half_cos: Implement using cos

Passes CTS on carrizo
v2: Use full precision implementation

Reviewer: Jeroen Ketema <j.ketema@xs4all.nl>
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
llvm-svn: 322889
GitOrigin-RevId: b5d556061d1f72b00a9d4c276e8bee76bdb24492
4 files changed