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

[Carter Schonwald]

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
>>>>
>>>>
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>>>>
>>>
>>>
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