[commit: ghc] master: Fix an egregious strictness analyser bug (Trac #4924) (f1a90f5)
Simon Marlow
marlowsd at gmail.com
Fri Jan 28 21:21:53 CET 2011
Repository : ssh://darcs.haskell.org//srv/darcs/ghc
On branch : master
http://hackage.haskell.org/trac/ghc/changeset/f1a90f54590e5a7a32a9c3ef2950740922b1f425
>---------------------------------------------------------------
commit f1a90f54590e5a7a32a9c3ef2950740922b1f425
Author: simonpj at microsoft.com <unknown>
Date: Fri Jan 28 08:07:48 2011 +0000
Fix an egregious strictness analyser bug (Trac #4924)
The "virgin" flag was being threaded rather than treated
like an environment. As a result, the second and subsequent
recursive definitions in a module were not getting a
correctly-initialised fixpoint loop, causing much worse
strictness analysis results. Indeed the symptoms in
Trac #4924 were quite bizarre.
Anyway, it's easily fixed. Merge to stable branch.
>---------------------------------------------------------------
compiler/stranal/DmdAnal.lhs | 229 ++++++++++++++++++++++-------------------
1 files changed, 123 insertions(+), 106 deletions(-)
diff --git a/compiler/stranal/DmdAnal.lhs b/compiler/stranal/DmdAnal.lhs
index 7c9ddd5..192d06f 100644
--- a/compiler/stranal/DmdAnal.lhs
+++ b/compiler/stranal/DmdAnal.lhs
@@ -74,35 +74,33 @@ dmdAnalTopBind :: SigEnv
-> CoreBind
-> (SigEnv, CoreBind)
dmdAnalTopBind sigs (NonRec id rhs)
- = let
- ( _, _, (_, rhs1)) = dmdAnalRhs TopLevel NonRecursive sigs (id, rhs)
- (sigs2, _, (id2, rhs2)) = dmdAnalRhs TopLevel NonRecursive sigs (id, rhs1)
- -- Do two passes to improve CPR information
- -- See comments with ignore_cpr_info in mk_sig_ty
- -- and with extendSigsWithLam
- in
- (sigs2, NonRec id2 rhs2)
+ = (sigs2, NonRec id2 rhs2)
+ where
+ ( _, _, (_, rhs1)) = dmdAnalRhs TopLevel NonRecursive (virgin sigs) (id, rhs)
+ (sigs2, _, (id2, rhs2)) = dmdAnalRhs TopLevel NonRecursive (nonVirgin sigs) (id, rhs1)
+ -- Do two passes to improve CPR information
+ -- See comments with ignore_cpr_info in mk_sig_ty
+ -- and with extendSigsWithLam
dmdAnalTopBind sigs (Rec pairs)
- = let
- (sigs', _, pairs') = dmdFix TopLevel sigs pairs
+ = (sigs', Rec pairs')
+ where
+ (sigs', _, pairs') = dmdFix TopLevel (virgin sigs) pairs
-- We get two iterations automatically
-- c.f. the NonRec case above
- in
- (sigs', Rec pairs')
\end{code}
\begin{code}
dmdAnalTopRhs :: CoreExpr -> (StrictSig, CoreExpr)
-- Analyse the RHS and return
-- a) appropriate strictness info
--- b) the unfolding (decorated with stricntess info)
+-- b) the unfolding (decorated with strictness info)
dmdAnalTopRhs rhs
= (sig, rhs2)
where
call_dmd = vanillaCall (exprArity rhs)
- (_, rhs1) = dmdAnal emptySigEnv call_dmd rhs
- (rhs_ty, rhs2) = dmdAnal emptySigEnv call_dmd rhs1
+ (_, rhs1) = dmdAnal (virgin emptySigEnv) call_dmd rhs
+ (rhs_ty, rhs2) = dmdAnal (nonVirgin emptySigEnv) call_dmd rhs1
sig = mkTopSigTy rhs rhs_ty
-- Do two passes; see notes with extendSigsWithLam
