[ARM] PR66791: Gate comparison in vca intrinsics on __FAST_MATH__

Kyrylo Tkachov Kyrylo.Tkachov@arm.com
Wed Jun 30 08:30:07 GMT 2021



> -----Original Message-----
> From: Prathamesh Kulkarni <prathamesh.kulkarni@linaro.org>
> Sent: 29 June 2021 08:21
> To: gcc Patches <gcc-patches@gcc.gnu.org>; Kyrylo Tkachov
> <Kyrylo.Tkachov@arm.com>
> Subject: Re: [ARM] PR66791: Gate comparison in vca intrinsics on
> __FAST_MATH__
> 
> On Tue, 22 Jun 2021 at 15:04, Prathamesh Kulkarni
> <prathamesh.kulkarni@linaro.org> wrote:
> >
> > Hi,
> > The attached patch gates abs(__a) cmp abs(__b) for vca intrinsics on
> > __FAST_MATH__. I moved vabs intrinsics before vcage_f32 since vca
> > intrinsics use those.
> > Bootstrapped+tested on arm-linux-gnueabihf.
> > OK to commit ?
> ping https://gcc.gnu.org/pipermail/gcc-patches/2021-June/573384.html

Hmm, does this result in better optimisation? I guess it's expressing the operation at a higher level, but there's now conceptually three operations (2xvabs + 1 comparison) that would need to be folded away by the optimisers...

Thanks,
Kyrill
> 
> Thanks,
> Prathamesh
> >
> > Thanks,
> > Prathamesh


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