Bug#572746: libm: sinf/cosf performance is awful on amd64

[Jerome Vizcaino <vizcaino_jerome@yahoo.fr>]

What do you mean sinf/cosf is supposed to be twice faster ?
You're mentionning calling it with bound values ?

Thank you.

Jerome

On Monday 08 March 2010, Aurelien Jarno wrote:
> On Mon, Mar 08, 2010 at 12:17:41AM +0100, Jerome Vizcaino wrote:
> > Ok about the patches : there had to be a reason for those not to be
> > merged upstream.
> 
> Also I think they have never been submitted upstream. They are from
> 2002...
> 
> > Some of my co-workers noticed the performance improvement when binding
> > values between -pi and pi but the thing is, this kind of trick do not
> > need to be applied when on 32 bits systems... Libm's behavior is not
> > really arch-proof in terms of performance which is a bit confusing (and I
> > would expect 64 bit being better than 32 bits when dealing with maths...
> > :(
> 
> cosf/sinf is actually twice faster on 64-bit than on 32-bit in normal
> cases, but can be a lot slower in the cases that concern you.
> 
> > Have you tried pushing your code upstream ? Maybe this would be useful
> > for future versions.
> 
> It's currently not clean enough to be send upstream. I'll try to send it
> upstream, but I don't have to much hope.
>