\section[SimplCore]{Driver for simplifying @Core@ programs}
\begin{code}
-module SimplCore ( core2core ) where
+module SimplCore ( core2core, simplifyExpr ) where
#include "HsVersions.h"
-import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..),
- SwitchResult(..), switchIsOn, intSwitchSet,
- opt_D_dump_occur_anal, opt_D_dump_rules,
- opt_D_dump_simpl_iterations,
- opt_D_dump_simpl_stats,
- opt_D_dump_simpl, opt_D_dump_rules,
- opt_D_verbose_core2core,
- opt_D_dump_occur_anal,
- opt_UsageSPOn,
+import CmdLineOpts ( CoreToDo(..), SimplifierSwitch(..),
+ SimplifierMode(..), DynFlags, DynFlag(..), dopt,
+ dopt_CoreToDo, buildCoreToDo
)
-import CoreLint ( beginPass, endPass )
import CoreSyn
+import TcIface ( loadImportedRules )
+import HscTypes ( HscEnv(..), ModGuts(..), ModGuts,
+ ModDetails(..), HomeModInfo(..) )
import CSE ( cseProgram )
-import Rules ( RuleBase, ProtoCoreRule(..), pprProtoCoreRule, prepareRuleBase, orphanRule )
-import CoreUnfold
-import PprCore ( pprCoreBindings )
-import OccurAnal ( occurAnalyseBinds )
-import CoreUtils ( exprIsTrivial, etaReduceExpr )
+import Rules ( RuleBase, ruleBaseIds,
+ extendRuleBaseList, pprRuleBase, getLocalRules,
+ ruleCheckProgram )
+import Module ( moduleEnvElts )
+import PprCore ( pprCoreBindings, pprCoreExpr, pprIdRules )
+import OccurAnal ( occurAnalyseBinds, occurAnalyseGlobalExpr )
+import CoreUtils ( coreBindsSize )
import Simplify ( simplTopBinds, simplExpr )
-import SimplUtils ( findDefault, simplBinders )
+import SimplUtils ( simplBinders )
import SimplMonad
-import Literal ( Literal(..), literalType, mkMachInt )
-import ErrUtils ( dumpIfSet )
+import ErrUtils ( dumpIfSet, dumpIfSet_dyn, showPass )
+import CoreLint ( endPass )
import FloatIn ( floatInwards )
import FloatOut ( floatOutwards )
-import Id ( Id, mkSysLocal, mkVanillaId, isBottomingId, isDataConWrapId,
- idType, setIdType, idName, idInfo, setIdNoDiscard
- )
-import VarEnv
+import Id ( idIsFrom, idSpecialisation, setIdSpecialisation )
import VarSet
-import Module ( Module )
-import Name ( mkLocalName, tidyOccName, tidyTopName,
- NamedThing(..), OccName
- )
-import TyCon ( TyCon, isDataTyCon )
-import PrelRules ( builtinRules )
-import Type ( Type,
- isUnLiftedType,
- tidyType, tidyTypes, tidyTopType, tidyTyVar, tidyTyVars,
- Type
- )
-import TysWiredIn ( smallIntegerDataCon, isIntegerTy )
import LiberateCase ( liberateCase )
import SAT ( doStaticArgs )
import Specialise ( specProgram)
-import UsageSPInf ( doUsageSPInf )
-import StrictAnal ( saBinds )
+import SpecConstr ( specConstrProgram)
+import DmdAnal ( dmdAnalPgm )
import WorkWrap ( wwTopBinds )
+#ifdef OLD_STRICTNESS
+import StrictAnal ( saBinds )
import CprAnalyse ( cprAnalyse )
+#endif
-import Unique ( Unique, Uniquable(..) )
-import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply, uniqFromSupply )
-import Util ( mapAccumL )
-import SrcLoc ( noSrcLoc )
-import Bag
-import Maybes
+import UniqSupply ( UniqSupply, mkSplitUniqSupply, splitUniqSupply )
import IO ( hPutStr, stderr )
import Outputable
-import Ratio ( numerator, denominator )
+import Maybes ( orElse )
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-core2core :: [CoreToDo] -- Spec of what core-to-core passes to do
- -> [CoreBind] -- Binds in
- -> [ProtoCoreRule] -- Rules
- -> IO ([CoreBind], [ProtoCoreRule])
+core2core :: HscEnv
