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* Modules: Core operations (#13009)Sylvain Henry2020-03-184-3916/+0
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* Modules: Core (#13009)Sylvain Henry2020-03-164-18/+18
| | | | Update submodule: haddock
* Comments onlySimon Peyton Jones2020-03-101-0/+6
| | | | Clarify code added in #17852 and MR !2724
* Modules: Core (#13009)Sylvain Henry2020-02-264-22/+22
| | | | Update haddock submodule
* Modules: Driver (#13009)Sylvain Henry2020-02-214-4/+4
| | | | submodule updates: nofib, haddock
* Normalize types when dropping absent arguments from workersAlexis King2020-02-201-7/+9
| | | | fixes #17852
* Separate CPR analysis from the Demand analyserwip/sep-cprSebastian Graf2020-02-124-387/+754
| | | | | | | | | | | | | | | | | | | The reasons for that can be found in the wiki: https://gitlab.haskell.org/ghc/ghc/wikis/nested-cpr/split-off-cpr We now run CPR after demand analysis (except for after the final demand analysis run just before code gen). CPR got its own dump flags (`-ddump-cpr-anal`, `-ddump-cpr-signatures`), but not its own flag to activate/deactivate. It will run with `-fstrictness`/`-fworker-wrapper`. As explained on the wiki page, this step is necessary for a sane Nested CPR analysis. And it has quite positive impact on compiler performance: Metric Decrease: T9233 T9675 T9961 T15263
* compiler: Qualify imports of Data.ListBen Gamari2020-02-081-1/+1
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* `-ddump-str-signatures` dumps Text, not STG [skip ci]Sebastian Graf2020-01-251-1/+1
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* Revert "`exprOkForSpeculation` for Note [IO hack in the demand analyser]"Sebastian Graf2020-01-161-11/+11
| | | | | | | | | | | | | This reverts commit ce64b397777408731c6dd3f5c55ea8415f9f565b on the grounds of the regression it would introduce in a couple of packages. Fixes #17653. Also undoes a slight metric increase in #13701 introduced by that commit that we didn't see prior to !1983. Metric Decrease: T13701
* Fix more typos, via an improved Levenshtein-style correctorBrian Wignall2020-01-121-2/+2
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* Fix typos, via a Levenshtein-style correctorBrian Wignall2020-01-041-1/+1
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* Module hierarchy (#13009): StgSylvain Henry2019-12-311-1/+1
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* Add GHC-API logging hooksSylvain Henry2019-12-181-3/+3
| | | | | | | | | | | | | | | | | | | | | | | * Add 'dumpAction' hook to DynFlags. It allows GHC API users to catch dumped intermediate codes and information. The format of the dump (Core, Stg, raw text, etc.) is now reported allowing easier automatic handling. * Add 'traceAction' hook to DynFlags. Some dumps go through the trace mechanism (for instance unfoldings that have been considered for inlining). This is problematic because: 1) dumps aren't written into files even with -ddump-to-file on 2) dumps are written on stdout even with GHC API 3) in this specific case, dumping depends on unsafe globally stored DynFlags which is bad for GHC API users We introduce 'traceAction' hook which allows GHC API to catch those traces and to avoid using globally stored DynFlags. * Avoid dumping empty logs via dumpAction/traceAction (but still write empty files to keep the existing behavior)
* Better arity for join pointsSimon Peyton Jones2019-10-281-2/+17
| | | | | | A join point was getting too large an arity, leading to #17294. I've tightened up the invariant: see CoreSyn, Note [Invariants on join points], invariant 2b
* Break up TcRnTypes, among other modules.Richard Eisenberg2019-10-161-0/+1
| | | | | | | | | | | | | | | | | | | | | This introduces three new modules: - basicTypes/Predicate.hs describes predicates, moving this logic out of Type. Predicates don't really exist in Core, and so don't belong in Type. - typecheck/TcOrigin.hs describes the origin of constraints and types. It was easy to remove from other modules and can often be imported instead of other, scarier modules. - typecheck/Constraint.hs describes constraints as used in the solver. It is taken from TcRnTypes. No work other than module splitting is in this patch. This is the first step toward homogeneous equality, which will rely more strongly on predicates. And homogeneous equality is the next step toward a dependently typed core language.
