diff --git a/xarray/core/nputils.py b/xarray/core/nputils.py
index 6970d37402f..6fd18ae052e 100644
--- a/xarray/core/nputils.py
+++ b/xarray/core/nputils.py
@@ -101,7 +101,8 @@ def _ensure_bool_is_ndarray(result, *args):
     # This function ensures that the result is the appropriate shape in these
     # cases
     if isinstance(result, bool):
-        shape = np.broadcast(*args).shape
+        # Avoid repeated broadcasting: save result
+        shape = np.broadcast_shapes(*(getattr(arg, "shape", ()) for arg in args))
         constructor = np.ones if result else np.zeros
         result = constructor(shape, dtype=bool)
     return result
@@ -115,8 +116,9 @@ def array_eq(self, other):
 
 def array_ne(self, other):
     with warnings.catch_warnings():
-        warnings.filterwarnings("ignore", r"elementwise comparison failed")
-        return _ensure_bool_is_ndarray(self != other, self, other)
+        warnings.simplefilter("ignore", category=UserWarning)
+        cmp_result = self != other
+        return _ensure_bool_is_ndarray(cmp_result, self, other)
 
 
 def _is_contiguous(positions):