-- Otherwise we get bogus CPR info for constructors like
@@ -119,14 +117,14 @@ dmdAnalTopRhs rhs
%************************************************************************
\begin{code}
-dmdAnal :: SigEnv -> Demand -> CoreExpr -> (DmdType, CoreExpr)
+dmdAnal :: AnalEnv -> Demand -> CoreExpr -> (DmdType, CoreExpr)
dmdAnal _ Abs e = (topDmdType, e)
-dmdAnal sigs dmd e
+dmdAnal env dmd e
| not (isStrictDmd dmd)
= let
- (res_ty, e') = dmdAnal sigs evalDmd e
+ (res_ty, e') = dmdAnal env evalDmd e
in
(deferType res_ty, e')
-- It's important not to analyse e with a lazy demand because
@@ -147,13 +145,13 @@ dmdAnal sigs dmd e
dmdAnal _ _ (Lit lit) = (topDmdType, Lit lit)
dmdAnal _ _ (Type ty) = (topDmdType, Type ty) -- Doesn't happen, in fact
-dmdAnal sigs dmd (Var var)
- = (dmdTransform sigs var dmd, Var var)
+dmdAnal env dmd (Var var)
+ = (dmdTransform env var dmd, Var var)
-dmdAnal sigs dmd (Cast e co)
+dmdAnal env dmd (Cast e co)
= (dmd_ty, Cast e' co)
where
- (dmd_ty, e') = dmdAnal sigs dmd' e
+ (dmd_ty, e') = dmdAnal env dmd' e
to_co = snd (coercionKind co)
dmd'
| Just (tc, _) <- splitTyConApp_maybe to_co
@@ -165,55 +163,55 @@ dmdAnal sigs dmd (Cast e co)
-- inside recursive products -- we might not reach
-- a fixpoint. So revert to a vanilla Eval demand
-dmdAnal sigs dmd (Note n e)
+dmdAnal env dmd (Note n e)
= (dmd_ty, Note n e')
where
- (dmd_ty, e') = dmdAnal sigs dmd e
+ (dmd_ty, e') = dmdAnal env dmd e
-dmdAnal sigs dmd (App fun (Type ty))
+dmdAnal env dmd (App fun (Type ty))
= (fun_ty, App fun' (Type ty))
where
- (fun_ty, fun') = dmdAnal sigs dmd fun
+ (fun_ty, fun') = dmdAnal env dmd fun
-- Lots of the other code is there to make this
-- beautiful, compositional, application rule :-)
-dmdAnal sigs dmd (App fun arg) -- Non-type arguments
+dmdAnal env dmd (App fun arg) -- Non-type arguments
= let -- [Type arg handled above]
- (fun_ty, fun') = dmdAnal sigs (Call dmd) fun
- (arg_ty, arg') = dmdAnal sigs arg_dmd arg
+ (fun_ty, fun') = dmdAnal env (Call dmd) fun
+ (arg_ty, arg') = dmdAnal env arg_dmd arg
(arg_dmd, res_ty) = splitDmdTy fun_ty
in
(res_ty `bothType` arg_ty, App fun' arg')
-dmdAnal sigs dmd (Lam var body)
+dmdAnal env dmd (Lam var body)
| isTyCoVar var
= let
- (body_ty, body') = dmdAnal sigs dmd body
+ (body_ty, body') = dmdAnal env dmd body
in
(body_ty, Lam var body')
| Call body_dmd <- dmd -- A call demand: good!
= let
- sigs' = extendSigsWithLam sigs var
- (body_ty, body') = dmdAnal sigs' body_dmd body
- (lam_ty, var') = annotateLamIdBndr sigs body_ty var
+ env' = extendSigsWithLam env var
+ (body_ty, body') = dmdAnal env' body_dmd body
+ (lam_ty, var') = annotateLamIdBndr env body_ty var
in
(lam_ty, Lam var' body')
| otherwise -- Not enough demand on the lambda; but do the body
= let -- anyway to annotate it and gather free var info
- (body_ty, body') = dmdAnal sigs evalDmd body
- (lam_ty, var') = annotateLamIdBndr sigs body_ty var
+ (body_ty, body') = dmdAnal env evalDmd body
+ (lam_ty, var') = annotateLamIdBndr env body_ty var
in
