diff --git a/mlir/lib/Transforms/Canonicalizer.cpp b/mlir/lib/Transforms/Canonicalizer.cpp
--- a/mlir/lib/Transforms/Canonicalizer.cpp
+++ b/mlir/lib/Transforms/Canonicalizer.cpp
@@ -55,7 +55,8 @@
     config.useTopDownTraversal = topDownProcessingEnabled;
     config.enableRegionSimplification = enableRegionSimplification;
     config.maxIterations = maxIterations;
-    (void)applyPatternsAndFoldGreedily(getOperation(), patterns, config);
+    if (failed(applyPatternsAndFoldGreedily(getOperation(), patterns, config)))
+      signalPassFailure();
   }
 
   FrozenRewritePatternSet patterns;