[llvm] [DebugInfo] Handle dbg.assigns in FastISel (PR #80734)

[Jeremy Morse via llvm-commits]

jmorse wrote:

For SelectionDAG it's already had dbg.assign/"assignment-tracking" plumbed into it. However it looks like GlobalISel could do with this too -- I'll add that to this review.

https://github.com/llvm/llvm-project/pull/80734