%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[SimplCore]{Driver for simplifying @Core@ programs}
\begin{code}
-#include "HsVersions.h"
-
module SimplCore ( core2core ) where
-IMP_Ubiq(){-uitous-}
-IMPORT_1_3(IO(hPutStr,stderr))
+#include "HsVersions.h"
-import AnalFBWW ( analFBWW )
-import Bag ( isEmptyBag, foldBag )
-import BinderInfo ( BinderInfo{-instance Outputable-} )
-import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..), switchIsOn,
- opt_D_show_passes,
+import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..),
+ SwitchResult, switchIsOn,
+ opt_D_dump_occur_anal,
+ opt_D_dump_simpl_iterations,
opt_D_simplifier_stats,
+ opt_D_dump_simpl,
opt_D_verbose_core2core,
- opt_DoCoreLinting,
- opt_FoldrBuildOn,
- opt_ReportWhyUnfoldingsDisallowed,
- opt_ShowImportSpecs,
- opt_LiberateCaseThreshold
+ opt_D_dump_occur_anal
)
-import CoreLint ( lintCoreBindings )
+import CoreLint ( beginPass, endPass )
import CoreSyn
-import CoreUtils ( coreExprType )
+import PprCore ( pprCoreBindings )
+import OccurAnal ( occurAnalyseBinds )
+import CoreUtils ( exprIsTrivial, coreExprType )
+import Simplify ( simplBind )
+import SimplUtils ( etaCoreExpr, findDefault )
+import SimplMonad
import CoreUnfold
-import Literal ( Literal(..), literalType, mkMachInt )
-import ErrUtils ( ghcExit )
-import FiniteMap ( FiniteMap )
+import Const ( Con(..), Literal(..), literalType, mkMachInt )
+import ErrUtils ( dumpIfSet )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
-import FoldrBuildWW ( mkFoldrBuildWW )
-import Id ( mkSysLocal, setIdVisibility,
- nullIdEnv, addOneToIdEnv, delOneFromIdEnv,
- lookupIdEnv, SYN_IE(IdEnv),
- GenId{-instance Outputable-}
+import Id ( Id, mkSysLocal, mkUserId, isBottomingId,
+ idType, setIdType, idName, idInfo, idDetails
+ )
+import IdInfo ( InlinePragInfo(..), specInfo, setSpecInfo,
+ inlinePragInfo, setInlinePragInfo,
+ setUnfoldingInfo
)
-import Name ( isExported, isLocallyDefined )
-import TyCon ( TyCon )
+import VarEnv
+import VarSet
+import Name ( mkLocalName, tidyOccName, tidyTopName, initTidyOccEnv, isExported,
+ Module, NamedThing(..), OccName
+ )
+import TyCon ( TyCon, isDataTyCon )
import PrimOp ( PrimOp(..) )
-import PrelVals ( unpackCStringId, unpackCString2Id,
+import PrelInfo ( unpackCStringId, unpackCString2Id,
integerZeroId, integerPlusOneId,
- integerPlusTwoId, integerMinusOneId
+ integerPlusTwoId, integerMinusOneId,
+ int2IntegerId, addr2IntegerId
+ )
+import Type ( Type, splitAlgTyConApp_maybe,
+ isUnLiftedType, mkTyVarTy,
+ tidyType, tidyTypes, tidyTopType, tidyTyVar, tidyTyVars,
+ Type
)
-import Type ( maybeAppDataTyCon, getAppDataTyConExpandingDicts, maybeAppSpecDataTyConExpandingDicts )
-import TysWiredIn ( stringTy )
+import Class ( Class, classSelIds )
+import TysWiredIn ( isIntegerTy )
import LiberateCase ( liberateCase )
-import MagicUFs ( MagicUnfoldingFun )
-import Outputable ( Outputable(..){-instance * (,) -} )
-import PprCore
-import PprStyle ( PprStyle(..) )
-import PprType ( GenType{-instance Outputable-}, GenTyVar{-ditto-} )
-import Pretty ( ppShow, ppAboves, ppAbove, ppCat, ppStr )
import SAT ( doStaticArgs )
-import SimplMonad ( zeroSimplCount, showSimplCount, SimplCount )
-import SimplPgm ( simplifyPgm )
-import Specialise
-import SpecUtils ( pprSpecErrs )
+import Specialise ( specProgram)
+import SpecEnv ( specEnvToList, specEnvFromList )
import StrictAnal ( saWwTopBinds )
-import TyVar ( nullTyVarEnv, GenTyVar{-instance Eq-} )
-import Unique ( integerTyConKey, ratioTyConKey, Unique{-instance Eq-} )
-import UniqSupply ( splitUniqSupply, getUnique )
-import Util ( mapAccumL, assertPanic, panic{-ToDo:rm-}, pprTrace, pprPanic )
-import SrcLoc ( noSrcLoc )
+import Var ( TyVar, mkId )
+import Unique ( Unique, Uniquable(..),
+ ratioTyConKey, mkUnique, incrUnique, initTidyUniques
+ )
+import UniqSupply ( UniqSupply, splitUniqSupply, uniqFromSupply )
import Constants ( tARGET_MIN_INT, tARGET_MAX_INT )
+import Util ( mapAccumL )
import Bag
import Maybes
-
-
-#ifndef OMIT_DEFORESTER
-import Deforest ( deforestProgram )
-import DefUtils ( deforestable )
-#endif
-
+import IO ( hPutStr, stderr )
+import Outputable
\end{code}
\begin{code}
-core2core :: [CoreToDo] -- spec of what core-to-core passes to do
- -> FAST_STRING -- module name (profiling only)
- -> PprStyle -- printing style (for debugging only)
- -> UniqSupply -- a name supply
- -> [TyCon] -- local data tycons and tycon specialisations
- -> FiniteMap TyCon [(Bool, [Maybe Type])]
- -> [CoreBinding] -- input...
- -> IO
- ([CoreBinding], -- results: program, plus...
