#1433: Difference in strictness/unpackability between Word64 and Word32 (on a 32
bit machine)
-------------------------+--------------------------------------------------
Reporter: sorear | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 6.7
Severity: normal | Resolution:
Keywords: | Difficulty: Unknown
Os: Linux | Testcase:
Architecture: x86 |
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Comment (by simonpj):
You don't say what "it" is, but I think I see what you mean. Here's the
code for `wmix1`:
{{{
HashStr.$wmix1 =
\ (ww_sp7 :: GHC.Word.Word32)
(ww1_spa :: GHC.Prim.Word#)
(ww2_spc :: GHC.Word.Word32) ->
case ww_sp7 of wild_anX { GHC.Word.W32# x#_anZ ->
(# wild_anX,
GHC.Word.W32#
(GHC.Prim.xor#
(GHC.Prim.xor#
ww1_spa (GHC.Prim.narrow32Word#
(GHC.Prim.uncheckedShiftL# x#_anZ 9)))
(GHC.Prim.narrow32Word# (GHC.Prim.uncheckedShiftL# x#_anZ
9))),
ww2_spc #)
}
}}}
I think your question is: why isn't the first argument, `ww_sp7`, passed
unboxed? The answer is that this argument is '''returned''' as part of the
result (see `wild_anX`). So if the first arg was passed unboxed, the
worker would have to re-box it in order to return it. GHC tries not to do
that.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1433>
GHC <http://www.haskell.org/ghc/>
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