[PATCH] #pragma vectorize

[Tyler Nowicki]

Ok, so trying to recap the consensus seems to be for the following syntax

#pragma interleave(_value_)
- indicates the loop body should be unrolled
- does not imply that it is safe to do so

#pragma vectorize width(_value_)/enable/disable
- behavior remains the same

And rename `class LoopVectorizeHints' to `class LoopHints'.

Is that right? Did I miss anything?

Tyler

On Apr 22, 2014, at 11:39 AM, Hal Finkel <hfinkel at anl.gov> wrote:

> ----- Original Message -----
>> From: "Nadav Rotem" <nrotem at apple.com>
>> To: "Raul Silvera" <rsilvera at google.com>
>> Cc: "Hal Finkel" <hfinkel at anl.gov>, "Alexey Bataev" <alexey.bataev at intel.com>, "llvm cfe" <cfe-commits at cs.uiuc.edu>
>> Sent: Tuesday, April 22, 2014 1:30:39 PM
>> Subject: Re: [PATCH] #pragma vectorize
>> 
>> 
>> 
>> 
>> On Apr 22, 2014, at 11:24 AM, Raul Silvera < rsilvera at google.com >
>> wrote:
>> 
>> 
>> 
>> 
>> Does this pragma widen also asserts safety, or does it depend on the
>> compiler proving independence?
>> 
>> 
>> This specific pragma only affects the decision of the vectorizer
>> 'cost model'.
>> 
>> 
>> 
>> 
>> 
>> 
>> widen does seem to imply the data types are being widened -- also a
>> form of vectorization. Perhaps interleave is another word to
>> consider?
>> 
>> 
>> I also like ‘interleave’.
>> 
> 
> I like this as well.
> 
> -Hal
> 
>> 
>> 
>> 
>> 
>> 
>> 
>> Raúl E Silvera | SWE | rsilvera at google.com | 408-789-2846
>> 
>> 
>> 
>> On Tue, Apr 22, 2014 at 10:49 AM, Hal Finkel < hfinkel at anl.gov >
>> wrote:
>> 
>> 
>> 
>> ----- Original Message -----
>>> From: "Nadav Rotem" < nrotem at apple.com >
>>> To: "Hal Finkel" < hfinkel at anl.gov >
>> 
>>> Cc: "Tyler Nowicki" < tnowicki at apple.com >, cfe-commits at cs.uiuc.edu
>>> , "Alexey Bataev" < alexey.bataev at intel.com >,
>>> "Alexander Musman" < alexander.musman at gmail.com >, "Chandler
>>> Carruth" < chandlerc at google.com >
>> 
>>> Sent: Tuesday, April 22, 2014 12:44:21 PM
>>> Subject: Re: [PATCH] #pragma vectorize
>>> 
>>> 
>>> 
>>> 
>> 
>>> On Apr 22, 2014, at 10:38 AM, Hal Finkel < hfinkel at anl.gov > wrote:
>>> 
>>> 
>>> Okay, this is reasonable, but I'm still not sure it should be in a
>>> pragma called 'vectorize'. This particular transformation can be
>>> applied (and more often than not is applied) to scalar code.
>>> Strictly speaking it is an optimization that exposes ILP, and has
>>> little to do with vectorization.
>>> 
>>> 
>>> This is a good point. Maybe ILP would be a better name?
>> 
>> No, actually I like widen better because it is an action word. I
>> don't think that ILP gives any idea of what the compiler is being
>> asked to do. Not that I'm in love with widen, but I don't have a
>> better suggestion -- unsequenced_unrolling or
>> unsequenced_iterations, etc. all seem a bit bulky ;)
>> 
>> -Hal
>> 
>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> That having been said, the fact that the correctness model for this
>>> 'widening' operation is similar (although not identical) to that
>>> for
>>> vectorization, and thus implemented by the vectorizer, is not facet
>>> of the implementation we should expose to the user. However, pragma
>>> widen is fine with me too.
>>> 
>> 
>> 
>> 
>> --
>> Hal Finkel
>> Assistant Computational Scientist
>> Leadership Computing Facility
>> Argonne National Laboratory
>> _______________________________________________
>> cfe-commits mailing list
>> cfe-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
>> 
>> 
>> 
> 
> -- 
> Hal Finkel
> Assistant Computational Scientist
> Leadership Computing Facility
> Argonne National Laboratory
> 
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> cfe-commits at cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits

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