Commit 0e953da1 authored by Joachim Breitner's avatar Joachim Breitner

Implement a dedicated exitfication pass #14152

The idea is described in #14152, and can be summarized: Float the exit
path out of a joinrec, so that the simplifier can do more with it.
See the test case for a nice example.

The floating goes against what the simplifier usually does, hence we
need to be careful not inline them back.

The position of exitification in the pipeline was chosen after a small
amount of experimentation, but may need to be improved. For example,
exitification can allow rewrite rules to fire, but for that it would
have to happen before the `simpl_phases`.

Perf.haskell.org reports these nice performance wins:

    Nofib allocations
    fannkuch-redux    78446640  - 99.92%      64560
    k-nucleotide     109466384  - 91.32%    9502040
    simple            72424696  -  5.96%   68109560

    Nofib instruction counts
    fannkuch-redux  1744331636  -  3.86% 1676999519
    k-nucleotide    2318221965  -  6.30% 2172067260
    scs             1978470869  -  3.35% 1912263779
    simple           669858104  -  3.38%  647206739
    spectral-norm    186423292  -  5.37%  176411536

Differential Revision: https://phabricator.haskell.org/D3903
parent 97ca0d24
......@@ -74,7 +74,7 @@ module Id (
DictId, isDictId, isEvVar,
-- ** Join variables
JoinId, isJoinId, isJoinId_maybe, idJoinArity,
JoinId, isJoinId, isJoinId_maybe, idJoinArity, isExitJoinId,
asJoinId, asJoinId_maybe, zapJoinId,
-- ** Inline pragma stuff
......@@ -497,6 +497,10 @@ isJoinId_maybe id
_ -> Nothing
| otherwise = Nothing
-- see Note [Exitification] and see Note [Do not inline exit join points]
isExitJoinId :: Var -> Bool
isExitJoinId id = isJoinId id && isOneOcc (idOccInfo id) && occ_in_lam (idOccInfo id)
idDataCon :: Id -> DataCon
-- ^ Get from either the worker or the wrapper 'Id' to the 'DataCon'. Currently used only in the desugarer.
--
......
......@@ -36,6 +36,7 @@ module Unique (
deriveUnique, -- Ditto
newTagUnique, -- Used in CgCase
initTyVarUnique,
initExitJoinUnique,
nonDetCmpUnique,
isValidKnownKeyUnique, -- Used in PrelInfo.knownKeyNamesOkay
......@@ -436,3 +437,6 @@ mkVarOccUnique fs = mkUnique 'i' (uniqueOfFS fs)
mkDataOccUnique fs = mkUnique 'd' (uniqueOfFS fs)
mkTvOccUnique fs = mkUnique 'v' (uniqueOfFS fs)
mkTcOccUnique fs = mkUnique 'c' (uniqueOfFS fs)
initExitJoinUnique :: Unique
initExitJoinUnique = mkUnique 's' 0
......@@ -268,6 +268,7 @@ coreDumpFlag (CoreDoFloatOutwards {}) = Just Opt_D_verbose_core2core
coreDumpFlag CoreLiberateCase = Just Opt_D_verbose_core2core
coreDumpFlag CoreDoStaticArgs = Just Opt_D_verbose_core2core
coreDumpFlag CoreDoCallArity = Just Opt_D_dump_call_arity
coreDumpFlag CoreDoExitify = Just Opt_D_dump_exitify
coreDumpFlag CoreDoStrictness = Just Opt_D_dump_stranal
coreDumpFlag CoreDoWorkerWrapper = Just Opt_D_dump_worker_wrapper
coreDumpFlag CoreDoSpecialising = Just Opt_D_dump_spec
......
......@@ -77,7 +77,7 @@ module CoreSyn (
collectAnnArgs, collectAnnArgsTicks,
-- ** Operations on annotations
deAnnotate, deAnnotate', deAnnAlt,
deAnnotate, deAnnotate', deAnnAlt, deAnnBind,
collectAnnBndrs, collectNAnnBndrs,
-- * Orphanhood
......@@ -2160,16 +2160,16 @@ deAnnotate' (AnnTick tick body) = Tick tick (deAnnotate body)
deAnnotate' (AnnLet bind body)
= Let (deAnnBind bind) (deAnnotate body)
where
deAnnBind (AnnNonRec var rhs) = NonRec var (deAnnotate rhs)
deAnnBind (AnnRec pairs) = Rec [(v,deAnnotate rhs) | (v,rhs) <- pairs]
deAnnotate' (AnnCase scrut v t alts)
= Case (deAnnotate scrut) v t (map deAnnAlt alts)
deAnnAlt :: AnnAlt bndr annot -> Alt bndr
deAnnAlt (con,args,rhs) = (con,args,deAnnotate rhs)
deAnnBind :: AnnBind b annot -> Bind b
deAnnBind (AnnNonRec var rhs) = NonRec var (deAnnotate rhs)
deAnnBind (AnnRec pairs) = Rec [(v,deAnnotate rhs) | (v,rhs) <- pairs]
-- | As 'collectBinders' but for 'AnnExpr' rather than 'Expr'
collectAnnBndrs :: AnnExpr bndr annot -> ([bndr], AnnExpr bndr annot)
collectAnnBndrs e
......