- SpecialiseData) -- specialisation data
-
-core2core core_todos module_name ppr_style us local_tycons tycon_specs binds
- = -- Print heading
- (if opt_D_verbose_core2core then
- hPutStr stderr "VERBOSE CORE-TO-CORE:\n"
- else return ()) >>
+core2core :: [CoreToDo] -- Spec of what core-to-core passes to do
+ -> Module -- Module name (profiling only)
+ -> [Class] -- Local classes
+ -> UniqSupply -- A name supply
+ -> [CoreBind] -- Input
+ -> IO [CoreBind] -- Result
+
+core2core core_todos module_name classes us binds
+ = do
+ let (us1, us2) = splitUniqSupply us
-- Do the main business
- foldl_mn do_core_pass
- (binds, us1, init_specdata, zeroSimplCount)
- core_todos
- >>= \ (processed_binds, _, spec_data, simpl_stats) ->
+ processed_binds <- doCorePasses us1 binds core_todos
+
+ -- Do the post-simplification business
+ post_simpl_binds <- doPostSimplification us2 processed_binds
-- Do the final tidy-up
- let
- final_binds = tidyCorePgm module_name us2 processed_binds
- in
-
- -- Report statistics
- (if opt_D_simplifier_stats then
- hPutStr stderr ("\nSimplifier Stats:\n") >>
- hPutStr stderr (showSimplCount simpl_stats) >>
- hPutStr stderr "\n"
- else return ()) >>
-
- --
- return (final_binds, spec_data)
- where
- (us1, us2) = splitUniqSupply us
- init_specdata = initSpecData local_tycons tycon_specs
-
- -------------
- core_linter = if opt_DoCoreLinting
- then lintCoreBindings ppr_style
- else ( \ whodunnit spec_done binds -> binds )
-
- --------------
- do_core_pass info@(binds, us, spec_data, simpl_stats) to_do
- = let
- (us1, us2) = splitUniqSupply us
- in
- case to_do of
- CoreDoSimplify simpl_sw_chkr
- -> _scc_ "CoreSimplify"
- begin_pass ("Simplify" ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild
- then " (foldr/build)" else "") >>
- case (simplifyPgm binds simpl_sw_chkr simpl_stats us1) of
- (p, it_cnt, simpl_stats2)
- -> end_pass False us2 p spec_data simpl_stats2
- ("Simplify (" ++ show it_cnt ++ ")"
- ++ if switchIsOn simpl_sw_chkr SimplDoFoldrBuild
- then " foldr/build" else "")
-
- CoreDoFoldrBuildWorkerWrapper
- -> _scc_ "CoreDoFoldrBuildWorkerWrapper"
- begin_pass "FBWW" >>
- case (mkFoldrBuildWW us1 binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "FBWW" }
-
- CoreDoFoldrBuildWWAnal
- -> _scc_ "CoreDoFoldrBuildWWAnal"
- begin_pass "AnalFBWW" >>
- case (analFBWW binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "AnalFBWW" }
-
- CoreLiberateCase
- -> _scc_ "LiberateCase"
- begin_pass "LiberateCase" >>
- case (liberateCase opt_LiberateCaseThreshold binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "LiberateCase" }
-
- CoreDoFloatInwards
- -> _scc_ "FloatInwards"
- begin_pass "FloatIn" >>
- case (floatInwards binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "FloatIn" }
-
- CoreDoFullLaziness
- -> _scc_ "CoreFloating"
- begin_pass "FloatOut" >>
- case (floatOutwards us1 binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "FloatOut" }
-
- CoreDoStaticArgs
- -> _scc_ "CoreStaticArgs"
- begin_pass "StaticArgs" >>
- case (doStaticArgs binds us1) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "StaticArgs" }
- -- Binds really should be dependency-analysed for static-
- -- arg transformation... Not to worry, they probably are.
- -- (I don't think it *dies* if they aren't [WDP 94/04/15])
-
- CoreDoStrictness
- -> _scc_ "CoreStranal"
- begin_pass "StrAnal" >>
- case (saWwTopBinds us1 binds) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "StrAnal" }
-
- CoreDoSpecialising
- -> _scc_ "Specialise"
- begin_pass "Specialise" >>
- case (specProgram us1 binds spec_data) of {
- (p, spec_data2@(SpecData _ spec_noerrs _ _ _
- spec_errs spec_warn spec_tyerrs)) ->
-
- -- if we got errors, we die straight away
- (if not spec_noerrs ||
- (opt_ShowImportSpecs && not (isEmptyBag spec_warn)) then
- hPutStr stderr (ppShow 1000 {-pprCols-}
- (pprSpecErrs module_name spec_errs spec_warn spec_tyerrs))
- >> hPutStr stderr "\n"
- else
- return ()) >>
-
- (if not spec_noerrs then -- Stop here if specialisation errors occured
- ghcExit 1
- else
- return ()) >>
-
- end_pass False us2 p spec_data2 simpl_stats "Specialise"
- }
-
- CoreDoDeforest
-#if OMIT_DEFORESTER
- -> error "ERROR: CoreDoDeforest: not built into compiler\n"
-#else
- -> _scc_ "Deforestation"
- begin_pass "Deforestation" >>
- case (deforestProgram binds us1) of { binds2 ->
- end_pass False us2 binds2 spec_data simpl_stats "Deforestation" }
-#endif
-
- CoreDoPrintCore -- print result of last pass
- -> end_pass True us2 binds spec_data simpl_stats "Print"
-
- -------------------------------------------------
-
- begin_pass
- = if opt_D_show_passes
- then \ what -> hPutStr stderr ("*** Core2Core: "++what++"\n")
- else \ what -> return ()
-
- end_pass print us2 binds2
- spec_data2@(SpecData spec_done _ _ _ _ _ _ _)
- simpl_stats2 what
- = -- report verbosely, if required
- (if (opt_D_verbose_core2core && not print) ||
- (print && not opt_D_verbose_core2core)
- then
- hPutStr stderr ("\n*** "++what++":\n")
- >>
- hPutStr stderr (ppShow 1000
- (ppAboves (map (pprCoreBinding ppr_style) binds2)))
- >>
- hPutStr stderr "\n"
- else
- return ()) >>
- let
- linted_binds = core_linter what spec_done binds2
- in
- return
- (linted_binds, -- processed binds, possibly run thru CoreLint
- us2, -- UniqueSupply for the next guy
- spec_data2, -- possibly-updated specialisation info
- simpl_stats2 -- accumulated simplifier stats
- )
-
--- here so it can be inlined...
