-- | Compute the predecessors of each /reachable/ block
zipPreds :: LastNode l => LGraph m l -> BlockEnv BlockSet
zipPreds g = foldl add emptyBlockEnv (postorder_dfs g)
- where add env block@(Block id _ _) =
+ where add env block@(Block id _) =
foldl (\env sid ->
let preds = lookupBlockEnv env sid `orElse` emptyBlockSet
in extendBlockEnv env sid (extendBlockSet preds id))