Replace archaic use of homebrew functionality with calls to the HC maths library. This fixes a hang observed when building hipTestDeviceDouble.

src/math_functions.cpp

@@ -84,7 +84,7 @@ __device__ float erfcf(float x)
 }
 __device__ float erfcinvf(float y)
 {
-    return __hip_erfinvf(1 - y);
+    return hc::precise_math::erfcinvf(y);
 }
 __device__ float erfcxf(float x)
 {
@@ -96,7 +96,7 @@ __device__ float erff(float x)
 }
 __device__ float erfinvf(float y)
 {
-    return __hip_erfinvf(y);
+    return hc::precise_math::erfinvf(y);//__hip_erfinvf(y);
 }
 __device__ float exp10f(float x)
 {
@@ -192,12 +192,7 @@ __device__ float ldexpf(float x, int exp)
 }
 __device__ float lgammaf(float x)
 {
-  float val = 0.0f;
-  float y = x - 1;
-  while(y > 0){
-    val += logf(y--);
-  }
-  return val;
+    return hc::precise_math::lgammaf(x);
 }
 __device__ long long int llrintf(float x)
 {