[llvm] [DebugInfo][SelectionDAG] Fix position of salvaged 'dangling' DBG_VALUEs (PR #94458)

[Orlando Cazalet-Hyams via llvm-commits]

OCHyams wrote:

Hi @asmok-g,

It's expected that some variables will get greater variable location coverage, and some variables which previously didn't get variable locations at all now may get some  coverage (reflected in b` 1-2% in vars_params_with_binary_location` increase).

I haven't run size tests myself so I don't know if the numbers you're seeing are indicative of anything going wrong, but they sound plausible without indicating an error IMO.

If you're able I'd suggest taking a look at a sample of some of the variable location changes and see if anything looks out of place. That said, I'm quite confident that this patch is doing the right thing and the size increase is just a consequence of us having more location data.

https://github.com/llvm/llvm-project/pull/94458