diff --git a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
index be7924e153088..7697e603507a4 100644
--- a/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
+++ b/mlir/lib/Transforms/Utils/GreedyPatternRewriteDriver.cpp
@@ -607,14 +607,15 @@ bool MultiOpPatternRewriteDriver::simplifyLocally(ArrayRef<Operation *> ops) {
   SmallVector<Value, 8> originalOperands, resultValues;
   while (!worklist.empty()) {
     Operation *op = popFromWorklist();
-    assert((!strictMode || strictModeFilteredOps.contains(op)) &&
-           "unexpected op was inserted under strict mode");
 
     // Nulls get added to the worklist when operations are removed, ignore
     // them.
     if (op == nullptr)
       continue;
 
+    assert((!strictMode || strictModeFilteredOps.contains(op)) &&
+           "unexpected op was inserted under strict mode");
+
     // If the operation is trivially dead - remove it.
     if (isOpTriviallyDead(op)) {
       notifyOperationRemoved(op);