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

[David Blaikie via llvm-commits]

dwblaikie wrote:

The Sony folks tend to be the ones most familiar with debug locations at the moment who might have some ideas about how to write more targeted tests here. @OCHyams @jmorse @SLTozer 

Not sure what techniques they usually use, but for middle end optimizations, I'd have thought maybe a constructive approach (building up a test case from scratch, more or less) might be more suitable than trying to reduce one - well, maybe reducing at the IR level (without debug info) then adding in enough debug info to tickle the merging problem by hand.

But probably don't run with that ^ suggestion until you hear back from the Sony folks,  as they've probably got better ideas that are less likely to be a huge time sink/send you the wrong way.

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