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* Tracing in OccAnal (commented out)Simon Peyton Jones2017-08-181-3/+4
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* CSE.cseOneExpr: Set InScopeSet correctlyJoachim Breitner2017-08-181-2/+8
| | | | | because this is a convenience function for API users, calculate the in-scope set from `exprFreeVars`.
* Simplify OccurAnal.tagRecBindersJoachim Breitner2017-08-011-6/+3
| | | | | | | No need to mark the binders with markNonTailCalled, as they already have been marked as such in rhs_udss' via adjust. Differential Revision: https://phabricator.haskell.org/D3810
* Typofixes [ci skip]Gabor Greif2017-08-011-1/+1
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* A bunch of typofixesGabor Greif2017-07-312-2/+2
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* Do a bit more CSESimon Peyton Jones2017-07-311-1/+1
| | | | | | | | I discovered that in let x = MkT y in ....(MKT y |> co).... we weren't CSE'ing the (MkT y). The fix is easy.
* Comments onlySimon Peyton Jones2017-07-261-1/+0
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* Spelling fixesGabor Greif2017-07-202-2/+2
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* More typos in comments [ci skip]Gabor Greif2017-06-281-1/+1
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* Zap stable unfoldings in worker/wrapperSimon Peyton Jones2017-06-281-2/+1
| | | | This patch fixes the buglet described in Trac #13890.
* Use lengthIs and friends in more placesRyan Scott2017-06-023-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Improve error msg for simplifier tick exhaustionDavid Feuer2017-05-191-9/+24
| | | | | | | | | | | | | | | Simplifier tick exhaustion is not necessarily "impossible", and isn't even always a GHC bug, per se. Improve the error message. Furthermore, the simplifier code has access to `IO`, so we can throw a proper `IO` exception instead of panicking. Reviewers: austin, bgamari, angerman Reviewed By: angerman Subscribers: angerman, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3597
* Handle type-lets betterSimon Peyton Jones2017-05-172-7/+11
| | | | | | | | | | | | | | | Core allows non-recursive type-lets, thus let a = TYPE ty in ... They are substituted away very quickly, but it's convenient for some passes to produce them (rather than to have to substitute immediately). Trac #13708 tried the effect of not running the simplifer at all (a rather bizarre thing to do, but still). That showed that some passes crashed because they always treated a let-bounder binder as an Id. This patch adds some easy fixes.
* Typos in comments [ci skip]Gabor Greif2017-05-051-1/+1
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* Fix a small Float-Out bugSimon Peyton Jones2017-05-021-8/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The float-out pass uses a heuristic based on strictness info. But it was getting the strictness info mis-aligned; I'd forgotten that strictness flags only apply to /value/ arguments. This patch fixes it. It has some surprising effects! -------------------------------------------------------------------------------- Program Size Allocs Runtime Elapsed TotalMem -------------------------------------------------------------------------------- integer -0.1% +9.9% +0.2% +0.2% +0.0% lcss +0.0% +0.0% -11.9% -11.9% +0.0% queens -0.2% +29.0% 0.02 0.02 +0.0% simple -0.1% -22.6% -21.7% -21.7% -3.6% treejoin +0.0% +0.0% -12.3% -12.6% +0.0% -------------------------------------------------------------------------------- Min -0.2% -22.6% -21.7% -21.7% -10.0% Max +3.3% +29.0% +19.2% +19.2% +50.0% Geometric Mean +0.0% +0.1% -2.1% -2.1% +0.2% The 'queens' and 'integer' allocation regressions are because, just before let-floatting, we get \v -> foldr k z (case x of I# y -> build ..y..) Becase of Note [Case MFEs] we don't float the build; so fusion happens. This increases allocation in queens because the build isn't shared; but actaully runtime improves solidly. Situation is similar in integer, although I think runtime gets a bit worse. The bug meant that, because of foldr's type arguments, the mis-aligned strictness info meant that the entire (case x ...) was floated, so fusion failed, but sharing happened. This is all very artificial-benchmark-ish so I'm not losing sleep over it. I did see some runtime numbers increasd, but I think it's noise; the differnce went away when I tried them one by one afterwards.
