A very common pattern in Halide code loads from an image using a clamped index:

Func clamped(x,y) = input(clamp(x,0,input.width() - 1), clamp(y,0,input.height() - 1);

In the current backend, this generates unnecessarily conservative code when vectorized. A better strategy would be to generate a dynamic branch which detects if the index vector is near the edge of the clamp range, and if not, removes the clamp and generates a simple dense aligned vector load.