good bug! -O or -O2 is irrelevant but it works if compiled with -fvia-C You (or someone else) should add it to http://hackage.haskell.org/trac/ghc
Christian Brad Clow wrote: > I upgraded from GHC 6.6.1 to 6.8.1 and around that time I noticed that > the output from an app I am working on changed. I have distilled the > code down to the following example that produces different output > depending on whether it is compiled with -O2 or not: > > main = do > let (T x) = read "T 3" > print $ f x > print $ g x > > data T = T Int deriving (Read, Show) > > f x = truncate $ 2000 / fromIntegral ((x * 25) + 10) > > g :: Int -> Int > g x = f x > > Here is the transcript from a shell (example code is saved in test.hs): > > $ ghc --make test.hs > [1 of 1] Compiling Main ( test.hs, test.o ) > Linking test ... > $ ./test > 23 > 23 > $ rm test.hi test.o test > $ ghc -O2 --make test.hs > [1 of 1] Compiling Main ( test.hs, test.o ) > Linking test ... > $ ./test > 23 > 24 > > It is a little disconcerting that -O2 changes the output. :-) > > Regards > brad > _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
