22 Dec
2007
22 Dec
'07
1:28 p.m.
On Sat, Dec 22, 2007 at 06:00:29PM +0000, Joost Behrends wrote:
Hi,
while still working on optimizing (naively programmed) primefactors i watched a very strange behavior of ghc. The last version below takes 2.34 minutes on my system for computing 2^61+1 = 3*768614,336404,564651. Importing Data.Char without anywhere using it reduces this time to 1.34 minute - a remarkable speed up. System is WindowsXP on 2.2GHZ Intel, 512MB Ram.
I give the complete code here - hopefully all tabs are (4) blanks. Can this be reproduced ? I compile just with --make -O2.
If you can reproduce it on your machine (rm <executable> *.o *.hi between tests for maximum reliability), it's definitely a bug. http://hackage.haskell.org/trac/ghc/wiki/ReportABug Stefan