[clang] [mlir] [OpenACC][NFCI] Implement 'helpers' for all of the clauses I've used so far (PR #137396)

[Andy Kaylor via cfe-commits]

================
@@ -76,6 +76,69 @@ struct LLVMPointerPointerLikeModel
                                             LLVM::LLVMPointerType> {
   Type getElementType(Type pointer) const { return Type(); }
 };
+
+/// Helper function for any of the times we need to modify an ArrayAttr based on
+/// a device type list.  Returns a new ArrayAttr with all of the
+/// existingDeviceTypes, plus the effective new ones(or an added none if hte new
+/// list is empty).
+mlir::ArrayAttr addDeviceTypeAffectedOperandHelper(
+    MLIRContext *context, mlir::ArrayAttr existingDeviceTypes,
+    llvm::ArrayRef<acc::DeviceType> newDeviceTypes) {
+  llvm::SmallVector<mlir::Attribute> deviceTypes;
+  if (existingDeviceTypes)
+    llvm::copy(existingDeviceTypes, std::back_inserter(deviceTypes));
+
+  if (newDeviceTypes.empty())
+    deviceTypes.push_back(
+        acc::DeviceTypeAttr::get(context, acc::DeviceType::None));
+
+  for (DeviceType DT : newDeviceTypes)
+    deviceTypes.push_back(acc::DeviceTypeAttr::get(context, DT));
+
+  return mlir::ArrayAttr::get(context, deviceTypes);
+}
+
+/// Helper function for any of the times we need to add operands that are
+/// affected by a device type list. Returns a new ArrayAttr with all of the
+/// existingDeviceTypes, plus the effective new ones(or an added none, if the
----------------
andykaylor wrote:

```suggestion
/// existingDeviceTypes, plus the effective new ones (or an added none, if the
```

https://github.com/llvm/llvm-project/pull/137396