[PATCH] [LoopVectorizer] if unsafe-fp-math FN attribute is set, enable reduction detection with float operations

[Pekka Jääskeläinen]

Hi Hal,

OK, I didn't know which way was the chosen "future approach" or
if they both are used for some use cases.

I just noticed that when I set -cl-fast-relaxed-math in OpenCL C,
it didn't propagate to the FP instructions as 'fast' attributes,
but the func attribute did get set.

So I suppose it should be investigated why the flags are not
generated to the produced instructions in this case instead
in case the fnattr is deprecated?

On 11/28/2014 07:43 PM, Hal Finkel wrote:
> Pekka,
>
> What's your motivation for doing this? Aside from the fact that we
> can't yet set fast math flags on function calls (to sqrt, etc.), I
> think we're pretty close to removing the function attribute all
> together. The instruction-level flags play much nicer with LTO, and
> give more precision control to the frontends; it is not clear to me
> that overriding them with the function-level attribute is desirable.
>
> -Hal
>
> ----- Original Message -----
>> From: "Pekka Jääskeläinen" <pekka.jaaskelainen at tut.fi> To: "Commit
>> Messages and Patches for LLVM" <llvm-commits at cs.uiuc.edu> Sent:
>> Friday, November 28, 2014 11:13:39 AM Subject: [PATCH]
>> [LoopVectorizer] if unsafe-fp-math FN attribute is set, enable
>> reduction detection with float operations
>>
>> Hi,
>>
>> The attached patch checks the function attributes for
>> "unsafe-fp-math" to relax FP constraints when detecting reduction
>> operations.
>>
>> -- --Pekka
>>
>> _______________________________________________ llvm-commits
>> mailing list llvm-commits at cs.uiuc.edu
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>>
>


-- 
--Pekka Jääskeläinen