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authorklebinger.andreas@gmx.at <klebinger.andreas@gmx.at>2018-08-21 12:10:38 -0400
committerBen Gamari <ben@smart-cactus.org>2018-08-21 18:52:42 -0400
commit09c1d5afba655a2427a448a9933bebe7d13b696b (patch)
treed23083a9e99afe785f632e89f0186af8b191aee2 /compiler/typecheck/FunDeps.hs
parent02518f9d99c2d038384263f9e039efcb09bc96ff (diff)
downloadhaskell-09c1d5afba655a2427a448a9933bebe7d13b696b.tar.gz
Replace most occurences of foldl with foldl'.
This patch adds foldl' to GhcPrelude and changes must occurences of foldl to foldl'. This leads to better performance especially for quick builds where GHC does not perform strictness analysis. It does change strictness behaviour when we use foldl' to turn a argument list into function applications. But this is only a drawback if code looks ONLY at the last argument but not at the first. And as the benchmarks show leads to fewer allocations in practice at O2. Compiler performance for Nofib: O2 Allocations: -1 s.d. ----- -0.0% +1 s.d. ----- -0.0% Average ----- -0.0% O2 Compile Time: -1 s.d. ----- -2.8% +1 s.d. ----- +1.3% Average ----- -0.8% O0 Allocations: -1 s.d. ----- -0.2% +1 s.d. ----- -0.1% Average ----- -0.2% Test Plan: ci Reviewers: goldfire, bgamari, simonmar, tdammers, monoidal Reviewed By: bgamari, monoidal Subscribers: tdammers, rwbarton, thomie, carter Differential Revision: https://phabricator.haskell.org/D4929
Diffstat (limited to 'compiler/typecheck/FunDeps.hs')
-rw-r--r--compiler/typecheck/FunDeps.hs2
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/typecheck/FunDeps.hs b/compiler/typecheck/FunDeps.hs
index 4052ccbbe4..768c78d28f 100644
--- a/compiler/typecheck/FunDeps.hs
+++ b/compiler/typecheck/FunDeps.hs
@@ -541,7 +541,7 @@ oclose preds fixed_tvs
| null tv_fds = fixed_tvs -- Fast escape hatch for common case.
| otherwise = fixVarSet extend fixed_tvs
where
- extend fixed_tvs = foldl add fixed_tvs tv_fds
+ extend fixed_tvs = foldl' add fixed_tvs tv_fds
where
add fixed_tvs (ls,rs)
| ls `subVarSet` fixed_tvs = fixed_tvs `unionVarSet` closeOverKinds rs