1. 30 Aug, 2010 8 commits
  2. 31 May, 2010 1 commit
    • simonpj@microsoft.com's avatar
      Robustify the treatement of DFunUnfolding · a90dc390
      simonpj@microsoft.com authored
      See Note [DFun unfoldings] in CoreSyn.  The issue here is that 
      you can't tell how many dictionary arguments a DFun needs just
      from looking at the Arity of the DFun Id: if the dictionary is
      represented by a newtype the arity might include the dictionary
      and value arguments of the (single) method.
      So we need to record the number of arguments need by the DFun
      in the DFunUnfolding itself.  Details in 
         Note [DFun unfoldings] in CoreSyn
  3. 07 Jun, 2010 2 commits
  4. 04 Jun, 2010 1 commit
  5. 01 Jun, 2010 1 commit
  6. 24 May, 2010 1 commit
  7. 06 May, 2010 1 commit
    • simonpj@microsoft.com's avatar
      Fix Trac #3966: warn about useless UNPACK pragmas · 215ce9f1
      simonpj@microsoft.com authored
      Warning about useless UNPACK pragmas wasn't as easy as I thought.
      I did quite a bit of refactoring, which improved the code by refining
      the types somewhat.  In particular notice that in DataCon, we have
          dcStrictMarks   :: [HsBang]
          dcRepStrictness :: [StrictnessMarks]
      The former relates to the *source-code* annotation, the latter to
      GHC's representation choice.
  8. 16 Mar, 2010 1 commit
  9. 11 Mar, 2010 1 commit
  10. 06 Jan, 2010 1 commit
    • simonpj@microsoft.com's avatar
      Improve the handling of default methods · 77166b17
      simonpj@microsoft.com authored
      See the long Note [INLINE and default methods].  
      This patch changes a couple of data types, with a knock-on effect on
      the format of interface files.  A lot of files get touched, but is a
      relatively minor change.  The main tiresome bit is the extra plumbing
      to communicate default methods between the type checker and the
  11. 03 Dec, 2009 1 commit
  12. 02 Dec, 2009 1 commit
    • simonpj@microsoft.com's avatar
      More work on the simplifier's inlining strategies · c86161c5
      simonpj@microsoft.com authored
      This patch collects a small raft of related changes
      * Arrange that during 
           (a) rule matching and 
           (b) uses of exprIsConApp_maybe
        we "look through" unfoldings only if they are active
        in the phase. Doing this for (a) required a bit of 
        extra plumbing in the rule matching code, but I think
        it's worth it.
        One wrinkle is that even if inlining is off (in the 'gentle'
        phase of simplification) during rule matching we want to
        "look through" things with inlinings.  
         See SimplUtils.activeUnfInRule.
        This fixes a long-standing bug, where things that were
        supposed to be (say) NOINLINE, could still be poked into
        via exprIsConApp_maybe. 
      * In the above cases, also check for (non-rule) loop breakers; 
        we never look through these.  This fixes a bug that could make
        the simplifier diverge (and did for Roman).  
        Test = simplCore/should_compile/dfun-loop
      * Try harder not to choose a DFun as a loop breaker. This is 
        just a small adjustment in the OccurAnal scoring function
      * In the scoring function in OccurAnal, look at the InlineRule
        unfolding (if there is one) not the actual RHS, beause the
        former is what'll be inlined.  
      * Make the application of any function to dictionary arguments
        CONLIKE.  Thus (f d1 d2) is CONLIKE.  
        Encapsulated in CoreUtils.isExpandableApp
        Reason: see Note [Expandable overloadings] in CoreUtils
      * Make case expressions seem slightly smaller in CoreUnfold.
        This reverses an unexpected consequences of charging for
      * Signficantly refactor the data type for Unfolding (again). 
        The result is much nicer.  
      * Add type synonym BasicTypes.CompilerPhase = Int
        and use it
      Many of the files touched by this patch are simply knock-on
      consequences of these two refactorings.
  13. 12 Nov, 2009 1 commit
  14. 09 Nov, 2009 1 commit
  15. 30 Oct, 2009 3 commits
  16. 29 Oct, 2009 1 commit
    • simonpj@microsoft.com's avatar
      The Big INLINE Patch: totally reorganise way that INLINE pragmas work · 72462499
      simonpj@microsoft.com authored
      This patch has been a long time in gestation and has, as a
      result, accumulated some extra bits and bobs that are only
      loosely related.  I separated the bits that are easy to split
      off, but the rest comes as one big patch, I'm afraid.
