Performance regression due to lack of inlining of `foldl` and `foldl'`.

For some reason Data.List.sum is much slower than the naive recursive definition for it. Does not seem happen in 7.8.

  import Data.List
  import Criterion.Main
 
  sum1 [] = 0
  sum1 (x:xs) = x + sum1 xs
 
  sum2 = foldr (+) 0
  sum3 = foldl' (+) 0
  sum4 = getSum #. foldMap Sum
 
 
  main = do
      let els = [1..100000]
      defaultMain [
       bench "sum0" $ whnf  (sum :: [Int] -> Int) els
       ,bench "sum" $ whnf  (sum :: [Int] -> Int) els
       ,bench "sum1" $ whnf (sum1:: [Int] -> Int) els
       ,bench "sum2" $ whnf (sum2:: [Int] -> Int) els
       ,bench "sum3" $ whnf (sum3:: [Int] -> Int) els
       ,bench "sum4" $ whnf (sum4:: [Int] -> Int) els
       ]
 
{-
 
benchmarking sum0
time                 128.0 ms   (121.7 ms .. 133.8 ms)
                     0.997 R²   (0.994 R² .. 1.000 R²)
mean                 132.8 ms   (130.1 ms .. 136.3 ms)
std dev              4.622 ms   (2.980 ms .. 6.577 ms)
variance introduced by outliers: 11% (moderately inflated)
 
benchmarking sum
time                 131.0 ms   (125.7 ms .. 136.7 ms)
                     0.998 R²   (0.993 R² .. 1.000 R²)
mean                 131.9 ms   (128.6 ms .. 136.7 ms)
std dev              5.971 ms   (2.903 ms .. 9.649 ms)
variance introduced by outliers: 11% (moderately inflated)
 
benchmarking sum1
time                 26.29 ms   (25.43 ms .. 27.24 ms)
                     0.995 R²   (0.991 R² .. 0.998 R²)
mean                 26.30 ms   (25.73 ms .. 26.98 ms)
std dev              1.293 ms   (953.2 μs .. 1.804 ms)
variance introduced by outliers: 15% (moderately inflated)
 
benchmarking sum2
time                 26.39 ms   (25.49 ms .. 27.26 ms)
                     0.995 R²   (0.991 R² .. 0.998 R²)
mean                 26.33 ms   (25.77 ms .. 26.95 ms)
std dev              1.295 ms   (941.5 μs .. 1.878 ms)
variance introduced by outliers: 15% (moderately inflated)
 
benchmarking sum3
time                 7.695 ms   (7.670 ms .. 7.722 ms)
                     1.000 R²   (1.000 R² .. 1.000 R²)
mean                 7.703 ms   (7.691 ms .. 7.733 ms)
std dev              51.21 μs   (25.43 μs .. 99.41 μs)
 
benchmarking sum4
time                 26.29 ms   (25.40 ms .. 27.21 ms)
                     0.995 R²   (0.989 R² .. 0.998 R²)
mean                 26.36 ms   (25.88 ms .. 27.08 ms)
std dev              1.364 ms   (954.5 μs .. 1.899 ms)
variance introduced by outliers: 20% (moderately inflated)
  
  -}

Trac metadata

Trac field	Value
Version	7.10.2
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
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