[llvm] [RISCV][TTI] Enable masked interleave vectorization (PR #150074)

[Mel Chen via llvm-commits]

Mel-Chen wrote:

> > Just checking, this sets out to do the same thing as #149981 right?
> 
> It appears to mostly cover the same ground. I prefer my version for a number of small reasons, but I'd not have posted it if I'd seen that first. I'd have just replied there with detailed comments.

I think that it's totally fine to prioritize merging this patch — you deserve it. :) 
I even hope it can land as soon as possible, so that my local VPInterleaveEVLRecipe can start to be reviewed. #149981 was only created because I realized it couldn't be converted to VPInterleaveEVLRecipe after I finished the implementation.

https://github.com/llvm/llvm-project/pull/150074