......@@ -429,6 +429,7 @@ Library
StgSyn
CallArity
DmdAnal
Exitify
WorkWrap
WwLib
FamInst
......
......@@ -360,6 +360,7 @@ data DumpFlag
| Opt_D_dump_prep
| Opt_D_dump_stg
| Opt_D_dump_call_arity
| Opt_D_dump_exitify
| Opt_D_dump_stranal
| Opt_D_dump_str_signatures
| Opt_D_dump_tc
......@@ -428,6 +429,7 @@ data GeneralFlag
-- optimisation opts
| Opt_CallArity
| Opt_Exitification
| Opt_Strictness
| Opt_LateDmdAnal
| Opt_KillAbsence
......@@ -3005,6 +3007,8 @@ dynamic_flags_deps = [
(setDumpFlag Opt_D_dump_stg)
, make_ord_flag defGhcFlag "ddump-call-arity"
(setDumpFlag Opt_D_dump_call_arity)
, make_ord_flag defGhcFlag "ddump-exitify"
(setDumpFlag Opt_D_dump_exitify)
, make_ord_flag defGhcFlag "ddump-stranal"
(setDumpFlag Opt_D_dump_stranal)
, make_ord_flag defGhcFlag "ddump-str-signatures"
......@@ -3706,6 +3710,7 @@ fFlagsDeps = [
flagGhciSpec "break-on-exception" Opt_BreakOnException,
flagSpec "building-cabal-package" Opt_BuildingCabalPackage,
flagSpec "call-arity" Opt_CallArity,
flagSpec "exitification" Opt_Exitification,
flagSpec "case-merge" Opt_CaseMerge,
flagSpec "case-folding" Opt_CaseFolding,
flagSpec "cmm-elim-common-blocks" Opt_CmmElimCommonBlocks,
......@@ -4159,6 +4164,7 @@ optLevelFlags -- see Note [Documenting optimisation flags]
, ([0], Opt_OmitInterfacePragmas)
, ([1,2], Opt_CallArity)
, ([1,2], Opt_Exitification)
, ([1,2], Opt_CaseMerge)
, ([1,2], Opt_CaseFolding)
, ([1,2], Opt_CmmElimCommonBlocks)
......
......@@ -114,6 +114,7 @@ data CoreToDo -- These are diff core-to-core passes,
| CoreDoPrintCore
| CoreDoStaticArgs
| CoreDoCallArity
| CoreDoExitify
| CoreDoStrictness
| CoreDoWorkerWrapper
| CoreDoSpecialising
......@@ -141,6 +142,7 @@ instance Outputable CoreToDo where
ppr CoreLiberateCase = text "Liberate case"
ppr CoreDoStaticArgs = text "Static argument"
ppr CoreDoCallArity = text "Called arity analysis"
ppr CoreDoExitify = text "Exitification transformation"
ppr CoreDoStrictness = text "Demand analysis"
ppr CoreDoWorkerWrapper = text "Worker Wrapper binds"
ppr CoreDoSpecialising = text "Specialise"
......
module Exitify ( exitifyProgram ) where
{-
Note [Exitification]
~~~~~~~~~~~~~~~~~~~~
This module implements Exitification. The goal is to pull as much code out of
recursive functions as possible, as the simplifier is better at inlining into
call-sites that are not in recursive functions.
Example:
let t = foo bar
joinrec go 0 x y = t (x*x)
go (n-1) x y = jump go (n-1) (x+y)
in …
We’d like to inline `t`, but that does not happen: Because t is a thunk and is
used in a recursive function, doing so might lose sharing in general. In
this case, however, `t` is on the _exit path_ of `go`, so called at most once.
How do we make this clearly visible to the simplifier?
