diff --git a/mlir/include/mlir/TableGen/Constraint.h b/mlir/include/mlir/TableGen/Constraint.h
--- a/mlir/include/mlir/TableGen/Constraint.h
+++ b/mlir/include/mlir/TableGen/Constraint.h
@@ -59,6 +59,9 @@
     return Constraint(reinterpret_cast<const llvm::Record *>(ptr));
   }
 
+  // Return the underlying def.
+  const llvm::Record *getDef() const { return def; }
+
 protected:
   Constraint(Kind kind, const llvm::Record *record);