[Mlir-commits] [mlir] [mlir] fix references of attributes which are not defined earlier (PR #134364)

[Mehdi Amini]

================
@@ -145,10 +145,13 @@ def generate_name(self, source_attribute_name):
         return attribute_name
 
     # Get the saved substitution name for the given attribute name. If no name
-    # has been generated for the given attribute yet, the source attribute name
-    # itself is returned.
+    # has been generated for the given attribute yet, None is returned.
     def get_name(self, source_attribute_name):
-        return self.map[source_attribute_name] if source_attribute_name in self.map else '?'
+        return (
+            self.map[source_attribute_name]
+            if source_attribute_name in self.map
+            else None
----------------
joker-eph wrote:

```suggestion
            self.map.get(source_attribute_name)
```

https://github.com/llvm/llvm-project/pull/134364