* Join-point refactoringSimon Peyton Jones2017-05-024-469/+540
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This commit has a raft of refactorings that improve the treatment of join points. I wasn't aiming so much as to gain performance as to make the code simpler. The two big things are these: * Make mkDupableCont work for SimplBind as well. This is simpler than I thought and quite neat. (Luke had aready done StrictArg.) That's a win in its own right. But also now /all/ continuations can be made dup-able * Now that all continuations can be made dup-able, I could simplify mkDupableCont to return just one SimplCont, instead of two. That really is a worthwhile simlification! Much easier to think about. Plus a bunch of smaller things: * Remove the join-arity that had been added to seIdSubst. It can be done more simply by putting it in DoneEx, which is the only constructor that actually needs it, and now we don't need the unsavoury isJoinIdInEnv_maybe. * Re-order the handling of join points in Simplify, so that we don't need the horrible resultTypeOfDupableCont * Add field names for StrictBind, StrictArg; and use them * Define simplMonad.newJoinId, and use it * Rename the seFloats field of SimplEnv to seLetFloats Binary sizes seem to go up slightly, but allocations generally improve, sometimes significantly. I don't believe the runtime numbers are reliable enough to draw any conclusions about -------------------------------------------------------------------------------- Program Size Allocs Runtime Elapsed TotalMem -------------------------------------------------------------------------------- event +1.1% -12.0% -0.2% -0.2% -8.7% fulsom +1.9% -11.8% -10.0% -10.0% +5.3% last-piece +2.3% -1.2% -1.2% -1.2% +0.0% mate +0.9% -1.4% -0.6% -0.7% +0.0% multiplier +1.5% -8.3% 0.17 0.17 +0.0% parser +2.0% +1.0% 0.04 0.04 +0.0% parstof +1.5% +0.7% 0.01 0.01 +0.0% sched +1.3% -6.1% 0.03 0.03 +0.0% simple +1.8% +1.0% +9.7% +9.6% +0.0% -------------------------------------------------------------------------------- Min +0.5% -12.0% -10.0% -10.0% -8.7% Max +3.0% +1.0% +14.2% +14.2% +50.0% Geometric Mean +1.4% -0.4% +0.3% +0.4% +0.5% There's also a tests/perf/compiler improvement of 20% allocation in T6048. I think it's because we now generate smaller code.
* Prefer #if defined to #ifdefBen Gamari2017-04-281-3/+3
| | | | Our new CPP linter enforces this.
* Re-engineer caseRules to add tagToEnum/dataToTagSimon Peyton Jones2017-04-281-54/+123
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | See Note [Scrutinee Constant Folding] in SimplUtils * Add cases for tagToEnum and dataToTag. This is the main new bit. It allows the simplifier to remove the pervasive uses of case tagToEnum (a > b) of False -> e1 True -> e2 and replace it by the simpler case a > b of DEFAULT -> e1 1# -> e2 See Note [caseRules for tagToEnum] and Note [caseRules for dataToTag] in PrelRules. * This required some changes to the API of caseRules, and hence to code in SimplUtils. See Note [Scrutinee Constant Folding] in SimplUtils. * Avoid duplication of work in the (unusual) case of case BIG + 3# of b DEFAULT -> e1 6# -> e2 Previously we got case BIG of DEFAULT -> let b = BIG + 3# in e1 3# -> let b = 6# in e2 Now we get case BIG of b# DEFAULT -> let b = b' + 3# in e1 3# -> let b = 6# in e2 * Avoid duplicated code in caseRules A knock-on refactoring: * Move Note [Word/Int underflow/overflow] to Literal, as documentation to accompany mkMachIntWrap etc; and get rid of PrelRuls.intResult' in favour of mkMachIntWrap
* CSE: Fix cut and paste errorBen Gamari2017-04-281-2/+2
| | | | | | | | | | | | | extendCSRecEnv took the map to be extended from cs_map instead of cs_rec_map. Oops! Test Plan: Validate Reviewers: simonpj, austin Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3510
* Be a bit more eager to inline in a strict contextSimon Peyton Jones2017-04-282-6/+22
| | | | | | | | | | | | | | | | | | | If we see f (g x), and f is strict, we want to be a bit more eager to inline g, because it may well expose an eval (on x perhaps) that can be eliminated or shared. I saw this in nofib boyer2, function RewriteFuns.onewayunify1. It showed up as a consequence of the preceding patch that makes the simplifier do less work (Trac #13379). We had f d (g x) where f was a class-op. Previously we simplified both d and (g x) with a RuleArgCtxt (making g a bit more eager to inline). But now we simplify only d that way, then fire the rule, and only then simplify (g x). Firing the rule produces a strict funciion, so we want to make a strict function encourage inlining a bit.
* Cure exponential behaviour in the simplifierSimon Peyton Jones2017-04-282-58/+152
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch nails a Bad Bug exposed in Trac #13379. Roughly, a deeply-nested application like f (f (f ....) ) ) could make the simplifier go exponential -- without producing an exponential-sized result! The reason was that we - simplified a (big) function argument - then decided to inline the function - then preInilneUnconditionally the argument - and then re-simplified the big argument And if the "big argument" itself had a similar structure things could get very bad. Once I'd understood, it was easy to fix: * See Note Note [Avoiding exponential behaviour] for an overview * The key change is that Simplify.simplLam now as a case for (isSimplified dup). This is what removes the perf bug. * But I also made simplCast more parsimonious about simplifying, avoiding doing so when the coercion is Refl * And similarly I now try to avoid simplifying arguments where possible before applying rules. See Note [Trying rewrite rules] The latter two points tackle common cases, and in those cases make the simplifier take fewer iterations.
