#3895: "Fix" pervasive-but-unnecessary signedness in GHC.Prim
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Reporter: pumpkin | Owner:
Type: proposal | Status: new
Priority: normal | Component: Compiler
Version: | Keywords:
Os: Unknown/Multiple | Testcase:
Architecture: Unknown/Multiple | Failure: None/Unknown
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I'm talking about the array primitives in particular:
{{{
writeFloatArray# :: MutableByteArray# s -> Int# -> Float# -> State# s ->
State# s
}}}
Conceptually, a Word# makes more sense as the index for all the array
functions. I'm not even sure what the semantics are if the Int# is
negative... is it checked? The three scenarios I can think of are:
Negativity is checked, and you get an exception.
Negativity is unchecked, and you get to write to memory that comes before
your array.
Negativity is ignored, and the back-end treats the Int# like a Word#
already.
I think the switch would be worthwhile in all of those cases, and could be
hidden in higher-level APIs that still use Int for indexes with a simple
int2Word#. Eventually we might even migrate to Word-based APIs at that
level?
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3895>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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