1. 23 Jan, 2017 1 commit
  2. 18 Jan, 2017 1 commit
  3. 25 Aug, 2016 2 commits
    • Joachim Breitner's avatar
      DmdAnal: Add a final, safe iteration · 8d92b88d
      Joachim Breitner authored
      this fixes #12368.
      
      It also refactors dmdFix a bit, removes some redundancies (such as
      passing around an strictness signature right next to an id, when that id
      is guaranteed to have been annotated with that strictness signature).
      
      Note that when fixed-point iteration does not terminate, we
      conservatively delete their strictness signatures (set them to nopSig).
      But this loses the information on how its strict free variables are
      used!
      
      Lazily used variables already escape via lazy_fvs. We ensure that in the
      case of an aborted fixed-point iteration, also the strict variables are
      put there (with a conservative demand of topDmd).
      
      Differential Revision: https://phabricator.haskell.org/D2392
      8d92b88d
    • Joachim Breitner's avatar
      7a86f584
  4. 12 Jul, 2016 1 commit
    • Joachim Breitner's avatar
      Demand analyser: Implement LetUp rule (#12370) · 45d8f4eb
      Joachim Breitner authored
      This makes the implementation match the description in the paper more
      closely: There, a let binding that is not a function has first its body
      analised, and then the binding’s RHS. This way, the demand on the bound
      variable by the body can be fed into the RHS, yielding more precise
      results.
      
      Performance measurements do unfortunately not show significant
      improvements or regessions.
      
      Differential Revision: https://phabricator.haskell.org/D2395
      45d8f4eb
  5. 01 May, 2016 1 commit
  6. 15 Apr, 2016 1 commit
  7. 14 Apr, 2016 1 commit
    • Joachim Breitner's avatar
      Add a final demand analyzer run right before TidyCore · f4fd98c7
      Joachim Breitner authored
      in order to have precise used-once information in the exported
      strictness signatures, as well as precise used-once information on
      thunks. This avoids the bad effects of #11731.
      
      The subsequent worker-wrapper pass is responsible for removing the
      demand environment part of the strictness signature. It does not run
      after the final demand analyzer pass, so remove this also in CoreTidy.
      
      The subsequent worker-wrapper pass is also responsible for removing
      used-once-information from the demands and strictness signatures, as
      these might not be preserved by the simplifier. This is _not_ done by
      CoreTidy, because we _do_ want this information, as produced by the last
      round of the demand analyzer, to be available to the code generator.
      
      Differential Revision: https://phabricator.haskell.org/D2073
      f4fd98c7
  8. 06 Apr, 2016 1 commit
    • Joachim Breitner's avatar
      Demand Analyzer: Do not set OneShot information (second try) · 0f58d348
      Joachim Breitner authored
      as suggested in ticket:11770#comment:1. This code was buggy
      (#11770), and the occurrence analyzer does the same job anyways.
      
      This also elaborates the notes in the occurrence analyzer accordingly.
      
      Previously, the worker/wrapper code would go through lengths to transfer
      the oneShot annotations from the original function to both the worker
      and the wrapper. We now simply transfer the demand on the worker, and
      let the subsequent occurrence analyzer push this onto the lambda
      binders.
      
      This also requires the occurrence analyzer to do this more reliably.
      Previously, it would not hand out OneShot annotatoins to things that
      would not `certainly_inline` (and it might not have mattered, as the
      Demand Analysis might have handed out the annotations). Now we hand out
      one-shot annotations unconditionally.
      
      Differential Revision: https://phabricator.haskell.org/D2085
      0f58d348
  9. 31 Mar, 2016 2 commits
  10. 25 Feb, 2016 1 commit
    • manav's avatar
      Make warning names more consistent · 66584914
      manav authored
      - Replace "Sigs" with "Signatures" in WarningFlag data constructors.
      - Replace "PatSyn" with "PatternSynonym" in WarningFlag data
        constructors.
      - Deprecate "missing-local-sigs" in favor of "missing-local-signatures".
      - Deprecate "missing-exported-sigs" in favor of
        "missing-exported-signatures".
      - Deprecate "missing-pat-syn-signatures" in favor of
        "missing-pattern-synonym-signatures".
      - Replace "ddump-strsigs" with "ddump-str-signatures"
      
      These complete the tasks that were explicitly mentioned in #11583
      
      Test Plan:
      Executed `ghc --show-options` and verified that the flags were changed
      as expected.
      
