0d92eb65d4
With sourceWidth = 1, we hit an unsynchronized vx_wspawn bug, where the previously spawned warps get killed and overridden by a new vx_wspawn call before all the warps complete execution. Setting sourceWidth = 1 somehow slows down the progress of the spawned warps in relation to warp 0 (presumably because fetch stalls, but not sure why they would slow down more than warp 0) and results in this bug. sourceWidth = 4 seems to work for vecadd.