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* Modules: Core (#13009)Sylvain Henry2020-02-261-2564/+0
| | | | Update haddock submodule
* Modules: Driver (#13009)Sylvain Henry2020-02-211-1/+1
| | | | submodule updates: nofib, haddock
* Separate CPR analysis from the Demand analyserwip/sep-cprSebastian Graf2020-02-121-1/+13
| | | | | | | | | | | | | | | | | | | 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
* Do CafInfo/SRT analysis in CmmÖmer Sinan Ağacan2020-01-311-124/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch removes all CafInfo predictions and various hacks to preserve predicted CafInfos from the compiler and assigns final CafInfos to interface Ids after code generation. SRT analysis is extended to support static data, and Cmm generator is modified to allow generating static_link fields after SRT analysis. This also fixes `-fcatch-bottoms`, which introduces error calls in case expressions in CorePrep, which runs *after* CoreTidy (which is where we decide on CafInfos) and turns previously non-CAFFY things into CAFFY. Fixes #17648 Fixes #9718 Evaluation ========== NoFib ----- Boot with: `make boot mode=fast` Run: `make mode=fast EXTRA_RUNTEST_OPTS="-cachegrind" NoFibRuns=1` -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- CS -0.0% 0.0% -0.0% -0.0% -0.0% CSD -0.0% 0.0% -0.0% -0.0% -0.0% FS -0.0% 0.0% -0.0% -0.0% -0.0% S -0.0% 0.0% -0.0% -0.0% -0.0% VS -0.0% 0.0% -0.0% -0.0% -0.0% VSD -0.0% 0.0% -0.0% -0.0% -0.5% VSM -0.0% 0.0% -0.0% -0.0% -0.0% anna -0.1% 0.0% -0.0% -0.0% -0.0% ansi -0.0% 0.0% -0.0% -0.0% -0.0% atom -0.0% 0.0% -0.0% -0.0% -0.0% awards -0.0% 0.0% -0.0% -0.0% -0.0% banner -0.0% 0.0% -0.0% -0.0% -0.0% bernouilli -0.0% 0.0% -0.0% -0.0% -0.0% binary-trees -0.0% 0.0% -0.0% -0.0% -0.0% boyer -0.0% 0.0% -0.0% -0.0% -0.0% boyer2 -0.0% 0.0% -0.0% -0.0% -0.0% bspt -0.0% 0.0% -0.0% -0.0% -0.0% cacheprof -0.0% 0.0% -0.0% -0.0% -0.0% calendar -0.0% 0.0% -0.0% -0.0% -0.0% cichelli -0.0% 0.0% -0.0% -0.0% -0.0% circsim -0.0% 0.0% -0.0% -0.0% -0.0% clausify -0.0% 0.0% -0.0% -0.0% -0.0% comp_lab_zift -0.0% 0.0% -0.0% -0.0% -0.0% compress -0.0% 0.0% -0.0% -0.0% -0.0% compress2 -0.0% 0.0% -0.0% -0.0% -0.0% constraints -0.0% 0.0% -0.0% -0.0% -0.0% cryptarithm1 -0.0% 0.0% -0.0% -0.0% -0.0% cryptarithm2 -0.0% 0.0% -0.0% -0.0% -0.0% cse -0.0% 0.0% -0.0% -0.0% -0.0% digits-of-e1 -0.0% 0.0% -0.0% -0.0% -0.0% digits-of-e2 -0.0% 0.0% -0.0% -0.0% -0.0% dom-lt -0.0% 0.0% -0.0% -0.0% -0.0% eliza -0.0% 0.0% -0.0% -0.0% -0.0% event -0.0% 0.0% -0.0% -0.0% -0.0% exact-reals -0.0% 0.0% -0.0% -0.0% -0.0% exp3_8 -0.0% 0.0% -0.0% -0.0% -0.0% expert -0.0% 0.0% -0.0% -0.0% -0.0% fannkuch-redux -0.0% 0.0% -0.0% -0.0% -0.0% fasta -0.0% 0.0% -0.0% -0.0% -0.0% fem -0.0% 0.0% -0.0% -0.0% -0.0% fft -0.0% 0.0% -0.0% -0.0% -0.0% fft2 -0.0% 0.0% -0.0% -0.0% -0.0% fibheaps -0.0% 0.0% -0.0% -0.0% -0.0% fish -0.0% 0.0% -0.0% -0.0% -0.0% fluid -0.1% 0.0% -0.0% -0.0% -0.0% fulsom -0.0% 0.0% -0.0% -0.0% -0.0% gamteb -0.0% 0.0% -0.0% -0.0% -0.0% gcd -0.0% 0.0% -0.0% -0.0% -0.0% gen_regexps -0.0% 0.0% -0.0% -0.0% -0.0% genfft -0.0% 0.0% -0.0% -0.0% -0.0% gg -0.0% 0.0% -0.0% -0.0% -0.0% grep -0.0% 0.0% -0.0% -0.0% -0.0% hidden -0.0% 0.0% -0.0% -0.0% -0.0% hpg -0.1% 0.0% -0.0% -0.0% -0.0% ida -0.0% 0.0% -0.0% -0.0% -0.0% infer -0.0% 0.0% -0.0% -0.0% -0.0% integer -0.0% 0.0% -0.0% -0.0% -0.0% integrate -0.0% 0.0% -0.0% -0.0% -0.0% k-nucleotide -0.0% 0.0% -0.0% -0.0% -0.0% kahan -0.0% 0.0% -0.0% -0.0% -0.0% knights -0.0% 0.0% -0.0% -0.0% -0.0% lambda -0.0% 0.0% -0.0% -0.0% -0.0% last-piece -0.0% 0.0% -0.0% -0.0% -0.0% lcss -0.0% 0.0% -0.0% -0.0% -0.0% life -0.0% 0.0% -0.0% -0.0% -0.0% lift -0.0% 0.0% -0.0% -0.0% -0.0% linear -0.1% 0.0% -0.0% -0.0% -0.0% listcompr -0.0% 0.0% -0.0% -0.0% -0.0% listcopy -0.0% 0.0% -0.0% -0.0% -0.0% maillist -0.0% 0.0% -0.0% -0.0% -0.0% mandel -0.0% 0.0% -0.0% -0.0% -0.0% mandel2 -0.0% 0.0% -0.0% -0.0% -0.0% mate -0.0% 0.0% -0.0% -0.0% -0.0% minimax -0.0% 0.0% -0.0% -0.0% -0.0% mkhprog -0.0% 0.0% -0.0% -0.0% -0.0% multiplier -0.0% 0.0% -0.0% -0.0% -0.0% n-body -0.0% 0.0% -0.0% -0.0% -0.0% nucleic2 -0.0% 0.0% -0.0% -0.0% -0.0% para -0.0% 0.0% -0.0% -0.0% -0.0% paraffins -0.0% 0.0% -0.0% -0.0% -0.0% parser -0.1% 0.0% -0.0% -0.0% -0.0% parstof -0.1% 0.0% -0.0% -0.0% -0.0% pic -0.0% 0.0% -0.0% -0.0% -0.0% pidigits -0.0% 0.0% -0.0% -0.0% -0.0% power -0.0% 0.0% -0.0% -0.0% -0.0% pretty -0.0% 0.0% -0.3% -0.4% -0.4% primes -0.0% 0.0% -0.0% -0.0% -0.0% primetest -0.0% 0.0% -0.0% -0.0% -0.0% prolog -0.0% 0.0% -0.0% -0.0% -0.0% puzzle -0.0% 0.0% -0.0% -0.0% -0.0% queens -0.0% 0.0% -0.0% -0.0% -0.0% reptile -0.0% 0.0% -0.0% -0.0% -0.0% reverse-complem -0.0% 0.0% -0.0% -0.0% -0.0% rewrite -0.0% 0.0% -0.0% -0.0% -0.0% rfib -0.0% 0.0% -0.0% -0.0% -0.0% rsa -0.0% 0.0% -0.0% -0.0% -0.0% scc -0.0% 0.0% -0.3% -0.5% -0.4% sched -0.0% 0.0% -0.0% -0.0% -0.0% scs -0.0% 0.0% -0.0% -0.0% -0.0% simple -0.1% 0.0% -0.0% -0.0% -0.0% solid -0.0% 0.0% -0.0% -0.0% -0.0% sorting -0.0% 0.0% -0.0% -0.0% -0.0% spectral-norm -0.0% 0.0% -0.0% -0.0% -0.0% sphere -0.0% 0.0% -0.0% -0.0% -0.0% symalg -0.0% 0.0% -0.0% -0.0% -0.0% tak -0.0% 0.0% -0.0% -0.0% -0.0% transform -0.0% 0.0% -0.0% -0.0% -0.0% treejoin -0.0% 0.0% -0.0% -0.0% -0.0% typecheck -0.0% 0.0% -0.0% -0.0% -0.0% veritas -0.0% 0.0% -0.0% -0.0% -0.0% wang -0.0% 0.0% -0.0% -0.0% -0.0% wave4main -0.0% 0.0% -0.0% -0.0% -0.0% wheel-sieve1 -0.0% 0.0% -0.0% -0.0% -0.0% wheel-sieve2 -0.0% 0.0% -0.0% -0.0% -0.0% x2n1 -0.0% 0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Min -0.1% 0.0% -0.3% -0.5% -0.5% Max -0.0% 0.0% -0.0% -0.0% -0.0% Geometric Mean -0.0% -0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Program Size Allocs Instrs Reads Writes -------------------------------------------------------------------------------- circsim -0.1% 0.0% -0.0% -0.0% -0.0% constraints -0.0% 0.0% -0.0% -0.0% -0.0% fibheaps -0.0% 0.0% -0.0% -0.0% -0.0% gc_bench -0.0% 0.0% -0.0% -0.0% -0.0% hash -0.0% 0.0% -0.0% -0.0% -0.0% lcss -0.0% 0.0% -0.0% -0.0% -0.0% power -0.0% 0.0% -0.0% -0.0% -0.0% spellcheck -0.0% 0.0% -0.0% -0.0% -0.0% -------------------------------------------------------------------------------- Min -0.1% 0.0% -0.0% -0.0% -0.0% Max -0.0% 0.0% -0.0% -0.0% -0.0% Geometric Mean -0.0% +0.0% -0.0% -0.0% -0.0% Manual inspection of programs in testsuite/tests/programs --------------------------------------------------------- I built these programs with a bunch of dump flags and `-O` and compared STG, Cmm, and Asm dumps and file sizes. (Below the numbers in parenthesis show number of modules in the program) These programs have identical compiler (same .hi and .o sizes, STG, and Cmm and Asm dumps): - Queens (1), andre_monad (1), cholewo-eval (2), cvh_unboxing (3), andy_cherry (7), fun_insts (1), hs-boot (4), fast2haskell (2), jl_defaults (1), jq_readsPrec (1), jules_xref (1), jtod_circint (4), jules_xref2 (1), lennart_range (1), lex (1), life_space_leak (1), bargon-mangler-bug (7), record_upd (1), rittri (1), sanders_array (1), strict_anns (1), thurston-module-arith (2), okeefe_neural (1), joao-circular (6), 10queens (1) Programs with different compiler outputs: - jl_defaults (1): For some reason GHC HEAD marks a lot of top-level `[Int]` closures as CAFFY for no reason. With this patch we no longer make them CAFFY and generate less SRT entries. For some reason Main.o is slightly larger with this patch (1.3%) and the executable sizes are the same. (I'd expect both to be smaller) - launchbury (1): Same as jl_defaults: top-level `[Int]` closures marked as CAFFY for no reason. Similarly `Main.o` is 1.4% larger but the executable sizes are the same. - galois_raytrace (13): Differences are in