raise RuntimeError for int base pow (#8852)

current implementation is not precise and blocking other simplification change

test/external/external_test_onnx_backend.py

@@ -95,6 +95,10 @@ backend_test.exclude('test_dequantizelinear_e5m2_cpu')
 # we don't support indexes
 backend_test.exclude('test_nonzero_*')
 
+# no support for int pow
+backend_test.exclude('test_pow_types_int32_int32_cpu')
+backend_test.exclude('test_pow_types_int64_int64_cpu')
+
 # no support for fmod
 backend_test.exclude('test_mod_int64_fmod_cpu')
 backend_test.exclude('test_mod_mixed_sign_float16_cpu')

test/test_ops.py

@@ -619,6 +619,7 @@ class TestOps(unittest.TestCase):
     # TODO: fix backward, should be nan
     helper_test_op(None, lambda x: (-2)**x, vals=[[-2.,-1,0,1,2,3]], forward_only=True)
 
+  @unittest.skip("not supported")
   def test_pow_int(self):
     def _test(base, exponent): helper_test_op(None, lambda x,y: x**y, vals=[base, exponent], forward_only=True)