pub fn ba_gates_cross_warp_pair(local_out: u32) -> (u32, u32)
The two warp partials summed for output local_out, in order — the parent’s smem[local_out * 2] + smem[local_out * 2 + 1].
local_out
smem[local_out * 2] + smem[local_out * 2 + 1]