[llvm] [X86] Truncates i64 add arithmetic to i32 when known zeroes in upper 33 bits (PR #191619)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon commented:

Sorry @2elliti - I've been incredibly busy this year and unless a ping arrives at the right time I often miss notifications - so keep pinging :) 

Please can merge against trunk latest and fix the merge conflicts?

Did you look at whether doing this later in X86ISelDAGToDAG was more stable?

https://github.com/llvm/llvm-project/pull/191619