[Dy2St]Refine covnert_var_shape in dy2st (#43348)

* Refine covnert_var_shape in dy2st

* Fix UT error

* Return paddle.shape only when has_negative and fix test_tensor_shape error

* Fix test_jit_save_load error

python/paddle/fluid/dygraph/dygraph_to_static/convert_operators.py

@@ -313,8 +313,7 @@ def convert_var_shape(x, idx=None, in_control_flow=False):
     #      # Assume x.shape=[3, -1] in static mode
     #      y = paddle.reshape(x, shape=[1, x.shape[1]])
     #      ```
-    if isinstance(x, Variable) and (in_control_flow
-                                    or has_negative(x.shape, idx)):
+    if isinstance(x, Variable) and has_negative(x.shape, idx):
         return nn.shape(x) if idx is None else nn.shape(x)[idx]
     else:
         return list(x.shape) if idx is None else x.shape[idx]

python/paddle/fluid/tests/unittests/dygraph_to_static/test_tensor_shape.py

@@ -409,9 +409,9 @@ class TestTensorShapeInIf2(TestTensorShapeBasic):
         self.dygraph_func = dyfunc_with_if_2
 
     def _set_expected_op_num(self):
-        self.expected_op_num = 14
-        self.expected_shape_op_num = 2
-        self.expected_slice_op_num = 1
+        self.expected_op_num = 2
+        self.expected_shape_op_num = 0
+        self.expected_slice_op_num = 0
 
 
 # 3. Tests with control flow for loop
@@ -421,9 +421,9 @@ class TestTensorShapeInFor1(TestTensorShapeBasic):
         self.dygraph_func = dyfunc_with_for_1
 
     def _set_expected_op_num(self):
-        self.expected_op_num = 22
-        self.expected_shape_op_num = 3
-        self.expected_slice_op_num = 3
+        self.expected_op_num = 7
+        self.expected_shape_op_num = 0
+        self.expected_slice_op_num = 0
 
 
 class TestTensorShapeInFor2(TestTensorShapeInFor1):
@@ -443,9 +443,9 @@ class TestTensorShapeInFor3(TestTensorShapeInFor1):
         self.dygraph_func = dyfunc_with_for_3
 
     def _set_expected_op_num(self):
-        self.expected_op_num = 25
-        self.expected_shape_op_num = 6
-        self.expected_slice_op_num = 3
+        self.expected_op_num = 3
+        self.expected_shape_op_num = 0
+        self.expected_slice_op_num = 0
 
 
 # 4. Tests with control flow while loop
@@ -454,6 +454,11 @@ class TestTensorShapeInWhile1(TestTensorShapeInFor1):
     def init_test_func(self):
         self.dygraph_func = dyfunc_with_while_1
 
+    def _set_expected_op_num(self):
+        self.expected_op_num = 4
+        self.expected_shape_op_num = 0
+        self.expected_slice_op_num = 0
+
 
 class TestTensorShapeInWhile2(TestTensorShapeInFor1):
 

python/paddle/fluid/tests/unittests/test_jit_save_load.py

@@ -1070,7 +1070,7 @@ class LayerSaved(paddle.nn.Layer):
     def forward(self, x):
         y = self._linear_0(x)
         # Multiple blocks
-        if x.shape[0] == 1:
+        if paddle.shape(x)[0] == 1:
             y = self._linear_1_0(y)
         else:
             y += self._linear_1_1(y + self._scale)
@@ -1097,7 +1097,7 @@ class LayerLoadFinetune(paddle.nn.Layer):
         y = self._linear_0(x)
         y = self._load_l1(y)
         # Multiple blocks
-        if x.shape[0] == 1:
+        if paddle.shape(x)[0] == 1:
             y = self._linear_1_0(y)
             y = self._load_l1(y)
         else: