[GHC] #9304: Floating point woes; Different behavior on 32- vs 64-bit x86

[Levent Erkok]

@carter: Yes; I think @rwbarton is quite right in his analysis!

@rwbarton: Thanks for nailing this one!

I'd consider this a bug; but I'm not sure how important it is to reserve
cycles. @simonpj can definitely make that call. Maybe it can be merged with
@carter's ticket #9276, and addressed within that context.


On Mon, Jul 14, 2014 at 10:17 AM, GHC <ghc-devs at haskell.org> wrote:

> #9304: Floating point woes; Different behavior on 32- vs 64-bit x86
> -------------------------------------+------------------------------------
>         Reporter:  lerkok            |            Owner:
>             Type:  bug               |           Status:  new
>         Priority:  normal            |        Milestone:
>        Component:  Compiler          |          Version:  7.8.3
>       Resolution:                    |         Keywords:  floating point
> Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
>  Type of failure:  None/Unknown      |       Difficulty:  Unknown
>        Test Case:                    |       Blocked By:  9276
>         Blocking:                    |  Related Tickets:
> -------------------------------------+------------------------------------
>
> Comment (by carter):
>
>  @lerkok I think @rwbarton has the problem nailed.
>
>  If I'm understanding everything correctly, the culprit here is that GHC's
>  const evaluation tooling doesn't respect the implicit floating point model
>  induced by -msse2 vs -f-excess-precision ?
>
> --
> Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9304#comment:29>
> GHC <http://www.haskell.org/ghc/>
> The Glasgow Haskell Compiler
>
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