diff --git a/taichi/transforms/loop_invariant_detector.h b/taichi/transforms/loop_invariant_detector.h
index d9ce963c505ca..3913b7bd46733 100644
--- a/taichi/transforms/loop_invariant_detector.h
+++ b/taichi/transforms/loop_invariant_detector.h
@@ -65,6 +65,8 @@ class LoopInvariantDetector : public BasicStmtVisitor {
     bool is_invariant = true;
 
     for (Stmt *operand : stmt->get_operands()) {
+      if (operand == nullptr)
+        continue;
       is_invariant &= is_operand_loop_invariant_impl(operand, current_scope);
     }
 
diff --git a/taichi/transforms/make_thread_local.cpp b/taichi/transforms/make_thread_local.cpp
index d88e8fcd946af..8756551610016 100644
--- a/taichi/transforms/make_thread_local.cpp
+++ b/taichi/transforms/make_thread_local.cpp
@@ -76,6 +76,8 @@ std::vector<std::pair<T *, AtomicOpType>> find_global_reduction_destinations(
             }
           }
           for (auto &op : stmt->get_operands()) {
+            if (op == nullptr)
+              continue;
             // Make sure the values of related atomic operations are not used.
             if (auto atomic = op->cast<AtomicOpStmt>()) {
               if (irpass::analysis::maybe_same_address(atomic->dest,