      Note that:
       * It comes together with a patch to the 'base' library
       * Interface file formats change slightly, so you need to
         recompile all libraries
      The patch is mainly giant tidy-up, driven in part by the
      particular stresses of the Data Parallel Haskell project. I don't
      expect a big performance win for random programs.  Still, here are the
      nofib results, relative to the state of affairs without the patch
              Program           Size    Allocs   Runtime   Elapsed
                  Min         -12.7%    -14.5%    -17.5%    -17.8%
                  Max          +4.7%    +10.9%     +9.1%     +8.4%
       Geometric Mean          +0.9%     -0.1%     -5.6%     -7.3%
      The +10.9% allocation outlier is rewrite, which happens to have a
      very delicate optimisation opportunity involving an interaction
      of CSE and inlining (see nofib/Simon-nofib-notes). The fact that
      the 'before' case found the optimisation is somewhat accidental.
      Runtimes seem to go down, but I never kno wwhether to really trust
      this number.  Binary sizes wobble a bit, but nothing drastic.
      The Main Ideas are as follows.
      When you say 
            {-# INLINE f #-}
            f x = <rhs>
      you intend that calls (f e) are replaced by <rhs>[e/x] So we
      should capture (\x.<rhs>) in the Unfolding of 'f', and never meddle
      with it.  Meanwhile, we can optimise <rhs> to our heart's content,
      leaving the original unfolding intact in Unfolding of 'f'.
      So the representation of an Unfolding has changed quite a bit
      (see CoreSyn).  An INLINE pragma gives rise to an InlineRule 
      Moreover, it's only used when 'f' is applied to the
      specified number of arguments; that is, the number of argument on 
      the LHS of the '=' sign in the original source definition. 
      For example, (.) is now defined in the libraries like this
         {-# INLINE (.) #-}
         (.) f g = \x -> f (g x)
      so that it'll inline when applied to two arguments. If 'x' appeared
      on the left, thus
         (.) f g x = f (g x)
      it'd only inline when applied to three arguments.  This slightly-experimental
      change was requested by Roman, but it seems to make sense.
      Other associated changes
      * Moving the deck chairs in DsBinds, which processes the INLINE pragmas
      * In the old system an INLINE pragma made the RHS look like
         (Note InlineMe <rhs>)
        The Note switched off optimisation in <rhs>.  But it was quite
        fragile in corner cases. The new system is more robust, I believe.
        In any case, the InlineMe note has disappeared 
      * The workerInfo of an Id has also been combined into its Unfolding,
        so it's no longer a separate field of the IdInfo.
      * Many changes in CoreUnfold, esp in callSiteInline, which is the critical
        function that decides which function to inline.  Lots of comments added!
      * exprIsConApp_maybe has moved to CoreUnfold, since it's so strongly
        associated with "does this expression unfold to a constructor application".
        It can now do some limited beta reduction too, which Roman found 
        was an important.
      Instance declarations
      It's always been tricky to get the dfuns generated from instance
      declarations to work out well.  This is particularly important in 
      the Data Parallel Haskell project, and I'm now on my fourth attempt,
      more or less.
      There is a detailed description in TcInstDcls, particularly in
      Note [How instance declarations are translated].   Roughly speaking
      we now generate a top-level helper function for every method definition
      in an instance declaration, so that the dfun takes a particularly
      stylised form:
        dfun a d1 d2 = MkD (op1 a d1 d2) (op2 a d1 d2) ...etc...
      In fact, it's *so* stylised that we never need to unfold a dfun.
      Instead ClassOps have a special rewrite rule that allows us to
      short-cut dictionary selection.  Suppose dfun :: Ord a -> Ord [a]
                                                  d :: Ord a
          compare (dfun a d)  -->   compare_list a d 
      in one rewrite, without first inlining the 'compare' selector
      and the body of the dfun.
      To support this
      a) ClassOps have a BuiltInRule (see MkId.dictSelRule)
      b) DFuns have a special form of unfolding (CoreSyn.DFunUnfolding)
         which is exploited in CoreUnfold.exprIsConApp_maybe
      Implmenting all this required a root-and-branch rework of TcInstDcls
      and bits of TcClassDcl.
