[llvm] [DAGCombiner] Don't drop atomic property of original load. (PR #75626)

[James Y Knight via llvm-commits]

jyknight wrote:

> I think this should still go ahead. I still think it's a good idea to get rid of ISD::ATOMIC_LOAD and migrate to using load with atomic operands. 

Not sure I agree with that.

> This is a code simplification anyway

Agreed, this patch is good to submit as a simplification and bugfix for the alignment, regardless of the issues around ATOMIC_LOAD.

https://github.com/llvm/llvm-project/pull/75626