[llvm] [LV] Transform tests for early-exit with stores (PR #183288)

[Graham Hunter via llvm-commits]

huntergr-arm wrote:

> > > Could you also add the VPlan printing test?
> > 
> > 
> > Done, though there's obviously no vplan generated at the moment.
> 
> Maybe it would be possible to use #178522 to have some basic VPlan dump here that the actual PR can "diff" against?

I could try that, but I don't think it's a good idea in this case, since the plan would not be a valid representation of the semantics of the scalar loop.

However, you have given me an idea for the main PR -- use the new test frontend to show the minimal transformation as well as the end result.

https://github.com/llvm/llvm-project/pull/183288