[llvm] [LV]: Teach LV to recursively (de)interleave. (PR #89018)

[Paul Walker via llvm-commits]

paulwalker-arm wrote:

> Would it be possible to directly add (de)interleave intrinsic 4 to achieve this? 

A significant risk of not being able to identify the larger interleave factors would be the main reason to introduce dedicated intrinsics. However, I'd expect the IR to emulate an 8-way interleave to be pretty fixed so I'd rather wait to see if this is proved incorrect before going down that route.

At the end of the day the code this PR will introduce will be required anyway to lower (de)interleave intrinsics a target does not support, so there shouldn't be much wasted effort.



https://github.com/llvm/llvm-project/pull/89018