      Default methods
      If you give an INLINE pragma to a default method, it should be just
      as if you'd written out that code in each instance declaration, including
      the INLINE pragma.  I think that it now *is* so.  As a result, library
      code can be simpler; less duplication.
      The CONLIKE pragma
      In the DPH project, Roman found cases where he had
         p n k = let x = replicate n k
                 in ...(f x)...(g x)....
         {-# RULE f (replicate x) = f_rep x #-}
      Normally the RULE would not fire, because doing so involves 
      (in effect) duplicating the redex (replicate n k).  A new
      experimental modifier to the INLINE pragma, {-# INLINE CONLIKE
      replicate #-}, allows you to tell GHC to be prepared to duplicate
      a call of this function if it allows a RULE to fire.
      See Note [CONLIKE pragma] in BasicTypes
      Join points
      See Note [Case binders and join points] in Simplify
      Other refactoring
      * I moved endPass from CoreLint to CoreMonad, with associated jigglings
      * Better pretty-printing of Core
      * The top-level RULES (ones that are not rules for locally-defined things)
        are now substituted on every simplifier iteration.  I'm not sure how
        we got away without doing this before.  This entails a bit more plumbing
        in SimplCore.
      * The necessary stuff to serialise and deserialise the new
        info across interface files.
      * Something about bottoming floats in SetLevels
            Note [Bottoming floats]
      * substUnfolding has moved from SimplEnv to CoreSubs, where it belongs
              Program           Size    Allocs   Runtime   Elapsed
                 anna          +2.4%     -0.5%      0.16      0.17
                 ansi          +2.6%     -0.1%      0.00      0.00
                 atom          -3.8%     -0.0%     -1.0%     -2.5%
               awards          +3.0%     +0.7%      0.00      0.00
               banner          +3.3%     -0.0%      0.00      0.00
           bernouilli          +2.7%     +0.0%     -4.6%     -6.9%
                boyer          +2.6%     +0.0%      0.06      0.07
               boyer2          +4.4%     +0.2%      0.01      0.01
                 bspt          +3.2%     +9.6%      0.02      0.02
            cacheprof          +1.4%     -1.0%    -12.2%    -13.6%
             calendar          +2.7%     -1.7%      0.00      0.00
             cichelli          +3.7%     -0.0%      0.13      0.14
              circsim          +3.3%     +0.0%     -2.3%     -9.9%
             clausify          +2.7%     +0.0%      0.05      0.06
        comp_lab_zift          +2.6%     -0.3%     -7.2%     -7.9%
             compress          +3.3%     +0.0%     -8.5%     -9.6%
            compress2          +3.6%     +0.0%    -15.1%    -17.8%
          constraints          +2.7%     -0.6%    -10.0%    -10.7%
         cryptarithm1          +4.5%     +0.0%     -4.7%     -5.7%
         cryptarithm2          +4.3%    -14.5%      0.02      0.02
                  cse          +4.4%     -0.0%      0.00      0.00
                eliza          +2.8%     -0.1%      0.00      0.00
                event          +2.6%     -0.0%     -4.9%     -4.4%
               exp3_8          +2.8%     +0.0%     -4.5%     -9.5%
               expert          +2.7%     +0.3%      0.00      0.00
                  fem          -2.0%     +0.6%      0.04      0.04
                  fft          -6.0%     +1.8%      0.05      0.06
                 fft2          -4.8%     +2.7%      0.13      0.14
             fibheaps          +2.6%     -0.6%      0.05      0.05
                 fish          +4.1%     +0.0%      0.03      0.04
                fluid          -2.1%     -0.2%      0.01      0.01
               fulsom          -4.8%     +9.2%     +9.1%     +8.4%
               gamteb          -7.1%     -1.3%      0.10      0.11
                  gcd          +2.7%     +0.0%      0.05      0.05
          gen_regexps          +3.9%     -0.0%      0.00      0.00
               genfft          +2.7%     -0.1%      0.05      0.06
                   gg          -2.7%     -0.1%      0.02      0.02
