[commit: ghc] new-demand-to-merge: proper unpacking strategy adapted (9bb7505)
Ilya Sergey <[email protected]>
| Newsgroups | gmane.comp.lang.haskell.cvs.ghc |
|---|---|
| Message-ID | <[email protected]> |
Repository : ssh://darcs.haskell.org//srv/darcs/ghc On branch : new-demand-to-merge http://hackage.haskell.org/trac/ghc/changeset/9bb7505dfdde8bb6ada4d9e63029886eac3566ae >--------------------------------------------------------------- commit 9bb7505dfdde8bb6ada4d9e63029886eac3566ae Author: ilyasergey <[email protected]> Date: Thu Nov 8 16:32:55 2012 +0100 proper unpacking strategy adapted >--------------------------------------------------------------- compiler/stranal/DmdAnal.lhs | 66 ++++++++++++++++++++++------------------- 1 files changed, 35 insertions(+), 31 deletions(-) diff --git a/compiler/stranal/DmdAnal.lhs b/compiler/stranal/DmdAnal.lhs index e6b12de..357453a 100644 --- a/compiler/stranal/DmdAnal.lhs +++ b/compiler/stranal/DmdAnal.lhs @@ -630,18 +630,19 @@ mkSigTy dflags top_lvl rec_flag env id rhs dmd_ty mk_sig_ty :: DynFlags -> Bool -> RecFlag -> CoreExpr -> DmdType -> (DmdEnv, StrictSig) -mk_sig_ty _dflags thunk_cpr_ok _rec_flag rhs (DmdType fv dmds res) +mk_sig_ty dflags thunk_cpr_ok _rec_flag rhs (DmdType fv dmds res) = (lazy_fv, mkStrictSig dmd_ty) -- Re unused never_inline, see Note [NOINLINE and strictness] where - dmd_ty = mkDmdType strict_fv dmds res' + dmd_ty = mkDmdType strict_fv final_dmds res' -- See Note [Lazy and strict free variables] lazy_fv = filterUFM (not . isStrictDmd) fv strict_fv = filterUFM isStrictDmd fv - -- final_dmds = setUnpackStrategy dmds - -- Set the unpacking strategy + -- Set the unpacking strategy + final_dmds = setUnpackStrategy dflags dmds + ignore_cpr_info = not (exprIsHNF rhs || thunk_cpr_ok) res' = if returnsCPR res && ignore_cpr_info @@ -654,33 +655,36 @@ or whether we'll just remember its strictness. If unpacking would give rise to a *lot* of worker args, we may decide not to unpack after all. \begin{code} --- setUnpackStrategy :: DynFlags -> [Demand] -> [Demand] --- setUnpackStrategy dflags ds --- = snd (go (maxWorkerArgs dflags - nonAbsentArgs ds) ds) --- where --- go :: Int -- Max number of args available for sub-components of [Demand] --- -> [Demand] --- -> (Int, [Demand]) -- Args remaining after subcomponents of [Demand] are unpacked - --- go n (Eval (Prod cs) : ds) --- | n' >= 0 = Eval (Prod cs') `cons` go n'' ds --- | otherwise = Box (Eval (Prod cs)) `cons` go n ds --- where --- (n'',cs') = go n' cs --- n' = n + 1 - non_abs_args --- -- Add one to the budget 'cos we drop the top-level arg --- non_abs_args = nonAbsentArgs cs --- -- Delete # of non-absent args to which we'll now be committed - --- go n (d:ds) = d `cons` go n ds --- go n [] = (n,[]) - --- cons d (n,ds) = (n, d:ds) - --- nonAbsentArgs :: [Demand] -> Int --- nonAbsentArgs [] = 0 --- nonAbsentArgs (d : ds) | isAbs = nonAbsentArgs ds --- nonAbsentArgs (_ : ds) = 1 + nonAbsentArgs ds +setUnpackStrategy :: DynFlags -> [Demand] -> [Demand] +setUnpackStrategy dflags ds + = snd (go (maxWorkerArgs dflags - nonAbsentArgs ds) ds) + where + go :: Int -- Max number of args available for sub-components of [Demand] + -> [Demand] + -> (Int, [Demand]) -- Args remaining after subcomponents of [Demand] are unpacked + + go n (d:ds) + | isProdDmd d && isStrictDmd d + = if n' >= 0 + then (mkProdDmd cs') `cons` go n'' ds + else d `cons` go n ds + where + cs = splitProdDmd d + (n'',cs') = go n' cs + n' = n + 1 - non_abs_args + -- Add one to the budget 'cos we drop the top-level arg + non_abs_args = nonAbsentArgs cs + -- Delete # of non-absent args to which we'll now be committed + + go n (d:ds) = d `cons` go n ds + go n [] = (n,[]) + + cons d (n,ds) = (n, d:ds) + +nonAbsentArgs :: [Demand] -> Int +nonAbsentArgs [] = 0 +nonAbsentArgs (d : ds) | isAbs d = nonAbsentArgs ds +nonAbsentArgs (_ : ds) = 1 + nonAbsentArgs ds \end{code} Note [CPR for thunks]