Add checks in ReduceWindowOpOnTensorsConversion.

The pattern does not support ops with non-zero padding config. Add a check to
prevent unexpected lowering.

It is not easy to add tests because other patterns will convert body ops, and
it causes issues like invalid IRs.

PiperOrigin-RevId: 367202450

lib/Dialect/mhlo/transforms/legalize_to_linalg.cc

@@ -1712,6 +1712,10 @@ struct ReduceWindowOpOnTensorsConversion
       return rewriter.notifyMatchFailure(op, "expected NHWC pooling-based op");
     }
 
+    if (op.padding() && !isSplatValue(*op.padding(), 0)) {
+      return rewriter.notifyMatchFailure(op, "require paddings are all zero");
+    }
+
     SmallVector<int64_t, 2> shapes;
     shapes.push_back(op.window_dimensions().getValue<int64_t>(1));
     shapes.push_back(op.window_dimensions().getValue<int64_t>(2));