scala/scala — pull request #683 by odersky (2012-06-08 13:41:32+00:00)
Title: Reduce time spent in lubs

Reduce time spent in lubs by making depth more adaptive. It now takes into account separately the depth of the lub types and the maximal depth of theior base type sequences. It cuts depth more aggressively if it is the base types instead of the types themselves that grow deep.

The old truncation behavior is retained under option -Xfull-lubs

Another change is that we now track depth more precisely, which should also help or at least allow better statistics.

Also added statistics that measure #lubs and time spent in them. (need statistics overhaul which will come in separate pull request. hand timings show that time spent in the single lub of the test file goes down from 10 to 1 sec. Still more room for improvement...