[llvm] [SROA] Fix debug locations for variables with non-zero offsets (PR #97750)

[Jeremy Morse via llvm-commits]

https://github.com/jmorse commented:

Some nits inline; I greatly appreciate that this upgrades the existing implementation from "here's a bucket of bits we swill around" into something that's reasoned and explained with comments and names. The sheer number of dimensions here is mind boggling.

Do we need tests for the composition of fragments and bit extracts? There's code here dealing with bit-extract stuff, but no extra testing for it, are there other tests out there which cover these code paths? (Didn't look at the reviews adding bit-extract stuff as I was in outer woop woop sorry).

https://github.com/llvm/llvm-project/pull/97750