the Parse module. There are a lot, but some of the changes are caused by the fact that for some reason (I think a bug) GHC HEAD marks the dictionary for `Functor Identity` as CAFFY. Parse.o is 0.4% larger, the executable size is the same. - north_array: We now generate less SRT entries because some of array primops used in this program like `NewArrayOp` get eliminated during Stg-to-Cmm and turn some CAFFY things into non-CAFFY. Main.o gets 24% larger (9224 bytes from 9000 bytes), executable sizes are the same. - seward-space-leak: Difference in this program is better shown by this smaller example: module Lib where data CDS = Case [CDS] [(Int, CDS)] | Call CDS CDS instance Eq CDS where Case sels1 rets1 == Case sels2 rets2 = sels1 == sels2 && rets1 == rets2 Call a1 b1 == Call a2 b2 = a1 == a2 && b1 == b2 _ == _ = False In this program GHC HEAD builds a new SRT for the recursive group of `(==)`, `(/=)` and the dictionary closure. Then `/=` points to `==` in its SRT field, and `==` uses the SRT object as its SRT. With this patch we use the closure for `/=` as the SRT and add `==` there. Then `/=` gets an empty SRT field and `==` points to `/=` in its SRT field. This change looks fine to me. Main.o gets 0.07% larger, executable sizes are identical. head.hackage ------------ head.hackage's CI script builds 428 packages from Hackage using this patch with no failures. Compiler performance -------------------- The compiler perf tests report that the compiler allocates slightly more (worst case observed so far is 4%). However most programs in the test suite are small, single file programs. To benchmark compiler performance on something more realistic I build Cabal (the library, 236 modules) with different optimisation levels. For the "max residency" row I run GHC with `+RTS -s -A100k -i0 -h` for more accurate numbers. Other rows are generated with just `-s`. (This is because `-i0` causes running GC much more frequently and as a result "bytes copied" gets inflated by more than 25x in some cases) * -O0 | | GHC HEAD | This MR | Diff | | --------------- | -------------- | -------------- | ------ | | Bytes allocated | 54,413,350,872 | 54,701,099,464 | +0.52% | | Bytes copied | 4,926,037,184 | 4,990,638,760 | +1.31% | | Max residency | 421,225,624 | 424,324,264 | +0.73% | * -O1 | | GHC HEAD | This MR | Diff | | --------------- | --------------- | --------------- | ------ | | Bytes allocated | 245,849,209,992 | 246,562,088,672 | +0.28% | | Bytes copied | 26,943,452,560 | 27,089,972,296 | +0.54% | | Max residency | 982,643,440 | 991,663,432 | +0.91% | * -O2 | | GHC HEAD | This MR | Diff | | --------------- | --------------- | --------------- | ------ | | Bytes allocated | 291,044,511,408 | 291,863,910,912 | +0.28% | | Bytes copied | 37,044,237,616 | 36,121,690,472 | -2.49% | | Max residency | 1,071,600,328 | 1,086,396,256 | +1.38% | Extra compiler allocations -------------------------- Runtime allocations of programs are as reported above (NoFib section). The compiler now allocates more than before. Main source of allocation in this patch compared to base commit is the new SRT algorithm (GHC.Cmm.Info.Build). Below is some of the extra work we do with this patch, numbers generated by profiled stage 2 compiler when building a pathological case (the test 'ManyConstructors') with '-O2': - We now sort the final STG for a module, which means traversing the entire program, generating free variable set for each top-level binding, doing SCC analysis, and re-ordering the program. In ManyConstructors this step allocates 97,889,952 bytes. - We now do SRT analysis on static data, which in a program like ManyConstructors causes analysing 10,000 bindings that we would previously just skip. This step allocates 70,898,352 bytes. - We now maintain an SRT map for the entire module as we compile