HERMIT.Dictionary.WorkerWrapper.Fix

The Worker/Wrapper Transformation

Note that many of these operations require fix to be in scope.

externals :: [External]

Externals for manipulating fixed points, and for the worker/wrapper transformation.

wwFacBR :: Maybe WWAssumption -> CoreExpr -> CoreExpr -> BiRewriteH CoreExpr

For any f :: A -> A, and given wrap :: B -> A and unwrap :: A -> B as arguments, then fix A f <==> wrap (fix B (\ b -> unwrap (f (wrap b))))

wwSplitR :: Maybe WWAssumption -> CoreExpr -> CoreExpr -> RewriteH CoreDef

\ wrap unwrap -> (prog = expr ==> prog = let f = \ prog -> expr in let work = unwrap (f (wrap work)) in wrap work)

wwSplitStaticArg :: Int -> [Int] -> Maybe WWAssumption -> CoreString -> CoreString -> RewriteH CoreDef

As wwSplit but performs the static-argument transformation for n static arguments first, and optionally provides some of those arguments (specified by index) to all calls of wrap and unwrap. This is useful if, for example, the expression, and wrap and unwrap, all have a forall type.

wwGenerateFusionT :: Maybe WWAssumption -> TransformH LCore ()

Save the recursive definition of work in the stash, so that we can later verify uses of wwFusionBR. Must be applied to a definition of the form: work = unwrap (f (wrap work)) Note that this is performed automatically as part of wwSplitR.

wwFusionBR :: BiRewriteH CoreExpr

Given wrap :: B -> A, unwrap :: A -> B and work :: B as arguments, then unwrap (wrap work) <==> work

wwAssA

Arguments

:: Maybe (RewriteH CoreExpr)

WW Assumption A

-> CoreExpr

wrap

-> CoreExpr

unwrap

-> BiRewriteH CoreExpr

wrap (unwrap a) <==> a

wwAssB

Arguments

:: Maybe (RewriteH CoreExpr)

WW Assumption B

-> CoreExpr

wrap

-> CoreExpr

unwrap

-> CoreExpr

f

-> BiRewriteH CoreExpr

wrap (unwrap (f a)) <==> f a

wwAssC

Arguments

:: Maybe (RewriteH CoreExpr)

WW Assumption C

-> CoreExpr

wrap

-> CoreExpr

unwrap

-> CoreExpr

f

-> BiRewriteH CoreExpr

fix A ( a -> wrap (unwrap (f a))) <==> fix A f