[llvm] [SelectionDAG] Fix null pointer dereference in resolveDanglingDebugInfo (PR #173947)

[via llvm-commits]

MetalOxideSemi wrote:

Hi @arsenm @MacDue 🙇 I've updated the patch with more conservative testing approaches. The core fix remains the same but tests are now restricted to Linux hosts only (`REQUIRES: system-linux`) to avoid the platform-specific failures we saw in #173500 and #173836.

The test failures on Darwin/BSD appear to expose deeper issues in DWARF generation that are **orthogonal** to this null pointer fix. This approach allows the crash fix to land while those underlying issues can be investigated separately.

Would appreciate another look when you have a chance. Thanks!

https://github.com/llvm/llvm-project/pull/173947