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| author | Gregory <greg7mdp@gmail.com> | 2017-04-17 11:24:31 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2017-04-17 20:34:40 -0400 |
| commit | 3d3975f2f4caf3af76a7ea27d2882ddaee7db3c9 (patch) | |
| tree | 5b98f23eb14d259364c03b17639ff94bc468dcc1 /libraries | |
| parent | ab2dcb1c474d918efdc875f3cca7ef5b6ebdce1a (diff) | |
| download | haskell-3d3975f2f4caf3af76a7ea27d2882ddaee7db3c9.tar.gz | |
Fix space leak in sortBy
This makes yields a small improvement in sort performance: around 3.5% in
runtime on random Ints.
Reviewers: austin, hvr, mpickering
Subscribers: siddhanathan, rwbarton, thomie
Differential Revision: https://phabricator.haskell.org/D3454
Diffstat (limited to 'libraries')
| -rw-r--r-- | libraries/base/Data/OldList.hs | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/libraries/base/Data/OldList.hs b/libraries/base/Data/OldList.hs index 428d3bded9..ec937e729b 100644 --- a/libraries/base/Data/OldList.hs +++ b/libraries/base/Data/OldList.hs @@ -1,5 +1,6 @@ {-# LANGUAGE Trustworthy #-} -{-# LANGUAGE CPP, NoImplicitPrelude, ScopedTypeVariables, MagicHash #-} +{-# LANGUAGE CPP, NoImplicitPrelude, ScopedTypeVariables, + MagicHash, BangPatterns #-} ----------------------------------------------------------------------------- -- | @@ -854,12 +855,14 @@ sortBy cmp = mergeAll . sequences ascending a as (b:bs) | a `cmp` b /= GT = ascending b (\ys -> as (a:ys)) bs - ascending a as bs = as [a]: sequences bs + ascending a as bs = let !x = as [a] + in x : sequences bs mergeAll [x] = x mergeAll xs = mergeAll (mergePairs xs) - mergePairs (a:b:xs) = merge a b: mergePairs xs + mergePairs (a:b:xs) = let !x = merge a b + in x : mergePairs xs mergePairs xs = xs merge as@(a:as') bs@(b:bs') |