* `exprOkForSpeculation` for Note [IO hack in the demand analyser]Sebastian Graf2019-09-281-11/+11
| | | | | | | | | | | | | | | | | | In #14998 I realised that the notion of speculative execution *exactly matches* eager evaluation of expressions in a case alternative where the scrutinee is an IO action. Normally we have to `deferIO` any result from that single case alternative to prevent this speculative execution, so we had a special case in place in the demand analyser that would check if the scrutinee was a prim-op, in which case we assumed that it would be ok to do the eager evaluation. Now we just check if the scrutinee is `exprOkForSpeculation`, corresponding to the notion that we want to push evaluation of the scrutinee *after* eagerly evaluating stuff from the case alternative. This fixes #14988, because it resolves the last open Item 4 there.
* Fix bogus type of case expressionwip/T17056Simon Peyton Jones2019-09-201-5/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issue #17056 revealed that we were sometimes building a case expression whose type field (in the Case constructor) was bogus. Consider a phantom type synonym type S a = Int and we want to form the case expression case x of K (a::*) -> (e :: S a) We must not make the type field of the Case constructor be (S a) because 'a' isn't in scope. We must instead expand the synonym. Changes in this patch: * Expand synonyms in the new function CoreUtils.mkSingleAltCase. * Use mkSingleAltCase in MkCore.wrapFloat, which was the proximate source of the bug (when called by exprIsConApp_maybe) * Use mkSingleAltCase elsewhere * Documentation CoreSyn new invariant (6) in Note [Case expression invariants] CoreSyn Note [Why does Case have a 'Type' field?] CoreUtils Note [Care with the type of a case expression] * I improved Core Lint's error reporting, which was pretty confusing in this case, because it didn't mention that the offending type was the return type of a case expression. * A little bit of cosmetic refactoring in CoreUtils
* Compute demand signatures assuming idAritySebastian Graf2019-04-303-101/+239
| | | | | | | | | | | | | | | | | | | | | | | | | | | | This does four things: 1. Look at `idArity` instead of manifest lambdas to decide whether to use LetUp 2. Compute the strictness signature in LetDown assuming at least `idArity` incoming arguments 3. Remove the special case for trivial RHSs, which is subsumed by 2 4. Don't perform the W/W split when doing so would eta expand a binding. Otherwise we would eta expand PAPs, causing unnecessary churn in the Simplifier. NoFib Results -------------------------------------------------------------------------------- Program Allocs Instrs -------------------------------------------------------------------------------- fannkuch-redux +0.3% 0.0% gg -0.0% -0.1% maillist +0.2% +0.2% minimax 0.0% +0.8% pretty 0.0% -0.1% reptile -0.0% -1.2% -------------------------------------------------------------------------------- Min -0.0% -1.2% Max +0.3% +0.8% Geometric Mean +0.0% -0.0%
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-153-22/+22
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Always do the worker/wrapper split for NOINLINEsSebastian Graf2019-03-071-0/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trac #10069 revealed that small NOINLINE functions didn't get split into worker and wrapper. This was due to `certainlyWillInline` saying that any unfoldings with a guidance of `UnfWhen` inline unconditionally. That isn't the case for NOINLINE functions, so we catch this case earlier now. Nofib results: -------------------------------------------------------------------------------- Program Allocs Instrs -------------------------------------------------------------------------------- fannkuch-redux -0.3% 0.0% gg +0.0% +0.1% maillist -0.2% -0.2% minimax 0.0% -0.8% -------------------------------------------------------------------------------- Min -0.3% -0.8% Max +0.0% +0.1% Geometric Mean -0.0% -0.0% Fixes #10069. ------------------------- Metric Increase: T9233 -------------------------
* Remove ExnStr and ThrowsExn businessSebastian Graf2019-02-011-1/+1
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* Stomp a few typos and grammarosGabor Greif2018-12-171-2/+2
| | | | Also use 'id'
* Remove another unused import from WwLibSimon Peyton Jones2018-12-131-1/+1
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* Remove dead codeSimon Peyton Jones2018-12-121-14/+0
| | | | | | | This is a follow-up to d77501cd5b Improvements to demand analysis I forgot to remove some now-dead code
