[llvm] [RISCV][IA] Use strided load for one active deinterleaveN(load) (PR #148892)

[Philip Reames via llvm-commits]

preames wrote:

This patch conflicts with https://github.com/llvm/llvm-project/pull/148716.  As I was already planning on reworking this to be a combine eventually, I'm going to close this for the moment, and post something new once the API has stabilized a bit.  

https://github.com/llvm/llvm-project/pull/148892