diff --git a/paddle/fluid/framework/op_desc.cc b/paddle/fluid/framework/op_desc.cc
index cbb2c79c5c47d82b576b18a1790fb8f68391acd6..ae33c993efe8fe29ba08d69d41e5826571c0fb85 100644
--- a/paddle/fluid/framework/op_desc.cc
+++ b/paddle/fluid/framework/op_desc.cc
@@ -721,6 +721,9 @@ CompileTimeInferShapeContext::CompileTimeInferShapeContext(
     : op_(op), block_(block) {}
 
 bool CompileTimeInferShapeContext::HasInput(const std::string &name) const {
+  if (op_.Inputs().find(name) == op_.Inputs().end()) {
+    return false;
+  }
   const std::vector<std::string> &input_names = op_.Input(name);
   auto length = input_names.size();
   if (length == 0) {
@@ -734,6 +737,9 @@ bool CompileTimeInferShapeContext::HasInput(const std::string &name) const {
 }
 
 bool CompileTimeInferShapeContext::HasOutput(const std::string &name) const {
+  if (op_.Outputs().find(name) == op_.Outputs().end()) {
+    return false;
+  }
   const std::vector<std::string> &output_names = op_.Output(name);
   auto length = output_names.size();
   if (length == 0) {
@@ -747,6 +753,9 @@ bool CompileTimeInferShapeContext::HasOutput(const std::string &name) const {
 }
 
 bool CompileTimeInferShapeContext::HasInputs(const std::string &name) const {
+  if (op_.Inputs().find(name) == op_.Inputs().end()) {
+    return false;
+  }
   const std::vector<std::string> &input_names = op_.Input(name);
   if (input_names.empty()) {
     return false;
@@ -758,6 +767,9 @@ bool CompileTimeInferShapeContext::HasInputs(const std::string &name) const {
 }
 
 bool CompileTimeInferShapeContext::HasOutputs(const std::string &name) const {
+  if (op_.Outputs().find(name) == op_.Outputs().end()) {
+    return false;
+  }
   const std::vector<std::string> &output_names = op_.Output(name);
   if (output_names.empty()) {
     return false;
diff --git a/paddle/fluid/operators/fill_constant_op.cc b/paddle/fluid/operators/fill_constant_op.cc
index 8fb12a952f6c6ecb05e0b6e586c1365773612bea..9794ddc672ab3cc1c99257e03870c56caab0582d 100644
--- a/paddle/fluid/operators/fill_constant_op.cc
+++ b/paddle/fluid/operators/fill_constant_op.cc
@@ -25,6 +25,16 @@ class FillConstantOp : public framework::OperatorWithKernel {
     OP_INOUT_CHECK(ctx->HasOutput("Out"), "Output", "Out", "FillConstant");
 
     auto& shape = ctx->Attrs().Get<std::vector<int64_t>>("shape");
+    if (!ctx->HasInput("ShapeTensor") && !ctx->HasInputs("ShapeTensorList")) {
+      for (size_t i = 0; i < shape.size(); ++i) {
+        PADDLE_ENFORCE_GE(
+            shape[i], 0,
+            platform::errors::InvalidArgument(
+                "Each value of attribute 'shape' is expected to be greater "
+                "than 0. But recieved: shape[%u] = %d; shape = [%s].",
+                i, shape[i], framework::make_ddim(shape)));
+      }
+    }
 
     if (shape.empty() && ctx->HasInput("ShapeTensor")) {
       auto shape_dims = ctx->GetInputDim("ShapeTensor");
diff --git a/python/paddle/fluid/tests/unittests/test_rnn_decode_api.py b/python/paddle/fluid/tests/unittests/test_rnn_decode_api.py
index 8b0b144c6d8815e9442e0981ef8f32c31d5758bd..6ca194b2694b6c7537ceb94e11eb1a1a0aeb8d8d 100644
--- a/python/paddle/fluid/tests/unittests/test_rnn_decode_api.py
+++ b/python/paddle/fluid/tests/unittests/test_rnn_decode_api.py
@@ -369,11 +369,11 @@ class SeqPGAgent(object):
             self.probs, self.samples, self.sample_length = self.model(
                 source, source_length, target, target_length)
             self.samples.stop_gradient = True
-            self.reward = fluid.layers.create_global_var(
+            self.reward = fluid.data(
                 name="reward",
-                shape=[-1, -1],  # batch_size, seq_len
-                value="1",
+                shape=[None, None],  # batch_size, seq_len
                 dtype=self.probs.dtype)
+            self.samples.stop_gradient = False
             self.cost = self.alg.learn(self.probs, self.samples, self.reward,
                                        self.sample_length)