-foldl_mn f z [] = return z
-foldl_mn f z (x:xs) = f z x >>= \ zz ->
- foldl_mn f zz xs
+ final_binds <- tidyCorePgm module_name classes post_simpl_binds
+
+ -- Return results
+ return final_binds
+
+doCorePasses us binds []
+ = return binds
+
+doCorePasses us binds (to_do : to_dos)
+ = do
+ let (us1, us2) = splitUniqSupply us
+ binds1 <- doCorePass us1 binds to_do
+ doCorePasses us2 binds1 to_dos
+
+doCorePass us binds (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm sw_chkr us binds
+doCorePass us binds CoreLiberateCase = _scc_ "LiberateCase" liberateCase binds
+doCorePass us binds CoreDoFloatInwards = _scc_ "FloatInwards" floatInwards binds
+doCorePass us binds CoreDoFullLaziness = _scc_ "CoreFloating" floatOutwards us binds
+doCorePass us binds CoreDoStaticArgs = _scc_ "CoreStaticArgs" doStaticArgs us binds
+doCorePass us binds CoreDoStrictness = _scc_ "CoreStranal" saWwTopBinds us binds
+doCorePass us binds CoreDoSpecialising = _scc_ "Specialise" specProgram us binds
\end{code}
+%************************************************************************
+%* *
+\subsection{The driver for the simplifier}
+%* *
+%************************************************************************
+
+\begin{code}
+simplifyPgm :: (SimplifierSwitch -> SwitchResult)
+ -> UniqSupply
+ -> [CoreBind] -- Input
+ -> IO [CoreBind] -- New bindings
+
+simplifyPgm sw_chkr us binds
+ = do {
+ beginPass "Simplify";
+
+ (termination_msg, it_count, counts, binds') <- iteration us 1 zeroSimplCount binds;
+
+ dumpIfSet opt_D_simplifier_stats "Simplifier statistics"
+ (vcat [text termination_msg <+> text "after" <+> ppr it_count <+> text "iterations",
+ text "",
+ pprSimplCount counts]);
+
+ endPass "Simplify"
+ (opt_D_verbose_core2core && not opt_D_dump_simpl_iterations)
+ binds'
+ }
+ where
+ max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations
+ simpl_switch_is_on = switchIsOn sw_chkr
+
+ core_iter_dump binds | opt_D_verbose_core2core = pprCoreBindings binds
+ | otherwise = empty
+
+ iteration us iteration_no counts binds
+ = do {
+ -- Occurrence analysis
+ let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds simpl_switch_is_on binds };
+ dumpIfSet opt_D_dump_occur_anal "Occurrence analysis"
+ (pprCoreBindings tagged_binds);
+
+ -- Simplify
+ let { (binds', counts') = initSmpl sw_chkr us1 (simplTopBinds tagged_binds);
+ all_counts = counts `plusSimplCount` counts'
+ } ;
+
+ -- Stop if nothing happened; don't dump output
+ if isZeroSimplCount counts' then
+ return ("Simplifier reached fixed point", iteration_no, all_counts, binds')
+ else do {
+
+ -- Dump the result of this iteration
+ dumpIfSet opt_D_dump_simpl_iterations
+ ("Simplifier iteration " ++ show iteration_no
+ ++ " out of " ++ show max_iterations)
+ (vcat[pprSimplCount counts',
+ text "",
+ core_iter_dump binds']) ;
+
+ -- Stop if we've run out of iterations
+ if iteration_no == max_iterations then
+ do {
+ if max_iterations > 1 then
+ hPutStr stderr ("NOTE: Simplifier still going after " ++
+ show max_iterations ++
+ " iterations; bailing out.\n")
+ else return ();
+
+ return ("Simplifier baled out", iteration_no, all_counts, binds')
+ }
+
+ -- Else loop
+ else iteration us2 (iteration_no + 1) all_counts binds'
+ } }
+ where
+ (us1, us2) = splitUniqSupply us
+
+
+simplTopBinds binds = go binds `thenSmpl` \ (binds', _) ->
+ returnSmpl binds'
+ where
+ go [] = returnSmpl ([], ())
+ go (bind1 : binds) = simplBind bind1 (go binds)
+\end{code}
+
%************************************************************************
%* *
-\subsection[SimplCore-indirections]{Eliminating indirections in Core code, and globalising}
+\subsection{Tidying core}
%* *
%************************************************************************
Several tasks are done by @tidyCorePgm@
-1. Eliminate indirections. The point here is to transform
- x_local = E
- x_exported = x_local
- ==>
- x_exported = E
-
-2. Make certain top-level bindings into Globals. The point is that
+1. Make certain top-level bindings into Globals. The point is that
Global things get externally-visible labels at code generation
time
-3. Make the representation of NoRep literals explicit, and
- float their bindings to the top level
-4. Convert
- case x of {...; x' -> ...x'...}
- ==>
- case x of {...; _ -> ...x... }
- See notes in SimplCase.lhs, near simplDefault for the reasoning here.
+2. Give all binders a nice print-name. Their uniques aren't changed;
+ rather we give them lexically unique occ-names, so that we can
+ safely print the OccNae only in the interface file. [Bad idea to
+ change the uniques, because the code generator makes global labels
+ from the uniques for local thunks etc.]
+
+
+\begin{code}
+tidyCorePgm :: Module -> [Class] -> [CoreBind] -> IO [CoreBind]
+tidyCorePgm mod local_classes binds_in
+ = do
+ beginPass "Tidy Core"
+ let (_, binds_out) = mapAccumL (tidyBind (Just mod)) init_tidy_env binds_in
+ endPass "Tidy Core" (opt_D_dump_simpl || opt_D_verbose_core2core) binds_out
+ where
+ -- Make sure to avoid the names of class operations
+ -- They don't have top-level bindings, so we won't see them
+ -- in binds_in; so we must initialise the tidy_env appropriately
+ --
+ -- We also make sure to avoid any exported binders. Consider
+ -- f{-u1-} = 1 -- Local decl
+ -- ...
+ -- f{-u2-} = 2 -- Exported decl
+ --
+ -- The second exported decl must 'get' the name 'f', so we
+ -- have to put 'f' in the avoids list before we get to the first
+ -- decl. Name.tidyName then does a no-op on exported binders.