                 grep          +3.2%     -0.0%      0.00      0.00
               hidden          -0.5%     +0.0%    -11.9%    -13.3%
                  hpg          -3.0%     -1.8%     +0.0%     -2.4%
                  ida          +2.6%     -1.2%      0.17     -9.0%
                infer          +1.7%     -0.8%      0.08      0.09
              integer          +2.5%     -0.0%     -2.6%     -2.2%
            integrate          -5.0%     +0.0%     -1.3%     -2.9%
              knights          +4.3%     -1.5%      0.01      0.01
                 lcss          +2.5%     -0.1%     -7.5%     -9.4%
                 life          +4.2%     +0.0%     -3.1%     -3.3%
                 lift          +2.4%     -3.2%      0.00      0.00
            listcompr          +4.0%     -1.6%      0.16      0.17
             listcopy          +4.0%     -1.4%      0.17      0.18
             maillist          +4.1%     +0.1%      0.09      0.14
               mandel          +2.9%     +0.0%      0.11      0.12
              mandel2          +4.7%     +0.0%      0.01      0.01
              minimax          +3.8%     -0.0%      0.00      0.00
              mkhprog          +3.2%     -4.2%      0.00      0.00
           multiplier          +2.5%     -0.4%     +0.7%     -1.3%
             nucleic2          -9.3%     +0.0%      0.10      0.10
                 para          +2.9%     +0.1%     -0.7%     -1.2%
            paraffins         -10.4%     +0.0%      0.20     -1.9%
               parser          +3.1%     -0.0%      0.05      0.05
              parstof          +1.9%     -0.0%      0.00      0.01
                  pic          -2.8%     -0.8%      0.01      0.02
                power          +2.1%     +0.1%     -8.5%     -9.0%
               pretty         -12.7%     +0.1%      0.00      0.00
               primes          +2.8%     +0.0%      0.11      0.11
            primetest          +2.5%     -0.0%     -2.1%     -3.1%
               prolog          +3.2%     -7.2%      0.00      0.00
               puzzle          +4.1%     +0.0%     -3.5%     -8.0%
               queens          +2.8%     +0.0%      0.03      0.03
              reptile          +2.2%     -2.2%      0.02      0.02
              rewrite          +3.1%    +10.9%      0.03      0.03
                 rfib          -5.2%     +0.2%      0.03      0.03
                  rsa          +2.6%     +0.0%      0.05      0.06
                  scc          +4.6%     +0.4%      0.00      0.00
                sched          +2.7%     +0.1%      0.03      0.03
                  scs          -2.6%     -0.9%     -9.6%    -11.6%
               simple          -4.0%     +0.4%    -14.6%    -14.9%
                solid          -5.6%     -0.6%     -9.3%    -14.3%
              sorting          +3.8%     +0.0%      0.00      0.00
               sphere          -3.6%     +8.5%      0.15      0.16
               symalg          -1.3%     +0.2%      0.03      0.03
                  tak          +2.7%     +0.0%      0.02      0.02
            transform          +2.0%     -2.9%     -8.0%     -8.8%
             treejoin          +3.1%     +0.0%    -17.5%    -17.8%
            typecheck          +2.9%     -0.3%     -4.6%     -6.6%
              veritas          +3.9%     -0.3%      0.00      0.00
                 wang          -6.2%     +0.0%      0.18     -9.8%
            wave4main         -10.3%     +2.6%     -2.1%     -2.3%
         wheel-sieve1          +2.7%     -0.0%     +0.3%     -0.6%
         wheel-sieve2          +2.7%     +0.0%     -3.7%     -7.5%
                 x2n1          -4.1%     +0.1%      0.03      0.04
                  Min         -12.7%    -14.5%    -17.5%    -17.8%
                  Max          +4.7%    +10.9%     +9.1%     +8.4%
       Geometric Mean          +0.9%     -0.1%     -5.6%     -7.3%
  17. 16 Oct, 2009 1 commit
  18. 15 Oct, 2009 4 commits
  19. 13 Jul, 2009 2 commits
  20. 07 Jul, 2009 1 commit
  21. 03 Jun, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Allow RULES for seq, and exploit them · 90ce88a0
      simonpj@microsoft.com authored
      Roman found situations where he had
            case (f n) of _ -> e
      where he knew that f (which was strict in n) would terminate if n did.
