[Beignet] [PATCH] 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..24ddaa4 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,  +1, +1,  -80,              0,-0,0,-0, 'INFINITY','INFINITY',+1,+1,0,2.5,'NAN','NAN','NAN' ]
+  powr_input_values2 = [5.5,6,7, +0,-0,-1,-15.67,'-INFINITY', '-INFINITY',1,  -2.7,10.5, 3.1415,3.5,-0,-0,0,0,   0,       -0,'INFINITY','-INFINITY','NAN','NAN',-1.5,0,1.5]
   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) || (y == -0)))
+        return 1;
+    else if (((x == +0) || (x == -0)) && ((y <0) || (y == -INFINITY)))
+        return +INFINITY;
+    else if (((x == +0) || (x == -0)) && (y > 0))
+        return +0;
+    else if (((x == +0) || (x == -0)) && ((y == +0) || (y == -0)))
+        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) || (y == -0)))
+        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