+ init_tidy_env = (initTidyOccEnv avoids, emptyVarEnv)
+ avoids = [getOccName sel_id | cls <- local_classes,
+ sel_id <- classSelIds cls]
+ ++
+ [getOccName bndr | bind <- binds_in,
+ bndr <- bindersOf bind,
+ isExported bndr]
+
+tidyBind :: Maybe Module -- (Just m) for top level, Nothing for nested
+ -> TidyEnv
+ -> CoreBind
+ -> (TidyEnv, CoreBind)
+tidyBind maybe_mod env (NonRec bndr rhs)
+ = let
+ (env', bndr') = tidyBndr maybe_mod env bndr
+ rhs' = tidyExpr env rhs
+ in
+ (env', NonRec bndr' rhs')
+
+tidyBind maybe_mod env (Rec pairs)
+ = let
+ -- We use env' when tidying the rhss
+ -- When tidying the binder itself we may tidy it's
+ -- specialisations; if any of these mention other binders
+ -- in the group we should really feed env' to them too;
+ -- but that seems (a) unlikely and (b) a bit tiresome.
+ -- So I left it out for now
+
+ (bndrs, rhss) = unzip pairs
+ (env', bndrs') = mapAccumL (tidyBndr maybe_mod) env bndrs
+ rhss' = map (tidyExpr env') rhss
+ in
+ (env', Rec (zip bndrs' rhss'))
+
+tidyExpr env (Type ty) = Type (tidyType env ty)
+tidyExpr env (Con con args) = Con con (map (tidyExpr env) args)
+tidyExpr env (App f a) = App (tidyExpr env f) (tidyExpr env a)
+tidyExpr env (Note n e) = Note (tidyNote env n) (tidyExpr env e)
+
+tidyExpr env (Let b e) = Let b' (tidyExpr env' e)
+ where
+ (env', b') = tidyBind Nothing env b
+
+tidyExpr env (Case e b alts) = Case (tidyExpr env e) b' (map (tidyAlt env') alts)
+ where
+ (env', b') = tidyNestedBndr env b
+
+tidyExpr env (Var v) = case lookupVarEnv var_env v of
+ Just v' -> Var v'
+ Nothing -> Var v
+ where
+ (_, var_env) = env
+
+tidyExpr env (Lam b e) = Lam b' (tidyExpr env' e)
+ where
+ (env', b') = tidyNestedBndr env b
+
+tidyAlt env (con, vs, rhs) = (con, vs', tidyExpr env' rhs)
+ where
+ (env', vs') = mapAccumL tidyNestedBndr env vs
+
+tidyNote env (Coerce t1 t2) = Coerce (tidyType env t1) (tidyType env t2)
+\end{code}
-5. *Mangle* cases involving fork# and par# in the discriminant. The
- original templates for these primops (see @PrelVals.lhs@) constructed
- case expressions with boolean results solely to fool the strictness
- analyzer, the simplifier, and anyone else who might want to fool with
- the evaluation order. At this point in the compiler our evaluation
- order is safe. Therefore, we convert expressions of the form:
+\begin{code}
+tidyBndr (Just mod) env id = tidyTopBndr mod env id
+tidyBndr Nothing env var = tidyNestedBndr env var
+
+tidyNestedBndr env tyvar
+ | isTyVar tyvar
+ = tidyTyVar env tyvar
+
+tidyNestedBndr env@(tidy_env, var_env) id
+ = -- Non-top-level variables
+ let
+ -- Give the Id a fresh print-name, *and* rename its type
+ name' = mkLocalName (getUnique id) occ'
+ (tidy_env', occ') = tidyOccName tidy_env (getOccName id)
+ ty' = tidyType env (idType id)
+ id' = mkUserId name' ty'
+ -- NB: This throws away the IdInfo of the Id, which we
+ -- no longer need. That means we don't need to
+ -- run over it with env, nor renumber it.
+ var_env' = extendVarEnv var_env id id'
+ in
+ ((tidy_env', var_env'), id')
+
+tidyTopBndr mod env@(tidy_env, var_env) id
+ = -- Top level variables
+ let
+ (tidy_env', name') = tidyTopName mod tidy_env (idName id)
+ ty' = tidyTopType (idType id)
+ idinfo' = tidyIdInfo env (idInfo id)
+ id' = mkId name' ty' (idDetails id) idinfo'
+ var_env' = extendVarEnv var_env id id'
+ in
+ ((tidy_env', var_env'), id')
+
+-- tidyIdInfo does these things:
+-- a) tidy the specialisation info (if any)
+-- b) zap a complicated ICanSafelyBeINLINEd pragma,
+-- c) zap the unfolding
+-- The latter two are to avoid space leaks
+
+tidyIdInfo env info
+ = info3
+ where
+ spec_items = specEnvToList (specInfo info)
+ spec_env' = specEnvFromList (map tidy_item spec_items)
+ info1 | null spec_items = info
+ | otherwise = spec_env' `setSpecInfo` info
+
+ info2 = case inlinePragInfo info of
+ ICanSafelyBeINLINEd _ _ -> NoInlinePragInfo `setInlinePragInfo` info1
+ other -> info1
+
+ info3 = noUnfolding `setUnfoldingInfo` info2
+
+ tidy_item (tyvars, tys, rhs)
+ = (tyvars', tidyTypes env' tys, tidyExpr env rhs)
+ where
+ (env', tyvars') = tidyTyVars env tyvars
+\end{code}
+
+
+
+%************************************************************************
+%* *
+\subsection{PostSimplification}
+%* *
+%************************************************************************
+
+Several tasks are performed by the post-simplification pass
+
+1. Make the representation of NoRep literals explicit, and
+ float their bindings to the top level. We only do the floating
+ part for NoRep lits inside a lambda (else no gain). We need to
+ take care with let x = "foo" in e
+ that we don't end up with a silly binding
+ let x = y in e
+ with a floated "foo". What a bore.
+
+2. *Mangle* cases involving par# in the discriminant. The unfolding
+ for par in PrelConc.lhs include case expressions with integer
+ results solely to fool the strictness analyzer, the simplifier,
+ and anyone else who might want to fool with the evaluation order.
+ At this point in the compiler our evaluation order is safe.
