[llvm] [AssignmentTracking] Skip large types in redundant debug info pruning (PR #74329)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

> What are the implications of over-sized types being ignored by this code, are there any correctness issues or is it just efficiency?

Just efficiency.

As well as choosing a smaller size limit, another easy win here could be to use byte sizes rather than bit sizes, which would bring down the bitvector sizes in all cases (at the cost accidentally not pruning where some fragments don't fit into bytes exactly, but that'll probably be a very rare situation and doesn't impose any correctness problems).

I can also have a look to see if there's something else we can use. Ideally we actually want something like an interval map, though IntervalMap as it exists now is not useful for this since it doesn't support overlapping insertion (and also might be a bit heavy weight too).

https://github.com/llvm/llvm-project/pull/74329