+ -> ModGuts
+ -> IO ModGuts
-core2core core_todos binds rules
+core2core hsc_env
+ mod_impl@(ModGuts { mg_binds = binds_in })
= do
- us <- mkSplitUniqSupply 's'
- let (cp_us, us1) = splitUniqSupply us
- (ru_us, ps_us) = splitUniqSupply us1
+ let dflags = hsc_dflags hsc_env
+ core_todos
+ | Just todo <- dopt_CoreToDo dflags = todo
+ | otherwise = buildCoreToDo dflags
- better_rules <- simplRules ru_us rules binds
+ us <- mkSplitUniqSupply 's'
+ let (cp_us, ru_us) = splitUniqSupply us
- let all_rules = builtinRules ++ better_rules
- -- Here is where we add in the built-in rules
+ -- COMPUTE THE RULE BASE TO USE
+ (rule_base, local_rule_ids, orphan_rules)
+ <- prepareRules hsc_env mod_impl ru_us
- let (binds1, rule_base) = prepareRuleBase binds all_rules
+ -- PREPARE THE BINDINGS
+ let binds1 = updateBinders local_rule_ids binds_in
- -- Do the main business
- (stats, processed_binds) <- doCorePasses zeroSimplCount cp_us binds1
- rule_base core_todos
+ -- DO THE BUSINESS
+ (stats, processed_binds)
+ <- doCorePasses dflags rule_base (zeroSimplCount dflags) cp_us binds1 core_todos
- dumpIfSet opt_D_dump_simpl_stats
+ dumpIfSet_dyn dflags Opt_D_dump_simpl_stats
"Grand total simplifier statistics"
(pprSimplCount stats)
-- Return results
- return (processed_binds, filter orphanRule better_rules)
-
+ -- We only return local orphan rules, i.e., local rules not attached to an Id
+ -- The bindings cotain more rules, embedded in the Ids
+ return (mod_impl { mg_binds = processed_binds, mg_rules = orphan_rules})
+
+
+simplifyExpr :: DynFlags -- includes spec of what core-to-core passes to do
+ -> CoreExpr
+ -> IO CoreExpr
+-- simplifyExpr is called by the driver to simplify an
+-- expression typed in at the interactive prompt
+simplifyExpr dflags expr
+ = do {
+ ; showPass dflags "Simplify"
+
+ ; us <- mkSplitUniqSupply 's'
+
+ ; let env = emptySimplEnv SimplGently [] emptyVarSet
+ (expr', _counts) = initSmpl dflags us (simplExprGently env expr)
+
+ ; dumpIfSet_dyn dflags Opt_D_dump_simpl "Simplified expression"
+ (pprCoreExpr expr')
+
+ ; return expr'
+ }
+
-doCorePasses stats us binds irs []
+doCorePasses :: DynFlags
+ -> RuleBase -- the main rule base
+ -> SimplCount -- simplifier stats
+ -> UniqSupply -- uniques
+ -> [CoreBind] -- local binds in (with rules attached)
+ -> [CoreToDo] -- which passes to do
+ -> IO (SimplCount, [CoreBind]) -- stats, binds, local orphan rules
+
+doCorePasses dflags rb stats us binds []
= return (stats, binds)
-doCorePasses stats us binds irs (to_do : to_dos)
+doCorePasses dflags rb stats us binds (to_do : to_dos)
= do
- let (us1, us2) = splitUniqSupply us
- (stats1, binds1) <- doCorePass us1 binds irs to_do
- doCorePasses (stats `plusSimplCount` stats1) us2 binds1 irs to_dos
-
-doCorePass us binds rb (CoreDoSimplify sw_chkr) = _scc_ "Simplify" simplifyPgm rb sw_chkr us binds
-doCorePass us binds rb CoreCSE = _scc_ "CommonSubExpr" noStats (cseProgram binds)
-doCorePass us binds rb CoreLiberateCase = _scc_ "LiberateCase" noStats (liberateCase binds)
-doCorePass us binds rb CoreDoFloatInwards = _scc_ "FloatInwards" noStats (floatInwards binds)
-doCorePass us binds rb (CoreDoFloatOutwards f) = _scc_ "FloatOutwards" noStats (floatOutwards f us binds)
-doCorePass us binds rb CoreDoStaticArgs = _scc_ "StaticArgs" noStats (doStaticArgs us binds)