+ Therefore, we convert expressions of the form:
case par# e of
- True -> rhs
- False -> parError#
+ 0# -> rhs
+ _ -> parError#
==>
case par# e of
_ -> rhs
-6. Eliminate polymorphic case expressions. We can't generate code for them yet.
+ fork# isn't handled like this - it's an explicit IO operation now.
+ The reason is that fork# returns a ThreadId#, which gets in the
+ way of the above scheme. And anyway, IO is the only guaranteed
+ way to enforce ordering --SDM.
-Eliminate indirections
-~~~~~~~~~~~~~~~~~~~~~~
-In @elimIndirections@, we look for things at the top-level of the form...
-\begin{verbatim}
- x_local = ....
- x_exported = x_local
-\end{verbatim}
-In cases we find like this, we go {\em backwards} and replace
-\tr{x_local} with \tr{x_exported}. This save a gratuitous jump
-(from \tr{x_exported} to \tr{x_local}), and makes strictness
-information propagate better.
-
-We rely on prior eta reduction to simplify things like
-\begin{verbatim}
- x_exported = /\ tyvars -> x_local tyvars
-==>
+3. Mangle cases involving seq# in the discriminant. Up to this
+ point, seq# will appear like this:
+
+ case seq# e of
+ 0# -> seqError#
+ _ -> ...
+
+ where the 0# branch is purely to bamboozle the strictness analyser
+ (see case 4 above). This code comes from an unfolding for 'seq'
+ in Prelude.hs. We translate this into
+
+ case e of
+ _ -> ...
+
+ Now that the evaluation order is safe.
+
+4. Do eta reduction for lambda abstractions appearing in:
+ - the RHS of case alternatives
+ - the body of a let
+
+ These will otherwise turn into local bindings during Core->STG;
+ better to nuke them if possible. (In general the simplifier does
+ eta expansion not eta reduction, up to this point. It does eta
+ on the RHSs of bindings but not the RHSs of case alternatives and
+ let bodies)
+
+
+------------------- NOT DONE ANY MORE ------------------------
+[March 98] Indirections are now elimianted by the occurrence analyser
+1. Eliminate indirections. The point here is to transform
+ x_local = E
x_exported = x_local
-\end{verbatim}
+ ==>
+ x_exported = E
+
+[Dec 98] [Not now done because there is no penalty in the code
+ generator for using the former form]
+2. Convert
+ case x of {...; x' -> ...x'...}
+ ==>
+ case x of {...; _ -> ...x... }
+ See notes in SimplCase.lhs, near simplDefault for the reasoning here.
+--------------------------------------------------------------
-If more than one exported thing is equal to a local thing (i.e., the
-local thing really is shared), then we do one only:
-\begin{verbatim}
- x_local = ....
- x_exported1 = x_local
- x_exported2 = x_local
-==>
- x_exported1 = ....
+Special case
+~~~~~~~~~~~~
- x_exported2 = x_exported1
-\end{verbatim}
+NOT ENABLED AT THE MOMENT (because the floated Ids are global-ish
+things, and we need local Ids for non-floated stuff):
-There's a possibility of leaving unchanged something like this:
-\begin{verbatim}
- x_local = ....
- x_exported1 = x_local Int
-\end{verbatim}
-By the time we've thrown away the types in STG land this
-could be eliminated. But I don't think it's very common
-and it's dangerous to do this fiddling in STG land
-because we might elminate a binding that's mentioned in the
-unfolding for something.
+ Don't float stuff out of a binder that's marked as a bottoming Id.
+ Reason: it doesn't do any good, and creates more CAFs that increase
+ the size of SRTs.
-General Strategy: first collect the info; then make a \tr{Id -> Id} mapping.
-Then blast the whole program (LHSs as well as RHSs) with it.
+eg.
+ f = error "string"
+is translated to
-\begin{code}
-tidyCorePgm :: Module -> UniqSupply -> [CoreBinding] -> [CoreBinding]
+ f' = unpackCString# "string"
+ f = error f'
-tidyCorePgm mod us binds_in
- = initTM mod indirection_env us $
- tidyTopBindings (catMaybes reduced_binds) `thenTM` \ binds ->
- returnTM (bagToList binds)
- where
- (indirection_env, reduced_binds) = mapAccumL try_bind nullIdEnv binds_in
-
- try_bind :: IdEnv Id -> CoreBinding -> (IdEnv Id, Maybe CoreBinding)
- try_bind env_so_far
- (NonRec exported_binder (Var local_id))
- | isExported exported_binder && -- Only if this is exported
- isLocallyDefined local_id && -- Only if this one is defined in this
- not (isExported local_id) && -- module, so that we *can* change its
- -- binding to be the exported thing!
- not (maybeToBool (lookupIdEnv env_so_far local_id))
- -- Only if not already substituted for
- = (addOneToIdEnv env_so_far local_id exported_binder, Nothing)
-
- try_bind env_so_far bind
- = (env_so_far, Just bind)
-\end{code}
+hence f' and f become CAFs. Instead, the special case for
+tidyTopBinding below makes sure this comes out as
-Top level bindings
-~~~~~~~~~~~~~~~~~~
-\begin{code}
-tidyTopBindings [] = returnTM emptyBag
-tidyTopBindings (b:bs)
- = tidyTopBinding b $
- tidyTopBindings bs
-
-tidyTopBinding :: CoreBinding
- -> TidyM (Bag CoreBinding)
- -> TidyM (Bag CoreBinding)
-
-tidyTopBinding (NonRec bndr rhs) thing_inside
- = getFloats (tidyCoreExpr rhs) `thenTM` \ (rhs',floats) ->
- mungeTopBinder bndr $ \ bndr' ->
- thing_inside `thenTM` \ binds ->
- returnTM ((floats `snocBag` NonRec bndr' rhs') `unionBags` binds)
-
-tidyTopBinding (Rec pairs) thing_inside
- = mungeTopBinders binders $ \ binders' ->
- getFloats (mapTM tidyCoreExpr rhss) `thenTM` \ (rhss', floats) ->
- thing_inside `thenTM` \ binds_inside ->
- returnTM ((floats `snocBag` Rec (binders' `zip` rhss')) `unionBags` binds_inside)
- where
- (binders, rhss) = unzip pairs
-\end{code}
+ f = let f' = unpackCString# "string" in error f'
+and we can safely ignore f as a CAF, since it can only ever be entered once.
