Futhark.Transform.FirstOrderTransform

The code generator cannot handle the array combinators (map and friends), so this module was written to transform them into the equivalent do-loops. The transformation is currently rather naive, and - it's certainly worth considering when we can express such transformations in-place.

Documentation

transformFunDef :: (MonadFreshNames m, Bindable tolore, BinderOps tolore, LetAttr SOACS ~ LetAttr tolore, CanBeAliased (Op tolore)) => FunDef -> m (FunDef tolore)

type Transformer m = (MonadBinder m, Bindable (Lore m), BinderOps (Lore m), LocalScope (Lore m) m, LetAttr SOACS ~ LetAttr (Lore m), LParamAttr SOACS ~ LParamAttr (Lore m), CanBeAliased (Op (Lore m)))

The constraints that a monad must uphold in order to be used for first-order transformation.

transformStmRecursively :: Transformer m => Stm -> m ()

First transform any nested Body or Lambda elements, then apply transformSOAC if the expression is a SOAC.

transformLambda :: (MonadFreshNames m, Bindable lore, BinderOps lore, LocalScope somelore m, SameScope somelore lore, LetAttr SOACS ~ LetAttr lore, CanBeAliased (Op lore)) => Lambda -> m (Lambda lore)

Recursively first-order-transform a lambda.

transformSOAC :: Transformer m => Pattern (Lore m) -> SOAC (Lore m) -> m ()

Transform a single SOAC into a do-loop. The body of the lambda is untouched, and may or may not contain further SOACs depending on the given lore.

transformBody :: Transformer m => Body -> m (Body (Lore m))

Utility

doLoopMapAccumL :: (LocalScope (Lore m) m, MonadBinder m, Bindable (Lore m), BinderOps (Lore m), LetAttr (Lore m) ~ Type, CanBeAliased (Op (Lore m))) => SubExp -> Lambda (Aliases (Lore m)) -> [SubExp] -> [VName] -> [VName] -> m (Exp (Lore m))

Turn a Haskell-style mapAccumL into a sequential do-loop. This is the guts of transforming a Redomap.

doLoopMapAccumL' :: (LocalScope (Lore m) m, MonadBinder m, Bindable (Lore m), BinderOps (Lore m), LetAttr (Lore m) ~ Type, CanBeAliased (Op (Lore m))) => SubExp -> Lambda (Aliases (Lore m)) -> [SubExp] -> [VName] -> [VName] -> m ([(FParam (Lore m), SubExp)], VName, Body (Lore m))