#1434: Slow conversion from Double to Int
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Reporter: [EMAIL PROTECTED] | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: libraries/base | Version: 6.4.1
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Os: Linux | Testcase:
Architecture: Unknown |
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Comment (by [EMAIL PROTECTED]):
In a more compact example using the GHC compiler and optimizations there
are no performance differences:
{{{
{-# OPTIONS -O2 -Wall #-}
module Main where
import GHC.Float (double2Int)
main :: IO ()
main = print (sum (map double2Int [-0.32,-0.29..(100000::Double)]) ::
Int)
main' :: IO ()
main' = print (sum (map truncate [-0.32,-0.29..(100000::Double)]) ::
Int)
}}}
However in a more complicated application I have, I generated a signal
with {{{round}}} in 4 seconds and with a replacement based on
{{{double2Int}}} in only one second. This may indicate an insufficient
inlining depth, but increasing it didn't help. Seems like I have to
extract a working example to demonstrate that.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1434>
GHC <http://www.haskell.org/ghc/>
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