-Local Bindings
-~~~~~~~~~~~~~~
-\begin{code}
-tidyCoreBinding (NonRec bndr rhs)
- = tidyCoreExpr rhs `thenTM` \ rhs' ->
- returnTM (NonRec bndr rhs')
-tidyCoreBinding (Rec pairs)
- = mapTM do_one pairs `thenTM` \ pairs' ->
- returnTM (Rec pairs')
- where
- do_one (bndr,rhs) = tidyCoreExpr rhs `thenTM` \ rhs' ->
- returnTM (bndr, rhs')
+\begin{code}
+doPostSimplification :: UniqSupply -> [CoreBind] -> IO [CoreBind]
+doPostSimplification us binds_in
+ = do
+ beginPass "Post-simplification pass"
+ let binds_out = initPM us (postSimplTopBinds binds_in)
+ endPass "Post-simplification pass" opt_D_verbose_core2core binds_out
+
+postSimplTopBinds :: [CoreBind] -> PostM [CoreBind]
+postSimplTopBinds binds
+ = mapPM postSimplTopBind binds `thenPM` \ binds' ->
+ returnPM (bagToList (unionManyBags binds'))
+
+postSimplTopBind :: CoreBind -> PostM (Bag CoreBind)
+postSimplTopBind (NonRec bndr rhs)
+ | isBottomingId bndr -- Don't lift out floats for bottoming Ids
+ -- See notes above
+ = getFloatsPM (postSimplExpr rhs) `thenPM` \ (rhs', floats) ->
+ returnPM (unitBag (NonRec bndr (foldrBag Let rhs' floats)))
+
+postSimplTopBind bind
+ = getFloatsPM (postSimplBind bind) `thenPM` \ (bind', floats) ->
+ returnPM (floats `snocBag` bind')
+
+postSimplBind (NonRec bndr rhs)
+ = postSimplExpr rhs `thenPM` \ rhs' ->
+ returnPM (NonRec bndr rhs')
+
+postSimplBind (Rec pairs)
+ = mapPM postSimplExpr rhss `thenPM` \ rhss' ->
+ returnPM (Rec (bndrs `zip` rhss'))
+ where
+ (bndrs, rhss) = unzip pairs
\end{code}
Expressions
~~~~~~~~~~~
\begin{code}
-tidyCoreExpr (Var v) = lookupTM v `thenTM` \ v' ->
- returnTM (Var v')
-
-tidyCoreExpr (Lit lit)
- = litToRep lit `thenTM` \ (_, lit_expr) ->
- returnTM lit_expr
-
-tidyCoreExpr (App fun arg)
- = tidyCoreExpr fun `thenTM` \ fun' ->
- tidyCoreArg arg `thenTM` \ arg' ->
- returnTM (App fun' arg')
-
-tidyCoreExpr (Con con args)
- = mapTM tidyCoreArg args `thenTM` \ args' ->
- returnTM (Con con args')
-
-tidyCoreExpr (Prim prim args)
- = mapTM tidyCoreArg args `thenTM` \ args' ->
- returnTM (Prim prim args')
-
-tidyCoreExpr (Lam bndr body)
- = tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Lam bndr body')
-
-tidyCoreExpr (Let bind body)
- = tidyCoreBinding bind `thenTM` \ bind' ->
- tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Let bind' body')
-
-tidyCoreExpr (SCC cc body)
- = tidyCoreExpr body `thenTM` \ body' ->
- returnTM (SCC cc body')
-
-tidyCoreExpr (Coerce coercion ty body)
- = tidyCoreExpr body `thenTM` \ body' ->
- returnTM (Coerce coercion ty body')
-
--- Wierd case for par, seq, fork etc. See notes above.
-tidyCoreExpr (Case scrut@(Prim op args) (PrimAlts _ (BindDefault binder rhs)))
- | funnyParallelOp op
- = tidyCoreExpr scrut `thenTM` \ scrut' ->
- tidyCoreExpr rhs `thenTM` \ rhs' ->
- returnTM (Case scrut' (PrimAlts [] (BindDefault binder rhs')))
-
--- Eliminate polymorphic case, for which we can't generate code just yet
-tidyCoreExpr (Case scrut (AlgAlts [] (BindDefault deflt_bndr rhs)))
- | not (maybeToBool (maybeAppSpecDataTyConExpandingDicts (coreExprType scrut)))
- = pprTrace "Warning: discarding polymophic case:" (ppr PprDebug scrut) $
- case scrut of
- Var v -> extendEnvTM deflt_bndr v (tidyCoreExpr rhs)
- other -> tidyCoreExpr (Let (NonRec deflt_bndr scrut) rhs)
-
-tidyCoreExpr (Case scrut alts)
- = tidyCoreExpr scrut `thenTM` \ scrut' ->
- tidy_alts alts `thenTM` \ alts' ->
- returnTM (Case scrut' alts')
+postSimplExpr (Var v) = returnPM (Var v)
+postSimplExpr (Type ty) = returnPM (Type ty)
+
+postSimplExpr (App fun arg)
+ = postSimplExpr fun `thenPM` \ fun' ->
+ postSimplExpr arg `thenPM` \ arg' ->
+ returnPM (App fun' arg')
+
+postSimplExpr (Con (Literal lit) args)
+ = ASSERT( null args )
+ litToRep lit `thenPM` \ (lit_ty, lit_expr) ->
+ getInsideLambda `thenPM` \ in_lam ->
+ if in_lam && not (exprIsTrivial lit_expr) then
+ -- It must have been a no-rep literal with a
+ -- non-trivial representation; and we're inside a lambda;
+ -- so float it to the top
+ addTopFloat lit_ty lit_expr `thenPM` \ v ->
+ returnPM (Var v)
+ else
+ returnPM lit_expr
+
+postSimplExpr (Con con args)
+ = mapPM postSimplExpr args `thenPM` \ args' ->
+ returnPM (Con con args')
+
+postSimplExpr (Lam bndr body)
+ = insideLambda bndr $
+ postSimplExpr body `thenPM` \ body' ->
+ returnPM (Lam bndr body')
+
+postSimplExpr (Let bind body)
+ = postSimplBind bind `thenPM` \ bind' ->
+ postSimplExprEta body `thenPM` \ body' ->
+ returnPM (Let bind' body')
+
+postSimplExpr (Note note body)
+ = postSimplExprEta body `thenPM` \ body' ->
+ returnPM (Note note body')
+
+-- seq#: see notes above.
