborough and M. Bruynooghe, Analysis of Shared Data 
Structures for Compile-time Garbage Collection in Logic Programs, 
submitted for ICLP'90.