Data.List.sum is slower than 6.8.3

[simonmar]

main = print (sum [1..100000000::Int])

with 6.8.3:

  MUT   time    1.76s  (  1.79s elapsed)

with HEAD (22/7/08)

  MUT   time    1.97s  (  1.99s elapsed)

complete guess: sum has been mis-optimised by SAT?

[simonpj]

I can't reproduce this. I compiled

module Main( main ) where
main = print (sum [1..100000000::Int])

with -O and -O2 with the HEAD and 6.8.3. Results are essentially identical.

I'll close this, but if anyone else can reproduce it, please re-open.

		   Allocs	Runtime(user)
ghc-HEAD    -O	   8.031M	1.82s
ghc-HEAD    -O2	   8.031M	1.82s		
ghc-6.8.3   -O	   8.031M	1.82s
ghc-6.8.3   -O2    8.031M	1.82

Simon

[simonmar]

We think it's necessary to compile the definition of sum itself with -O2 in order to reproduce this.

[simonpj]

I did that and it's still fine. Re-open if you think otherwise!

Simon

[simonmar]

unreproducible for me too now.