address comments

onnxruntime/core/providers/webnn/builders/impl/lstm_op_builder.cc

@@ -160,19 +160,20 @@ Status LstmOpBuilder::AddToModelBuilderImpl(ModelBuilder& model_builder, const N
 bool LstmOpBuilder::IsOpSupportedImpl(const InitializedTensorSet& initializers, const Node& node,
                                       const WebnnDeviceType /*device_type*/, const logging::Logger& logger) const {
   const auto& input_defs = node.InputDefs();
+
+  std::vector<int64_t> input_shape;
+  if (!GetShape(*input_defs[0], input_shape, logger)) {
+    LOGS(logger, ERROR) << "Cannot get input's shape";
+    return false;
+  }
+  int32_t steps = static_cast<int32_t>(input_shape[0]);
+
   if (input_defs.size() > 4 && input_defs[4]->Exists()) {
     if (!Contains(initializers, input_defs[4]->Name())) {
-      LOGS(logger, ERROR) << "LSTM: sequence_lens must be constant and the values must be equal to input shape[0]";
+      LOGS(logger, ERROR) << "LSTM: sequence_lens must be constant";
       return false;
     }
 
-    std::vector<int64_t> input_shape;
-    if (!GetShape(*input_defs[0], input_shape, logger)) {
-      LOGS(logger, ERROR) << "Cannot get input's shape";
-      return false;
-    }
-    int32_t steps = static_cast<int32_t>(input_shape[0]);
-
     const auto& sequence_lens_tensor = *initializers.at(input_defs[4]->Name());
     std::vector<int32_t> sequence_lens;
     if (!ReadIntArrayFrom1DTensor(sequence_lens_tensor, sequence_lens, logger)) {
@@ -189,22 +190,26 @@ bool LstmOpBuilder::IsOpSupportedImpl(const InitializedTensorSet& initializers,
   NodeAttrHelper helper(node);
   if (helper.HasAttr("activations")) {
     const auto activations = helper.Get("activations", std::vector<std::string>{"Sigmoid", "Tanh", "Tanh"});
-    if (activations.size() >= 6 &&
-        (activations[0] != activations[3] || activations[1] != activations[4] || activations[2] != activations[5])) {
-      LOGS(logger, ERROR) << "LSTM: forward and reverse directions must have the same activations";
-      return false;
-    }
 
-    if (activations.size() >= 6 && (helper.HasAttr("activation_alpha") || helper.HasAttr("activation_beta"))) {
-      LOGS(logger, ERROR) << "LSTM: activation_alpha and activation_beta are not supported when provided 6 activations";
-      return false;
+    if (activations.size() >= 6) {
+      if (activations[0] != activations[3] || activations[1] != activations[4] || activations[2] != activations[5]) {
+        LOGS(logger, ERROR) << "LSTM: forward and reverse directions must have the same activations";
+        return false;
+      }
+      // TODO(shiyi9801): support activation_alpha and activation_beta when provided 6 activations.
+      if (helper.HasAttr("activation_alpha") || helper.HasAttr("activation_beta")) {
+        LOGS(logger, ERROR)
+            << "LSTM: activation_alpha and activation_beta are not supported when provided 6 activations";
+        return false;
+      }
     }
 
-    if (!std::all_of(activations.begin(), activations.end(), [](const std::string& activation) -> bool {
-          return activation == "Affine" || activation == "Relu" || activation == "LeakyRelu" || activation == "Tanh" ||
-                 activation == "Sigmoid" || activation == "HardSigmoid" || activation == "Elu" ||
-                 activation == "Softsign" || activation == "Softplus";
-        })) {
+    const InlinedHashSet<std::string> supported_activations = {"Affine", "Relu", "LeakyRelu", "Tanh", "Sigmoid",
+                                                               "HardSigmoid", "Elu", "Softsign", "Softplus"};
+    if (!std::all_of(activations.begin(), activations.end(),
+                     [&supported_activations](const std::string& activation) -> bool {
+                       return supported_activations.contains(activation);
+                     })) {
       LOGS(logger, ERROR) << "LSTM: activations must be one of Affine, Relu, LeakyRelu, Tanh, Sigmoid, HardSigmoid, "
                              "Elu, Softsign, Softplus";
       return false;