-doCorePass us binds rb CoreDoStrictness = _scc_ "Stranal" noStats (saBinds binds)
-doCorePass us binds rb CoreDoWorkerWrapper = _scc_ "WorkWrap" noStats (wwTopBinds us binds)
-doCorePass us binds rb CoreDoSpecialising = _scc_ "Specialise" noStats (specProgram us binds)
-doCorePass us binds rb CoreDoCPResult = _scc_ "CPResult" noStats (cprAnalyse binds)
-doCorePass us binds rb CoreDoPrintCore = _scc_ "PrintCore" noStats (printCore binds)
-doCorePass us binds rb CoreDoUSPInf
- = _scc_ "CoreUsageSPInf"
- if opt_UsageSPOn then
- noStats (doUsageSPInf us binds)
- else
- trace "WARNING: ignoring requested -fusagesp pass; requires -fusagesp-on" $
- noStats (return binds)
+ let (us1, us2) = splitUniqSupply us
+
+ (stats1, binds1) <- doCorePass dflags rb us1 binds to_do
+
+ doCorePasses dflags rb (stats `plusSimplCount` stats1) us2 binds1 to_dos
+
+doCorePass dfs rb us binds (CoreDoSimplify mode switches)
+ = _scc_ "Simplify" simplifyPgm dfs rb mode switches us binds
+doCorePass dfs rb us binds CoreCSE
+ = _scc_ "CommonSubExpr" noStats dfs (cseProgram dfs binds)
+doCorePass dfs rb us binds CoreLiberateCase
+ = _scc_ "LiberateCase" noStats dfs (liberateCase dfs binds)
+doCorePass dfs rb us binds CoreDoFloatInwards
+ = _scc_ "FloatInwards" noStats dfs (floatInwards dfs binds)
+doCorePass dfs rb us binds (CoreDoFloatOutwards f)
+ = _scc_ "FloatOutwards" noStats dfs (floatOutwards dfs f us binds)
+doCorePass dfs rb us binds CoreDoStaticArgs
+ = _scc_ "StaticArgs" noStats dfs (doStaticArgs us binds)
+doCorePass dfs rb us binds CoreDoStrictness
+ = _scc_ "Stranal" noStats dfs (dmdAnalPgm dfs binds)
+doCorePass dfs rb us binds CoreDoWorkerWrapper
+ = _scc_ "WorkWrap" noStats dfs (wwTopBinds dfs us binds)
+doCorePass dfs rb us binds CoreDoSpecialising
+ = _scc_ "Specialise" noStats dfs (specProgram dfs us binds)
+doCorePass dfs rb us binds CoreDoSpecConstr
+ = _scc_ "SpecConstr" noStats dfs (specConstrProgram dfs us binds)
+#ifdef OLD_STRICTNESS
+doCorePass dfs rb us binds CoreDoOldStrictness
+ = _scc_ "OldStrictness" noStats dfs (doOldStrictness dfs binds)
+#endif
+doCorePass dfs rb us binds CoreDoPrintCore
+ = _scc_ "PrintCore" noStats dfs (printCore binds)
+doCorePass dfs rb us binds CoreDoGlomBinds
+ = noStats dfs (glomBinds dfs binds)
+doCorePass dfs rb us binds (CoreDoRuleCheck phase pat)
+ = noStats dfs (ruleCheck dfs phase pat binds)
+doCorePass dfs rb us binds CoreDoNothing
+ = noStats dfs (return binds)
+
+#ifdef OLD_STRICTNESS
+doOldStrictness dfs binds
+ = do binds1 <- saBinds dfs binds
+ binds2 <- cprAnalyse dfs binds1
+ return binds2
+#endif
printCore binds = do dumpIfSet True "Print Core"
(pprCoreBindings binds)
return binds
-noStats thing = do { result <- thing; return (zeroSimplCount, result) }
+ruleCheck dflags phase pat binds = do showPass dflags "RuleCheck"
+ printDump (ruleCheckProgram phase pat binds)
+ return binds
+
+-- most passes return no stats and don't change rules
+noStats dfs thing = do { binds <- thing; return (zeroSimplCount dfs, binds) }
+
\end{code}
+
%************************************************************************
%* *
\subsection{Dealing with rules}
%* *
%************************************************************************
-We must do some gentle simplifiation on the template (but not the RHS)
+-- prepareLocalRuleBase takes the CoreBinds and rules defined in this module.
