diff --git a/mlir/lib/Dialect/SparseTensor/Transforms/Sparsification.cpp b/mlir/lib/Dialect/SparseTensor/Transforms/Sparsification.cpp
--- a/mlir/lib/Dialect/SparseTensor/Transforms/Sparsification.cpp
+++ b/mlir/lib/Dialect/SparseTensor/Transforms/Sparsification.cpp
@@ -1854,7 +1854,8 @@
                                 PatternRewriter &rewriter) const override {
     // Detects sparse annotations and translate the per-dimension sparsity
     // information for all tensors to loop indices in the kernel.
-    assert(op.getNumOutputs() == 1);
+    if (op.getNumOutputs() != 1)
+      return failure();
     unsigned numTensors = op.getNumInputsAndOutputs();
     unsigned numLoops = op.iterator_types().getValue().size();
     Merger merger(numTensors, numLoops);