GPU Calc: masked formulae that aren't supported well on some OpenCL platforms

Change-Id: I67849c6339ecfa5940285f1921d9b8fd4959ba63
Signed-off-by: haochen <haochen@multicorewareinc.com>
Signed-off-by: I-Jui (Ray) Sung <ray@multicorewareinc.com>