      Reviewers: svenpanne, austin, bgamari
      
      Reviewed By: austin, bgamari
      
      Subscribers: mpickering, thomie
      
      Differential Revision: https://phabricator.haskell.org/D1939
      
      GHC Trac Issues: #11583
      66584914
  11. 11 Feb, 2016 1 commit
  12. 18 Jan, 2016 1 commit
    • Jan Stolarek's avatar
      Replace calls to `ptext . sLit` with `text` · b8abd852
      Jan Stolarek authored
      Summary:
      In the past the canonical way for constructing an SDoc string literal was the
      composition `ptext . sLit`.  But for some time now we have function `text` that
      does the same.  Plus it has some rules that optimize its runtime behaviour.
      This patch takes all uses of `ptext . sLit` in the compiler and replaces them
      with calls to `text`.  The main benefits of this patch are clener (shorter) code
      and less dependencies between module, because many modules now do not need to
      import `FastString`.  I don't expect any performance benefits - we mostly use
      SDocs to report errors and it seems there is little to be gained here.
      
      Test Plan: ./validate
      
      Reviewers: bgamari, austin, goldfire, hvr, alanz
      
      Subscribers: goldfire, thomie, mpickering
      
      Differential Revision: https://phabricator.haskell.org/D1784
      b8abd852
  13. 07 Jan, 2016 1 commit
    • Simon Peyton Jones's avatar
      Make demand analysis understand catch · 9915b656
      Simon Peyton Jones authored
      As Trac #11222, and #10712 note, the strictness analyser
      needs to be rather careful about exceptions.  Previously
      it treated them as identical to divergence, but that
      won't quite do.
      
      See Note [Exceptions and strictness] in Demand, which
      explains the deal.
      
      Getting more strictness in 'catch' and friends is a
      very good thing.  Here is the nofib summary, keeping
      only the big ones.
      
      --------------------------------------------------------------------------------
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
                fasta          -0.1%     -6.9%     -3.0%     -3.0%     +0.0%
                  hpg          -0.1%     -2.0%     -6.2%     -6.2%     +0.0%
             maillist          -0.1%     -0.3%      0.08      0.09     +1.2%
      reverse-complem          -0.1%    -10.9%     -6.0%     -5.9%     +0.0%
               sphere          -0.1%     -4.3%      0.08      0.08     +0.0%
                 x2n1          -0.1%     -0.0%      0.00      0.00     +0.0%
      --------------------------------------------------------------------------------
                  Min          -0.2%    -10.9%    -17.4%    -17.3%     +0.0%
                  Max          -0.0%     +0.0%     +4.3%     +4.4%     +1.2%
       Geometric Mean          -0.1%     -0.3%     -2.9%     -3.0%     +0.0%
      
      On the way I did quite a bit of refactoring in Demand.hs
      9915b656
  14. 11 Dec, 2015 1 commit
    • eir@cis.upenn.edu's avatar
      Add kind equalities to GHC. · 67465497
      eir@cis.upenn.edu authored
      This implements the ideas originally put forward in
      "System FC with Explicit Kind Equality" (ICFP'13).
      
      There are several noteworthy changes with this patch:
       * We now have casts in types. These change the kind
         of a type. See new constructor `CastTy`.
      
       * All types and all constructors can be promoted.
         This includes GADT constructors. GADT pattern matches
         take place in type family equations. In Core,
         types can now be applied to coercions via the
         `CoercionTy` constructor.
      
       * Coercions can now be heterogeneous, relating types
         of different kinds. A coercion proving `t1 :: k1 ~ t2 :: k2`
         proves both that `t1` and `t2` are the same and also that
         `k1` and `k2` are the same.
      
       * The `Coercion` type has been significantly enhanced.
         The documentation in `docs/core-spec/core-spec.pdf` reflects
         the new reality.
      
       * The type of `*` is now `*`. No more `BOX`.
      
       * Users can write explicit kind variables in their code,
         anywhere they can write type variables. For backward compatibility,
         automatic inference of kind-variable binding is still permitted.
      
       * The new extension `TypeInType` turns on the new user-facing
         features.
      
