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* Make SpecConstr specialise for constant arguments againsimonpj@microsoft.com2007-08-051-65/+83
| | | | | | | | | | | | | | | | | | | | | | | | Consider lvl = Just True foo :: Maybe Bool -> Int -> Int foo (Just True) i = i foo _ i = foo lvl i SpecConstr should specialise foo, but it wasn't doing so (spotted by Roman). Reason: lvl's unfolding wasn't in the cloned version of lvl. Solution: extend the value environment to record top-level bindings too At the same time I made it work if 'lvl' is a lambda, in which case it is again worth specialisg. This meant renaming ConEnv to ValueEnv, and adding a case for 'LambdaVal'. (To make specialisation on lambdas work properly, we have to do lambda lifting as well, but this gets part of the way, and fixes a bug too.)
* Store a SrcSpan instead of a SrcLoc inside a NameSimon Marlow2007-05-111-2/+2
| | | | This has been a long-standing ToDo.
* Fix cloning bugs in SpecConstrsimonpj@microsoft.com2007-05-101-14/+26
| | | | | | | These bugs produced a core-lint error when compiling GHC.PArr with -O2. Roman found and fixed them; this patch also includes some type synonyms to make things a bit clearer.
* Major improvement to SpecConstrsimonpj@microsoft.com2007-02-091-234/+412
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch improves the SpecConstr pass, by a) making it work with join points b) making it generate specialisations transitively As part of it, SpecConstr now carries a substitution with it, which runs over the whole program as it goes. This turned out to be a big win; simplified the implementation quite a bit. I have *disabled* the specialisation on lambdas; it's pretty fragile, and sometimes generates more and more specialisations. Something to come back to, perhaps. I rejigged the flag-handling a bit. Now the specification of passes in DynFlags is a bit nicer; see - optLevelFlags top-level data structure - runWhen function - CoreDoPasses constructor There are now command-line flags -fspec-constr -fliberate-case -fspec-threshold=N which do the obvious thing. -O2 switches on both spec-constr and liberate-case. You can use -fno-liberate-case, -fno-spec-constr after -O2 to switch them off again. The spec-threshold applies to both these transformations; default value 200 for now.
* Do more wild-carding in SpecConstr; I'm not quite sure about this, but it ↵simonpj@microsoft.com2007-02-061-0/+6
| | | | does no harm
* Fix a small bug when comparing patterns for equalitysimonpj@microsoft.com2007-02-061-3/+8
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* Look through Notes when generating and matching RULESsimonpj@microsoft.com2007-02-021-0/+9
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* Remove tracesimonpj@microsoft.com2006-11-291-5/+5
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* Teach SpecConstr how to handle mutually-recursive functionssimonpj@microsoft.com2006-11-291-74/+78
| | | | | | | | | | | | | | | | | | | | | Roman found cases where it was important to do SpecConstr for mutually-recursive definitions. Here is one: foo :: Maybe Int -> Int foo Nothing = 0 foo (Just 0) = foo Nothing foo (Just n) = foo (Just (n-1)) By the time SpecConstr gets to it, it looks like this: lvl = foo Nothing foo Nothing = 0 foo (Just 0) = lvl foo (Just n) = foo (Just (n-1)) Happily, it turns out to be rather straightforward to generalise the transformation to mutually-recursive functions. Look, ma, only 4 extra lines of ocde!
* Comments onlysimonpj@microsoft.com2006-11-291-3/+22
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* Make SpecConstr work right for nullary constructorssimonpj@microsoft.com2006-11-291-41/+40
| | | | | | | | | | | For totally stupid reasons, SpecConstr didn't work for the (particularly easy) case of nullary constructors like True and False. I just had some equations in the wrong order, so that a Var case came first, which matches a nullary constructor, with the constructor-application case afterwards. The fix is easy. I did a bit of refactoring at the same time.
* Make SpecConstr more aggressive, by neglecting reboxingsimonpj@microsoft.com2006-11-241-13/+22
| | | | | | | | | | | | | | | | SpecConstr was conservative about avoiding reboxing (see Note [Reboxing]) but that meant it lost useful opportunities. This patch makes it much more aggressive, but at the risk of doing some reboxing. Actually, the strictness analyser has the same property (it's possible for it to generate reboxing code, and thus increase allocation), but we don't worry so much about that. Maybe we should. Ideally, one would do some more sophisticated analysis that spotted the reboxing cases without excluding the useful ones. But meanwhile, let's try this.
* Major overhaul of the Simplifiersimonpj@microsoft.com2006-11-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This big patch completely overhauls the Simplifier. The simplifier had grown old and crufty, and was hard to understand and maintain. This new version is still quite complicated, because the simplifier does a lot, but it's much easier to understand, for me at least. It does mean that I have touched almost every line of the simplifier, so the diff is a large one. Big changes are these * When simplifying an Expr we generate a simplified Expr plus a bunch of "floats", which are bindings that have floated out of the Expr. Before, this float stuff was returned separately, but not they are embedded in the SimplEnv, which makes the plumbing much easier and more robust. In particular, the SimplEnv already meaintains the "in-scope set", and making that travel with the floats helps to ensure that we always use the right in-scope set. This change has a pervasive effect. * Rather than simplifying the args of a call before trying rules and inlining, we now defer simplifying the args until both rules and inlining have failed, so we're going to leave a call in the result. This avoids the risk of repeatedly simplifying an argument, which was handled by funny ad-hoc flags before. The downside is that we must apply the substitution to the args before rule-matching; and if thep rule doesn't match that is wasted work. But having any rules at all is the exception not the rule, and the substitution is lazy, so we only substitute until a no-match is found. The code is much more elegant though. * A SimplCont is now more zipper-like. It used to have an embedded function, but that was a bit hard to think about, and now it's nice and consistent. The relevant constructors are StrictArg and StrictBind * Each Rule now has an *arity* (gotten by CoreSyn.ruleArity), which tells how many arguments it matches against. This entailed adding a field ru_nargs to a BuiltinRule. And that made me look at PrelRules; I did quite a bit of refactoring in the end, so the diff in PrelRules looks much biggger than it really is. * A little refactoring in OccurAnal. The key change is that in the RHS of x = y `cast` co we regard 'y' as "many", so that it doesn't get inlined into the RHS of x. This allows x to be inlined elsewhere. It's very like the existing situation for x = Just y where we treat 'y' as "many".
