IMO a lot of LLVM bug fixes are driven by particular devs motivated to fix issues in the area that they contributed or that they're willing to take the time to investigate.

If your bug happens to hit a use case important to flagships like XCode or Android -- or any of the internal projects at Apple or Google, you have a much better chance of seeing it fixed.

Unless your bug shows a clear regression and is interesting enough to be a release blocker, it probably won't get prioritized. OTOH if you supply a patch with your bug report, it probably has a decent chance of getting accepted.

LLVM doesn't not care about rust. It's just not a pet project of a heavy hitter yet. So rust devs dig down and find llvm bugs. But a best case scenario would be a "llvm developer" working for Google/Apple/Mozilla who will prioritize features and fixes impacting rust. But that's not necessarily better than another "rust Dev" willing to dig down and find llvm bugs.

I'm not knocking LLVM, I think it's a great community. Just strikes me as more of a BYO-bugfix kinda gang.