Re: [commit: ghc] master: Fix popcnt calls (2293238)

Ian Lynagh <[email protected]>
Newsgroups gmane.comp.lang.haskell.cvs.ghc
Message-ID <[email protected]>
On Thu, Nov 01, 2012 at 08:27:52PM +0000, Simon Marlow wrote:
> On 01/11/12 17:29, Ian Lynagh wrote:
> >
> >commit 229323898b0809047b19b79c181085430cce9850
> >Author: Ian Lynagh <[email protected]>
> >Date:   Thu Nov 1 14:13:05 2012 +0000
> >
> >     Fix popcnt calls
> >
> >     We don't want to narrow the argument size before making the foreign
> >     call: Word8 still gets passed as a Word-sized argument
> 
> I'm not sure this is right (I added the narrowing, FWIW).  The fact
> that Word8 gets promoted to Word is part of the C ABI, and we don't
> want to do that when popcnt is being implemented directly by the
> native codegen.  I know it is currently broken on some platforms,
> but I think the fix is to implement the proper type promotion in the
> compilation of C calls.

Ah; I've filed a ticket for this:
http://hackage.haskell.org/trac/ghc/ticket/7383


Thanks
Ian
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