[llvm] [ReachingDefAnalysis] Extend the analysis to stack objects. (PR #118097)

[Michael Maitland via llvm-commits]

michaelmaitland wrote:

Here is a suggestion on how to rework the MBBFrameObjsReachingDefsInfo data structure [here](https://github.com/llvm/llvm-project/compare/main...michaelmaitland:llvm-project:perf/mmaitland-rda-ss?expand=1)

You can see that it does not have the "catastrophic memory usage regressions" [here](https://llvm-compile-time-tracker.com/compare.php?from=beba4b08f72152abbb7d26df024f0d9338a7038b&to=a51148b62cee5f01e3bbb6dd3e7608a1ea274388&stat=max-rss)

Feel free to take it verbatim or make your own modifications to it.

https://github.com/llvm/llvm-project/pull/118097