unsafeCoerce# between integral and floating point types
daniel.is.fischer at web.de
Thu Jul 8 12:56:50 EDT 2010
On Thursday 08 July 2010 18:15:44, Ian Lynagh wrote:
> On Thu, Jul 08, 2010 at 04:49:00PM +0200, Daniel Fischer wrote:
> > unsafeCoerce# :: Word64# -> Double# ?
> > By the docs, that isn't supposed to work. Is it not supposed to work
> > only because it's not value-preserving (unsafeCoerce# 1## /=## 1.0##)
> > or are there more pitfalls?
> It can fail to compile, even; see
Yeah, tried that myself, with optimisations:
[2 of 2] Compiling Main ( testUCastD.hs, testUCastD.o )
ghc: panic! (the 'impossible' happened)
(GHC version 6.12.3 for i386-unknown-linux):
getRegister(x86) I64[R1 + 3]
Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug
But without optimisations, it compiles and seems to work (I won't rely on
that, was just curious).
Should I report it or is the panic okay since unsafeCoerce# isn't supposed
to work for those types?
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