powr: Port from amd_builtins

Passes piglit on turks and carrizo
fp64 passes cts on carrizo

v2: fix formatting
    check fp32 denormal support at runtime

Reviewer: Jeroen Ketema <j.ketema@xs4all.nl>
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
llvm-svn: 322762
GitOrigin-RevId: c45ec604f593fcb03d770f4398142d2446017f68
6 files changed