[llvm] [InstCombine] Retain debug information on store to null instruction (PR #86105)

[Adrian Prantl via llvm-commits]

adrian-prantl wrote:

If none of the cases outlined in https://llvm.org/docs/HowToUpdateDebugInfo.html apply, and there is no comment in the existing code, chances are good that this was just an oversight in the existing implementation. Is the store in the same basic block as indicated by the source location?

https://github.com/llvm/llvm-project/pull/86105