transformations: (reconcile-unrealized-casts) pass does not handle 1 to n and n to 1 casts

[watermelonwolverine]

The reconcile-unrealized-casts pass from xDSL fails to reconcile 1 to n and n to 1 casts.

Example:

Using the pass on

module {

  func.func @reconcile_unrealized_casts(
    %value1 : f64,
    %value2 : f64
  ) -> (f64, f64) {

    %box = "builtin.unrealized_conversion_cast"(%value1, %value2) : (f64, f64) -> !box.box<[f64, f64]>
    %value1_, %value2_ = "builtin.unrealized_conversion_cast"(%box) : (!box.box<[f64, f64]>) -> (f64, f64)

    func.return %value1_, %value2_ : f64, f64
  }
}

raises an exception:

Traceback (most recent call last):
  File "/workspaces/Master_Thesis_Code/.venv/lib/python3.10/site-packages/xdsl/pattern_rewriter.py", line 835, in _process_worklist
    self.pattern.match_and_rewrite(op, rewriter)
  File "/workspaces/Master_Thesis_Code/.venv/lib/python3.10/site-packages/xdsl/pattern_rewriter.py", line 433, in impl
    func(self, op, rewriter)
  File "/workspaces/Master_Thesis_Code/.venv/lib/python3.10/site-packages/xdsl/transforms/reconcile_unrealized_casts.py", line 110, in match_and_rewrite
    _try_remove_cast_chain(op, rewriter, self.warn_on_failure)
  File "/workspaces/Master_Thesis_Code/.venv/lib/python3.10/site-packages/xdsl/transforms/reconcile_unrealized_casts.py", line 71, in _try_remove_cast_chain
    assert len(cast.results) == len(op.inputs)
AssertionError

mlir-opt succeeds with:

module {
  func.func @reconcile_unrealized_casts(%arg0: f64, %arg1: f64) -> (f64, f64) {
    return %arg0, %arg1 : f64, f64
  }
}