* Teach SpecConstr about Cast2006-10-05simonpj@microsoft.com2006-10-051-10/+46
| | | | | This patch teaches SpecConstr about casts; see Note [SpecConstr for casts]
* Improve specialisation in SpecConstrsimonpj@microsoft.com2006-09-221-0/+7
| | | | | | | | | | This patch enables argToPat to look through let expressions e.g. f (let v = rhs in \y -> ...v...) Here we can specialise for f (\y -> ...) because the rule-matcher will look through the let.
* Remove use of isVanillaDataCon, which was wrong under the new FC dispensationsimonpj@microsoft.com2006-09-221-4/+1
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* Trim imports, reformattingsimonpj@microsoft.com2006-09-221-13/+5
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* Adapt new SpecConstr functionality to GADT dataconsManuel M T Chakravarty2006-09-191-2/+3
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* Massive patch for the first months work adding System FC to GHC #31Manuel M T Chakravarty2006-09-151-22/+4
| | | | | | | | | | | Fri Aug 4 18:13:56 EDT 2006 Manuel M T Chakravarty <chak@cse.unsw.edu.au> * Massive patch for the first months work adding System FC to GHC #31 Broken up massive patch -=chak Original log message: This is (sadly) all done in one patch to avoid Darcs bugs. It's not complete work... more FC stuff to come. A compiler using just this patch will fail dismally.
* Add missing Cast cases to libCase and scExprkevind@bu.edu2006-08-011-0/+2
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* Tuning for argToPatsimonpj@microsoft.com2006-08-161-27/+27
| | | | | | | argToPat is a crucial function for SpecConstr, because it decides what patterns are worth specialising. I was being much too gung-ho about constants. This patch makes it much better.
* Refactoring, plus record recursive-function *components* as RecArg toosimonpj@microsoft.com2006-08-161-50/+55
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* Record constructor arg occs correctly (bug-fix)simonpj@microsoft.com2006-08-161-10/+30
| | | | | I was forgetting the non-pattern-matched type args of a constructor.
* SpecConstr now specialises on constants and lambdas simonpj@microsoft.com2006-08-151-111/+210
| | | | | | | | | | | | | | | | Roman inspired me to beef up SpecConstr to deal with a) constant arguments b) lambda arguments This is described in elaborate comments in the file: Note [Specialising for constant parameters] Note [Specialising for lambda parameters] I also took the opportunity to fix the usage analysis done by SpecConstr, which was only handling the top-level correctly. Now it does nesting too.
* Comments about improvements to SpecConstrsimonpj@microsoft.com2006-08-101-66/+112
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* Add comments to SpecConstrsimonpj@microsoft.com2006-06-271-0/+136
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* Make SpecConstr work better for nested functionssimonpj@microsoft.com2006-06-271-1/+7
| | | | | | | | | In SpecConstr.scBind, we should pass the optimised body (body') to specialise, not the un-optimised one. In this way we'll benefit from specialising any nested functions inside body. Discovered by Roman.
* More SpecConstr tuningsimonpj@microsoft.com2006-06-261-5/+15
| | | | | | | | | For some reason, SpecConstr wasn't taking account of let-bound constructors: let v = Just 4 in ...(f v)... Now it does. An easy fix fortunately.
* Run simplifier before SpecConstrsimonpj@microsoft.com2006-05-231-1/+29
| | | | | | | | | | | | Arrange to run the simplifier before SpecConstr, to (almost entirely) eliminate shadowing. Reason: otherwise SpecConstr can generate a RULE that never files; and LiberateCase specifically *does* generate lots of shadowing. See Note [Shadowing] in SpecConstr.lhs
* Fix constructor-specialisation bugsimonpj@microsoft.com2006-05-041-12/+17
| | | | | | | | | | | | | | | The constructor-specialisation optimisation was not dealing with the case of (letrec ... in f) a1 a2 We need to apply constructor specialisation in the letrec; previously we were leaving it untouched on the grounds that the function part of an application is almost always a variable. But in fact, float-in immediately precedes SpecConstr, so we can get these odd-looking applications.
* Cosmetics in SpecConstrsimonpj@microsoft.com2006-04-121-1/+4
| | | | | | | | | | | SpecConstr currently uses substExpr for tiresome reasons to do with GADTs. Unfortunately the substExpr generates some WARNINGS (when DEBUG) is on, because we aren't adding all the in-scope Ids to the in-scope set of the substitution. When we move to FC these substExprs will go away, so I'm not going to worry about this now.
* Reorganisation of the source treeSimon Marlow2006-04-071-0/+625
Most of the other users of the fptools build system have migrated to Cabal, and with the move to darcs we can now flatten the source tree without losing history, so here goes. The main change is that the ghc/ subdir is gone, and most of what it contained is now at the top level. The build system now makes no pretense at being multi-project, it is just the GHC build system. No doubt this will break many things, and there will be a period of instability while we fix the dependencies. A straightforward build should work, but I haven't yet fixed binary/source distributions. Changes to the Building Guide will follow, too.
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