[llvm] [LV][EVL] Generate negative strided load/store for reversed load/store (PR #123608)

[Alexey Bataev via llvm-commits]

alexey-bataev wrote:

> > > And we don't seem to currently check if it's supported anyway?
> > 
> > 
> > Yes, because we never emit strided ops in LV for now. To emit it, need to correctly implement legality checks and cost model
> 
> I meant as in we don't check if llvm.experimental.vp.reverse is supported, and it doesn't look like there's a default expansion for it

It is not correct and should be checked

https://github.com/llvm/llvm-project/pull/123608