(deferType lam_ty, Lam var' body')
-dmdAnal sigs dmd (Case scrut case_bndr ty [alt@(DataAlt dc, _, _)])
+dmdAnal env dmd (Case scrut case_bndr ty [alt@(DataAlt dc, _, _)])
| let tycon = dataConTyCon dc
, isProductTyCon tycon
, not (isRecursiveTyCon tycon)
= let
- sigs_alt = extendSigEnv NotTopLevel sigs case_bndr case_bndr_sig
- (alt_ty, alt') = dmdAnalAlt sigs_alt dmd alt
+ env_alt = extendAnalEnv NotTopLevel env case_bndr case_bndr_sig
+ (alt_ty, alt') = dmdAnalAlt env_alt dmd alt
(alt_ty1, case_bndr') = annotateBndr alt_ty case_bndr
(_, bndrs', _) = alt'
case_bndr_sig = cprSig
@@ -251,23 +249,23 @@ dmdAnal sigs dmd (Case scrut case_bndr ty [alt@(DataAlt dc, _, _)])
scrut_dmd = alt_dmd `both`
idDemandInfo case_bndr'
- (scrut_ty, scrut') = dmdAnal sigs scrut_dmd scrut
+ (scrut_ty, scrut') = dmdAnal env scrut_dmd scrut
in
(alt_ty1 `bothType` scrut_ty, Case scrut' case_bndr' ty [alt'])
-dmdAnal sigs dmd (Case scrut case_bndr ty alts)
+dmdAnal env dmd (Case scrut case_bndr ty alts)
= let
- (alt_tys, alts') = mapAndUnzip (dmdAnalAlt sigs dmd) alts
- (scrut_ty, scrut') = dmdAnal sigs evalDmd scrut
+ (alt_tys, alts') = mapAndUnzip (dmdAnalAlt env dmd) alts
+ (scrut_ty, scrut') = dmdAnal env evalDmd scrut
(alt_ty, case_bndr') = annotateBndr (foldr1 lubType alt_tys) case_bndr
in
-- pprTrace "dmdAnal:Case" (ppr alts $$ ppr alt_tys)
(alt_ty `bothType` scrut_ty, Case scrut' case_bndr' ty alts')
-dmdAnal sigs dmd (Let (NonRec id rhs) body)
+dmdAnal env dmd (Let (NonRec id rhs) body)
= let
- (sigs', lazy_fv, (id1, rhs')) = dmdAnalRhs NotTopLevel NonRecursive sigs (id, rhs)
- (body_ty, body') = dmdAnal sigs' dmd body
+ (sigs', lazy_fv, (id1, rhs')) = dmdAnalRhs NotTopLevel NonRecursive env (id, rhs)
+ (body_ty, body') = dmdAnal (updSigEnv env sigs') dmd body
(body_ty1, id2) = annotateBndr body_ty id1
body_ty2 = addLazyFVs body_ty1 lazy_fv
in
@@ -285,11 +283,11 @@ dmdAnal sigs dmd (Let (NonRec id rhs) body)
-- bother to re-analyse the RHS.
(body_ty2, Let (NonRec id2 rhs') body')
-dmdAnal sigs dmd (Let (Rec pairs) body)
+dmdAnal env dmd (Let (Rec pairs) body)
= let
bndrs = map fst pairs
- (sigs', lazy_fv, pairs') = dmdFix NotTopLevel sigs pairs
- (body_ty, body') = dmdAnal sigs' dmd body
+ (sigs', lazy_fv, pairs') = dmdFix NotTopLevel env pairs
+ (body_ty, body') = dmdAnal (updSigEnv env sigs') dmd body
body_ty1 = addLazyFVs body_ty lazy_fv
in
sigs' `seq` body_ty `seq`
@@ -303,10 +301,10 @@ dmdAnal sigs dmd (Let (Rec pairs) body)
(body_ty2, Let (Rec pairs') body')
-dmdAnalAlt :: SigEnv -> Demand -> Alt Var -> (DmdType, Alt Var)
-dmdAnalAlt sigs dmd (con,bndrs,rhs)
+dmdAnalAlt :: AnalEnv -> Demand -> Alt Var -> (DmdType, Alt Var)
+dmdAnalAlt env dmd (con,bndrs,rhs)
= let
- (rhs_ty, rhs') = dmdAnal sigs dmd rhs
+ (rhs_ty, rhs') = dmdAnal env dmd rhs
rhs_ty' = addDataConPatDmds con bndrs rhs_ty
(alt_ty, bndrs') = annotateBndrs rhs_ty' bndrs
final_alt_ty | io_hack_reqd = alt_ty `lubType` topDmdType
@@ -388,14 +386,14 @@ argument, and pass an Int to $wfoo!