       * Type families and synonyms are now promoted to kinds. This causes
         trouble with parsing `*`, leading to the somewhat awkward new
         `HsAppsTy` constructor for `HsType`. This is dispatched with in
         the renamer, where the kind `*` can be told apart from a
         type-level multiplication operator. Without `-XTypeInType` the
         old behavior persists. With `-XTypeInType`, you need to import
         `Data.Kind` to get `*`, also known as `Type`.
      
       * The kind-checking algorithms in TcHsType have been significantly
         rewritten to allow for enhanced kinds.
      
       * The new features are still quite experimental and may be in flux.
      
       * TODO: Several open tickets: #11195, #11196, #11197, #11198, #11203.
      
       * TODO: Update user manual.
      
      Tickets addressed: #9017, #9173, #7961, #10524, #8566, #11142.
      Updates Haddock submodule.
      67465497
  15. 03 Aug, 2015 1 commit
  16. 30 Jul, 2015 1 commit
    • Simon Peyton Jones's avatar
      Fix Trac #10694: CPR analysis · 499b926b
      Simon Peyton Jones authored
      In this commit
         commit 0696fc6d
         Author: Simon Peyton Jones <simonpj@microsoft.com>
         Date:   Fri Jun 26 11:40:01 2015 +0100
      
      I made an error in the is_var_scrut tests in extendEnvForProdAlt.
      
      This patch fixes it, thereby fixing Trac #10694.
      499b926b
  17. 21 Jul, 2015 1 commit
    • Simon Peyton Jones's avatar
      Improve strictness analysis for exceptions · 7c0fff41
      Simon Peyton Jones authored
      Two things here:
      
      * For exceptions-catching primops like catch#, we know
        that the main argument function will be called, so
        we can use strictApply1Dmd, rather than lazy
      
        Changes in primops.txt.pp
      
      * When a 'case' scrutinises a I/O-performing primop,
        the Note [IO hack in the demand analyser] was
        throwing away all strictness from the code that
        followed.
      
        I found that this was causing quite a bit of unnecessary
        reboxing in the (heavily used) function
        GHC.IO.Handle.Internals.wantReadableHandle
      
        So this patch prevents the hack applying when the
        case scrutinises a primop.  See the revised
        Note [IO hack in the demand analyser]
      
      Thse two things buy us quite a lot in programs that do a lot of IO.
      
              Program           Size    Allocs   Runtime   Elapsed  TotalMem
      --------------------------------------------------------------------------------
                  hpg          -0.4%     -2.9%     -0.9%     -1.0%     +0.0%
      reverse-complem          -0.4%    -10.9%    +10.7%    +10.9%     +0.0%
               simple          -0.3%     -0.0%    +26.2%    +26.2%     +3.7%
               sphere          -0.3%     -6.3%      0.09      0.09     +0.0%
      --------------------------------------------------------------------------------
                  Min          -0.7%    -10.9%     -4.6%     -4.7%     -1.7%
                  Max          -0.2%     +0.0%    +26.2%    +26.2%     +6.5%
       Geometric Mean          -0.4%     -0.3%     +2.1%     +2.1%     +0.1%
      
      I think the increase in runtime for 'simple' is measurement error.
      7c0fff41
  18. 26 Jun, 2015 2 commits
    • Simon Peyton Jones's avatar
      Improve CPR behavior for strict constructors · 0696fc6d
      Simon Peyton Jones authored
      When working on Trac #10482 I noticed that we could give constructor
      arguments the CPR property if they are use strictly.
      
      This is documented carefully in
          Note [CPR in a product case alternative]
      and also
          Note [Initial CPR for strict binders]
      
      There are a bunch of intersting examples in
          Note [CPR examples]
      which I have added to the test suite as T10482a.
      
      I also added a test for #10482 itself.
      0696fc6d
    • Simon Peyton Jones's avatar
      Fix addDataConStrictness · 9014a7ee
      Simon Peyton Jones authored
      See Note [Add demands for strict constructors].
      
      The new bit is the test for isAbsDmd in addDataConStrictness.
      There was a cryptic note that said that this function
      should add a seqDmd even for Absent arguments, but that
      is definitely a bad thing (as the Note now says), causing
      unused arguments to be passed to the worker.
      
