[llvm] [AArch64] Lower partial add reduction to udot or svdot (PR #101010)

[Paul Walker via llvm-commits]

paulwalker-arm wrote:

I request that we defer creating a dedicated ISD node for now, with the precedent already set (see get_active_lane_mask and cttz_elts).  In this instance I don't think we'll be waiting long for a dedicated ISD node but my concern is that such a node it unlikely to want to follow the exact semantics of the intrinsic and so I'd rather take the time to see how the functionality plays out before committing ourselves rather than hastily implementing all the functionality that typically comes from adding a new ISD node.

https://github.com/llvm/llvm-project/pull/101010