Cmm groups: data ModuleSRTInfo = ModuleSRTInfo { ... , moduleSRTMap :: SRTMap } (SRTMap is just a strict Map from the 'containers' library) This map gets an entry for most bindings in a module (exceptions are THUNKs and CAFFY static functions). For ManyConstructors this map gets 50015 entries. - Once we're done with code generation we generate a NameSet from SRTMap for the non-CAFFY names in the current module. This set gets the same number of entries as the SRTMap. - Finally we update CafInfos in ModDetails for the non-CAFFY Ids, using the NameSet generated in the previous step. This usually does the least amount of allocation among the work listed here. Only place with this patch where we do less work in the CAF analysis in the tidying pass (CoreTidy). However that doesn't save us much, as the pass still needs to traverse the whole program and update IdInfos for other reasons. Only thing we don't here do is the `hasCafRefs` pass over the RHS of bindings, which is a stateless pass that returns a boolean value, so it doesn't allocate much. (Metric changes blow are all increased allocations) Metric changes -------------- Metric Increase: ManyAlternatives ManyConstructors T13035 T14683 T1969 T9961
* Fix more typos, via an improved Levenshtein-style correctorBrian Wignall2020-01-121-4/+4
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* Module hierarchy: Iface (cf #13009)Sylvain Henry2020-01-061-2/+2
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* Split up coercionKindSimon Peyton Jones2019-12-061-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements the idea in #17515, splitting `coercionKind` into: * `coercion{Left,Right}Kind`, which computes the left/right side of the pair * `coercionKind`, which computes the pair of coercible types This is reduces allocation since we frequently only need only one side of the pair. Specifically, we see the following improvements on x86-64 Debian 9: | test | new | old | relative chg. | | :------- | ---------: | ------------: | ------------: | | T5030 | 695537752 | 747641152.0 | -6.97% | | T5321Fun | 449315744 | 474009040.0 | -5.21% | | T9872a | 2611071400 | 2645040952.0 | -1.28% | | T9872c | 2957097904 | 2994260264.0 | -1.24% | | T12227 | 773435072 | 812367768.0 | -4.79% | | T12545 | 3142687224 | 3215714752.0 | -2.27% | | T14683 | 9392407664 | 9824775000.0 | -4.40% | Metric Decrease: T12545 T9872a T14683 T5030 T12227 T9872c T5321Fun T9872b
* Make CorePrep.tryEtaReducePrep and CoreUtils.tryEtaReduce line upMatheus Magalhães de Alcantara2019-11-231-0/+2
| | | | | | | Simon PJ says he prefers this fix to #17429 over banning eta-reduction for jumps entirely. Sure enough, this also works. Test case: simplCore/should_compile/T17429.hs
* 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.
* Fix bogus type of case expressionwip/T17056Simon Peyton Jones2019-09-201-4/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* CoreUtils: Use mightBeUnliftedType in exprIsTopLevelBindableBen Gamari2019-09-191-1/+3
| | | | Also add reference from isUnliftedType to mightBeUnliftedType.
* Move 'Platform' to ghc-bootJohn Ericson2019-06-191-1/+1
| | | | | | | ghc-pkg needs to be aware of platforms so it can figure out which subdire within the user package db to use. This is admittedly roundabout, but maybe Cabal could use the same notion of a platform as GHC to good affect too.
* Update Trac ticket URLs to point to GitLabRyan Scott2019-03-151-16/+16
| | | | | This moves all URL references to Trac tickets to their corresponding GitLab counterparts.
* Fix map/coerce rule for newtypes with wrappersKrzysztof Gogolewski2019-03-051-1/+0
| | | | | | | | This addresses Trac #16208 by marking newtype wrapper unfoldings as compulsory. Furthermore, we can remove the special case for newtypes in exprIsConApp_maybe (introduced in 7833cf407d1f).
