expand dtype conversion support in aten_bridge (#6845)

Summary:
Pull Request resolved: #6845

The dtype tables by necessity have to match exaclty so just casting to the int and then recasting to the other enum is safe

Reviewed By: dulinriley

Differential Revision: D65897501

Author: JacobSzwejbka

extension/aten_util/aten_bridge.cpp

@@ -57,76 +57,41 @@ ET_CHECK_MSG(
   ET_CHECK_MSG(
       b.scalar_type() == torch_to_executorch_scalar_type(a.options().dtype()),
       "dtypes dont match a %hhd vs. b %hhd",
-      torch_to_executorch_scalar_type(a.options().dtype()),
-      b.scalar_type());
+      static_cast<int8_t>(torch_to_executorch_scalar_type(a.options().dtype())),
+      static_cast<int8_t>(b.scalar_type()));
 }
 } // namespace
 
-torch::executor::ScalarType torch_to_executorch_scalar_type(
+executorch::runtime::etensor::ScalarType torch_to_executorch_scalar_type(
     caffe2::TypeMeta type) {
-  switch (c10::typeMetaToScalarType(type)) {
-    case c10::ScalarType::Byte:
-      return torch::executor::ScalarType::Byte;
-    case c10::ScalarType::Char:
-      return torch::executor::ScalarType::Char;
-    case c10::ScalarType::Short:
-      return torch::executor::ScalarType::Short;
-    case c10::ScalarType::Half:
-      return torch::executor::ScalarType::Half;
-    case c10::ScalarType::BFloat16:
-      return torch::executor::ScalarType::BFloat16;
-    case c10::ScalarType::Int:
-      return torch::executor::ScalarType::Int;
-    case c10::ScalarType::Float:
-      return torch::executor::ScalarType::Float;
-    case c10::ScalarType::Long:
-      return torch::executor::ScalarType::Long;
-    case c10::ScalarType::Double:
-      return torch::executor::ScalarType::Double;
-    case c10::ScalarType::Bool:
-      return torch::executor::ScalarType::Bool;
-    case c10::ScalarType::QInt8:
-      return torch::executor::ScalarType::QInt8;
-    case c10::ScalarType::QUInt8:
-      return torch::executor::ScalarType::QUInt8;
-    default:
-      ET_ASSERT_UNREACHABLE_MSG(
-          "Unrecognized dtype: %hhd",
-          static_cast<int8_t>(c10::typeMetaToScalarType(type)));
-  }
+  const auto intermediate =
+      static_cast<std::underlying_type<c10::ScalarType>::type>(
+          c10::typeMetaToScalarType(type));
+
+  ET_CHECK_MSG(
+      intermediate >= 0 &&
+          intermediate <= static_cast<std::underlying_type<
+                              executorch::runtime::etensor::ScalarType>::type>(
+                              executorch::runtime::etensor::ScalarType::UInt64),
+      "ScalarType %d unsupported in Executorch",
+      intermediate);
+  return static_cast<executorch::runtime::etensor::ScalarType>(intermediate);
 }
 
 c10::ScalarType executorch_to_torch_scalar_type(
     torch::executor::ScalarType type) {
-  switch (type) {
-    case torch::executor::ScalarType::Byte:
-      return c10::ScalarType::Byte;
-    case torch::executor::ScalarType::Char:
-      return c10::ScalarType::Char;
-    case torch::executor::ScalarType::Short:
-      return c10::ScalarType::Short;
-    case torch::executor::ScalarType::Half:
-      return c10::ScalarType::Half;
-    case torch::executor::ScalarType::BFloat16:
-      return c10::ScalarType::BFloat16;
-    case torch::executor::ScalarType::Int:
-      return c10::ScalarType::Int;
-    case torch::executor::ScalarType::Float:
-      return c10::ScalarType::Float;
-    case torch::executor::ScalarType::Long:
-      return c10::ScalarType::Long;
-    case torch::executor::ScalarType::Double:
-      return c10::ScalarType::Double;
-    case torch::executor::ScalarType::Bool:
-      return c10::ScalarType::Bool;
-    case torch::executor::ScalarType::QInt8:
-      return c10::ScalarType::QInt8;
-    case torch::executor::ScalarType::QUInt8:
-      return c10::ScalarType::QUInt8;
-    default:
-      ET_ASSERT_UNREACHABLE_MSG(
-          "Unrecognized dtype: %hhd", static_cast<int8_t>(type));
-  }
+  const auto intermediate = static_cast<
+      std::underlying_type<executorch::runtime::etensor::ScalarType>::type>(
+      type);
+
+  ET_CHECK_MSG(
+      intermediate >= 0 &&
+          intermediate <= static_cast<std::underlying_type<
+                              executorch::runtime::etensor::ScalarType>::type>(
+                              executorch::runtime::etensor::ScalarType::UInt64),
+      "ScalarType %d unsupported in Executorch",
+      intermediate);
+  return static_cast<c10::ScalarType>(intermediate);
 }
 
 /*