fix(//core/conversion/evaluators): Change how schemas are handled

in aten::range evaluator

Signed-off-by: Naren Dasan <narens@nvidia.com>
Signed-off-by: Naren Dasan <naren@narendasan.com>

Author: narendasan

core/conversion/evaluators/aten.cpp

@@ -620,22 +620,19 @@ auto aten_registrations TORCHTRT_UNUSED =
                  {"aten::tensor(t[] data, *, int? dtype=None, Device? device=None, bool requires_grad=False) -> (Tensor)"})})
         .evaluator({c10::Symbol::fromQualString("aten::arange"),
                     [](const torch::jit::Node* n, kwargs& args) -> c10::optional<torch::jit::IValue> {
-                      int input_size = n->inputs().size();
-                      int scalar_count = 0;
-                      for (int i = 0; i < input_size; i++) {
-                        if (args.at(n->input(i)).IValue()->isScalar()) {
-                          scalar_count += 1;
-                        }
-                      }
-                      if (scalar_count == 1) {
+                      auto schema = n->maybeSchema();
+                      TORCHTRT_CHECK(schema, "Unable to get schema for node: " << *n);
+                      auto name = schema->operator_name();
+
+                      if (c10::toString(name) == "aten::arange") {
                         if (args.at(n->input(0)).IValue()->isInt()) {
                           int end_scalar = args.at(n->input(0)).unwrapToInt();
                           return torch::arange(end_scalar);
                         } else if (args.at(n->input(0)).IValue()->isDouble()) {
                           float end_scalar = args.at(n->input(0)).unwrapToScalar().to<float>();
                           return torch::arange(end_scalar);
                         }
-                      } else if (scalar_count == 2) {
+                      } else if (c10::toString(name) == "aten::arange.start") {
                         if (args.at(n->input(0)).IValue()->isDouble() || args.at(n->input(1)).IValue()->isDouble()) {
                           float start_scalar = args.at(n->input(0)).unwrapToScalar().to<float>();
                           float end_scalar = args.at(n->input(1)).unwrapToScalar().to<float>();
@@ -645,7 +642,7 @@ auto aten_registrations TORCHTRT_UNUSED =
                           int end_scalar = args.at(n->input(1)).unwrapToInt();
                           return torch::arange(start_scalar, end_scalar);
                         }
-                      } else if (scalar_count == 3) {
+                      } else if (c10::toString(name) == "aten::arange.start_step") {
                         if (args.at(n->input(0)).IValue()->isDouble() || args.at(n->input(1)).IValue()->isDouble() ||
                             args.at(n->input(2)).IValue()->isDouble()) {
                           float start_scalar = args.at(n->input(0)).unwrapToScalar().to<float>();
@@ -659,8 +656,7 @@ auto aten_registrations TORCHTRT_UNUSED =
                           return torch::arange(start_scalar, end_scalar, step_scalar);
                         }
                       } else {
-                        TORCHTRT_THROW_ERROR(
-                            "Invalid input argument size for aten::arange, input argument size: " << input_size);
+                        TORCHTRT_THROW_ERROR("Unsupported aten::arange variant: " << name);
                       }
                       return {};
                     },