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

[Aurelien Jarno <aurelien@aurel32.net>]

On Wed, Mar 17, 2010 at 11:29:00AM +0100, Vincent Lefevre wrote:
> On 2010-03-07 16:17:08 +0100, Aurelien Jarno wrote:
> > On amd64, only sincos has an optimized version,
> 
> It may be optimized, but completely buggy. For instance, on 1e22,
> sincos returns 0.46261304076460174617 for the sine instead of
> -0.85220084976718879499 (correctly rounded value). Even the sign
> is incorrect!
> 

Where did you get this result? In my tests both the x87 FPU and the
current glibc code give the following result when using double variables
and the sincos() function:

sin (1e22) =  0.46261304076460174617
cos (1e22) = -0.88656030506363692201


-- 
Aurelien Jarno	                        GPG: 1024D/F1BCDB73
aurelien@aurel32.net                 http://www.aurel32.net