A code path (i.e., an expression in a tail-recursive position) in a recursive
function is an exit path if it does not contain a recursive call. We can bind
this expression outside the recursive function, as a join-point.
Example result:
let t = foo bar
join exit x = t (x*x)
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
in …
Now `t` is no longer in a recursive function, and good things happen!
-}
import GhcPrelude
import Var
import Id
import IdInfo
import CoreSyn
import CoreUtils
import State
import Unique
import VarSet
import VarEnv
import CoreFVs
import FastString
import Type
import Data.Bifunctor
import Control.Monad
-- | Traverses the AST, simply to find all joinrecs and call 'exitify' on them.
exitifyProgram :: CoreProgram -> CoreProgram
exitifyProgram binds = map goTopLvl binds
where
goTopLvl (NonRec v e) = NonRec v (go in_scope_toplvl e)
goTopLvl (Rec pairs) = Rec (map (second (go in_scope_toplvl)) pairs)
in_scope_toplvl = emptyInScopeSet `extendInScopeSetList` bindersOfBinds binds
go :: InScopeSet -> CoreExpr -> CoreExpr
go _ e@(Var{}) = e
go _ e@(Lit {}) = e
go _ e@(Type {}) = e
go _ e@(Coercion {}) = e
go in_scope (Lam v e') = Lam v (go in_scope' e')
where in_scope' = in_scope `extendInScopeSet` v
go in_scope (App e1 e2) = App (go in_scope e1) (go in_scope e2)
go in_scope (Case scrut bndr ty alts)
= Case (go in_scope scrut) bndr ty (map (goAlt in_scope') alts)
where in_scope' = in_scope `extendInScopeSet` bndr
go in_scope (Cast e' c) = Cast (go in_scope e') c
go in_scope (Tick t e') = Tick t (go in_scope e')
go in_scope (Let bind body) = goBind in_scope bind (go in_scope' body)
where in_scope' = in_scope `extendInScopeSetList` bindersOf bind
goAlt :: InScopeSet -> CoreAlt -> CoreAlt
goAlt in_scope (dc, pats, rhs) = (dc, pats, go in_scope' rhs)
where in_scope' = in_scope `extendInScopeSetList` pats
goBind :: InScopeSet -> CoreBind -> (CoreExpr -> CoreExpr)
goBind in_scope (NonRec v rhs) = Let (NonRec v (go in_scope rhs))
goBind in_scope (Rec pairs)
| is_join_rec = exitify in_scope' pairs'
| otherwise = Let (Rec pairs')
where pairs' = map (second (go in_scope')) pairs
is_join_rec = any (isJoinId . fst) pairs
in_scope' = in_scope `extendInScopeSetList` bindersOf (Rec pairs)
-- | Given a recursive group of a joinrec, identifies “exit paths” and binds them as
-- join-points outside the joinrec.
exitify :: InScopeSet -> [(Var,CoreExpr)] -> (CoreExpr -> CoreExpr)
exitify in_scope pairs =
\body ->mkExitLets exits (mkLetRec pairs' body)
where
mkExitLets ((exitId, exitRhs):exits') = mkLetNonRec exitId exitRhs . mkExitLets exits'
mkExitLets [] = id
-- We need the set of free variables of many subexpressions here, so
-- annotate the AST with them
-- see Note [Calculating free variables]
ann_pairs = map (second freeVars) pairs
-- Which are the recursive calls?
recursive_calls = mkVarSet $ map fst pairs
(pairs',exits) = (`runState` []) $ do
forM ann_pairs $ \(x,rhs) -> do
-- go past the lambdas of the join point
let (args, body) = collectNAnnBndrs (idJoinArity x) rhs
body' <- go args body
let rhs' = mkLams args body'
return (x, rhs')
-- main working function. Goes through the RHS (tail-call positions only),
-- checks if there are no more recursive calls, if so, abstracts over
-- variables bound on the way and lifts it out as a join point.
--
-- It uses a state monad to keep track of floated binds
go :: [Var] -- ^ variables to abstract over
-> CoreExprWithFVs -- ^ current expression in tail position
-> State [(Id, CoreExpr)] CoreExpr
go captured ann_e
-- Do not touch an expression that is already a join jump where all arguments
-- are captured variables. See Note [Idempotency]
-- But _do_ float join jumps with interesting arguments.
