[Beignet] [PATCH 3/3] libocl: Flush denorm input into zero in rootn()

[Ruiling Song]

Gen does not support denorm. We have to flush input to zero.

Signed-off-by: Ruiling Song <ruiling.song at intel.com>
---
 backend/src/libocl/tmpl/ocl_math.tmpl.cl |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/backend/src/libocl/tmpl/ocl_math.tmpl.cl b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
index c7be47e..248ddd0 100644
--- a/backend/src/libocl/tmpl/ocl_math.tmpl.cl
+++ b/backend/src/libocl/tmpl/ocl_math.tmpl.cl
@@ -3414,7 +3414,15 @@ OVERLOADABLE float pow(float x, float y) {
 OVERLOADABLE float rootn(float x, int n) {
   float ax,re;
   int sign = 0;
+  int hx;
   if( n == 0 )return NAN;
+
+  GEN_OCL_GET_FLOAT_WORD(hx, x);
+  // Gen does not support denorm, flush to zero
+  if ((hx & 0x7fffffff) < 0x00800000) {
+    x = hx < 0 ? -0.0f : 0.0f;
+  }
+
   //rootn ( x, n )  returns a NaN for x < 0 and n is even.
   if( x < 0 && 0 == (n&1) )
     return NAN;
-- 
1.7.10.4