diff options
Diffstat (limited to 'compiler/coreSyn/CorePrep.hs')
| -rw-r--r-- | compiler/coreSyn/CorePrep.hs | 44 |
1 files changed, 32 insertions, 12 deletions
diff --git a/compiler/coreSyn/CorePrep.hs b/compiler/coreSyn/CorePrep.hs index 0d82be5abc..b3d78172dc 100644 --- a/compiler/coreSyn/CorePrep.hs +++ b/compiler/coreSyn/CorePrep.hs @@ -668,13 +668,8 @@ cpeApp :: CorePrepEnv -> CoreExpr -> UniqSM (Floats, CpeRhs) -- May return a CpeRhs because of saturating primops cpeApp top_env expr = do { let (terminal, args, depth) = collect_args expr - ; (head, app, floats) <- cpe_app top_env terminal args depth - - -- Now deal with the function - ; case head of - Just fn_id -> do { sat_app <- maybeSaturate fn_id app depth - ; return (floats, sat_app) } - _other -> return (floats, app) } + ; cpe_app top_env terminal args depth + } where -- We have a nested data structure of the form @@ -702,11 +697,25 @@ cpeApp top_env expr -> CoreExpr -> [CpeArg] -> Int - -> UniqSM (Maybe Id, CpeApp, Floats) + -> UniqSM (Floats, CpeRhs) cpe_app env (Var f) (CpeArg Type{} : CpeArg arg : args) depth | f `hasKey` lazyIdKey -- Replace (lazy a) with a, and || f `hasKey` noinlineIdKey -- Replace (noinline a) with a - = cpe_app env arg args (depth - 1) + -- Consider the code: + -- + -- lazy (f x) y + -- + -- We need to make sure that we need to recursively collect arguments on + -- "f x", otherwise we'll float "f x" out (it's not a variable) and + -- end up with this awful -ddump-prep: + -- + -- case f x of f_x { + -- __DEFAULT -> f_x y + -- } + -- + -- rather than the far superior "f x y". Test case is par01. + = let (terminal, args', depth') = collect_args arg + in cpe_app env terminal (args' ++ args) (depth + depth' - 1) cpe_app env (Var f) [CpeArg _runtimeRep@Type{}, CpeArg _type@Type{}, CpeArg arg] 1 | f `hasKey` runRWKey -- Replace (runRW# f) by (f realWorld#), beta reducing if possible (this @@ -724,7 +733,7 @@ cpeApp top_env expr -- cpe_ExprIsTrivial). But note that we need the type of the -- expression, not the id. ; (app, floats) <- rebuild_app args e2 (exprType e2) emptyFloats stricts - ; return (hd, app, floats) } + ; mb_saturate hd app floats depth } where stricts = case idStrictness v of StrictSig (DmdType _ demands _) @@ -737,16 +746,27 @@ cpeApp top_env expr -- Here, we can't evaluate the arg strictly, because this -- partial application might be seq'd + -- We inlined into something that's not a var and has no args. + -- Bounce it back up to cpeRhsE. + cpe_app env fun [] _ = cpeRhsE env fun + -- N-variable fun, better let-bind it - cpe_app env fun args _ + cpe_app env fun args depth = do { (fun_floats, fun') <- cpeArg env evalDmd fun ty -- The evalDmd says that it's sure to be evaluated, -- so we'll end up case-binding it ; (app, floats) <- rebuild_app args fun' ty fun_floats [] - ; return (Nothing, app, floats) } + ; mb_saturate Nothing app floats depth } where ty = exprType fun + -- Saturate if necessary + mb_saturate head app floats depth = + case head of + Just fn_id -> do { sat_app <- maybeSaturate fn_id app depth + ; return (floats, sat_app) } + _other -> return (floats, app) + -- Deconstruct and rebuild the application, floating any non-atomic -- arguments to the outside. We collect the type of the expression, -- the head of the application, and the number of actual value arguments, |