+-- It attaches those rules that are for local Ids to their binders, and
+-- returns the remainder attached to Ids in an IdSet. It also returns
+-- Ids mentioned on LHS of some rule; these should be blacklisted.
+
+-- The rule Ids and LHS Ids are black-listed; that is, they aren't inlined
+-- so that the opportunity to apply the rule isn't lost too soon
+
+\begin{code}
+prepareRules :: HscEnv
+ -> ModGuts
+ -> UniqSupply
+ -> IO (RuleBase, -- Full rule base
+ IdSet, -- Local rule Ids
+ [IdCoreRule]) -- Orphan rules defined in this module
+
+prepareRules hsc_env@(HscEnv { hsc_dflags = dflags, hsc_HPT = hpt })
+ guts@(ModGuts { mg_binds = binds, mg_rules = local_rules, mg_module = this_mod })
+ us
+ = do { pkg_rule_base <- loadImportedRules hsc_env guts
+
+ ; let env = emptySimplEnv SimplGently [] local_ids
+ (better_rules,_) = initSmpl dflags us (mapSmpl (simplRule env) local_rules)
+
+ imp_rule_base = foldl add_rules pkg_rule_base (moduleEnvElts hpt)
+ full_rule_base = extendRuleBaseList imp_rule_base better_rules
+
+ (local_rule_ids, final_rule_base) = getLocalRules this_mod full_rule_base
+ -- NB: the imported rules may include rules for Ids in this module
+ -- which is why we suck the local rules out of full_rule_base
+
+ orphan_rules = filter (not . idIsFrom this_mod . fst) better_rules
+
+ ; dumpIfSet_dyn dflags Opt_D_dump_rules "Transformation rules"
+ (vcat [text "Local rules", pprIdRules better_rules,
+ text "",
+ text "Imported rules", pprRuleBase final_rule_base])
+
+ ; return (final_rule_base, local_rule_ids, orphan_rules)
+ }
+ where
+ add_rules rule_base mod_info = extendRuleBaseList rule_base (md_rules (hm_details mod_info))
+
+ -- Boringly, we need to gather the in-scope set.
+ local_ids = foldr (unionVarSet . mkVarSet . bindersOf) emptyVarSet binds
+
+
+updateBinders :: IdSet -- Locally defined ids with their Rules attached
+ -> [CoreBind] -> [CoreBind]
+ -- A horrible function
+
+-- Update the binders of top-level bindings by
+-- attaching the rules for each locally-defined Id to that Id.
+--
+-- Reason
+-- - It makes the rules easier to look up
+-- - It means that transformation rules and specialisations for
+-- locally defined Ids are handled uniformly
+-- - It keeps alive things that are referred to only from a rule
+-- (the occurrence analyser knows about rules attached to Ids)
+-- - It makes sure that, when we apply a rule, the free vars
+-- of the RHS are more likely to be in scope
+
+updateBinders rule_ids binds
+ = map update_bndrs binds
+ where
+ update_bndrs (NonRec b r) = NonRec (update_bndr b) r
+ update_bndrs (Rec prs) = Rec [(update_bndr b, r) | (b,r) <- prs]
+
+ update_bndr bndr = case lookupVarSet rule_ids bndr of
+ Nothing -> bndr
+ Just id -> bndr `setIdSpecialisation` idSpecialisation id
+\end{code}
+
+
+We must do some gentle simplification on the template (but not the RHS)
of each rule. The case that forced me to add this was the fold/build rule,
which without simplification looked like:
fold k z (build (/\a. g a)) ==> ...