* Add AnonArgFlag to FunTySimon Peyton Jones2019-02-231-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The big payload of this patch is: Add an AnonArgFlag to the FunTy constructor of Type, so that (FunTy VisArg t1 t2) means (t1 -> t2) (FunTy InvisArg t1 t2) means (t1 => t2) The big payoff is that we have a simple, local test to make when decomposing a type, leading to many fewer calls to isPredTy. To me the code seems a lot tidier, and probably more efficient (isPredTy has to take the kind of the type). See Note [Function types] in TyCoRep. There are lots of consequences * I made FunTy into a record, so that it'll be easier when we add a linearity field, something that is coming down the road. * Lots of code gets touched in a routine way, simply because it pattern matches on FunTy. * I wanted to make a pattern synonym for (FunTy2 arg res), which picks out just the argument and result type from the record. But alas the pattern-match overlap checker has a heart attack, and either reports false positives, or takes too long. In the end I gave up on pattern synonyms. There's some commented-out code in TyCoRep that shows what I wanted to do. * Much more clarity about predicate types, constraint types and (in particular) equality constraints in kinds. See TyCoRep Note [Types for coercions, predicates, and evidence] and Note [Constraints in kinds]. This made me realise that we need an AnonArgFlag on AnonTCB in a TyConBinder, something that was really plain wrong before. See TyCon Note [AnonTCB InivsArg] * When building function types we must know whether we need VisArg (mkVisFunTy) or InvisArg (mkInvisFunTy). This turned out to be pretty easy in practice. * Pretty-printing of types, esp in IfaceType, gets tidier, because we were already recording the (->) vs (=>) distinction in an ad-hoc way. Death to IfaceFunTy. * mkLamType needs to keep track of whether it is building (t1 -> t2) or (t1 => t2). See Type Note [mkLamType: dictionary arguments] Other minor stuff * Some tidy-up in validity checking involving constraints; Trac #16263
* Look through newtype wrappers (Trac #16254)Krzysztof Gogolewski2019-02-191-0/+1
| | | | | | exprIsConApp_maybe could detect that I# 10 is a constructor application, but not that Size (I# 10) is, because it was an application with a nontrivial argument.
* Stomp a few typos and grammarosGabor Greif2018-12-171-1/+1
| | | | Also use 'id'
* Careful tweaking to exprOkForSpeculationSimon Peyton Jones2018-12-071-43/+82
| | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does several things: * Make exprOkForSpeculation ignore evaluatedness of variables See the Note [exprOkForSpeculation and evaluated variables] This means that the binder-swap transformation no longer invaliates the let/app invariant. * Make exprOkForSpeculation return False for DataToTagOp and SeqOp. See Note [exprOkForSpeculation and SeqOp/DataToTagOp] * Remove the 'can_fail' property from dataToTag#; it was always a hack (described in the old Note [dataToTag#] in primops.txt.pp), and now its not necessary because of the fixes above. * Make SetLevels use exprIsHNF, /not/ exprOkForSpeculation, when floating single-alternative cases. See SetLevels Note [Floating single-alternative cases] * Fix a buglet in FloatIn; probably never bites in practice See Note [Dead bindings] Collectively, these changes finally fix Trac #15696.
* Rename literal constructorsSylvain Henry2018-11-221-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | 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
* Refactor the treatment of predicate typesSimon Peyton Jones2018-10-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trac #15648 showed that GHC was a bit confused about the difference between the types for * Predicates * Coercions * Evidence (in the typechecker constraint solver) This patch cleans it up. See especially Type.hs Note [Types for coercions, predicates, and evidence] Particular changes * Coercion types (a ~# b) and (a ~#R b) are not predicate types (so isPredTy reports False for them) and are not implicitly instantiated by the type checker. This is a real change, but it consistently reflects that fact that (~#) and (~R#) really are different from predicates. * isCoercionType is renamed to isCoVarType * During type inference, simplifyInfer, we do /not/ want to infer a constraint (a ~# b), because that is no longer a predicate type. So we 'lift' it to (a ~ b). See TcType Note [Lift equality constaints when quantifying] * During type inference for pattern synonyms, we need to 'lift' provided constraints of type (a ~# b) to (a ~ b). See Note [Equality evidence in pattern synonyms] in PatSyn * But what about (forall a. Eq a => a ~# b)? Is that a predicate type? No -- it does not have kind Constraint. Is it an evidence type? Perhaps, but awkwardly so. In the end I decided NOT to make it an evidence type, and to ensure the the type inference engine never meets it. This made me /simplify/ the code in TcCanonical.makeSuperClasses; see TcCanonical Note [Equality superclasses in quantified constraints] Instead I moved the special treatment for primitive equality to TcInteract.doTopReactOther. See TcInteract Note [Looking up primitive equalities in quantified constraints] Also see Note [Evidence for quantified constraints] in Type. All this means I can have isEvVarType ty = isCoVarType ty || isPredTy ty which is nice. All in all, rather a lot of work for a small refactoring, but I think it's a real improvement.