%************************************************************************
\begin{code}
-dmdTransform :: SigEnv -- The strictness environment
+dmdTransform :: AnalEnv -- The strictness environment
-> Id -- The function
-> Demand -- The demand on the function
-> DmdType -- The demand type of the function in this context
-- Returned DmdEnv includes the demand on
-- this function plus demand on its free variables
-dmdTransform sigs var dmd
+dmdTransform env var dmd
------ DATA CONSTRUCTOR
| isDataConWorkId var -- Data constructor
@@ -439,7 +437,7 @@ dmdTransform sigs var dmd
topDmdType
------ LOCAL LET/REC BOUND THING
- | Just (StrictSig dmd_ty, top_lvl) <- lookupSigEnv sigs var
+ | Just (StrictSig dmd_ty, top_lvl) <- lookupSigEnv env var
= let
fn_ty | dmdTypeDepth dmd_ty <= call_depth = dmd_ty
| otherwise = deferType dmd_ty
@@ -467,22 +465,26 @@ dmdTransform sigs var dmd
\begin{code}
dmdFix :: TopLevelFlag
- -> SigEnv -- Does not include bindings for this binding
+ -> AnalEnv -- Does not include bindings for this binding
-> [(Id,CoreExpr)]
-> (SigEnv, DmdEnv,
[(Id,CoreExpr)]) -- Binders annotated with stricness info
-dmdFix top_lvl sigs orig_pairs
- = loop 1 initial_sigs orig_pairs
+dmdFix top_lvl env orig_pairs
+ = loop 1 initial_env orig_pairs
where
bndrs = map fst orig_pairs
- initial_sigs = addInitialSigs top_lvl sigs bndrs
+ initial_env = addInitialSigs top_lvl env bndrs
loop :: Int
- -> SigEnv -- Already contains the current sigs
+ -> AnalEnv -- Already contains the current sigs
-> [(Id,CoreExpr)]
-> (SigEnv, DmdEnv, [(Id,CoreExpr)])
- loop n sigs pairs
+ loop n env pairs
+ = -- pprTrace "dmd loop" (ppr n <+> ppr bndrs $$ ppr env) $
+ loop' n env pairs
+
+ loop' n env pairs
| found_fixpoint
= (sigs', lazy_fv, pairs')
-- Note: return pairs', not pairs. pairs' is the result of
@@ -492,11 +494,11 @@ dmdFix top_lvl sigs orig_pairs
| n >= 10
= pprTrace "dmdFix loop" (ppr n <+> (vcat
- [ text "Sigs:" <+> ppr [ (id,lookupSigEnv sigs id, lookupSigEnv sigs' id)
+ [ text "Sigs:" <+> ppr [ (id,lookupVarEnv sigs id, lookupVarEnv sigs' id)
| (id,_) <- pairs],
- text "env:" <+> ppr sigs,
+ text "env:" <+> ppr env,
text "binds:" <+> pprCoreBinding (Rec pairs)]))
- (emptySigEnv, lazy_fv, orig_pairs) -- Safe output
+ (sigEnv env, lazy_fv, orig_pairs) -- Safe output
-- The lazy_fv part is really important! orig_pairs has no strictness
-- info, including nothing about free vars. But if we have
-- letrec f = ....y..... in ...f...
@@ -504,42 +506,45 @@ dmdFix top_lvl sigs orig_pairs
-- otherwise y will get recorded as absent altogether
| otherwise
- = loop (n+1) (setNonVirgin sigs') pairs'
+ = loop (n+1) (nonVirgin sigs') pairs'
where
+ sigs = sigEnv env
found_fixpoint = all (same_sig sigs sigs') bndrs
- -- Use the new signature to do the next pair
+
+ ((sigs',lazy_fv), pairs') = mapAccumL my_downRhs (sigs, emptyDmdEnv) pairs
+ -- mapAccumL: Use the new signature to do the next pair
-- The occurrence analyser has arranged them in a good order
-- so this can significantly reduce the number of iterations needed
- ((sigs',lazy_fv), pairs') = mapAccumL my_downRhs (sigs, emptyDmdEnv) pairs
- my_downRhs (sigs,lazy_fv) (id,rhs) = ((sigs', lazy_fv'), pair')
- where
- (sigs', lazy_fv1, pair') = dmdAnalRhs top_lvl Recursive sigs (id,rhs)
- lazy_fv' = plusVarEnv_C both lazy_fv lazy_fv1
+ my_downRhs (sigs,lazy_fv) (id,rhs)
+ = ((sigs', lazy_fv'), pair')
+ where
+ (sigs', lazy_fv1, pair') = dmdAnalRhs top_lvl Recursive (updSigEnv env sigs) (id,rhs)
+ lazy_fv' = plusVarEnv_C both lazy_fv lazy_fv1
same_sig sigs sigs' var = lookup sigs var == lookup sigs' var
- lookup sigs var = case lookupSigEnv sigs var of
+ lookup sigs var = case lookupVarEnv sigs var of
Just (sig,_) -> sig
Nothing -> pprPanic "dmdFix" (ppr var)
dmdAnalRhs :: TopLevelFlag -> RecFlag
- -> SigEnv -> (Id, CoreExpr)
+ -> AnalEnv -> (Id, CoreExpr)
-> (SigEnv, DmdEnv, (Id, CoreExpr))
-- Process the RHS of the binding, add the strictness signature
-- to the Id, and augment the environment with the signature as well.