      Easy fix!
      9014a7ee
  19. 21 Apr, 2015 3 commits
    • Simon Peyton Jones's avatar
      Wibble to DmdAnal · 5c7e4db5
      Simon Peyton Jones authored
      This fixes a typo in d5773a49
          Teach DmdAnal that coercions are value arguments!
          (Trac #10288)
      
      Sorry about that; I'm not sure how it slipped through.
      5c7e4db5
    • Simon Peyton Jones's avatar
      Support unboxing for GADT product types · f2d1b7fc
      Simon Peyton Jones authored
      Beofre this commit we never unboxed GADT, even if they
      are perfectly civilised products.
      
      This patch liberalises unboxing slightly.
      See Note [Product types] in TyCon.
      
      Still to come
       - for strictness, we could maybe deal with existentials too
       - todo: unboxing constructor arguments
      f2d1b7fc
    • Simon Peyton Jones's avatar
      Teach DmdAnal about free coercion variables · 3bec1ac0
      Simon Peyton Jones authored
      Coercion variables are used in casts and coercions, so the demand
      analyser should jolly well not regard them as absent!
      
      In fact this bug never makes a difference because even absent
      unboxed-coercion arguments are passed anyway;
      see WwLib.mk_abesnt_let, which returns Nothing for coercion Ids.
      
      But it was simply wrong before and that is never cool.
      3bec1ac0
  20. 20 Apr, 2015 1 commit
    • Simon Peyton Jones's avatar
      Teach DmdAnal that coercions are value arguments! · d5773a49
      Simon Peyton Jones authored
      The demand analyser was treating coercion args like type args,
      which meant that the arguments in a strictness signature got
      out of step with the arguments of a call.  Result chaos and
      disaster.  Trac #10288 showed it up.
      
      It's hard to get this bug to show up in practice because
       - functions abstracted over coercions are usually abstracted
         over *boxed* coercions
       - we don't currently unbox a boxed-coercion arg because it's
         GADT (I see how to fix this too)
      
      But after floating, optimisation, and so on, Trac #10288 did
      get a function abstracted over an unboxed coercion, and then
      the -flate-dmd-anal pass went wrong.
      
      I don't think I can come up with a test case, but I don't think
      it matters too much.
      
      Still to come
       - Fix a second bug, namely that coercion variables are wrongly
         marked as absent because DmdAnal doesn't check the the free
         variables of casts. I think this never bites in practice
         (see the follow-up commit)
      
       - Make GADT products work with strictness analysis
      d5773a49
  21. 14 Apr, 2015 1 commit
    • Simon Peyton Jones's avatar
      Zap usage info in CSE (Trac #10218) · d261d4cb
      Simon Peyton Jones authored
      Trac #10218 reports a subtle bug that turned out to be:
      
      - CSE invalidated the usage information computed
        by earlier demand analysis, by increasing sharing
      
      - that made a single-entry thunk into a multi-entry thunk
      
      - and with -feager-blackholing, that led to <<loop>>
      
      The patch fixes it by making the CSE pass zap usage information for
      let-bound identifiers.   It can be restored by -flate-dmd-anal.
      
      (But making -flate-dmd-anal the default needs some careful work;
      see Trac #7782.)
      d261d4cb
  22. 10 Apr, 2015 1 commit
  23. 07 Apr, 2015 1 commit
    • Simon Peyton Jones's avatar
      Fix a long-standing bug in the demand analyser · 9f0f99fd
      Simon Peyton Jones authored
      This patch fixes Trac #10148, an outright and egregious
      bug in the demand analyser.
      
      It is explained in Note [Demand on case-alternative binders]
      in Demand.hs.
      
      I did some other minor refactoring.
      
      To my astonishment I got some big compiler perf changes
      
      * perf/compiler/T5837: bytes allocated -76%
      * perf/compiler/T5030: bytes allocated -10%
      * perf/compiler/T3294: max bytes used  -25%
      
      Happy days
      9f0f99fd
  24. 10 Feb, 2015 1 commit
  25. 01 Dec, 2014 1 commit
  26. 20 Aug, 2014 1 commit
  27. 01 Jul, 2014 1 commit
    • Simon Peyton Jones's avatar
      Fix demand analyser for unboxed types · d6ee82b2
      Simon Peyton Jones authored
      This is a tricky case exposed by Trac #9254.  I'm surprised it hasn't
      shown up before, because it's happens when you use unsafePerformIO in
      the right way.
      