* Comments and white spaceSimon Peyton Jones2018-10-241-3/+2
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* Add RubbishLit for absent bindings of UnliftedRepSebastian Graf2018-10-141-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* Fix dataToTag# argument evaluationÖmer Sinan Ağacan2018-10-101-17/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | See #15696 for more details. We now always enter dataToTag# argument (done in generated Cmm, in StgCmmExpr). Any high-level optimisations on dataToTag# applications are done by the simplifier. Looking at tag bits (instead of reading the info table) for small types is left to another diff. Incorrect test T14626 is removed. We no longer do this optimisation (see comment:44, comment:45, comment:60). Comments and notes about special cases around dataToTag# are removed. We no longer have any special cases around it in Core. Other changes related to evaluating primops (seq# and dataToTag#) will be pursued in follow-up diffs. Test Plan: Validates with three regression tests Reviewers: simonpj, simonmar, hvr, bgamari, dfeuer Reviewed By: simonmar Subscribers: rwbarton, carter GHC Trac Issues: #15696 Differential Revision: https://phabricator.haskell.org/D5201
* Fix get getIdFromTrivialExprSimon Peyton Jones2018-09-231-8/+14
| | | | | | | | | | | | | This bug, discovered by Trac #15325, has been lurking since commit 1c9fd3f1c5522372fcaf250c805b959e8090a62c Author: Simon Peyton Jones <simonpj@microsoft.com> Date: Thu Dec 3 12:57:54 2015 +0000 Case-of-empty-alts is trivial (Trac #11155) I'd forgotttnen to modify getIdFromTrivialExpr when I modified exprIsTrivial. Easy to fix, though.
* Coercion Quantificationningning2018-09-151-9/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch corresponds to #15497. According to https://ghc.haskell.org/trac/ghc/wiki/DependentHaskell/Phase2, we would like to have coercion quantifications back. This will allow us to migrate (~#) to be homogeneous, instead of its current heterogeneous definition. This patch is (lots of) plumbing only. There should be no user-visible effects. An overview of changes: - Both `ForAllTy` and `ForAllCo` can quantify over coercion variables, but only in *Core*. All relevant functions are updated accordingly. - Small changes that should be irrelevant to the main task: 1. removed dead code `mkTransAppCo` in Coercion 2. removed out-dated Note Computing a coercion kind and roles in Coercion 3. Added `Eq4` in Note Respecting definitional equality in TyCoRep, and updated `mkCastTy` accordingly. 4. Various updates and corrections of notes and typos. - Haddock submodule needs to be changed too. Acknowledgments: This work was completed mostly during Ningning Xie's Google Summer of Code, sponsored by Google. It was advised by Richard Eisenberg, supported by NSF grant 1704041. Test Plan: ./validate Reviewers: goldfire, simonpj, bgamari, hvr, erikd, simonmar Subscribers: RyanGlScott, monoidal, rwbarton, carter GHC Trac Issues: #15497 Differential Revision: https://phabricator.haskell.org/D5054
* Allow (~) in the head of a quantified constraintsSimon Peyton Jones2018-09-131-3/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the introduction of quantified constraints, GHC has rejected a quantified constraint with (~) in the head, thus f :: (forall a. blah => a ~ ty) => stuff I am frankly dubious that this is ever useful. But /is/ necessary for Coercible (representation equality version of (~)) and it does no harm to allow it for (~) as well. Plus, our users are asking for it (Trac #15359, #15625). It was really only excluded by accident, so this patch lifts the restriction. See TcCanonical Note [Equality superclasses in quantified constraints] There are a number of wrinkles: * If the context of the quantified constraint is empty, we can get trouble when we get down to unboxed equality (a ~# b) or (a ~R# b), as Trac #15625 showed. This is even more of a corner case, but it produced an outright crash, so I elaborated the superclass machinery in TcCanonical.makeStrictSuperClasses to add a void argument in this case. See Note [Equality superclasses in quantified constraints] * The restriction on (~) was in TcValidity.checkValidInstHead. In lifting the restriction I discovered an old special case for (~), namely | clas_nm `elem` [ heqTyConName, eqTyConName] , nameModule clas_nm /= this_mod This was (solely) to support the strange instance instance a ~~ b => a ~ b in Data.Type.Equality. But happily that is no longer with us, since commit f265008fb6f70830e7e92ce563f6d83833cef071 Refactor (~) to reduce the suerpclass stack So I removed the special case. * I found that the Core invariants on when we could have co = <expr> were entirely not written down. (Getting this wrong ws the proximate source of the crash in Trac #15625. So - Documented them better in CoreSyn Note [CoreSyn type and coercion invariant], - Modified CoreOpt and CoreLint to match - Modified CoreUtils.bindNonRec to match - Made MkCore.mkCoreLet use bindNonRec, rather than duplicate its logic - Made Simplify.rebuildCase case-to-let respect Note [CoreSyn type and coercion invariant],
* A few typofixes in commentsGabor Greif2018-06-291-1/+1
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* Built-in Natural literals in CoreSylvain Henry2018-06-151-8/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for built-in Natural literals in Core. - Replace MachInt,MachWord, LitInteger, etc. with a single LitNumber constructor with a LitNumType field - Support built-in Natural literals - Add desugar warning for negative literals - Move Maybe(..) from GHC.Base to GHC.Maybe for module dependency reasons This patch introduces only a few rules for Natural literals (compared to Integer's rules). Factorization of the built-in rules for numeric literals will be done in another patch as this one is already big to review. Test Plan: validate test build with integer-simple Reviewers: hvr, bgamari, goldfire, Bodigrim, simonmar Reviewed By: bgamari Subscribers: phadej, simonpj, RyanGlScott, carter, hsyl20, rwbarton, thomie GHC Trac Issues: #14170, #14465 Differential Revision: https://phabricator.haskell.org/D4212
* Fix corner case in typeKind, plus refactoringSimon Peyton Jones2018-06-151-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | This is a continuation of commit 9d600ea68c283b0d38ac663c3cc48baba6b94f57 Author: Simon Peyton Jones <simonpj@microsoft.com> Date: Fri Jun 1 16:36:57 2018 +0100 Expand type synonyms when Linting a forall That patch pointed out that there was a lurking hole in typeKind, where it could return an ill-scoped kind, because of not expanding type synonyms enough. This patch fixes it, quite nicely * Use occCheckExpand to expand those synonyms (it was always designed for that exact purpose), and call it from Type.typeKind CoreUtils.coreAltType CoreLint.lintTYpe * Consequently, move occCheckExpand from TcUnify.hs to Type.hs, and generalise it to take a list of type variables. I also tidied up lintType a bit.