-- See Note [Jumps can be interesting]
| (Var f, args) <- collectArgs e
, isJoinId f
, all isCapturedVarArg args
= return e
-- Do not touch a boring expression (see Note [Interesting expression])
| is_exit, not is_interesting = return e
-- Cannot float out if local join points are used, as
-- we cannot abstract over them
| is_exit, captures_join_points = return e
-- We have something to float out!
| is_exit = do
-- Assemble the RHS of the exit join point
let rhs = mkLams args e
ty = exprType rhs
let avoid = in_scope `extendInScopeSetList` captured
-- Remember this binding under a suitable name
v <- addExit avoid ty (length args) rhs
-- And jump to it from here
return $ mkVarApps (Var v) args
where
-- An exit expression has no recursive calls
is_exit = disjointVarSet fvs recursive_calls
-- Used to detect exit expressoins that are already proper exit jumps
isCapturedVarArg (Var v) = v `elem` captured
isCapturedVarArg _ = False
-- An interesting exit expression has free, non-imported
-- variables from outside the recursive group
-- See Note [Interesting expression]
is_interesting = anyVarSet isLocalId (fvs `minusVarSet` mkVarSet captured)
-- The possible arguments of this exit join point
args = filter (`elemVarSet` fvs) captured
-- We cannot abstract over join points
captures_join_points = any isJoinId args
e = deAnnotate ann_e
fvs = dVarSetToVarSet (freeVarsOf ann_e)
-- Case right hand sides are in tail-call position
go captured (_, AnnCase scrut bndr ty alts) = do
alts' <- forM alts $ \(dc, pats, rhs) -> do
rhs' <- go (captured ++ [bndr] ++ pats) rhs
return (dc, pats, rhs')
return $ Case (deAnnotate scrut) bndr ty alts'
go captured (_, AnnLet ann_bind body)
-- join point, RHS and body are in tail-call position
| AnnNonRec j rhs <- ann_bind
, Just join_arity <- isJoinId_maybe j
= do let (params, join_body) = collectNAnnBndrs join_arity rhs
join_body' <- go (captured ++ params) join_body
let rhs' = mkLams params join_body'
body' <- go (captured ++ [j]) body
return $ Let (NonRec j rhs') body'
-- rec join point, RHSs and body are in tail-call position
| AnnRec pairs <- ann_bind
, isJoinId (fst (head pairs))
= do let js = map fst pairs
pairs' <- forM pairs $ \(j,rhs) -> do
let join_arity = idJoinArity j
(params, join_body) = collectNAnnBndrs join_arity rhs
join_body' <- go (captured ++ js ++ params) join_body
let rhs' = mkLams params join_body'
return (j, rhs')
body' <- go (captured ++ js) body
return $ Let (Rec pairs') body'
-- normal Let, only the body is in tail-call position
| otherwise
= do body' <- go (captured ++ bindersOf bind ) body
return $ Let bind body'
where bind = deAnnBind ann_bind
go _ ann_e = return (deAnnotate ann_e)
-- Picks a new unique, which is disjoint from
-- * the free variables of the whole joinrec
-- * any bound variables (captured)
-- * any exit join points created so far.
mkExitJoinId :: InScopeSet -> Type -> JoinArity -> ExitifyM JoinId
mkExitJoinId in_scope ty join_arity = do
fs <- get
let avoid = in_scope `extendInScopeSetList` (map fst fs)
`extendInScopeSet` exit_id_tmpl -- just cosmetics
return (uniqAway avoid exit_id_tmpl)
where
exit_id_tmpl = mkSysLocal (fsLit "exit") initExitJoinUnique ty
`asJoinId` join_arity
`setIdOccInfo` exit_occ_info
-- See Note [Do not inline exit join points]
exit_occ_info =
OneOcc { occ_in_lam = True
, occ_one_br = True
, occ_int_cxt = False
, occ_tail = AlwaysTailCalled join_arity }
addExit :: InScopeSet -> Type -> JoinArity -> CoreExpr -> ExitifyM JoinId
addExit in_scope ty join_arity rhs = do
-- Pick a suitable name
v <- mkExitJoinId in_scope ty join_arity
fs <- get
put ((v,rhs):fs)
return v
type ExitifyM = State [(JoinId, CoreExpr)]
{-
Note [Interesting expression]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We do not want this to happen:
joinrec go 0 x y = x
go (n-1) x y = jump go (n-1) (x+y)
in …
==>
join exit x = x
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
in …
because the floated exit path (`x`) is simply a parameter of `go`; there are
not useful interactions exposed this way.
Neither do we want this to happen
joinrec go 0 x y = x+x
go (n-1) x y = jump go (n-1) (x+y)
in …
==>
join exit x = x+x
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
in …
where the floated expression `x+x` is a bit more complicated, but still not
intersting.
