Proposal: Add Data.Bits.popCount

[Johan Tibell]

On Wed, Aug 17, 2011 at 7:44 PM, Maciej Marcin Piechotka
<uzytkownik2 at gmail.com> wrote:
> I posted bug for various similar instructions some time ago:
>
> http://hackage.haskell.org/trac/ghc/ticket/4102
>
> Probably the update should be done in batch (i.e. popCount,
> trailing/leading zeros etc.)

I'd be happy to see these as well. If someone would like to do the GHC
work needed to have them translate into single machine instructions
where available, have a look at the implementation of the popCnt#
primops here:

    https://github.com/ghc/ghc/commit/2d0438f329ac153f9e59155f405d27fac0c43d65
    https://github.com/ghc/packages-ghc-prim/commit/cefc19afafe5107ff98d5205c204b190da1d497b
    https://github.com/ghc/testsuite/commit/2f4d13348e2140f7fc0d4b8b995a2be0fa6291f0

I don't have time to do so at the moment.

I'd prefer to not wait with adding popCount until this is done, unless
someone takes it on them to add the others before GHC 7.4.

-- Johan