This doesn't match unless you do eta reduction on the build argument.
\begin{code}
-simplRules :: UniqSupply -> [ProtoCoreRule] -> [CoreBind] -> IO [ProtoCoreRule]
-simplRules us rules binds
- = do let (better_rules,_) = initSmpl sw_chkr us bind_vars black_list_all (mapSmpl simplRule rules)
-
- dumpIfSet opt_D_dump_rules
- "Transformation rules"
- (vcat (map pprProtoCoreRule better_rules))
-
- return better_rules
- where
- black_list_all v = not (isDataConWrapId v)
- -- This stops all inlining except the
- -- wrappers for data constructors
-
- sw_chkr any = SwBool False -- A bit bogus
-
- -- Boringly, we need to gather the in-scope set.
- -- Typically this thunk won't even be force, but the test in
- -- simpVar fails if it isn't right, and it might conceivably matter
- bind_vars = foldr (unionVarSet . mkVarSet . bindersOf) emptyVarSet binds
-
-
-simplRule rule@(ProtoCoreRule is_local id (Rule name bndrs args rhs))
- | not is_local
- = returnSmpl rule -- No need to fiddle with imported rules
- | otherwise
- = simplBinders bndrs $ \ bndrs' ->
- mapSmpl simpl_arg args `thenSmpl` \ args' ->
- simplExpr rhs `thenSmpl` \ rhs' ->
- returnSmpl (ProtoCoreRule is_local id (Rule name bndrs' args' rhs'))
-
-simpl_arg e
--- I've seen rules in which a LHS like
+simplRule env rule@(id, BuiltinRule _ _)
+ = returnSmpl rule
+simplRule env rule@(id, Rule act name bndrs args rhs)
+ = simplBinders env bndrs `thenSmpl` \ (env, bndrs') ->
+ mapSmpl (simplExprGently env) args `thenSmpl` \ args' ->
+ simplExprGently env rhs `thenSmpl` \ rhs' ->
+ returnSmpl (id, Rule act name bndrs' args' rhs')
+
+-- It's important that simplExprGently does eta reduction.
+-- For example, in a rule like:
-- augment g (build h)
--- turns into
+-- we do not want to get
-- augment (\a. g a) (build h)
--- So it's a help to eta-reduce the args as we simplify them.
--- Otherwise we don't match when given an argument like
+-- otherwise we don't match when given an argument like
-- (\a. h a a)
- = simplExpr e `thenSmpl` \ e' ->
- returnSmpl (etaReduceExpr e')
+--
+-- The simplifier does indeed do eta reduction (it's in
+-- Simplify.completeLam) but only if -O is on.
\end{code}
+\begin{code}
+simplExprGently :: SimplEnv -> CoreExpr -> SimplM CoreExpr
+-- Simplifies an expression
+-- does occurrence analysis, then simplification
+-- and repeats (twice currently) because one pass
+-- alone leaves tons of crud.
+-- Used (a) for user expressions typed in at the interactive prompt
+-- (b) the LHS and RHS of a RULE
+--
+-- The name 'Gently' suggests that the SimplifierMode is SimplGently,
+-- and in fact that is so.... but the 'Gently' in simplExprGently doesn't
+-- enforce that; it just simplifies the expression twice
+
+simplExprGently env expr
+ = simplExpr env (occurAnalyseGlobalExpr expr) `thenSmpl` \ expr1 ->
+ simplExpr env (occurAnalyseGlobalExpr expr1)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Glomming}
+%* *
+%************************************************************************
+
+\begin{code}
+glomBinds :: DynFlags -> [CoreBind] -> IO [CoreBind]
+-- Glom all binds together in one Rec, in case any
+-- transformations have introduced any new dependencies
+--
+-- NB: the global invariant is this:
+-- *** the top level bindings are never cloned, and are always unique ***
+--
+-- We sort them into dependency order, but applying transformation rules may
+-- make something at the top refer to something at the bottom:
+-- f = \x -> p (q x)
+-- h = \y -> 3
+--
+-- RULE: p (q x) = h x
+--
+-- Applying this rule makes f refer to h,
+-- although it doesn't appear to in the source program.