      Notice that the result of (f n) is discarded. So it makes sense to
      transform to
            case n of _ -> e
      Rather than attempt some general analysis to support this, I've added
      enough support that you can do this using a rewrite rule:
        RULE "f/seq" forall n.  seq (f n) e = seq n e
      You write that rule.  When GHC sees a case expression that discards
      its result, it mentally transforms it to a call to 'seq' and looks for
      a RULE.  (This is done in Simplify.rebuildCase.)  As usual, the
      correctness of the rule is up to you.
      This patch implements the extra stuff.  I have not documented it explicitly
      in the user manual yet... let's see how useful it is first.
      The patch looks bigger than it is, because
        a) Comments; see esp MkId Note [seqId magic]
        b) Some refactoring.  Notably, I moved the special desugaring for
           seq from MkCore back into DsUtils where it properly belongs.
           (It's really a desugaring thing, not a CoreSyn invariant.)
        c) Annoyingly, in a RULE left-hand side we need to be careful that
           the magical desugaring done in MkId Note [seqId magic] item (c) 
           is *not* done on the LHS of a rule. Or rather, we arrange to 
           un-do it, in DsBinds.decomposeRuleLhs.
  22. 07 Mar, 2009 1 commit
  23. 06 Mar, 2009 2 commits
  24. 02 Jan, 2009 1 commit
    • simonpj@microsoft.com's avatar
      Make record selectors into ordinary functions · 9ffadf21
      simonpj@microsoft.com authored
      This biggish patch addresses Trac #2670.  The main effect is to make
      record selectors into ordinary functions, whose unfoldings appear in
      interface files, in contrast to their previous existence as magic
      "implicit Ids".  This means that the usual machinery of optimisation,
      analysis, and inlining applies to them, which was failing before when
      the selector was somewhat complicated.  (Which it can be when
      strictness annotations, unboxing annotations, and GADTs are involved.)
      The change involves the following points
      * Changes in Var.lhs to the representation of Var.  Now a LocalId can
        have an IdDetails as well as a GlobalId.  In particular, the
        information that an Id is a record selector is kept in the
        IdDetails.  While compiling the current module, the record selector
        *must* be a LocalId, so that it participates properly in compilation
        (free variables etc).
        This led me to change the (hidden) representation of Var, so that there
        is now only one constructor for Id, not two.
      * The IdDetails is persisted into interface files, so that an
        importing module can see which Ids are records selectors.
      * In TcTyClDecls, we generate the record-selector bindings in renamed,
        but not typechecked form.  In this way, we can get the typechecker
        to add all the types and so on, which is jolly helpful especially
        when GADTs or type families are involved.  Just like derived
        instance declarations.
        This is the big new chunk of 180 lines of code (much of which is
        commentary).  A call to the same function, mkAuxBinds, is needed in
        TcInstDcls for associated types.
      * The typechecker therefore has to pin the correct IdDetails on to 
        the record selector, when it typechecks it.  There was a neat way
        to do this, by adding a new sort of signature to HsBinds.Sig, namely
        IdSig.  This contains an Id (with the correct Name, Type, and IdDetails);
        the type checker uses it as the binder for the final binding.  This
        worked out rather easily.
      * Record selectors are no longer "implicit ids", which entails changes to
        (These three functions must agree.)
      * MkId.mkRecordSelectorId is deleted entirely, some 300+ lines (incl
        comments) of very error prone code.  Happy days.
      * A TyCon no longer contains the list of record selectors: 
        algTcSelIds is gone
      The renamer is unaffected, including the way that import and export of
      record selectors is handled.
      Other small things
      * IfaceSyn.ifaceDeclSubBndrs had a fragile test for whether a data
        constructor had a wrapper.  I've replaced that with an explicit flag
        in the interface file. More robust I hope.
      * I renamed isIdVar to isId, which touched a few otherwise-unrelated files.
  25. 16 Dec, 2008 1 commit
    • Simon Marlow's avatar
      Rollback INLINE patches · e79c9ce0
      Simon Marlow authored
      rolling back:
      Fri Dec  5 16:54:00 GMT 2008  simonpj@microsoft.com
        * Completely new treatment of INLINE pragmas (big patch)
        This is a major patch, which changes the way INLINE pragmas work.
        Although lots of files are touched, the net is only +21 lines of
        code -- and I bet that most of those are comments!
