[llvm] [CVP] Check whether the default case is reachable (PR #79993)

[via llvm-commits]

eaeltsin wrote:

> > > Thanks for looking! I'd say if it's not convenient to prepare a fix by around Tuesday, it would likely be better to revert (I can take care of this) until you're back from the holidays. Happy New Year, btw! ;)
> > 
> > 
> > Hi, this is causing quite a significant number of failures in our internal testing - many protocol buffer generated files are timing out. We really appreciate it if you submit the fix soon or revert this until the fix is ready. Thanks!
> 
> Potential fix: #78582

Yes, I see, but reading through comments, I don't understand how close it is to being submitted. And we really need to mitigate the issue soon.


https://github.com/llvm/llvm-project/pull/79993