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author | klebinger.andreas@gmx.at <klebinger.andreas@gmx.at> | 2018-08-21 12:10:38 -0400 |
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committer | Ben Gamari <ben@smart-cactus.org> | 2018-08-21 18:52:42 -0400 |
commit | 09c1d5afba655a2427a448a9933bebe7d13b696b (patch) | |
tree | d23083a9e99afe785f632e89f0186af8b191aee2 /compiler/types/Type.hs | |
parent | 02518f9d99c2d038384263f9e039efcb09bc96ff (diff) | |
download | haskell-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/types/Type.hs')
-rw-r--r-- | compiler/types/Type.hs | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/compiler/types/Type.hs b/compiler/types/Type.hs index ac1c8b9261..4f0bcf8372 100644 --- a/compiler/types/Type.hs +++ b/compiler/types/Type.hs @@ -706,13 +706,13 @@ mkAppTys (CastTy fun_ty co) arg_tys -- much more efficient then nested mkAppTy -- Why do this? See (EQ1) of -- Note [Respecting definitional equality] -- in TyCoRep - = foldl AppTy ((mkAppTys fun_ty casted_arg_tys) `mkCastTy` res_co) leftovers + = foldl' AppTy ((mkAppTys fun_ty casted_arg_tys) `mkCastTy` res_co) leftovers where (arg_cos, res_co) = decomposePiCos co (coercionKind co) arg_tys (args_to_cast, leftovers) = splitAtList arg_cos arg_tys casted_arg_tys = zipWith mkCastTy args_to_cast arg_cos mkAppTys (TyConApp tc tys1) tys2 = mkTyConApp tc (tys1 ++ tys2) -mkAppTys ty1 tys2 = foldl AppTy ty1 tys2 +mkAppTys ty1 tys2 = foldl' AppTy ty1 tys2 ------------- splitAppTy_maybe :: Type -> Maybe (Type, Type) |