[llvm] [CodeGen] Use first EHLabel as a stop gate for live range shrinking (PR #114195)

[via llvm-commits]

MuellerMP wrote:

> Not really sure why you can't do this in the !MBBPad case

well not for the map at least -> otherwise we are missing the phis in the map and thus we can't hoist their uses 

https://github.com/llvm/llvm-project/pull/114195