* Improvements to demand analysisSimon Peyton Jones2018-12-122-66/+175
| | | | | | | | | | | | | | | | | | | | | | | | This patch collects a few improvements triggered by Trac #15696, and fixing Trac #16029 * Stop making toCleanDmd behave specially for unlifted types. This special case was the cause of stupid behaviour in Trac #16029. And to my joy I discovered the let/app invariant rendered it unnecessary. (Maybe the special case pre-dated the let/app invariant.) Result: less special-case handling in the compiler, and better perf for the compiled code. * In WwLib.mkWWstr_one, treat seqDmd like U(AAA). It was not being so treated before, which again led to stupid code. * Update and improve Notes There are .stderr test wibbles because we get slightly different strictness signatures for an argumment of unlifted type: <L,U> rather than <S,U> for Int# <S,U> rather than <S(S),U(U)> for Int
* dmdAnal: Move handling of datacon strictness to mkWWstr_oneBen Gamari2018-12-112-59/+81
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously datacon strictness was accounted for when we demand analysed a case analysis. However, this results in pessimistic demands in some cases. For instance, consider the program (from T10482) data family Bar a data instance Bar (a, b) = BarPair !(Bar a) !(Bar b) newtype instance Bar Int = Bar Int foo :: Bar ((Int, Int), Int) -> Int -> Int foo f k = case f of BarPair x y -> case burble of True -> case x of BarPair p q -> ... False -> ... We really should be able to assume that `p` is already evaluated since it came from a strict field of BarPair. However, as written the demand analyser can not conclude this since we may end up in the False branch of the case on `burble` (which places no demand on `x`). By accounting for the data con strictness later, applied to the demand of the RHS, we get the strict demand signature we want. See Note [Add demands for strict constructors] for a more comprehensive discussion. Test Plan: Validate Reviewers: simonpj, osa1, goldfire Subscribers: rwbarton, carter GHC Trac Issues: #15696 Differential Revision: https://phabricator.haskell.org/D5226
* Rename literal constructorsSylvain Henry2018-11-221-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | In a previous patch we replaced some built-in literal constructors (MachInt, MachWord, etc.) with a single LitNumber constructor. In this patch we replace the `Mach` prefix of the remaining constructors with `Lit` for consistency (e.g., LitChar, LitLabel, etc.). Sadly the name `LitString` was already taken for a kind of FastString and it would become misleading to have both `LitStr` (literal constructor renamed after `MachStr`) and `LitString` (FastString variant). Hence this patch renames the FastString variant `PtrString` (which is more accurate) and the literal string constructor now uses the least surprising `LitString` name. Both `Literal` and `LitString/PtrString` have recently seen breaking changes so doing this kind of renaming now shouldn't harm much. Reviewers: hvr, goldfire, bgamari, simonmar, jrtc27, tdammers Subscribers: tdammers, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4881
* Fix cardinality change of fields in addDataConStrictnessÖmer Sinan Ağacan2018-10-151-1/+1
| | | | | | | | | | | | Test Plan: This validates Reviewers: simonpj, bgamari Reviewed By: bgamari Subscribers: rwbarton, carter Differential Revision: https://phabricator.haskell.org/D5225
* Add RubbishLit for absent bindings of UnliftedRepSebastian Graf2018-10-141-10/+26
| | | | | | | | | | | | | | | | | | | | | | | | | Summary: Trac #9279 reminded us that the worker wrapper transformation copes really badly with absent unlifted boxed bindings. As `Note [Absent errors]` in WwLib.hs points out, we can't just use `absentError` for unlifted bindings because there is no bottom to hide the error in. So instead, we synthesise a new `RubbishLit` of type `forall (a :: TYPE 'UnliftedRep). a`, which code-gen may subsitute for any boxed value. We choose `()`, so that there is a good chance that the program crashes instead instead of leading to corrupt data, should absence analysis have been too optimistic (#11126). Reviewers: simonpj, hvr, goldfire, bgamari, simonmar Reviewed By: simonpj Subscribers: osa1, rwbarton, carter GHC Trac Issues: #15627, #9279, #4306, #11126 Differential Revision: https://phabricator.haskell.org/D5153
* Define activeAfterInitial, activeDuringFinalSimon Peyton Jones2018-09-051-2/+2
| | | | | | | This is pure refactoring, just adding a couple of definitions to BasicTypes, and using them. Plus some whitespace stuff.
