diff --git a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
--- a/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
+++ b/mlir/lib/Dialect/StandardOps/IR/Ops.cpp
@@ -3003,6 +3003,7 @@
            << expectedType
            << " or a rank-reduced version. (mismatch of result affine map)";
   }
+  llvm_unreachable("unexpected subview verification result");
 }
 
 template <typename OpType>