[llvm] [LoopVectorizer] Prune VFs based on plan register pressure (PR #132190)

[Sam Tebbs via llvm-commits]

SamTebbs33 wrote:

> > > > Thank you for the approvals. I'll rebase and merge once Elvis's PR is in.
> > > 
> > > 
> > > Could you link the depenency in the description? My understanding was that all dependencies already landed for the PR
> > 
> > 
> > Sure it's [this](https://github.com/llvm/llvm-project/pull/113903) one. This PR introduces a regression in mve-reduction-types.ll ([context](https://github.com/llvm/llvm-project/pull/132190#discussion_r2013585095)) and 113903 eliminates that regression.
> 
> Yeah, I also got confused looking at this patch today wondering why it couldn't be merged. It looks like #113903 is still some way off due to it also depending upon another patch. Would be good to mention this in the commit message!

Done, thank you.

https://github.com/llvm/llvm-project/pull/132190