* Add note documenting refineDefaultAltMatthew Pickering2018-05-131-0/+88
| | | | | | | | | | Reviewers: sjakobi, bgamari Reviewed By: sjakobi Subscribers: rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4687
* Caching coercion roles in NthCo and coercionKindsRole refactoringTobias Dammers2018-04-201-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While addressing nonlinear behavior related to coercion roles, particularly `NthCo`, we noticed that coercion roles are recalculated often even though they should be readily at hand already in most cases. This patch adds a `Role` to the `NthCo` constructor so that we can cache them rather than having to recalculate them on the fly. https://ghc.haskell.org/trac/ghc/ticket/11735#comment:23 explains the approach. Performance improvement over GHC HEAD, when compiling Grammar.hs (see below): GHC 8.2.1: ``` ghc Grammar.hs 176.27s user 0.23s system 99% cpu 2:56.81 total ``` before patch (but with other optimizations applied): ``` ghc Grammar.hs -fforce-recomp 175.77s user 0.19s system 100% cpu 2:55.78 total ``` after: ``` ../../ghc/inplace/bin/ghc-stage2 Grammar.hs 10.32s user 0.17s system 98% cpu 10.678 total ``` Introduces the following regressions: - perf/compiler/parsing001 (possibly false positive) - perf/compiler/T9872 - perf/compiler/haddock.base Reviewers: goldfire, bgamari, simonpj Reviewed By: simonpj Subscribers: rwbarton, thomie, carter GHC Trac Issues: #11735 Differential Revision: https://phabricator.haskell.org/D4394
* CoreUtils.filterAlts: Correct docsSimon Jakobi2018-04-071-2/+0
| | | | `refineDefaultAlt` takes care of refining the default alt these days.
* Improve documentation for refineDefaultAltSimon Jakobi2018-04-071-5/+6
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* Fix seq# case of exprOkForSpeculationSimon Peyton Jones2018-03-201-1/+23
| | | | | | | | | This subtle patch fixes Trac #5129 (again; comment:20 and following). I took the opportunity to document seq# properly; see Note [seq# magic] in PrelRules, and Note [seq# and expr_ok] in CoreUtils.
* Allow top level ticked string literalsBartosz Nitka2018-03-061-7/+22
| | | | | | | | | | | | | | | | | | | | This reverts f5b275a239d2554c4da0b7621211642bf3b10650 and changes the places that looked for `Lit (MachStr _))` to use `exprIsMbTickedLitString_maybe` to unwrap ticks as necessary. Also updated relevant comments. Test Plan: I added 3 new tests that previously reproduced. GHC HEAD now builds with -g Reviewers: simonpj, simonmar, bgamari, hvr, goldfire Subscribers: rwbarton, thomie, carter GHC Trac Issues: #14779 Differential Revision: https://phabricator.haskell.org/D4470
* Comments onlySimon Peyton Jones2018-02-271-0/+2
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* Fix the lone-variable case in callSiteInlineSimon Peyton Jones2018-01-251-30/+72
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | See Note [Lone variables] in CoreUnfold and Note [exprIsExpandable] in CoreUtils. Helpfully pointed out by Matthew Pickering in Trac #14688 Nofib results are good: -------------------------------------------------------------------------------- Program Size Allocs Runtime Elapsed TotalMem -------------------------------------------------------------------------------- anna +0.1% +0.3% 0.151 0.151 0.0% awards +0.0% -0.2% 0.001 0.001 0.0% compress2 +0.6% -0.7% -4.8% -5.0% -4.0% eliza +0.0% -2.4% 0.001 0.001 0.0% fulsom +0.4% -13.3% -7.6% -7.6% +190.0% gamteb +0.0% -0.6% 0.062 0.062 0.0% gg +0.1% -0.4% 0.016 0.016 0.0% ida +0.1% +0.3% 0.110 0.110 0.0% kahan +0.0% -0.7% -0.9% -0.9% 0.0% mate +0.1% -5.2% -4.9% -4.9% 0.0% n-body +0.0% -0.2% -0.3% -3.0% 0.0% pretty +0.0% -2.8% 0.000 0.000 0.0% scs +0.0% -0.2% +1.6% +2.4% 0.0% simple +0.4% -0.2% -2.3% -2.3% -3.4% veritas +0.4% -1.0% 0.003 0.003 0.0% wang +0.0% -1.6% 0.165 0.165 0.0% -------------------------------------------------------------------------------- Min -0.0% -13.3% -16.2% -18.8% -4.0% Max +0.6% +0.3% +4.9% +4.9% +190.0% Geometric Mean +0.1% -0.3% -1.7% -2.4% +0.9%
* Fix quadratic behavior of prepareAltsBartosz Nitka2018-01-151-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Summary: This code is quadratic and a simple test case I used managed to tickle it. The example (same one as #14667) looks like this: ``` module A10000 where data A = A | A00001 | A00002 ... | A10000 f :: A -> Int f A00001 = 19900001 f A00002 = 19900002 ... f A10000 = 19910000 ``` Applied on top of a fix for #14667, it gives a 30% compile time improvement. Test Plan: ./validate Reviewers: simonpj, bgamari Subscribers: rwbarton, thomie, simonmar, carter Differential Revision: https://phabricator.haskell.org/D4307
