Futhark.Pass.ExtractKernels.Interchange

It is well known that fully parallel loops can always be interchanged inwards with a sequential loop. This module implements that transformation.

This is also where we implement loop-switching (for branches), which is semantically similar to interchange.

Documentation

data SeqLoop

An encoding of a sequential do-loop with no existential context, alongside its result pattern.

Constructors

SeqLoop [Int] Pattern [(FParam, SubExp)] (LoopForm SOACS) Body

interchangeLoops :: (MonadFreshNames m, HasScope SOACS m) => KernelNest -> SeqLoop -> m (Stms SOACS)

Given a (parallel) map nesting and an inner sequential loop, move the maps inside the sequential loop. The result is several statements - one of these will be the loop, which will then contain statements with Map expressions.

data Branch

Constructors

Branch [Int] Pattern SubExp Body Body (IfAttr (BranchType SOACS))

interchangeBranch :: (MonadFreshNames m, HasScope SOACS m) => KernelNest -> Branch -> m (Stms SOACS)