+-- This pass lets us control where it happens.
+--
+-- NOTICE that this cannot happen for rules whose head is a locally-defined
+-- function. It only happens for rules whose head is an imported function
+-- (p in the example above). So, for example, the rule had been
+-- RULE: f (p x) = h x
+-- then the rule for f would be attached to f itself (in its IdInfo)
+-- by prepareLocalRuleBase and h would be regarded by the occurrency
+-- analyser as free in f.
+
+glomBinds dflags binds
+ = do { showPass dflags "GlomBinds" ;
+ let { recd_binds = [Rec (flattenBinds binds)] } ;
+ return recd_binds }
+ -- Not much point in printing the result...
+ -- just consumes output bandwidth
+\end{code}
+
+
%************************************************************************
%* *
\subsection{The driver for the simplifier}
%************************************************************************
\begin{code}
-simplifyPgm :: RuleBase
- -> (SimplifierSwitch -> SwitchResult)
+simplifyPgm :: DynFlags
+ -> RuleBase
+ -> SimplifierMode
+ -> [SimplifierSwitch]
-> UniqSupply
- -> [CoreBind] -- Input
- -> IO (SimplCount, [CoreBind]) -- New bindings
+ -> [CoreBind] -- Input
+ -> IO (SimplCount, [CoreBind]) -- New bindings
-simplifyPgm (imported_rule_ids, rule_lhs_fvs)
- sw_chkr us binds
+simplifyPgm dflags rule_base
+ mode switches us binds
= do {
- beginPass "Simplify";
-
- -- Glom all binds together in one Rec, in case any
- -- transformations have introduced any new dependencies
- --
- -- NB: the global invariant is this:
- -- *** the top level bindings are never cloned, and are always unique ***
- --
- -- We sort them into dependency order, but applying transformation rules may
- -- make something at the top refer to something at the bottom:
- -- f = \x -> p (q x)
- -- h = \y -> 3
- --
- -- RULE: p (q x) = h x
- --
- -- Applying this rule makes f refer to h, although it doesn't appear to in the
- -- source program. Our solution is to do this occasional glom-together step,
- -- just once per overall simplfication step.
-
- let { recd_binds = [Rec (flattenBinds binds)] };
-
- (termination_msg, it_count, counts_out, binds') <- iteration us 1 zeroSimplCount recd_binds;
-
- dumpIfSet (opt_D_verbose_core2core && opt_D_dump_simpl_stats)
+ showPass dflags "Simplify";
+
+ (termination_msg, it_count, counts_out, binds')
+ <- iteration us 1 (zeroSimplCount dflags) binds;
+
+ dumpIfSet (dopt Opt_D_verbose_core2core dflags
+ && dopt Opt_D_dump_simpl_stats dflags)
"Simplifier statistics"
(vcat [text termination_msg <+> text "after" <+> ppr it_count <+> text "iterations",
text "",
pprSimplCount counts_out]);
- endPass "Simplify"
- (opt_D_verbose_core2core && not opt_D_dump_simpl_iterations)
- binds' ;
+ endPass dflags "Simplify" Opt_D_verbose_core2core binds';
return (counts_out, binds')
}
where
- max_iterations = getSimplIntSwitch sw_chkr MaxSimplifierIterations
- black_list_fn = blackListed rule_lhs_fvs (intSwitchSet sw_chkr SimplInlinePhase)
-
- core_iter_dump binds | opt_D_verbose_core2core = pprCoreBindings binds
- | otherwise = empty
-
+ phase_info = case mode of
+ SimplGently -> "gentle"
+ SimplPhase n -> show n
+
+ imported_rule_ids = ruleBaseIds rule_base
+ simpl_env = emptySimplEnv mode switches imported_rule_ids
+ sw_chkr = getSwitchChecker simpl_env
+ max_iterations = intSwitchSet sw_chkr MaxSimplifierIterations `orElse` 2
+
iteration us iteration_no counts binds
+ -- iteration_no is the number of the iteration we are
+ -- about to begin, with '1' for the first
+ | iteration_no > max_iterations -- Stop if we've run out of iterations
+ = do {
+#ifdef DEBUG
+ if max_iterations > 2 then
+ hPutStr stderr ("NOTE: Simplifier still going after " ++
+ show max_iterations ++
+ " iterations; bailing out.\n")
+ else
+ return ();
+#endif
+ -- Subtract 1 from iteration_no to get the
+ -- number of iterations we actually completed
+ return ("Simplifier baled out", iteration_no - 1, counts, binds)
+ }
+
+ -- Try and force thunks off the binds; significantly reduces
+ -- space usage, especially with -O. JRS, 000620.
