fix inference prepare data bug

paddle/fluid/framework/operator.cc

@@ -1531,7 +1531,12 @@ Scope* OperatorWithKernel::PrepareData(
   // the rest iterations to save the elapsed time.
   // We do not support skipping PrepareData in while block, because the Op's
   // input may be changed by subsequent Ops, which may cause an error.
-  if (pre_scope_ == &scope && new_scope == nullptr) {
+
+  // For inference, ops that behind conditional branch aren't supported well,
+  // so disable prepare optimization conservatively.
+  bool force_prepare_data = HasAttr("inference_force_prepare_data") &&
+                            Attr<bool>("inference_force_prepare_data");
+  if (pre_scope_ == &scope && new_scope == nullptr && !force_prepare_data) {
     need_prepare_data_ = false;
   }
 

paddle/fluid/inference/api/analysis_predictor.cc

@@ -270,7 +270,45 @@ bool AnalysisPredictor::CreateExecutor() {
   executor_.reset(new paddle::framework::NaiveExecutor(place_));
   return true;
 }
+
+static bool IsPrepareDataOptTargetOp(framework::OpDesc *op) {
+  // here is prepare data optimization related bad cases:
+  // let's assume an op behind conditional_block and if conditional_block
+  // chooses branch 1, the op need to call prepare data. else the op don't need
+  // to call prepare data. In running, if predictor chooses branch 2, then
+  // optimization takes effect, later issue is followed if predictor chooses
+  // branch 1, because the op lost chance to prepare data.
+  std::vector<std::string> op_type = {"conditional_block_infer",
+                                      "select_input"};
+  for (const auto &type : op_type) {
+    if (op->Type() == type) {
+      return true;
+    }
+  }
+  return false;
+}
+
+static void DisablePrepareDataOpt(
+    std::shared_ptr<framework::ProgramDesc> inference_program, int block,
+    bool pre_disable_opt) {
+  bool disable_opt = false;
+  for (auto *op : inference_program->Block(block).AllOps()) {
+    if (disable_opt || pre_disable_opt) {
+      op->SetAttr("inference_force_prepare_data", true);
+    }
+    if (op->HasAttr("sub_block")) {
+      int blockID = op->GetBlockAttrId("sub_block");
+      DisablePrepareDataOpt(inference_program, blockID, disable_opt);
+    }
+    if (IsPrepareDataOptTargetOp(op)) {
+      disable_opt = true;
+    }
+  }
+}
+
 bool AnalysisPredictor::PrepareExecutor() {
+  DisablePrepareDataOpt(inference_program_, 0, false);
+
   executor_->Prepare(sub_scope_, *inference_program_, 0,
                      config_.use_feed_fetch_ops_);
 

python/paddle/fluid/tests/unittests/ir/inference/test_trt_conv_pass.py

@@ -195,7 +195,7 @@ def setUp(self):
             }, {
                 "conv2d_0.tmp_0": [16, 6, 16, 16],
                 "data": [16, 6, 16, 16],
-                "depthwise_conv2d_0.tmp_0": [32, 6, 64, 64]
+                "depthwise_conv2d_0.tmp_0": [16, 6, 16, 16]
             }, False)
         self.fetch_list = [conv_out]