Fix atan2 mangling in OpenCL

loopy/target/opencl.py

@@ -139,6 +139,7 @@ def _register_vector_types(dtype_registry):
 
 _CL_SIMPLE_MULTI_ARG_FUNCTIONS = {
         "clamp": 3,
+        "atan2": 2,
         }
 
 
@@ -164,7 +165,7 @@ def opencl_function_mangler(kernel, name, arg_dtypes):
     if not isinstance(name, str):
         return None
 
-    if name in ["max", "min", "atan2"] and len(arg_dtypes) == 2:
+    if name in ["max", "min"] and len(arg_dtypes) == 2:
         dtype = np.find_common_type(
                 [], [dtype.numpy_dtype for dtype in arg_dtypes])
 
@@ -204,7 +205,7 @@ def opencl_function_mangler(kernel, name, arg_dtypes):
         return CallMangleInfo(
                 target_name=name,
                 result_dtypes=(result_dtype,),
-                arg_dtypes=(result_dtype,)*3)
+                arg_dtypes=(result_dtype,)*num_args)
 
     if name in VECTOR_LITERAL_FUNCS:
         base_tp_name, dtype, count = VECTOR_LITERAL_FUNCS[name]