From: Matthijs Kooijman Date: Fri, 14 Aug 2009 12:38:11 +0000 (+0200) Subject: Make letflat work with non-recursive lets. X-Git-Url: https://git.stderr.nl/gitweb?a=commitdiff_plain;h=78793ddabc41998c386589564d6c47411279b29f;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git Make letflat work with non-recursive lets. This replaces the implementation that worked with recursive lets, since that is no longer needed. --- diff --git "a/c\316\273ash/CLasH/Normalize.hs" "b/c\316\273ash/CLasH/Normalize.hs" index dd8244d..07ded20 100644 --- "a/c\316\273ash/CLasH/Normalize.hs" +++ "b/c\316\273ash/CLasH/Normalize.hs" @@ -169,23 +169,14 @@ letsimpltop = everywhere ("letsimpl", letsimpl) -------------------------------- -- let flattening -------------------------------- +-- Takes a let that binds another let, and turns that into two nested lets. +-- e.g., from: +-- let b = (let b' = expr' in res') in res +-- to: +-- let b' = expr' in (let b = res' in res) letflat, letflattop :: Transform -letflat (Let (Rec binds) expr) = do - -- Turn each binding into a list of bindings (possibly containing just one - -- element, of course) - bindss <- Monad.mapM flatbind binds - -- Concat all the bindings - let binds' = concat bindss - -- Return the new let. We don't use change here, since possibly nothing has - -- changed. If anything has changed, flatbind has already flagged that - -- change. - return $ Let (Rec binds') expr - where - -- Turns a binding of a let into a multiple bindings, or any other binding - -- into a list with just that binding - flatbind :: (CoreBndr, CoreExpr) -> TransformMonad [(CoreBndr, CoreExpr)] - flatbind (b, Let (Rec binds) expr) = change ((b, expr):binds) - flatbind (b, expr) = return [(b, expr)] +letflat (Let (NonRec b (Let (NonRec b' expr') res')) res) = + change $ Let (NonRec b' expr') (Let (NonRec b res') res) -- Leave all other expressions unchanged letflat expr = return expr -- Perform this transform everywhere