Added cast from half to real [skip ci]

src/half.c

@@ -439,6 +439,19 @@ float4_to_half(PG_FUNCTION_ARGS)
 	PG_RETURN_HALF(h);
 }
 
+/*
+ * Convert half to float4
+ */
+PGDLLEXPORT PG_FUNCTION_INFO_V1(half_to_float4);
+Datum
+half_to_float4(PG_FUNCTION_ARGS)
+{
+	half		h = PG_GETARG_HALF(0);
+	float		f = HalfToFloat4(h);
+
+	PG_RETURN_FLOAT4(f);
+}
+
 /*
  * Get the L2 distance between half arrays
  */