* Fix another literal-string bugletSimon Peyton Jones2017-04-121-6/+7
| | | | | | | We were failing to float a nested binding x :: Addr# = "foo"# to top level, even though we /were/ floating string literals themselves. A small oversight, easily fixed.
* Kill off complications in CoreFVsSimon Peyton Jones2017-04-121-139/+230
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing type-in-type, Richard introduce some substantial complications in CoreFVs, gathering types and free variables of type. In Trac #13160 we decided that this complication was unnecessary, so this patch removes it. Unfortnately I then fell down a twisty rabbit hole. Roughly: * An apparently-innocuous change in the AnnApp case of fiExpr made the fuction a little bit stricter, so we ended up peering into the arguments when we didn't before (namely when there are no bindings being floated inwards). I've rejigged it so that it's not fragile any more. * Peering into the arguments was sometimes expensive, becuase exprIsExpandable can be expensive because it looks deeply into the expression. * The combination of the two led to a non-linear explosion of work when the argument of a function is a deeep nest of constructors. This bug has been lurking for ages. I solved it by replacing exprIsExpandable with exprIsHNF + exprIsTrivial; see Note [noFloatInto considerations] * The code around floating case-expressions turned out to be very delicate, because can_fail primops (which we want to float inwards) can't be floated outwards; so we have to be careful never to float them too far. Note [Floating primops] has the details * I ended up refactoring some rather opaque code in sepBindsByDropPoint. Working all this out meant that I rewrote quite a bit of code, so it's now a reasonably substantial patch. But it's a net improvement.
* Typos in comments [ci skip]Gabor Greif2017-04-112-3/+3
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* Add a Note [Call Arity and Join Points]Joachim Breitner2017-04-091-1/+23
| | | | as discussed in #13479.
* Do Note [Improving seq] alwaysSimon Peyton Jones2017-04-071-57/+81
| | | | | | | | | | This patch fixes Trac #13468, and at the same time makes the code simpler and more uniform. In particular, I've eliminated the awkward conflict between the old built-in rule for seq (which elimianted a cast), and the desire to make case scrutinse a data type by doing type-family reduction (which adds a cast). Nice.
* More changes to fix a space leak in the simplifier (#13426)Reid Barton2017-04-061-13/+72
| | | | | | | | | | | | | | | | | | | Part of e13419c55 was accidentally lost during a rebase. This commit adds the missing change, along with some more improvements regarding where we do and don't use `seqType`. Also include a comment about where the space leak showed up and a Note explaining the strategy being used here. Test Plan: harbormaster, plus local testing on DynFlags Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3421
* Replace Digraph's Node type synonym with a data typeMatthew Pickering2017-04-041-9/+12
| | | | | | | | | | | | | This refactoring makes it more obvious when we are constructing a Node for the digraph rather than a less useful 3-tuple. Reviewers: austin, goldfire, bgamari, simonmar, dfeuer Reviewed By: dfeuer Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3414
* Minor comment updates on CSE.Edward Z. Yang2017-04-021-3/+13
| | | | Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>
* Remove Core Lint pass on occurrence analysis output (#13220)Reid Barton2017-03-311-1/+0
| | | | | | | | | | | | | | | It was expensive, as the simplifier runs for many iterations, and probably not very useful. Test Plan: harbormaster Reviewers: austin, bgamari, dfeuer Reviewed By: dfeuer Subscribers: dfeuer, thomie Differential Revision: https://phabricator.haskell.org/D3391
* Fix space leaks in simplifier (#13426)Reid Barton2017-03-311-1/+4
| | | | | | | | | | | | | | | | | | | The Join points commit (8d5cf8bf) introduced a space leak somewhere in the simplifier. The extra strictness added in this commit fixes the leak. Unfortunately I don't really understand the details. Unfortunately, the extra strictness appears to result in more overall allocations in some cases, even while the peak heap size decreases in others. Test Plan: harbormaster Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D3399
* Refactor simplExpr (Type ty)Simon Peyton Jones2017-03-311-16/+38
| | | | | | | | | This small refactoring, provoked by comment:18 on Trac #13426, makes it so that simplExprF never gets a (Type ty) expression to simplify, which in turn means that calls to exprType on its argument will always succeed. No change in behaviour.
