diff --git a/mlir/lib/IR/OperationSupport.cpp b/mlir/lib/IR/OperationSupport.cpp
--- a/mlir/lib/IR/OperationSupport.cpp
+++ b/mlir/lib/IR/OperationSupport.cpp
@@ -97,7 +97,7 @@
   }
 
   auto *it = llvm::lower_bound(attrs, name);
-  if (it->first != name)
+  if (it == attrs.end() || it->first != name)
     return attrs.end();
   return it;
 }