* Replace most occurences of foldl with foldl'.klebinger.andreas@gmx.at2018-08-211-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds foldl' to GhcPrelude and changes must occurences of foldl to foldl'. This leads to better performance especially for quick builds where GHC does not perform strictness analysis. It does change strictness behaviour when we use foldl' to turn a argument list into function applications. But this is only a drawback if code looks ONLY at the last argument but not at the first. And as the benchmarks show leads to fewer allocations in practice at O2. Compiler performance for Nofib: O2 Allocations: -1 s.d. ----- -0.0% +1 s.d. ----- -0.0% Average ----- -0.0% O2 Compile Time: -1 s.d. ----- -2.8% +1 s.d. ----- +1.3% Average ----- -0.8% O0 Allocations: -1 s.d. ----- -0.2% +1 s.d. ----- -0.1% Average ----- -0.2% Test Plan: ci Reviewers: goldfire, bgamari, simonmar, tdammers, monoidal Reviewed By: bgamari, monoidal Subscribers: tdammers, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4929
* Revert "Don't inline functions with RULES too early"Ben Gamari2018-08-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit causes significant performance regressions: ``` bytes allocated value is too high: Expected T9872d(normal) bytes allocated: 578498120 +/-5% Lower bound T9872d(normal) bytes allocated: 549573214 Upper bound T9872d(normal) bytes allocated: 607423026 Actual T9872d(normal) bytes allocated: 677179968 Deviation T9872d(normal) bytes allocated: 17.1 % bytes allocated value is too high: Expected T9872c(normal) bytes allocated: 3096670112 +/-5% Lower bound T9872c(normal) bytes allocated: 2941836606 Upper bound T9872c(normal) bytes allocated: 3251503618 Actual T9872c(normal) bytes allocated: 3601872536 Deviation T9872c(normal) bytes allocated: 16.3 % bytes allocated value is too high: Expected T9872b(normal) bytes allocated: 3730686224 +/-5% Lower bound T9872b(normal) bytes allocated: 3544151912 Upper bound T9872b(normal) bytes allocated: 3917220536 Actual T9872b(normal) bytes allocated: 4374298272 Deviation T9872b(normal) bytes allocated: 17.3 % bytes allocated value is too high: Expected T9872a(normal) bytes allocated: 2729927408 +/-5% Lower bound T9872a(normal) bytes allocated: 2593431037 Upper bound T9872a(normal) bytes allocated: 2866423779 Actual T9872a(normal) bytes allocated: 3225788896 Deviation T9872a(normal) bytes allocated: 18.2 % ``` It's not clear that this was intentional so I'm going to revert for now. This reverts commit 2110738b280543698407924a16ac92b6d804dc36.
* Don't inline functions with RULES too earlySimon Peyton Jones2018-07-311-2/+2
| | | | | | | | | Trac #15445 showed that a function with an automatically generated specialisation RULE coudl be inlined before the RULE had a chance to fire. This patch attaches a NOINLINE[2] activation to the Id, to stop this happening.
* WorkWrap: Rip out unsafeGlobalDynFlags usage in mkWwInlineRuleBen Gamari2018-06-071-1/+1
| | | | | | Subscribers: rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4775
* Conservatively estimate levity in worker/wrapperBen Gamari2018-06-021-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | The worker/wrapper transform needs to determine the levity of the result to determine whether it needs to introduce a lambda to preserve laziness of the result. For this is previously used isUnliftedType. However, this may fail in the presence of levity polymorphism. We now instead use isLiftedType_maybe, assuming that a lambda is needed if the levity of the result cannot be determined. Fixes #15186. Test Plan: make test=T15186 Reviewers: simonpj, goldfire, tdammers Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #15186 Differential Revision: https://phabricator.haskell.org/D4755
* Do not unpack class dictionaries with INLINABLESimon Peyton Jones2018-04-262-28/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Matthew Pickering uncovered a bad performance hole in the way that single-method dictionaries work, described in Trac #14955. See Note [Do not unpack class dictionaries] in WwLib. I tried to fix this 6 years ago, but got it slightly wrong. This patch fixes it, which makes a dramatic improvement in the test case. Nofib highlights: not much happening: Program Size Allocs Runtime Elapsed TotalMem ----------------------------------------------------------------- VSM -0.3% +2.7% -7.4% -7.4% 0.0% cacheprof -0.0% +0.1% +0.3% +0.7% 0.0% integer -0.0% +1.1% +7.5% +7.5% 0.0% tak -0.1% -0.2% 0.024 0.024 0.0% ----------------------------------------------------------------- Min -4.4% -0.2% -7.4% -7.4% -8.0% Max +0.6% +2.7% +7.5% +7.5% 0.0% Geom Mean -0.1% +0.0% +0.1% +0.1% -0.2% I investigated VSM. The patch unpacks class dictionaries a bit more than before (i.e. does so if there is no INLINABLE pragma). And that gives better code in VSM (less dictionary selection etc), but one closure gets one word bigger. I'll accept these changes in exchange for more robust performance. Some ghci.debugger output wobbled around (order of bindings being displayed). I have no idea why; but I accepted the changes.
