[llvm] [WebAssembly] Split separate component LiveIntervals for TEEs (PR #131561)

[Heejin Ahn via llvm-commits]

aheejin wrote:

@qcolombet I think `if (LIS->shrinkToUses(LI, Dead))` condition in
https://github.com/llvm/llvm-project/blob/9d92d4b01ce0ddfdcbb2bd5ec0ec3208ad480ccc/llvm/lib/CodeGen/RegisterCoalescer.cpp#L341-L353
was first written in https://github.com/llvm/llvm-project/commit/0ddd315db0990d11e9f608a86b489b8da8d8c4f6 authored by you. It's a long time ago, but in case you remember the context, could you explain what this condition means, and why it does not return true in some cases when there are unconnected components (as described in the test case of this PR)?

https://github.com/llvm/llvm-project/pull/131561