* Print module when dumping rulesMatthew Pickering2017-03-291-3/+10
| | | | | | | | | | | | | It is sometimes hard to find where a rule is defined. Printing the module where it comes from will make it much easier to find. Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3378
* Zap Call Arity info in the simplifierJoachim Breitner2017-03-281-1/+6
| | | | | | | | | | | | | As #13479 shows, there are corner cases where the simplifier decides to not eta-expand a function as much as its call arity would suggest, but instead transforms the code that the call arity annotation becomes a lie. As the call arity information is only meant to be used by the immediatelly following simplifier run, it makes sense to simply zap the information there. Differential Revision: https://phabricator.haskell.org/D3390
* Spelling in comments only [ci skip]Gabor Greif2017-03-281-1/+1
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* Remove utterly bogus codeSimon Peyton Jones2017-03-271-6/+1
| | | | | | | | | | | | | | | | | | | | | | | | | The commit 6746549772c5cc0ac66c0fce562f297f4d4b80a2 Author: Richard Eisenberg <eir@cis.upenn.edu> Date: Fri Dec 11 18:19:53 2015 -0500 Add kind equalities to GHC. added this entirely bogus code to Simplify.simplLam: env' | Coercion co <- arg = extendCvSubst env bndr co | otherwise = env It's bogus because 'co' is an 'InCoercion', but a CvSubst should have only OutCoercions in it. Moreover, completeBind does the job nicely. This led to an ASSERT failure in an experimental branch; but I have not got a repro case that works on HEAD. But still, the patch deletes code and fixes a bug, so it must be good. The only mystery is why Richard added it in the first place :-). I hope I'm not missing anything. But it validates fine.
* Improve tracing in OccurAnalMatthew Pickering2017-03-241-1/+1
| | | | | | | | | | | | | One commented out tracing function didn't type check and also show the scores of loop breaker nodes. Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3371
* Typos in comments (notes too) [ci skip]Gabor Greif2017-03-242-7/+6
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* OccurAnal.hs: Add an assert for an invariantÖmer Sinan Ağacan2017-03-191-1/+2
| | | | | | | | | | Reviewers: austin, bgamari, dfeuer Reviewed By: bgamari, dfeuer Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3360
* OccurAnal.hs: Fix "Adjusting for lambdas" note nameÖmer Sinan Ağacan2017-03-181-2/+2
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* No join-point from an INLINE function with wrong aritySimon Peyton Jones2017-03-171-26/+4
| | | | | | | | | | | | | | | | | | | | | | | | The main payload of this patch is NOT to make a join-point from a function with an INLINE pragma and the wrong arity; see Note [Join points and INLINE pragmas] in CoreOpt. This is what caused Trac #13413. But we must do the exact same thing in simpleOptExpr, which drove me to the following refactoring: * Move simpleOptExpr and simpleOptPgm from CoreSubst to a new module CoreOpt along with a few others (exprIsConApp_maybe, pushCoArg, etc) This eliminates a module loop altogether (delete CoreArity.hs-boot), and stops CoreSubst getting too huge. * Rename Simplify.matchOrConvertToJoinPoint to joinPointBinding_maybe Move it to the new CoreOpt Use it in simpleOptExpr as well as in Simplify * Define CoreArity.joinRhsArity and use it
* Typos in manual and comments [ci skip]Gabor Greif2017-03-171-1/+1
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* Introduce putLogMsgBen Gamari2017-03-152-3/+2
| | | | | | | | | | | | | This factors out the repetition of (log_action dflags dflags) and will hopefully allow us to someday better abstract log output. Test Plan: Validate Reviewers: austin, hvr, goldfire Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3334
* Fix CaseIdentity optimisation AGAINSimon Peyton Jones2017-03-141-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | In this commit commit 02ac2974ce8e537372bff8d9e0a6efb461ed2c59 Author: Simon Peyton Jones <simonpj@microsoft.com> Date: Wed Nov 16 10:37:47 2011 +0000 Fix CaseIdentity optimisaion In fixing one bug I'd introduced another; case x of { T -> T; F -> F } wasn't getting optmised! Trivial to fix. I introduced yet another! This line of code in SimplUtils.mkCase1 check_eq (Var v) (DataAlt con) [] = v == dataConWorkId con -- Optimisation only is patently false when arg_tys is non-empty. Astonishing that it has not shown up before now. Easily fixed though. This was all shown up by Trac #13417, which is now fixed. Merge to 8.0, 8.2.
* Typos in manual and commentsGabor Greif2017-03-141-1/+1
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* Fix #13382: Put join ceiling underneath lambdasLuke Maurer2017-03-131-1/+2
| | | | | | | | | | | | Test Plan: No new test (bug is latent) Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3285
* Remove `runs` function which already exists in baseÖmer Sinan Ağacan2017-03-121-2/+1
| | | | | | | | | | Reviewers: austin, bgamari Reviewed By: bgamari Subscribers: rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3320
* Comments only [ci skip]Gabor Greif2017-03-091-2/+2
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* Typos in changelog and commentsGabor Greif2017-03-071-1/+1
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* Typos in comments and manualGabor Greif2017-03-062-2/+2
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