!11677 add isfinite grad

From: @jiangzg001
Reviewed-by: @liangchenghui,@c_34
Signed-off-by: @liangchenghui

mindspore/ops/_grad/grad_math_ops.py

@@ -778,6 +778,16 @@ def get_bprop_reduce_mean(self):
     return bprop
 
 
+@bprop_getters.register(P.IsFinite)
+def get_bprop_isfinite(self):
+    """Grad definition for `IsFinite` operation."""
+
+    def bprop(x, out, dout):
+        return (zeros_like(x),)
+
+    return bprop
+
+
 @bprop_getters.register(P.Equal)
 def get_bprop_equal(self):
     """Grad definition for `Equal` operation."""

tests/ut/python/ops/test_ops.py

@@ -1401,6 +1401,10 @@ test_case_math_ops = [
         'block': P.RealDiv(),
         'desc_inputs': [[4, 5], [2, 3, 4, 5]],
         'desc_bprop': [[2, 3, 4, 5]]}),
+    ('IsFinite', {
+        'block': P.IsFinite(),
+        'desc_inputs': [Tensor(np.random.random((3, 4, 5)).astype(np.float32))],
+        'desc_bprop': [Tensor(np.random.random((3, 4, 5)).astype(np.bool))]}),
     ('Div', {
         'block': P.Div(),
         'desc_inputs': [[4, 5], [2, 3, 4, 5]],