[LLVMdev] SIMD trigonometry/logarithms?

[Redmond, Paul]

Additionally, I think this relates to my suggestion to transform library calls into intrinsics.

Early on you want to canonicalize math library calls into intrinsics. The vectorizers trivially widen the intrinsics and before codegen you replace the intrinsics with calls.

If you insert calls to the bc math library too early you won't benefit from intrinsic aware optimizations.

Basically I think what you need is a module that provides intrinsic implementations for various vector widths.

paul

On 2013-01-27, at 9:22 AM, Justin Holewinski wrote:

I'm wondering if it makes sense to instead supply a bc math library.  I would think it would be easier to maintain and debug, and should still give you all of the benefits.  You could just link with it early in the optimization pipeline to ensure inlining.  This may also make it easier to maintain SIMD functions for multiple backends.


On Sun, Jan 27, 2013 at 8:49 AM, Hal Finkel <hfinkel at anl.gov<mailto:hfinkel at anl.gov>> wrote:
----- Original Message -----
> From: "Dimitri Tcaciuc" <dtcaciuc at gmail.com<mailto:dtcaciuc at gmail.com>>
> To: llvmdev at cs.uiuc.edu<mailto:llvmdev at cs.uiuc.edu>
> Sent: Sunday, January 27, 2013 3:42:42 AM
> Subject: [LLVMdev] SIMD trigonometry/logarithms?
>
>
>
> Hi everyone,
>
>
> I was looking at loop vectorizer code and wondered if there was any
> current or planned effort to introduce SIMD implementations of
> sin/cos/exp/log intrinsics (in particular for x86-64 backend)?

Ralf Karrenberg had implemented some of these as part of his whole-function vectorization project:
https://github.com/karrenberg/wfv/blob/master/src/utils/nativeSSEMathFunctions.hpp
https://github.com/karrenberg/wfv/blob/master/src/utils/nativeAVXMathFunctions.hpp

Opinions on pulling these into the X86 backend?

 -Hal

>
>
> Cheers,
>
>
>
>
> Dimitri.
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--

Thanks,

Justin Holewinski
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