* Typos in commentsGabor Greif2018-01-031-2/+2
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* Get rid of some stuttering in comments and docsGabor Greif2017-12-191-1/+1
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* Typofix in commentGabor Greif2017-12-131-1/+1
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* Fix nasty bug in w/w for absence analysisSimon Peyton Jones2017-10-031-11/+21
| | | | | | | | | | | | | | | | | | | | 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
* compiler: introduce custom "GhcPrelude" PreludeHerbert Valerio Riedel2017-09-191-0/+2
| | | | | | | | | | | | | | | | | | 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
* Bottoming expressions should not be expandableSimon Peyton Jones2017-08-251-27/+47
| | | | | | | | | | | | | | | | | | | | | | | | This patch changes isExpandableApp and isWorkFreeApp to respond False to bottoming applications. I found that if we had x = undefined <dict-expr> then prepareRhs was ANF'ing it to d = <dict-expr> x = undefined d which is stupid (no gain); and worse it made the simplifier iterate indefinitely. It showed up when I started marking 'x' as a bottoming Id more aggresssively than before; but it's been a lurking bug for ages. It was convenient to make isWorkFreeApp also return False for bottoming applications, and I see no reason not to do so. That leaves isCheapApp. It currently replies True to bottoming applications, but I don't see why that's good.. Something to try later.
* Restrict exprOkForSpeculation/case to unlifted typesSimon Peyton Jones2017-08-251-45/+85
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Consider case x of y DEFAULT -> let v::Int# = case y of True -> e1 False -> e2 in ... Previously this would have been ok-for-speculation because y is evaluated. But the binder-swap done by SetLevels would transform the inner alternative to DEFAULT -> let v::Int# = case x of { ... } in ...) which does /not/ satisfy the let/app invariant, because x is not evaluated. I don't know why this has never bitten us before, but it began to bite when I did upcoming refactoring of the Simplifier. So this patch narrows exprOkForSpeculation to only work for /unlifted/ cases. To make this work I had to make exprOkForSpeculation non-polymorphic in the binder type, which has a little knock-on for is use in SetLevels. (It's annoying that we need to handle cases at all, but see Note [exprOkForSpeculation: case expressions])
* Introduce -fcatch-bottomsBen Gamari2017-07-201-0/+1
| | | | | | | | | | | | | | | This flag instructs the simplifier to emit ``error`` expressions in the continutation of empty case analyses (which should bottom and consequently not return). This is helpful when debugging demand analysis bugs which can sometimes manifest as segmentation faults. Test Plan: Validate Reviewers: simonpj, austin Subscribers: niteria, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3736
* Spelling fixesGabor Greif2017-07-201-1/+1
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* Use lengthIs and friends in more placesRyan Scott2017-06-021-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | While investigating #12545, I discovered several places in the code that performed length-checks like so: ``` length ts == 4 ``` This is not ideal, since the length of `ts` could be much longer than 4, and we'd be doing way more work than necessary! There are already a slew of helper functions in `Util` such as `lengthIs` that are designed to do this efficiently, so I found every place where they ought to be used and did just that. I also defined a couple more utility functions for list length that were common patterns (e.g., `ltLength`). Test Plan: ./validate Reviewers: austin, hvr, goldfire, bgamari, simonmar Reviewed By: bgamari, simonmar Subscribers: goldfire, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3622
* Make let and app consistent in exprIsCheapXSimon Peyton Jones2017-04-121-18/+30
| | | | | | | | This fixes Trac #13558, by making App and Let behave consistently; see Note [Arguments and let-bindings exprIsCheapX] I renamed the mysterious exprIsOk to exprIsCheapX. (The "X" is because it is parameterised over a CheapAppFun.)
* Fix name of NoteBen Gamari2017-04-061-1/+1
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