diff --git a/mlir/lib/Analysis/Liveness.cpp b/mlir/lib/Analysis/Liveness.cpp
--- a/mlir/lib/Analysis/Liveness.cpp
+++ b/mlir/lib/Analysis/Liveness.cpp
@@ -297,7 +297,7 @@
 
   // Local printing helpers
   auto printValueRef = [&](Value value) {
-    if (Operation *defOp = value.getDefiningOp())
+    if (value.getDefiningOp())
       os << "val_" << valueIds[value];
     else {
       auto blockArg = value.cast<BlockArgument>();