+-- NB: seq# :: forall a. a -> Int#
+postSimplExpr (Case scrut@(Con (PrimOp SeqOp) [Type ty, e]) bndr alts)
+ = postSimplExpr e `thenPM` \ e' ->
+ let
+ -- The old binder can't have been used, so we
+ -- can gaily re-use it (yuk!)
+ new_bndr = setIdType bndr ty
+ in
+ postSimplExprEta default_rhs `thenPM` \ rhs' ->
+ returnPM (Case e' new_bndr [(DEFAULT,[],rhs')])
where
- tidy_alts (AlgAlts alts deflt)
- = mapTM tidy_alg_alt alts `thenTM` \ alts' ->
- tidy_deflt deflt `thenTM` \ deflt' ->
- returnTM (AlgAlts alts' deflt')
-
- tidy_alts (PrimAlts alts deflt)
- = mapTM tidy_prim_alt alts `thenTM` \ alts' ->
- tidy_deflt deflt `thenTM` \ deflt' ->
- returnTM (PrimAlts alts' deflt')
-
- tidy_alg_alt (con,bndrs,rhs) = tidyCoreExpr rhs `thenTM` \ rhs' ->
- returnTM (con,bndrs,rhs')
+ (other_alts, maybe_default) = findDefault alts
+ Just default_rhs = maybe_default
+
+-- par#: see notes above.
+postSimplExpr (Case scrut@(Con (PrimOp op) args) bndr alts)
+ | funnyParallelOp op && maybeToBool maybe_default
+ = postSimplExpr scrut `thenPM` \ scrut' ->
+ postSimplExprEta default_rhs `thenPM` \ rhs' ->
+ returnPM (Case scrut' bndr [(DEFAULT,[],rhs')])
+ where
+ (other_alts, maybe_default) = findDefault alts
+ Just default_rhs = maybe_default
- tidy_prim_alt (lit,rhs) = tidyCoreExpr rhs `thenTM` \ rhs' ->
- returnTM (lit,rhs')
+postSimplExpr (Case scrut case_bndr alts)
+ = postSimplExpr scrut `thenPM` \ scrut' ->
+ mapPM ps_alt alts `thenPM` \ alts' ->
+ returnPM (Case scrut' case_bndr alts')
+ where
+ ps_alt (con,bndrs,rhs) = postSimplExprEta rhs `thenPM` \ rhs' ->
+ returnPM (con, bndrs, rhs')
- -- We convert case x of {...; x' -> ...x'...}
- -- to
- -- case x of {...; _ -> ...x... }
- --
- -- See notes in SimplCase.lhs, near simplDefault for the reasoning.
- -- It's quite easily done: simply extend the environment to bind the
- -- default binder to the scrutinee.
-
- tidy_deflt NoDefault = returnTM NoDefault
- tidy_deflt (BindDefault bndr rhs)
- = extend_env (tidyCoreExpr rhs) `thenTM` \ rhs' ->
- returnTM (BindDefault bndr rhs')
- where
- extend_env = case scrut of
- Var v -> extendEnvTM bndr v
- other -> \x -> x
+postSimplExprEta e = postSimplExpr e `thenPM` \ e' ->
+ returnPM (etaCoreExpr e')
\end{code}
-Arguments
-~~~~~~~~~
\begin{code}
-tidyCoreArg :: CoreArg -> TidyM CoreArg
-
-tidyCoreArg (VarArg v)
- = lookupTM v `thenTM` \ v' ->
- returnTM (VarArg v')
-
-tidyCoreArg (LitArg lit)
- = litToRep lit `thenTM` \ (lit_ty, lit_expr) ->
- case lit_expr of
- Var v -> returnTM (VarArg v)
- Lit l -> returnTM (LitArg l)
- other -> addTopFloat lit_ty lit_expr `thenTM` \ v ->
- returnTM (VarArg v)
-
-tidyCoreArg (TyArg ty) = returnTM (TyArg ty)
-tidyCoreArg (UsageArg u) = returnTM (UsageArg u)
-\end{code}
+funnyParallelOp ParOp = True
+funnyParallelOp _ = False
+\end{code}
%************************************************************************
binding out to the top level.
\begin{code}
-
-litToRep :: Literal -> TidyM (Type, CoreExpr)
+litToRep :: Literal -> PostM (Type, CoreExpr)
-litToRep (NoRepStr s)
- = returnTM (stringTy, rhs)
+litToRep (NoRepStr s ty)
+ = returnPM (ty, rhs)
where
rhs = if (any is_NUL (_UNPK_ s))
then -- Must cater for NULs in literal string
- mkGenApp (Var unpackCString2Id)
- [LitArg (MachStr s),
- LitArg (mkMachInt (toInteger (_LENGTH_ s)))]
+ mkApps (Var unpackCString2Id)
+ [mkLit (MachStr s),
+ mkLit (mkMachInt (toInteger (_LENGTH_ s)))]
else -- No NULs in the string
- App (Var unpackCStringId) (LitArg (MachStr s))
+ App (Var unpackCStringId) (mkLit (MachStr s))
is_NUL c = c == '\0'
\end{code}
\begin{code}
litToRep (NoRepInteger i integer_ty)
- = returnTM (integer_ty, rhs)
+ = returnPM (integer_ty, rhs)
where
- rhs | i == 0 = Var integerZeroId -- Extremely convenient to look out for
- | i == 1 = Var integerPlusOneId -- a few very common Integer literals!
