#6156: Optimiser bug on linux-powerpc
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Reporter: erikd | Owner: pcapriotti
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):
Slightly simplified test case (may not be as complete as the original),
but which should make debugging easier is:
{{{
{-# LANGUAGE MagicHash #-}
import GHC.Base
import GHC.Word
import GHC.IntWord64
import Numeric (showHex)
input :: Word64
input = 1238988323332265734
result :: Word32
result = case input of
W64# x -> W32# (word64ToWord# x)
main :: IO ()
main = putStrLn $ "Result 0x" ++ showHex result ""
}}}
Compiling on PowerPC with `-O1` gives the correct result of `0xcd139706`
and with `-O1 -fno-enable-rewrite-rule` gives an incorrect result of
`0x9706`.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6156#comment:24>
GHC <http://www.haskell.org/ghc/>
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