Comparability results
•
Comparisons:
–
declared types: 60% as many comparisons
–
Lackwit: 5% as many comparisons; scales
well
•
Runtime: 40-70% improvement
•
Few differences in reported invariants
Declared types are worse for larger procedures
Lackwit types are better for larger procedures
“Few differences”:
among any of the three techniques.
This is a
success
and a
failure
:
•
comparison numbers are new (and gratifyingly low)
•
runtime improvement
•
the system already does a good job of eliminating irrelevant invariants (Lackwit is largely, but not entirely, irrelevant)
All the invariants eliminated by Lackwit were uninteresting (so it improved output a bit, but not a huge amount).
