Function hoist_selects 

pub fn hoist_selects(
    df: &DecisionFabric,
    width: u32,
) -> Result<DecisionFabric, String>

df with every select its arithmetic or compares read cofactored away and its tree of selects ordered latest predicate first, at datapath width width (64 on silicon; narrower so our SAT can check the pass exhaustively). Refused when df holds a cell with no combinational form (a functional unit, a memory or heap tile), or when the expansion outgrows HOIST_NODE_LIMIT.