move trunc_op's infere shape to phi (#39772)

* move trunc_op's infere shape

* modify according to risheng's comment

paddle/fluid/operators/trunc_op.cc

@@ -12,8 +12,10 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License. */
 
+#include "paddle/fluid/framework/infershape_utils.h"
 #include "paddle/fluid/framework/op_registry.h"
-#include "paddle/fluid/framework/operator.h"
+#include "paddle/phi/core/infermeta_utils.h"
+#include "paddle/phi/infermeta/unary.h"
 
 namespace paddle {
 namespace operators {
@@ -21,14 +23,6 @@ namespace operators {
 class TruncOp : public framework::OperatorWithKernel {
  public:
   using framework::OperatorWithKernel::OperatorWithKernel;
-
-  void InferShape(framework::InferShapeContext *ctx) const override {
-    OP_INOUT_CHECK(ctx->HasInput("X"), "Input", "X", "trunc");
-    OP_INOUT_CHECK(ctx->HasOutput("Out"), "Output", "Out", "trunc");
-    auto input_dims = ctx->GetInputDim("X");
-    ctx->SetOutputDim("Out", input_dims);
-    ctx->ShareLoD("X", /*->*/ "Out");
-  }
 };
 
 class TruncOpMaker : public framework::OpProtoAndCheckerMaker {
@@ -75,9 +69,13 @@ class TruncGradOpMaker : public framework::SingleGradOpMaker<T> {
 }  // namespace operators
 }  // namespace paddle
 
+DELCARE_INFER_SHAPE_FUNCTOR(trunc, TruncInferShapeFunctor,
+                            PT_INFER_META(phi::UnchangedInferMeta));
+
 namespace ops = paddle::operators;
 REGISTER_OPERATOR(trunc, ops::TruncOp, ops::TruncOpMaker,
                   ops::TruncGradOpMaker<paddle::framework::OpDesc>,
-                  ops::TruncGradOpMaker<paddle::imperative::OpBase>);
+                  ops::TruncGradOpMaker<paddle::imperative::OpBase>,
+                  TruncInferShapeFunctor);
 
 REGISTER_OPERATOR(trunc_grad, ops::TruncGradOp);