half_recip: Implement using 1/x

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: 322896
GitOrigin-RevId: 398108b91e0a7fa01d8216406bc6a0c6f1e2ff43
4 files changed