pandas-dev#56147 negative offset and year end interaction

Author: jrmylow

pandas/core/arrays/datetimes.py

@@ -2756,7 +2756,10 @@ def _generate_range(
     if start and not offset.is_on_offset(start):
         # Incompatible types in assignment (expression has type "datetime",
         # variable has type "Optional[Timestamp]")
-        start = offset.rollforward(start)  # type: ignore[assignment]
+        if offset.n >= 0:
+            start = offset.rollforward(start)  # type: ignore[assignment]
+        else:
+            start = offset.rollback(start) # type: ignore[assignment]
 
     # Unsupported operand types for < ("Timestamp" and "None")
     if periods is None and end < start and offset.n >= 0:  # type: ignore[operator]