-dmdAnalRhs top_lvl rec_flag sigs (id, rhs)
+dmdAnalRhs top_lvl rec_flag env (id, rhs)
= (sigs', lazy_fv, (id', rhs'))
where
arity = idArity id -- The idArity should be up to date
-- The simplifier was run just beforehand
- (rhs_dmd_ty, rhs') = dmdAnal sigs (vanillaCall arity) rhs
+ (rhs_dmd_ty, rhs') = dmdAnal env (vanillaCall arity) rhs
(lazy_fv, sig_ty) = WARN( arity /= dmdTypeDepth rhs_dmd_ty && not (exprIsTrivial rhs), ppr id )
-- The RHS can be eta-reduced to just a variable,
-- in which case we should not complain.
mkSigTy top_lvl rec_flag id rhs rhs_dmd_ty
id' = id `setIdStrictness` sig_ty
- sigs' = extendSigEnv top_lvl sigs id sig_ty
+ sigs' = extendSigEnv top_lvl (sigEnv env) id sig_ty
\end{code}
@@ -841,13 +846,13 @@ annotateBndr dmd_ty@(DmdType fv ds res) var
annotateBndrs :: DmdType -> [Var] -> (DmdType, [Var])
annotateBndrs = mapAccumR annotateBndr
-annotateLamIdBndr :: SigEnv
+annotateLamIdBndr :: AnalEnv
-> DmdType -- Demand type of body
-> Id -- Lambda binder
-> (DmdType, -- Demand type of lambda
Id) -- and binder annotated with demand
-annotateLamIdBndr sigs (DmdType fv ds res) id
+annotateLamIdBndr env (DmdType fv ds res) id
-- For lambdas we add the demand to the argument demands
-- Only called for Ids
= ASSERT( isId id )
@@ -858,7 +863,7 @@ annotateLamIdBndr sigs (DmdType fv ds res) id
Nothing -> main_ty
Just unf -> main_ty `bothType` unf_ty
where
- (unf_ty, _) = dmdAnal sigs dmd unf
+ (unf_ty, _) = dmdAnal env dmd unf
main_ty = DmdType fv' (hacked_dmd:ds) res
@@ -906,9 +911,9 @@ forget that fact, otherwise we might make 'x' absent when it isn't.
