[llvm] [llvm-objdump] Optimize live element tracking (PR #158763)

[James Henderson via llvm-commits]

https://github.com/jh7370 commented:

Thanks. Your numbers are certainly compelling. Is it possible to get peak memory usage too? I imagine the cost is small comparatively, but would be interesting to see them, since you'll be increasing the usage with this change (the age old memory versus speed trade-off).

I've started reviewing this, but will need to come back to finish off. I've left a couple of comments for you to get on with.

https://github.com/llvm/llvm-project/pull/158763