Simd ghc and llvm Re: PSA: GHC can now be built with Clang

[Carter Schonwald]

woops, heres the ticket http://hackage.haskell.org/trac/ghc/ticket/8033


On Tue, Jul 2, 2013 at 10:27 PM, Carter Schonwald <
carter.schonwald at gmail.com> wrote:

> I've added a ticket to trac proposing the change I believe we'd need to
> hand over to the LLVM folks to support 256bit simd,
>
> should be fully compatible with current ghcs and how they do code
> generation
>
> feedback would of course be appreciated
>
>
> On Tue, Jul 2, 2013 at 8:03 PM, Carter Schonwald <
> carter.schonwald at gmail.com> wrote:
>
>> 1-2 typoes may have made it unclear.
>>
>> Avx2 machines (intel haswell CPUs) have a rich array of 256bit simd
>> registers.  And lots of useful instructions for them.
>>
>> The ghc calling convention in llvm currently only exposes being able to
>> use those simd registers in their 128 bit form.
>>
>> Would be backwards compatible and future proof to add support for the
>> 256bit registers in the calling convention spec in llvm.
>>
>> If there's a clear concensus  on this, I'm happy / willing to do the work
>> to try and get that patch under consideration for the next llvm point
>> release.
>>
>>
>> On Tuesday, July 2, 2013, Carter Schonwald wrote:
>>
>>> Which reminds me: should we look into getting a patch into llvm'd ghc
>>> calling convention so that on avx2 capable machines  so we can eventually
>>> add support for the 256bit Ymm resisters and primops to ghc?  We really
>>> should make sure it's patched in on the llvm side first.
>>>
>>> I believe it'd be a 2 line patch, might even be something we could get
>>> into the next llvm point release if there's a clear agreement about it too.
>>>
>>> Thoughts? I'm happy to put a ticket on trac for this andor do the leg
>>> work to make it happen if everyone agrees.
>>>
>>>
>>> On Tuesday, July 2, 2013, Ryan Newton wrote:
>>>
>>>> Gosh, sorry, yes it's not obvious from the list of accepted papers:
>>>>
>>>> "Automatic SIMD Vectorization for Haskell" Leaf Petersen, Dominic
>>>> Orchard and Neal Glew
>>>> One of the authors has a link for it but it appears there's no preprint
>>>> up yet:
>>>>     http://www.leafpetersen.com/leaf/publications.htm
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Tue, Jul 2, 2013 at 5:36 AM, Nicolas Trangez <nicolas at incubaid.com>wrote:
>>>>
>>>>> On Mon, 2013-07-01 at 12:05 -0400, Ryan Newton wrote:
>>>>> > Err, GCC replacement.  But, ironically, GHC [backend] replacement as
>>>>> well,
>>>>> > as of the recent ICFP paper.
>>>>>
>>>>> Got a link or reference?
>>>>>
>>>>> Nicolas
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> ghc-devs mailing list
>>>>> ghc-devs at haskell.org
>>>>> http://www.haskell.org/mailman/listinfo/ghc-devs
>>>>>
>>>>
>>>>
>
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