* Inline wrappers earlierSimon Peyton Jones2018-04-201-53/+84
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch has a single significant change: strictness wrapper functions are inlined earlier, in phase 2 rather than phase 0. As shown by Trac #15056, this gives a better chance for RULEs to fire. Before this change, a function that would have inlined early without strictness analyss was instead inlining late. Result: applying "optimisation" made the program worse. This does not make too much difference in nofib, but I've stumbled over the problem more than once, so even a "no-change" result would be quite acceptable. Here are the headlines: -------------------------------------------------------------------------------- Program Size Allocs Runtime Elapsed TotalMem -------------------------------------------------------------------------------- cacheprof -0.5% -0.5% +2.5% +2.5% 0.0% fulsom -1.0% +2.6% -0.1% -0.1% 0.0% mate -0.6% +2.4% -0.9% -0.9% 0.0% veritas -0.7% -23.2% 0.002 0.002 0.0% -------------------------------------------------------------------------------- Min -1.4% -23.2% -12.5% -15.3% 0.0% Max +0.6% +2.6% +4.4% +4.3% +19.0% Geometric Mean -0.7% -0.2% -1.4% -1.7% +0.2% * A worthwhile reduction in binary size. * Runtimes are not to be trusted much but look as if they are moving the right way. * A really big win in veritas, described in comment:1 of Trac #15056; more fusion rules fired. * I investigated the losses in 'mate' and 'fulsom'; see #15056.
* Fix grammaros in commentsGabor Greif2017-10-171-1/+1
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* Fix nasty bug in w/w for absence analysisSimon Peyton Jones2017-10-031-14/+23
| | | | | | | | | | | | | | | | | | | | This dark corner was exposed by Trac #14285. It involves the interaction between absence analysis and INLINABLE pragmas. There is a full explanation in Note [aBSENT_ERROR_ID] in MkCore, which you can read there. The changes in this patch are * Make exprIsHNF return True for absentError, treating absentError like an honorary data constructor. * Make absentError /not/ be diverging, unlike other error Ids. This is all a bit horrible. * While doing this I found that exprOkForSpeculation didn't have a case for value lambdas so I added one. It's not really called on lifted types much, but it seems like the right thing
* Comments onlySimon Peyton Jones2017-10-031-1/+1
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* A bunch of typofixesGabor Greif2017-09-261-1/+1
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* compiler: introduce custom "GhcPrelude" PreludeHerbert Valerio Riedel2017-09-193-0/+6
| | | | | | | | | | | | | | | | | | This switches the compiler/ component to get compiled with -XNoImplicitPrelude and a `import GhcPrelude` is inserted in all modules. This is motivated by the upcoming "Prelude" re-export of `Semigroup((<>))` which would cause lots of name clashes in every modulewhich imports also `Outputable` Reviewers: austin, goldfire, bgamari, alanz, simonmar Reviewed By: bgamari Subscribers: goldfire, rwbarton, thomie, mpickering, bgamari Differential Revision: https://phabricator.haskell.org/D3989
* Allow CSE'ing of work-wrapped bindings (#14186)Joachim Breitner2017-09-121-1/+5
| | | | | | | | the worker/wrapper creates an artificial INLINE pragma, which caused CSE to not do its work. We now recognize such artificial pragmas by using `NoUserInline` instead of `Inline` as the `InlineSpec`. Differential Revision: https://phabricator.haskell.org/D3939
* Zap stable unfoldings in worker/wrapperSimon Peyton Jones2017-06-281-2/+5
| | | | This patch fixes the buglet described in Trac #13890.
* Typos in comments [ci skip]Gabor Greif2017-05-051-8/+8
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* Improve demand analysis for join pointsSimon Peyton Jones2017-04-121-20/+62
| | | | | | | | | I realised (Trac #13543) that we can improve demand analysis for join point quite straightforwardly. The idea is explained in Note [Demand analysis for join points] in DmdAnal
* Add comments on DmdAnal space leak fixSimon Peyton Jones2017-04-061-0/+3
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* Stamp out space leaks from demand analysisReid Barton2017-04-011-1/+21
| | | | | | | | | | | | | | | | This reduces peak memory usage by ~30% on my test case (DynFlags), and (probably as a result of reduced GC work) decreases compilation time by a few percent as well. Also fix a bug in seqStrDmd so that demeand info is fully evaluated. Reviewers: simonpj, austin, bgamari Reviewed By: bgamari Subscribers: dfeuer, thomie Differential Revision: https://phabricator.haskell.org/D3400
* Broaden demand analysis IO hack notesDavid Feuer2017-03-131-4/+8
| | | | | | | | | | | | | | | The I/O hack for demand analysis has broader and arguably more important implications than the note expressed. Broaden it. [skip ci] Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: carter, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3307
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