#6156: Optimiser bug on linux-powerpc
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Reporter: erikd | Owner: igloo
Type: bug | Status: new
Priority: normal | Milestone: 7.6.1
Component: Compiler | Version: 7.4.1
Resolution: | Keywords:
Os: Linux | Architecture: powerpc
Failure: Incorrect result at runtime | Difficulty: Unknown
Testcase: | Blockedby:
Blocking: | Related:
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Comment(by erikd):
Digging deeper:
{{{
{-# LANGUAGE MagicHash #-}
import GHC.Int
import GHC.Word
import GHC.IntWord64
import Numeric (showHex)
main :: IO ()
main = putStrLn (showHex (wordToInt64 input) "")
input :: Word64
input = 0x1a2a3a4a5a6a7a8a
wordToInt64 :: Word64 -> Int64
wordToInt64 (W64# x) = I64# (word64ToInt64# x)
}}}
also gives an incorrect result when optimisation is on. The
`word64ToInt64#` is foreign imported as:
{{{
foreign import ccall unsafe "hs_word64ToInt64" word64ToInt64# :: Word64#
-> Int64#
}}}
and `hs_word64ToInt64` is defined in C as :
{{{
HsInt64 hs_word64ToInt64 (HsWord64 w) {return (HsInt64) w;}
}}}
and testing that function in isolation in a small C program shows no
problem.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6156#comment:35>
GHC <http://www.haskell.org/ghc/>
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