        HEADS UP: interface file format has changed, so you'll need to
        recompile everything.
        There is not much effect on overall performance for nofib, 
        probably because those programs don't make heavy use of INLINE pragmas.
                Program           Size    Allocs   Runtime   Elapsed
                    Min         -11.3%     -6.9%     -9.2%     -8.2%
                    Max          -0.1%     +4.6%     +7.5%     +8.9%
         Geometric Mean          -2.2%     -0.2%     -1.0%     -0.8%
        (The +4.6% for on allocs is cichelli; see other patch relating to
        The old INLINE system
        The old system worked like this. A function with an INLINE pragam
        got a right-hand side which looked like
             f = __inline_me__ (\xy. e)
        The __inline_me__ part was an InlineNote, and was treated specially
        in various ways.  Notably, the simplifier didn't inline inside an
        __inline_me__ note.  
        As a result, the code for f itself was pretty crappy. That matters
        if you say (map f xs), because then you execute the code for f,
        rather than inlining a copy at the call site.
        The new story: InlineRules
        The new system removes the InlineMe Note altogether.  Instead there
        is a new constructor InlineRule in CoreSyn.Unfolding.  This is a 
        bit like a RULE, in that it remembers the template to be inlined inside
        the InlineRule.  No simplification or inlining is done on an InlineRule,
        just like RULEs.  
        An Id can have an InlineRule *or* a CoreUnfolding (since these are two
        constructors from Unfolding). The simplifier treats them differently:
          - An InlineRule is has the substitution applied (like RULES) but 
            is otherwise left undisturbed.
          - A CoreUnfolding is updated with the new RHS of the definition,
            on each iteration of the simplifier.
        An InlineRule fires regardless of size, but *only* when the function
        is applied to enough arguments.  The "arity" of the rule is specified
        (by the programmer) as the number of args on the LHS of the "=".  So
        it makes a difference whether you say
          	{-# INLINE f #-}
        	f x = \y -> e     or     f x y = e
        This is one of the big new features that InlineRule gives us, and it
        is one that Roman really wanted.
        In contrast, a CoreUnfolding can fire when it is applied to fewer
        args than than the function has lambdas, provided the result is small
        Consequential stuff
        * A 'wrapper' no longer has a WrapperInfo in the IdInfo.  Instead,
          the InlineRule has a field identifying wrappers.
        * Of course, IfaceSyn and interface serialisation changes appropriately.
        * Making implication constraints inline nicely was a bit fiddly. In
          the end I added a var_inline field to HsBInd.VarBind, which is why
          this patch affects the type checker slightly
        * I made some changes to the way in which eta expansion happens in
          CorePrep, mainly to ensure that *arguments* that become let-bound
          are also eta-expanded.  I'm still not too happy with the clarity
          and robustness fo the result.
        * We now complain if the programmer gives an INLINE pragma for
          a recursive function (prevsiously we just ignored it).  Reason for
          change: we don't want an InlineRule on a LoopBreaker, because then
          we'd have to check for loop-breaker-hood at occurrence sites (which
          isn't currenlty done).  Some tests need changing as a result.
        This patch has been in my tree for quite a while, so there are
        probably some other minor changes.
