Fix the bug where XLA doesn't provide shardings for all the outputs i…

…f all the elements in the output tuple have the same sharding. XLA decides to run the `FusionTupleDeduplicator` to put the sharding on ROOT instead of the tuple.

PiperOrigin-RevId: 477343328

jax/interpreters/pxla.py

@@ -3126,8 +3126,16 @@ def _get_op_sharding_shardings_from_executable(
 
   in_op_shardings, out_op_shardings = pjit._get_op_sharding_from_executable(xla_executable)
 
-  return ([OpShardingSharding(device_assignment, i) for i in in_op_shardings],
-          [OpShardingSharding(device_assignment, o) for o in out_op_shardings])
+  in_shardings_xla = [OpShardingSharding(device_assignment, i) for i in in_op_shardings]
+  out_shardings_xla = [OpShardingSharding(device_assignment, o) for o in out_op_shardings]
+  # This condition happens when all the elements in the output tuple have the
+  # same sharding, so XLA decides to run the `FusionTupleDeduplicator` to
+  # put the sharding on ROOT instead of the tuple.
+  # TODO(b/245667823): Remove this when XLA fixes this.
+  if len(out_shardings_xla) == 1 and len(out_shardings_xla) < num_out_avals:
+    out_shardings_xla = out_shardings_xla * num_out_avals
+  return in_shardings_xla, out_shardings_xla
+
 
 
 # TODO(yashkatariya): Remove this function after `AUTO` can return shardings