An upper/lower lower/upper kind of question

[hgm]

Thanks, interesting and useful. But the entries still have to be initialized, since otherwise one might be used with a spurious value, no?

True, when a hash entry is created after a miss it should be informationless, i.e. have bounds initialized to -INF and +INF. The same holds for a hit with unsufficient depth; stepping up the depth should reset the bounds.