          M ./compiler/basicTypes/Id.lhs -11
          M ./compiler/basicTypes/IdInfo.lhs -82
          M ./compiler/basicTypes/MkId.lhs -2 +2
          M ./compiler/coreSyn/CoreFVs.lhs -2 +25
          M ./compiler/coreSyn/CoreLint.lhs -5 +1
          M ./compiler/coreSyn/CorePrep.lhs -59 +53
          M ./compiler/coreSyn/CoreSubst.lhs -22 +31
          M ./compiler/coreSyn/CoreSyn.lhs -66 +92
          M ./compiler/coreSyn/CoreUnfold.lhs -112 +112
          M ./compiler/coreSyn/CoreUtils.lhs -185 +184
          M ./compiler/coreSyn/MkExternalCore.lhs -1
          M ./compiler/coreSyn/PprCore.lhs -4 +40
          M ./compiler/deSugar/DsBinds.lhs -70 +118
          M ./compiler/deSugar/DsForeign.lhs -2 +4
          M ./compiler/deSugar/DsMeta.hs -4 +3
          M ./compiler/hsSyn/HsBinds.lhs -3 +3
          M ./compiler/hsSyn/HsUtils.lhs -2 +7
          M ./compiler/iface/BinIface.hs -11 +25
          M ./compiler/iface/IfaceSyn.lhs -13 +21
          M ./compiler/iface/MkIface.lhs -24 +19
          M ./compiler/iface/TcIface.lhs -29 +23
          M ./compiler/main/TidyPgm.lhs -55 +49
          M ./compiler/parser/ParserCore.y -5 +6
          M ./compiler/simplCore/CSE.lhs -2 +1
          M ./compiler/simplCore/FloatIn.lhs -6 +1
          M ./compiler/simplCore/FloatOut.lhs -23
          M ./compiler/simplCore/OccurAnal.lhs -36 +5
          M ./compiler/simplCore/SetLevels.lhs -59 +54
          M ./compiler/simplCore/SimplCore.lhs -48 +52
          M ./compiler/simplCore/SimplEnv.lhs -26 +22
          M ./compiler/simplCore/SimplUtils.lhs -28 +4
          M ./compiler/simplCore/Simplify.lhs -91 +109
          M ./compiler/specialise/Specialise.lhs -15 +18
          M ./compiler/stranal/WorkWrap.lhs -14 +11
          M ./compiler/stranal/WwLib.lhs -2 +2
          M ./compiler/typecheck/Inst.lhs -1 +3
          M ./compiler/typecheck/TcBinds.lhs -17 +27
          M ./compiler/typecheck/TcClassDcl.lhs -1 +2
          M ./compiler/typecheck/TcExpr.lhs -4 +6
          M ./compiler/typecheck/TcForeign.lhs -1 +1
          M ./compiler/typecheck/TcGenDeriv.lhs -14 +13
          M ./compiler/typecheck/TcHsSyn.lhs -3 +2
          M ./compiler/typecheck/TcInstDcls.lhs -5 +4
          M ./compiler/typecheck/TcRnDriver.lhs -2 +11
          M ./compiler/typecheck/TcSimplify.lhs -10 +17
          M ./compiler/vectorise/VectType.hs +7
      Mon Dec  8 12:43:10 GMT 2008  simonpj@microsoft.com
        * White space only
          M ./compiler/simplCore/Simplify.lhs -2
      Mon Dec  8 12:48:40 GMT 2008  simonpj@microsoft.com
        * Move simpleOptExpr from CoreUnfold to CoreSubst
          M ./compiler/coreSyn/CoreSubst.lhs -1 +87
          M ./compiler/coreSyn/CoreUnfold.lhs -72 +1
      Mon Dec  8 17:30:18 GMT 2008  simonpj@microsoft.com
        * Use CoreSubst.simpleOptExpr in place of the ad-hoc simpleSubst (reduces code too)
          M ./compiler/deSugar/DsBinds.lhs -50 +16
      Tue Dec  9 17:03:02 GMT 2008  simonpj@microsoft.com
        * Fix Trac #2861: bogus eta expansion
        Urghlhl!  I "tided up" the treatment of the "state hack" in CoreUtils, but
        missed an unexpected interaction with the way that a bottoming function
        simply swallows excess arguments.  There's a long
             Note [State hack and bottoming functions]
        to explain (which accounts for most of the new lines of code).
          M ./compiler/coreSyn/CoreUtils.lhs -16 +53
      Mon Dec 15 10:02:21 GMT 2008  Simon Marlow <marlowsd@gmail.com>
        * Revert CorePrep part of "Completely new treatment of INLINE pragmas..."
        The original patch said:
        * I made some changes to the way in which eta expansion happens in
          CorePrep, mainly to ensure that *arguments* that become let-bound
          are also eta-expanded.  I'm still not too happy with the clarity
          and robustness fo the result.
        Unfortunately this change apparently broke some invariants that were
        relied on elsewhere, and in particular lead to panics when compiling
        with profiling on.
        Will re-investigate in the new year.
          M ./compiler/coreSyn/CorePrep.lhs -53 +58
          M ./configure.ac -1 +1
      Mon Dec 15 12:28:51 GMT 2008  Simon Marlow <marlowsd@gmail.com>
        * revert accidental change to configure.ac
          M ./configure.ac -1 +1