[llvm] [RISCV] Lower unmasked zero-stride vp.stride to a splat of one scalar load. (PR #97394)

[Craig Topper via llvm-commits]

topperc wrote:

> We may use -1 to represent VLMAX?

This is undefined behavior for VP intrinsics. The EVL cannot be larger than the runtime vector length.

https://github.com/llvm/llvm-project/pull/97394