+ | let sz = coreBindsSize binds in sz == sz
= do {
-- Occurrence analysis
let { tagged_binds = _scc_ "OccAnal" occurAnalyseBinds binds } ;
- dumpIfSet opt_D_dump_occur_anal "Occurrence analysis"
+ dumpIfSet_dyn dflags Opt_D_dump_occur_anal "Occurrence analysis"
(pprCoreBindings tagged_binds);
- -- Simplify
- let { (binds', counts') = initSmpl sw_chkr us1 imported_rule_ids
- black_list_fn
- (simplTopBinds tagged_binds);
+ -- SIMPLIFY
+ -- We do this with a *case* not a *let* because lazy pattern
+ -- matching bit us with bad space leak!
+ -- With a let, we ended up with
+ -- let
+ -- t = initSmpl ...
+ -- counts' = snd t
+ -- in
+ -- case t of {(_,counts') -> if counts'=0 then ... }
+ -- So the conditional didn't force counts', because the
+ -- selection got duplicated. Sigh!
+ case initSmpl dflags us1 (simplTopBinds simpl_env tagged_binds) of {
+ (binds', counts') -> do {
-- The imported_rule_ids are used by initSmpl to initialise
-- the in-scope set. That way, the simplifier will change any
-- occurrences of the imported id to the one in the imported_rule_ids
-- set, which are decorated with their rules.
- all_counts = counts `plusSimplCount` counts'
- } ;
+ let { all_counts = counts `plusSimplCount` counts' ;
+ herald = "Simplifier phase " ++ phase_info ++
+ ", iteration " ++ show iteration_no ++
+ " out of " ++ show max_iterations
+ } ;
-- Stop if nothing happened; don't dump output
if isZeroSimplCount counts' then
else do {
-- Dump the result of this iteration
- dumpIfSet opt_D_dump_simpl_iterations
- ("Simplifier iteration " ++ show iteration_no
- ++ " out of " ++ show max_iterations)
- (pprSimplCount counts') ;
-
- if opt_D_dump_simpl_iterations then
- endPass ("Simplifier iteration " ++ show iteration_no ++ " result")
- opt_D_verbose_core2core
- binds'
- else
- return [] ;
-
- -- Stop if we've run out of iterations
- if iteration_no == max_iterations then
- do {
-#ifdef DEBUG
- if max_iterations > 2 then
- hPutStr stderr ("NOTE: Simplifier still going after " ++
- show max_iterations ++
- " iterations; bailing out.\n")
- else
-#endif
- return ();
+ dumpIfSet_dyn dflags Opt_D_dump_simpl_iterations herald
+ (pprSimplCount counts') ;
- return ("Simplifier baled out", iteration_no, all_counts, binds')
- }
+ endPass dflags herald Opt_D_dump_simpl_iterations binds' ;
- -- Else loop
- else iteration us2 (iteration_no + 1) all_counts binds'
- } }
+ -- Loop
+ iteration us2 (iteration_no + 1) all_counts binds'
+ } } } }
where
(us1, us2) = splitUniqSupply us
\end{code}
projects / ghc-hetmet.git / blobdiff