[llvm] [NFC] Allow fragment expressions in extractIfOffset (PR #69006)

[Jeremy Morse via llvm-commits]

jmorse wrote:

For Scott's ideas (@slinder1  ?), they're summarised in this conference presentation last year https://www.youtube.com/watch?v=HEhigWu_0uE, and RFC here: https://discourse.llvm.org/t/rfc-heterogeneous-debug-info/66872 . I think the most attractive part is the idea of shifting the fragment information into metadata nodes, and then referring to those nodes from the debug intrinsics. So dbg.values would refer to a DIFragment (I think?) that then refers to a DILocalVariable. The problem of "what fragment does this thing refer to" is then largely not considered during optimisation passes. There are a bunch of other ideas for taking information out of DIExpressions, and I think there's a prototype in the AMD LLVM repo somewhere?

https://github.com/llvm/llvm-project/pull/69006