fix tensorrt output shape error (#29308) (#29338)

* fix tensorrt output shape error

* fix unittest tensorrt_engine_op_test

* fix code style for unitest

paddle/fluid/inference/analysis/ir_passes/tensorrt_subgraph_pass.cc

@@ -147,9 +147,11 @@ void TensorRtSubgraphPass::CreateTensorRTOp(
 
   std::set<std::string> output_names;
   std::set<std::string> output_names_with_id;
+  std::vector<int> origin_output_dims;
   for (auto *x : node->outputs) {
     output_names.insert(x->Name());
     output_names_with_id.insert(x->Name() + std::to_string(x->id()));
+    origin_output_dims.push_back(x->Var()->GetShape().size());
   }
 
   std::unordered_map<std::string, std::string> output_name_map;
@@ -215,6 +217,7 @@ void TensorRtSubgraphPass::CreateTensorRTOp(
   op_desc->SetAttr("workspace_size", Get<int>("workspace_size"));
   op_desc->SetAttr("gpu_id", Get<int>("gpu_device_id"));
   op_desc->SetAttr("output_name_mapping", output_mapping);
+  op_desc->SetAttr("origin_output_dims", origin_output_dims);
   op_desc->SetAttr("parameters", params);
 
   // we record all inputs' shapes in attr to check if they are consistent

paddle/fluid/operators/tensorrt/tensorrt_engine_op.h

@@ -273,6 +273,8 @@ class TensorRTEngineOp : public framework::OperatorBase {
 
     // Bind output tensor to TRT.
     int output_index = 0;
+    std::vector<int> origin_output_dims =
+        Attr<std::vector<int>>("origin_output_dims");
     VLOG(4) << "TensorRT Engine Op Outputs:";
     for (const auto &y : Outputs("Ys")) {
       const int bind_index =
@@ -291,7 +293,10 @@ class TensorRTEngineOp : public framework::OperatorBase {
         auto dims = trt_context->getBindingDimensions(bind_index);
         int nb_dims = dims.nbDims;
         for (; nb_dims > 0; nb_dims--) {
-          if (dims.d[nb_dims - 1] != 1) break;
+          // some 'x 1' of shape is normal, no need to remove it
+          if (dims.d[nb_dims - 1] != 1 ||
+              nb_dims == origin_output_dims[output_index])
+            break;
         }
         for (int i = 0; i < nb_dims; i++) ddim.push_back(dims.d[i]);
 #endif

paddle/fluid/operators/tensorrt/tensorrt_engine_op_test.cc

@@ -109,6 +109,7 @@ TEST(TensorRTEngineOp, manual) {
   engine_op_desc.SetAttr("use_calib_mode", static_cast<bool>(false));
   engine_op_desc.SetAttr("output_name_mapping",
                          std::vector<std::string>({"z0"}));
+  engine_op_desc.SetAttr("origin_output_dims", std::vector<int>({2}));
   engine_op_desc.SetAttr("subgraph", std::string(block_->SerializeAsString()));
   engine_op_desc.SetAttr("engine_serialized_data", std::string(""));
   int device_id = 0;
@@ -210,6 +211,7 @@ void Execute(int batch_size, int input_dim, int output_dim, int nlayers = 1) {
   engine_op_desc.SetAttr("use_calib_mode", static_cast<bool>(false));
   engine_op_desc.SetAttr("output_name_mapping",
                          std::vector<std::string>({"z3"}));
+  engine_op_desc.SetAttr("origin_output_dims", std::vector<int>({2}));
   engine_op_desc.SetAttr("subgraph", std::string(block_->SerializeAsString()));
   engine_op_desc.SetAttr("engine_serialized_data", std::string(""));
   int device_id = 0;