      Anyway, fixed now.  See Note [Analysing with absent demand]
      in Demand.lhs
      d6ee82b2
  28. 11 Jun, 2014 1 commit
  29. 15 May, 2014 1 commit
    • Herbert Valerio Riedel's avatar
      Add LANGUAGE pragmas to compiler/ source files · 23892440
      Herbert Valerio Riedel authored
      In some cases, the layout of the LANGUAGE/OPTIONS_GHC lines has been
      reorganized, while following the convention, to
      
      - place `{-# LANGUAGE #-}` pragmas at the top of the source file, before
        any `{-# OPTIONS_GHC #-}`-lines.
      
      - Moreover, if the list of language extensions fit into a single
        `{-# LANGUAGE ... -#}`-line (shorter than 80 characters), keep it on one
        line. Otherwise split into `{-# LANGUAGE ... -#}`-lines for each
        individual language extension. In both cases, try to keep the
        enumeration alphabetically ordered.
        (The latter layout is preferable as it's more diff-friendly)
      
      While at it, this also replaces obsolete `{-# OPTIONS ... #-}` pragma
      occurences by `{-# OPTIONS_GHC ... #-}` pragmas.
      23892440
  30. 08 Apr, 2014 1 commit
    • Simon Peyton Jones's avatar
      Allow a longer demand signature than arity · 848f5952
      Simon Peyton Jones authored
      See Note [Demand analysis for trivial right-hand sides] in DmdAnal.
      This allows a function with arity 2 to have a DmdSig with 3 args;
      which in turn had a knock-on effect, which showed up in the test for
      Trac #8963.
      
      In fact it seems entirely reasonable, so this patch removes the
      WARN and CoreLint checks that were complaining.
      848f5952
  31. 06 Mar, 2014 2 commits
    • Simon Peyton Jones's avatar
      Make the demand on a binder compatible with type (fixes Trac #8569) · 4b355cd2
      Simon Peyton Jones authored
      Because of GADTs and casts we were getting binders whose
      demand annotation was more deeply nested than made sense
      for its type.
      
      See Note [Trimming a demand to a type], in Demand.lhs,
      which I reproduce here:
      
         Note [Trimming a demand to a type]
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         Consider this:
      
           f :: a -> Bool
           f x = case ... of
                   A g1 -> case (x |> g1) of (p,q) -> ...
                   B    -> error "urk"
      
         where A,B are the constructors of a GADT.  We'll get a U(U,U) demand
         on x from the A branch, but that's a stupid demand for x itself, which
         has type 'a'. Indeed we get ASSERTs going off (notably in
         splitUseProdDmd, Trac #8569).
      
         Bottom line: we really don't want to have a binder whose demand is more
         deeply-nested than its type.  There are various ways to tackle this.
         When processing (x |> g1), we could "trim" the incoming demand U(U,U)
         to match x's type.  But I'm currently doing so just at the moment when
         we pin a demand on a binder, in DmdAnal.findBndrDmd.
      4b355cd2
    • Simon Peyton Jones's avatar
      Add some debug tracing · eeb1400a
      Simon Peyton Jones authored
      eeb1400a
  32. 23 Jan, 2014 1 commit
    • Joachim Breitner's avatar
      Some polishing of the demand analyser. · 8d34ae39
      Joachim Breitner authored
      I did some refactoring of the demand analyser, because I was smelling
      some minor code smell. Most of my changes I had to undo, though,
      adding notes and testcases on why the existing code was correct after
      all.
      
      Especially the semantics of the DmdResult is confusing, as it differs in
      a DmdType and a StrictSig.
      
      I got to imrpove the readability of the code for lubDmdType, though.
      
      Also, dmdAnalRhs was a bit fishy in how it removed the demand on
      further arguments of the body, but used the DmdResult. This would be
      wrong if a body would return a demand type of "<L>m" (which currently
      does not happen).  This is now treated better in removeDmdTyArgs.
      8d34ae39
  33. 20 Jan, 2014 1 commit
  34. 16 Dec, 2013 1 commit