From e1e3d37b988c8839a74552bcebeef7f9293b0a6c Mon Sep 17 00:00:00 2001 From: "simonpj@microsoft.com" Date: Tue, 21 Oct 2008 14:30:19 +0000 Subject: [PATCH] Don't float an expression wrapped in a cast There is no point in floating out an expression wrapped in a coercion; If we do we'll transform lvl = e |> co [_$_] to lvl' = e; lvl = lvl' |> co and then inline lvl. Better just to float out the payload (e). --- compiler/simplCore/SetLevels.lhs | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/compiler/simplCore/SetLevels.lhs b/compiler/simplCore/SetLevels.lhs index 2c84589..e20bc83 100644 --- a/compiler/simplCore/SetLevels.lhs +++ b/compiler/simplCore/SetLevels.lhs @@ -376,6 +376,13 @@ lvlMFE :: Bool -- True <=> strict context [body of case or let] lvlMFE _ _ _ (_, AnnType ty) = return (Type ty) +-- No point in floating out an expression wrapped in a coercion; +-- If we do we'll transform lvl = e |> co +-- to lvl' = e; lvl = lvl' |> co +-- and then inline lvl. Better just to float out the payload. +lvlMFE strict_ctxt ctxt_lvl env (_, AnnCast e co) + = do { expr' <- lvlMFE strict_ctxt ctxt_lvl env e + ; return (Cast expr' co) } lvlMFE strict_ctxt ctxt_lvl env ann_expr@(fvs, _) | isUnLiftedType ty -- Can't let-bind it; see Note [Unlifted MFEs] -- 1.7.10.4