[llvm] [GlobalISel] Compact large match tables (PR #202642)

[Nikita Popov via llvm-commits]

nikic wrote:

This seems to implement two largely unrelated changes. The in-opcode root numbers and the relative references. These can be separated. And the first one doesn't really seem like something that should be using after the fact compaction and can just be directly emitted that way.

https://github.com/llvm/llvm-project/pull/202642