-- By not inlining any other reference, we also prevent looping problems
-- with funextract and inlinedict.
inlinetoplevel :: Transform
-inlinetoplevel (LetBinding:_) expr | not (is_fun expr) =
+inlinetoplevel c expr | not (null c) && is_letbinding_ctx (head c) && not (is_fun expr) =
case collectArgs expr of
(Var f, args) -> do
body_maybe <- needsInline f
-- body consisting of a bunch of nested lambdas containing a
-- non-function value (e.g., a complete application).
eta :: Transform
-eta (AppFirst:_) expr = return expr
+eta c expr | not (null c) && is_appfirst_ctx (head c) = return expr
-- Also don't apply to arguments, since this can cause loops with
-- funextract. This isn't the proper solution, but due to an
-- implementation bug in notappargs, this is how it used to work so far.
-eta (AppSecond:_) expr = return expr
-eta c expr | is_fun expr && not (is_lam expr) = do
+ | not (null c) && is_appsecond_ctx (head c) = return expr
+ | is_fun expr && not (is_lam expr) = do
let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr
id <- Trans.lift $ mkInternalVar "param" arg_ty
change (Lam id (App expr (Var id)))
-- Extract the return value from the body of the top level lambdas (of
-- which ther could be zero), unless it is a let expression (in which
-- case the next clause applies).
-retvalsimpl c expr | all (== LambdaBody) c && not (is_lam expr) && not (is_let expr) = do
+retvalsimpl c expr | all is_lambdabody_ctx c && not (is_lam expr) && not (is_let expr) = do
local_var <- Trans.lift $ is_local_var expr
repr <- isRepr expr
if not local_var && repr
-- Extract the return value from the body of a let expression, which is
-- itself the body of the top level lambdas (of which there could be
-- zero).
-retvalsimpl c expr@(Let (Rec binds) body) | all (== LambdaBody) c = do
+retvalsimpl c expr@(Let (Rec binds) body) | all is_lambdabody_ctx c = do
-- Don't extract values that are already a local variable, to prevent
-- loops with ourselves.
local_var <- Trans.lift $ is_local_var body
-- Make sure the scrutinee of a case expression is a local variable
-- reference.
scrutsimpl :: Transform
--- Don't touch scrutinees that are already simple
-scrutsimpl c expr@(Case (Var _) _ _ _) = return expr
--- Replace all other cases with a let that binds the scrutinee and a new
+-- Replace a case expression with a let that binds the scrutinee and a new
-- simple scrutinee, but only when the scrutinee is representable (to prevent
-- loops with inlinenonrep, though I don't think a non-representable scrutinee
--- will be supported anyway...)
+-- will be supported anyway...) and is not a local variable already.
scrutsimpl c expr@(Case scrut b ty alts) = do
repr <- isRepr scrut
- if repr
+ local_var <- Trans.lift $ is_local_var scrut
+ if repr && not local_var
then do
id <- Trans.lift $ mkBinderFor scrut "scrut"
change $ Let (NonRec id scrut) (Case (Var id) b ty alts)
-- Wilden the binders of one alt, producing a list of bindings as a
-- sideeffect.
doalt :: CoreAlt -> TransformMonad ([(CoreBndr, CoreExpr)], CoreAlt)
- doalt (con, bndrs, expr) = do
+ doalt (LitAlt _, _, _) = error $ "Don't know how to handle LitAlt in case expression: " ++ pprString expr
+ doalt alt@(DEFAULT, [], expr) = do
+ local_var <- Trans.lift $ is_local_var expr
+ repr <- isRepr expr
+ -- Extract any expressions that is not a local var already and is
+ -- representable (to prevent loops with inlinenonrep).
+ (exprbinding_maybe, expr') <- if (not local_var) && repr
+ then do
+ id <- Trans.lift $ mkBinderFor expr "caseval"
+ -- We don't flag a change here, since casevalsimpl will do that above
+ -- based on Just we return here.
+ return (Just (id, expr), Var id)
+ else
+ -- Don't simplify anything else
+ return (Nothing, expr)
+ let newalt = (DEFAULT, [], expr')
+ let bindings = Maybe.catMaybes [exprbinding_maybe]
+ return (bindings, newalt)
+ doalt (DataAlt dc, bndrs, expr) = do
-- Make each binder wild, if possible
bndrs_res <- Monad.zipWithM dobndr bndrs [0..]
let (newbndrs, bindings_maybe) = unzip bndrs_res
let uses_bndrs = not $ VarSet.isEmptyVarSet $ CoreFVs.exprSomeFreeVars (`elem` newbndrs) expr
(exprbinding_maybe, expr') <- doexpr expr uses_bndrs
-- Create a new alternative
- let newalt = (con, newbndrs, expr')
+ let newalt = (DataAlt dc, newbndrs, expr')
let bindings = Maybe.catMaybes (bindings_maybe ++ [exprbinding_maybe])
return (bindings, newalt)
where
-- inlinenonrep).
if (not wild) && repr
then do
- caseexpr <- Trans.lift $ mkSelCase scrut i
+ let dc_i = datacon_index (CoreUtils.exprType scrut) dc
+ caseexpr <- Trans.lift $ mkSelCase scrut dc_i i
-- Create a new binder that will actually capture a value in this
-- case statement, and return it.
return (wildbndrs!!i, Just (b, caseexpr))
res_bndr <- Trans.lift $ mkBinderFor newapp "res"
-- Create extractor case expressions to extract each of the
-- free variables from the tuple.
- sel_cases <- Trans.lift $ mapM (mkSelCase (Var res_bndr)) [0..n_free_vars-1]
+ sel_cases <- Trans.lift $ mapM (mkSelCase (Var res_bndr) 0) [0..n_free_vars-1]
-- Bind the res_bndr to the result of the new application
-- and each of the free variables to the corresponding
-- Leave all other expressions unchanged
inlinenonrepresult c expr = return expr
+----------------------------------------------------------------
+-- Type-class transformations
+----------------------------------------------------------------
+
--------------------------------
-- ClassOp resolution
--------------------------------