[llvm-branch-commits] LiveRangeShrink: Early exit when encountering a code motion barrier. (PR #136806)

[Peter Collingbourne via llvm-branch-commits]

https://github.com/pcc created https://github.com/llvm/llvm-project/pull/136806

Without this, we end up with quadratic behavior affecting functions with
large numbers of code motion barriers, such as CFI jump tables.