%************************************************************************
\begin{code}
-data SigEnv
- = SE { se_env :: VarEnv (StrictSig, TopLevelFlag)
- , se_virgin :: Bool } -- True on first iteration only
+data AnalEnv
+ = AE { ae_sigs :: SigEnv
+ , ae_virgin :: Bool } -- True on first iteration only
-- See Note [Initialising strictness]
-- We use the se_env to tell us whether to
-- record info about a variable in the DmdEnv
@@ -917,36 +922,48 @@ data SigEnv
-- The DmdEnv gives the demand on the free vars of the function
-- when it is given enough args to satisfy the strictness signature
-instance Outputable SigEnv where
- ppr (SE { se_env = env, se_virgin = virgin })
- = ptext (sLit "SE") <+> braces (vcat
- [ ptext (sLit "se_virgin =") <+> ppr virgin
- , ptext (sLit "se_env =") <+> ppr env ])
+type SigEnv = VarEnv (StrictSig, TopLevelFlag)
+
+instance Outputable AnalEnv where
+ ppr (AE { ae_sigs = env, ae_virgin = virgin })
+ = ptext (sLit "AE") <+> braces (vcat
+ [ ptext (sLit "ae_virgin =") <+> ppr virgin
+ , ptext (sLit "ae_sigs =") <+> ppr env ])
emptySigEnv :: SigEnv
-emptySigEnv = SE { se_env = emptyVarEnv, se_virgin = True }
+emptySigEnv = emptyVarEnv
+
+sigEnv :: AnalEnv -> SigEnv
+sigEnv = ae_sigs
+
+updSigEnv :: AnalEnv -> SigEnv -> AnalEnv
+updSigEnv env sigs = env { ae_sigs = sigs }
+
+extendAnalEnv :: TopLevelFlag -> AnalEnv -> Id -> StrictSig -> AnalEnv
+extendAnalEnv top_lvl env var sig
+ = env { ae_sigs = extendSigEnv top_lvl (ae_sigs env) var sig }
extendSigEnv :: TopLevelFlag -> SigEnv -> Id -> StrictSig -> SigEnv
-extendSigEnv top_lvl sigs var sig
- = sigs { se_env = extendVarEnv (se_env sigs) var (sig, top_lvl) }
+extendSigEnv top_lvl sigs var sig = extendVarEnv sigs var (sig, top_lvl)
-lookupSigEnv :: SigEnv -> Id -> Maybe (StrictSig, TopLevelFlag)
-lookupSigEnv sigs id = lookupVarEnv (se_env sigs) id
+lookupSigEnv :: AnalEnv -> Id -> Maybe (StrictSig, TopLevelFlag)
+lookupSigEnv env id = lookupVarEnv (ae_sigs env) id
-addInitialSigs :: TopLevelFlag -> SigEnv -> [Id] -> SigEnv
+addInitialSigs :: TopLevelFlag -> AnalEnv -> [Id] -> AnalEnv
-- See Note [Initialising strictness]
-addInitialSigs top_lvl sigs@(SE { se_env = env, se_virgin = virgin }) ids
- = sigs { se_env = extendVarEnvList env [ (id, (init_sig id, top_lvl))
- | id <- ids ] }
+addInitialSigs top_lvl env@(AE { ae_sigs = sigs, ae_virgin = virgin }) ids
+ = env { ae_sigs = extendVarEnvList sigs [ (id, (init_sig id, top_lvl))
+ | id <- ids ] }
where
init_sig | virgin = \_ -> botSig
| otherwise = idStrictness
-setNonVirgin :: SigEnv -> SigEnv
-setNonVirgin sigs = sigs { se_virgin = False }
+virgin, nonVirgin :: SigEnv -> AnalEnv
+virgin sigs = AE { ae_sigs = sigs, ae_virgin = True }
+nonVirgin sigs = AE { ae_sigs = sigs, ae_virgin = False }
-extendSigsWithLam :: SigEnv -> Id -> SigEnv
--- Extend the SigEnv when we meet a lambda binder
+extendSigsWithLam :: AnalEnv -> Id -> AnalEnv
+-- Extend the AnalEnv when we meet a lambda binder
-- If the binder is marked demanded with a product demand, then give it a CPR
-- signature, because in the likely event that this is a lambda on a fn defn
-- [we only use this when the lambda is being consumed with a call demand],
@@ -961,13 +978,13 @@ extendSigsWithLam :: SigEnv -> Id -> SigEnv
-- definitely has product type, else we may get over-optimistic
-- CPR results (e.g. from \x -> x!).
-extendSigsWithLam sigs id
+extendSigsWithLam env id
= case idDemandInfo_maybe id of
- Nothing -> extendSigEnv NotTopLevel sigs id cprSig
+ Nothing -> extendAnalEnv NotTopLevel env id cprSig
-- Optimistic in the Nothing case;
-- See notes [CPR-AND-STRICTNESS]
- Just (Eval (Prod _)) -> extendSigEnv NotTopLevel sigs id cprSig
- _ -> sigs
+ Just (Eval (Prod _)) -> extendAnalEnv NotTopLevel env id cprSig
+ _ -> env
\end{code}
Note [Initialising strictness]
@@ -986,8 +1003,8 @@ plan.)
But on the *first* iteration we want to *ignore* the current strictness
of the Id, and start from "bottom". Nowadays the Id can have a current
strictness, because interface files record strictness for nested bindings.
-To know when we are in the first iteration, we look at the se_virgin
-field of the SigEnv.
+To know when we are in the first iteration, we look at the ae_virgin
+field of the AnalEnv.
%************************************************************************
More information about the Cvs-ghc
mailing list