[Beignet] [PATCH v2] fix a powr function issue in cpu compiler math

[Meng Mengmeng]

In OpenCL spec, gentype powr(gentype x, gentype y). In the meantime,
added edge tests for powr.
---
 utests/utest_math_gen.py | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/utests/utest_math_gen.py b/utests/utest_math_gen.py
index 83edcc3..424af41 100755
--- a/utests/utest_math_gen.py
+++ b/utests/utest_math_gen.py
@@ -467,14 +467,30 @@ static float pown(float x, int y){
   pownUtests = func('pown','pown',[pown_input_type1,pown_input_type2],pown_output_type,[pown_input_values1,pown_input_values2],'16 * FLT_ULP', pown_cpu_func)
   
   ##### gentype powr(gentype x, gentype y)
-  powr_input_values1 = [80, -80, 3.14, -3.14, 0.5, 1, -1, 0.0,6,1500.24,-1500.24]
-  powr_input_values2 = [5,6,7,8,10,11,12,13,14,0,12]
+  powr_input_values1 = [80, -80, 3.14, 1, 1.257, +0.0, -0.0, +0.0, -0.0, +0.0, -0.0, +1, +1, -80, +0.0, -0.0, +0.0, -0.0, 'INFINITY','INFINITY', +1, +1, +0.0, 2.5,' NAN', 'NAN', 'NAN']
+  powr_input_values2 = [5.5, 6,7, +0.0, -0.0, -1, -15.67, '-INFINITY', '-INFINITY', 1,  -2.7, 10.5, 3.1415, 3.5, -0.0, -0.0, +0.0, +0.0, +0.0, -0.0, 'INFINITY', '-INFINITY', 'NAN', 'NAN', -1.5, +0.0, 1.5]
   powr_input_type1 = ['float','float2','float4','float8','float16']
   powr_input_type2 = ['float','float2','float4','float8','float16']
   powr_output_type = ['float','float2','float4','float8','float16']
   powr_cpu_func='''
-static float powr(float x, int y){
-    if (x<0)
+static float powr(float x, float y){
+    if (((x > 0) && (x != +INFINITY)) && (y == 0.0f))
+        return 1;
+    else if ((x == 0.0f) && ((y < 0 ) || (y == -INFINITY)))
+        return +INFINITY;
+    else if ((x == 0.0f) && (y > 0))
+        return +0;
+    else if ((x == 0.0f) && (y == 0.0f))
+        return NAN;
+    else if ((x == +1) && ((y == +INFINITY) || (y == -INFINITY)))
+        return NAN;
+    else if ((x == +1) && ((y != +INFINITY) && (y != -INFINITY)))
+        return 1;
+    else if ((x == +INFINITY) && (y == 0.0f))
+        return NAN;
+    else if (isnan(x) || (x < 0))
+        return NAN;
+    else if ((x >=  0) && (isnan(y)))
         return NAN;
     else
         return powf(x,y);
-- 
1.9.1