Expressions are interesting when they move an occurrence of a variable outside
the recursive `go` that can benefit from being obviously called once, for example:
* a local thunk that can then be inlined (see example in note [Exitification])
* the parameter of a function, where the demand analyzer then can then
see that it is called at most once, and hence improve the function’s
strictness signature
So we only hoist an exit expression out if it mentiones at least one free,
non-imported variable.
Note [Jumps can be interesting]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
A jump to a join point can be interesting, if its arguments contain free
non-exported variables (z in the following example):
joinrec go 0 x y = jump j (x+z)
go (n-1) x y = jump go (n-1) (x+y)
in …
==>
join exit x y = jump j (x+z)
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
The join point itself can be interesting, even if none if
its arguments are (assume `g` to be an imported function that, on its own, does
not make this interesting):
join j y = map f y
joinrec go 0 x y = jump j (map g x)
go (n-1) x y = jump go (n-1) (x+y)
in …
Here, `j` would not be inlined because we do not inline something that looks
like an exit join point (see Note [Do not inline exit join points]).
But after exitification we have
join j y = map f y
join exit x = jump j (map g x)
joinrec go 0 x y = jump j (map g x)
go (n-1) x y = jump go (n-1) (x+y)
in …
and now we can inline `j` and this will allow `map/map` to fire.
Note [Idempotency]
~~~~~~~~~~~~~~~~~~
We do not want this to happen, where we replace the floated expression with
essentially the same expression:
join exit x = t (x*x)
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
in …
==>
join exit x = t (x*x)
join exit' x = jump exit x
joinrec go 0 x y = jump exit' x
go (n-1) x y = jump go (n-1) (x+y)
in …
So when the RHS is a join jump, and all of its arguments are captured variables,
then we leave it in place.
Note that `jump exit x` in this example looks interesting, as `exit` is a free
variable. Therefore, idempotency does not simply follow from floating only
interesting expressions.
Note [Calculating free variables]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We have two options where to annotate the tree with free variables:
A) The whole tree.
B) Each individual joinrec as we come across it.
Downside of A: We pay the price on the whole module, even outside any joinrecs.
Downside of B: We pay the price per joinrec, possibly multiple times when
joinrecs are nested.
Further downside of A: If the exitify function returns annotated expressions,
it would have to ensure that the annotations are correct.
Note [Do not inline exit join points]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
When we have
let t = foo bar
join exit x = t (x*x)
joinrec go 0 x y = jump exit x
go (n-1) x y = jump go (n-1) (x+y)
in …
we do not want the simplifier to simply inline `exit` back in (which it happily
would).
To prevent this, we need to recognize exit join points, and then disable
inlining.
Exit join points, recognizeable using `isExitJoinId` are join points with an
occurence in a recursive group, and can be recognized using `isExitJoinId`.
This function detects joinpoints with `occ_in_lam (idOccinfo id) == True`,
because the lambdas of a non-recursive join point are not considered for
`occ_in_lam`. For example, in the following code, `j1` is /not/ marked
occ_in_lam, because `j2` is called only once.
join j1 x = x+1
join j2 y = join j1 (y+2)
We create exit join point ids with such an `OccInfo`, see `exit_occ_info`.
To prevent inlining, we check for that in `preInlineUnconditionally` directly.
For `postInlineUnconditionally` and unfolding-based inlining, the function
`simplLetUnfolding` simply gives exit join points no unfolding, which prevents
this kind of inlining.