+ rhs | i == 0 = Var integerZeroId -- Extremely convenient to look out for
+ | i == 1 = Var integerPlusOneId -- a few very common Integer literals!
| i == 2 = Var integerPlusTwoId
| i == (-1) = Var integerMinusOneId
| i > tARGET_MIN_INT && -- Small enough, so start from an Int
i < tARGET_MAX_INT
- = Prim Int2IntegerOp [LitArg (mkMachInt i)]
+ = App (Var int2IntegerId) (Con (Literal (mkMachInt i)) [])
| otherwise -- Big, so start from a string
- = Prim Addr2IntegerOp [LitArg (MachStr (_PK_ (show i)))]
+ = App (Var addr2IntegerId) (Con (Literal (MachStr (_PK_ (show i)))) [])
litToRep (NoRepRational r rational_ty)
- = tidyCoreArg (LitArg (NoRepInteger (numerator r) integer_ty)) `thenTM` \ num_arg ->
- tidyCoreArg (LitArg (NoRepInteger (denominator r) integer_ty)) `thenTM` \ denom_arg ->
- returnTM (rational_ty, Con ratio_data_con [num_arg, denom_arg])
+ = postSimplExpr (mkLit (NoRepInteger (numerator r) integer_ty)) `thenPM` \ num_arg ->
+ postSimplExpr (mkLit (NoRepInteger (denominator r) integer_ty)) `thenPM` \ denom_arg ->
+ returnPM (rational_ty, mkConApp ratio_data_con [Type integer_ty, num_arg, denom_arg])
where
(ratio_data_con, integer_ty)
- = case (maybeAppDataTyCon rational_ty) of
+ = case (splitAlgTyConApp_maybe rational_ty) of
Just (tycon, [i_ty], [con])
- -> ASSERT(is_integer_ty i_ty && uniqueOf tycon == ratioTyConKey)
+ -> ASSERT(isIntegerTy i_ty && getUnique tycon == ratioTyConKey)
(con, i_ty)
_ -> (panic "ratio_data_con", panic "integer_ty")
- is_integer_ty ty
- = case (maybeAppDataTyCon ty) of
- Just (tycon, [], _) -> uniqueOf tycon == integerTyConKey
- _ -> False
-
-litToRep other_lit = returnTM (literalType other_lit, Lit other_lit)
+litToRep other_lit = returnPM (literalType other_lit, mkLit other_lit)
\end{code}
-\begin{code}
-funnyParallelOp SeqOp = True
-funnyParallelOp ParOp = True
-funnyParallelOp ForkOp = True
-funnyParallelOp _ = False
-\end{code}
-
%************************************************************************
%* *
%************************************************************************
\begin{code}
-type TidyM a = Module
- -> IdEnv Id
- -> (UniqSupply, Bag CoreBinding)
- -> (a, (UniqSupply, Bag CoreBinding))
-
-initTM mod env us m
- = case m mod env (us,emptyBag) of
- (result, (us',floats)) -> result
-
-returnTM v mod env usf = (v, usf)
-thenTM m k mod env usf = case m mod env usf of
- (r, usf') -> k r mod env usf'
-
-mapTM f [] = returnTM []
-mapTM f (x:xs) = f x `thenTM` \ r ->
- mapTM f xs `thenTM` \ rs ->
- returnTM (r:rs)
-\end{code}
-
-
-\begin{code}
-getFloats :: TidyM a -> TidyM (a, Bag CoreBinding)
-getFloats m mod env (us,floats)
- = case m mod env (us,emptyBag) of
- (r, (us',floats')) -> ((r, floats'), (us',floats))
-
-
--- Need to extend the environment when we munge a binder, so that occurrences
--- of the binder will print the correct way (i.e. as a global not a local)
-mungeTopBinder :: Id -> (Id -> TidyM a) -> TidyM a
-mungeTopBinder id thing_inside mod env usf
- = case lookupIdEnv env id of
- Just global -> thing_inside global mod env usf
- Nothing -> thing_inside new_global mod new_env usf
- where
- new_env = addOneToIdEnv env id new_global
- new_global = setIdVisibility mod id
-
-mungeTopBinders [] k = k []
-mungeTopBinders (b:bs) k = mungeTopBinder b $ \ b' ->
- mungeTopBinders bs $ \ bs' ->
- k (b' : bs')
-
-addTopFloat :: Type -> CoreExpr -> TidyM Id
-addTopFloat lit_ty lit_rhs mod env (us, floats)
- = (lit_id, (us', floats `snocBag` NonRec lit_id lit_rhs))
- where
- lit_local = mkSysLocal SLIT("nrlit") uniq lit_ty noSrcLoc
- lit_id = setIdVisibility mod lit_local
- (us', us1) = splitUniqSupply us
- uniq = getUnique us1
-
-lookupTM v mod env usf
- = case lookupIdEnv env v of
- Nothing -> (v, usf)
- Just v' -> (v', usf)
-
-extendEnvTM v v' m mod env usf
- = m mod (addOneToIdEnv env v v') usf
+type PostM a = Bool -- True <=> inside a *value* lambda
+ -> (UniqSupply, Bag CoreBind) -- Unique supply and Floats in
+ -> (a, (UniqSupply, Bag CoreBind))
+
+initPM :: UniqSupply -> PostM a -> a
+initPM us m
+ = case m False {- not inside lambda -} (us, emptyBag) of
+ (result, _) -> result
+
+returnPM v in_lam usf = (v, usf)
+thenPM m k in_lam usf = case m in_lam usf of
+ (r, usf') -> k r in_lam usf'
+
+mapPM f [] = returnPM []
+mapPM f (x:xs) = f x `thenPM` \ r ->
+ mapPM f xs `thenPM` \ rs ->
+ returnPM (r:rs)
+
+insideLambda :: CoreBndr -> PostM a -> PostM a
+insideLambda bndr m in_lam usf | isId bndr = m True usf
+ | otherwise = m in_lam usf
+
+getInsideLambda :: PostM Bool
+getInsideLambda in_lam usf = (in_lam, usf)
+
+getFloatsPM :: PostM a -> PostM (a, Bag CoreBind)
+getFloatsPM m in_lam (us, floats)
+ = let
+ (a, (us', floats')) = m in_lam (us, emptyBag)
+ in
+ ((a, floats'), (us', floats))
+
+addTopFloat :: Type -> CoreExpr -> PostM Id
+addTopFloat lit_ty lit_rhs in_lam (us, floats)
+ = let
+ (us1, us2) = splitUniqSupply us
+ uniq = uniqFromSupply us1
+ lit_id = mkSysLocal SLIT("lf") uniq lit_ty
+ in
+ (lit_id, (us2, floats `snocBag` NonRec lit_id lit_rhs))
\end{code}
projects / ghc-hetmet.git / blobdiff