diff --git a/mlir/lib/Transforms/Vectorize.cpp b/mlir/lib/Transforms/Vectorize.cpp
--- a/mlir/lib/Transforms/Vectorize.cpp
+++ b/mlir/lib/Transforms/Vectorize.cpp
@@ -1003,7 +1003,10 @@
     return nullptr;
   }
   // 3. vectorize constant.
-  if (auto constant = dyn_cast<ConstantOp>(operand.getDefiningOp())) {
+  auto operandOp = operand.getDefiningOp();
+  if (!operandOp)
+    return nullptr;
+  if (auto constant = dyn_cast<ConstantOp>(operandOp)) {
     return vectorizeConstant(
         op, constant,
         VectorType::get(state->strategy->vectorSizes, operand.getType()));
@@ -1037,6 +1040,8 @@
     auto memRef = store.getMemRef();
     auto value = store.getValueToStore();
     auto vectorValue = vectorizeOperand(value, opInst, state);
+    if (!vectorValue)
+      return nullptr;
 
     ValueRange mapOperands = store.getMapOperands();
     SmallVector<Value, 8> indices;