Note [Placement of the exitification pass]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
I (Joachim) experimented with multiple positions for the Exitification pass in
the Core2Core pipeline:
A) Before the `simpl_phases`
B) Between the `simpl_phases` and the "main" simplifier pass
C) After demand_analyser
D) Before the final simplification phase
Here is the table (this is without inlining join exit points in the final
simplifier run):
Program | Allocs | Instrs
| ABCD.log A.log B.log C.log D.log | ABCD.log A.log B.log C.log D.log
----------------|---------------------------------------------------|-------------------------------------------------
fannkuch-redux | -99.9% +0.0% -99.9% -99.9% -99.9% | -3.9% +0.5% -3.0% -3.9% -3.9%
fasta | -0.0% +0.0% +0.0% -0.0% -0.0% | -8.5% +0.0% +0.0% -0.0% -8.5%
fem | 0.0% 0.0% 0.0% 0.0% +0.0% | -2.2% -0.1% -0.1% -2.1% -2.1%
fish | 0.0% 0.0% 0.0% 0.0% +0.0% | -3.1% +0.0% -1.1% -1.1% -0.0%
k-nucleotide | -91.3% -91.0% -91.0% -91.3% -91.3% | -6.3% +11.4% +11.4% -6.3% -6.2%
scs | -0.0% -0.0% -0.0% -0.0% -0.0% | -3.4% -3.0% -3.1% -3.3% -3.3%
simple | -6.0% 0.0% -6.0% -6.0% +0.0% | -3.4% +0.0% -5.2% -3.4% -0.1%
spectral-norm | -0.0% 0.0% 0.0% -0.0% +0.0% | -2.7% +0.0% -2.7% -5.4% -5.4%
----------------|---------------------------------------------------|-------------------------------------------------
Min | -95.0% -91.0% -95.0% -95.0% -95.0% | -8.5% -3.0% -5.2% -6.3% -8.5%
Max | +0.2% +0.2% +0.2% +0.2% +1.5% | +0.4% +11.4% +11.4% +0.4% +1.5%
Geometric Mean | -4.7% -2.1% -4.7% -4.7% -4.6% | -0.4% +0.1% -0.1% -0.3% -0.2%
Position A is disqualified, as it does not get rid of the allocations in
fannkuch-redux.
Position A and B are disqualified because it increases instructions in k-nucleotide.
Positions C and D have their advantages: C decreases allocations in simpl, but D instructions in fasta.
Assuming we have a budget of _one_ run of Exitification, then C wins (but we
could get more from running it multiple times, as seen in fish).
-}
......@@ -45,6 +45,7 @@ import Specialise ( specProgram)
import SpecConstr ( specConstrProgram)
import DmdAnal ( dmdAnalProgram )
import CallArity ( callArityAnalProgram )
import Exitify ( exitifyProgram )
import WorkWrap ( wwTopBinds )
import Vectorise ( vectorise )
import SrcLoc
......@@ -122,6 +123,7 @@ getCoreToDo dflags
max_iter = maxSimplIterations dflags
rule_check = ruleCheck dflags
call_arity = gopt Opt_CallArity dflags
exitification = gopt Opt_Exitification dflags
strictness = gopt Opt_Strictness dflags
full_laziness = gopt Opt_FullLaziness dflags
do_specialise = gopt Opt_Specialise dflags
......@@ -308,6 +310,9 @@ getCoreToDo dflags
runWhen strictness demand_analyser,
runWhen exitification CoreDoExitify,
-- See note [Placement of the exitification pass]
runWhen full_laziness $
CoreDoFloatOutwards FloatOutSwitches {
floatOutLambdas = floatLamArgs dflags,
......@@ -476,6 +481,9 @@ doCorePass CoreDoStaticArgs = {-# SCC "StaticArgs" #-}
doCorePass CoreDoCallArity = {-# SCC "CallArity" #-}
doPassD callArityAnalProgram
doCorePass CoreDoExitify = {-# SCC "Exitify" #-}
doPass exitifyProgram
doCorePass CoreDoStrictness = {-# SCC "NewStranal" #-}
doPassDFM dmdAnalProgram
......
......@@ -1090,6 +1090,7 @@ preInlineUnconditionally env top_lvl bndr rhs
| isStableUnfolding (idUnfolding bndr) = False -- Note [Stable unfoldings and preInlineUnconditionally]
| isTopLevel top_lvl && isBottomingId bndr = False -- Note [Top-level bottoming Ids]
| isCoVar bndr = False -- Note [Do not inline CoVars unconditionally]
| isExitJoinId bndr = False
| otherwise = case idOccInfo bndr of
IAmDead -> True -- Happens in ((\x.1) v)
occ@OneOcc { occ_one_br = True }
......
......@@ -51,6 +51,7 @@ import Util
import ErrUtils
import Module ( moduleName, pprModuleName )
{-
The guts of the simplifier is in this module, but the driver loop for
the simplifier is in SimplCore.hs.
......@@ -3235,6 +3236,8 @@ simplLetUnfolding :: SimplEnv-> TopLevelFlag
simplLetUnfolding env top_lvl cont_mb id new_rhs unf
| isStableUnfolding unf
= simplStableUnfolding env top_lvl cont_mb id unf
| isExitJoinId id
= return noUnfolding -- see Note [Do not inline exit join points]
| otherwise
= mkLetUnfolding (seDynFlags env) top_lvl InlineRhs id new_rhs
......