diff --git a/mlir/test/lib/Dialect/Test/CMakeLists.txt b/mlir/test/lib/Dialect/Test/CMakeLists.txt
--- a/mlir/test/lib/Dialect/Test/CMakeLists.txt
+++ b/mlir/test/lib/Dialect/Test/CMakeLists.txt
@@ -13,7 +13,7 @@
 mlir_tablegen(TestOpInterfaces.cpp.inc -gen-op-interface-defs)
 add_public_tablegen_target(MLIRTestInterfaceIncGen)
 
-set(LLVM_TARGET_DEFINITIONS TestAttrDefs.td)
+set(LLVM_TARGET_DEFINITIONS TestOps.td)
 mlir_tablegen(TestAttrDefs.h.inc -gen-attrdef-decls)
 mlir_tablegen(TestAttrDefs.cpp.inc -gen-attrdef-defs)
 add_public_tablegen_target(MLIRTestAttrDefIncGen)
diff --git a/mlir/test/lib/Dialect/Test/TestDialect.h b/mlir/test/lib/Dialect/Test/TestDialect.h
--- a/mlir/test/lib/Dialect/Test/TestDialect.h
+++ b/mlir/test/lib/Dialect/Test/TestDialect.h
@@ -14,6 +14,7 @@
 #ifndef MLIR_TESTDIALECT_H
 #define MLIR_TESTDIALECT_H
 
+#include "TestAttributes.h"
 #include "TestInterfaces.h"
 #include "mlir/Dialect/DLTI/DLTI.h"
 #include "mlir/Dialect/DLTI/Traits.h"
diff --git a/mlir/test/lib/Dialect/Test/TestOps.td b/mlir/test/lib/Dialect/Test/TestOps.td
--- a/mlir/test/lib/Dialect/Test/TestOps.td
+++ b/mlir/test/lib/Dialect/Test/TestOps.td
@@ -40,11 +40,6 @@
     void registerAttributes();
     void registerTypes();
 
-    ::mlir::Attribute parseAttribute(::mlir::DialectAsmParser &parser,
-                                     ::mlir::Type type) const override;
-    void printAttribute(::mlir::Attribute attr,
-                        ::mlir::DialectAsmPrinter &printer) const override;
-
     // Provides a custom printing/parsing for some operations.
     ::llvm::Optional<ParseOpHook>
       getParseOperationHook(::llvm::StringRef opName) const override;
@@ -59,6 +54,10 @@
   }];
 }
 
+// Include the attribute definitions.
+include "TestAttrDefs.td"
+
+
 class TEST_Op<string mnemonic, list<OpTrait> traits = []> :
     Op<Test_Dialect, mnemonic, traits>;
 
@@ -1868,6 +1867,11 @@
   let assemblyFormat = "(`then` $isFirstBranchPresent^):(`else`)? attr-dict";
 }
 
+def FormatCompoundAttr : TEST_Op<"format_compound_attr"> {
+  let arguments = (ins CompoundAttrA:$compound);
+  let assemblyFormat = "$compound attr-dict-with-keyword";
+}
+
 //===----------------------------------------------------------------------===//
 // Custom Directives
 
diff --git a/mlir/test/mlir-tblgen/op-format.mlir b/mlir/test/mlir-tblgen/op-format.mlir
--- a/mlir/test/mlir-tblgen/op-format.mlir
+++ b/mlir/test/mlir-tblgen/op-format.mlir
@@ -252,6 +252,13 @@
 // CHECK: test.format_optional_else else
 test.format_optional_else else
 
+//===----------------------------------------------------------------------===//
+// Format a custom attribute
+//===----------------------------------------------------------------------===//
+
+// CHECK: test.format_compound_attr #test.cmpnd_a<1, !test.smpla, [5, 6]>
+test.format_compound_attr #test.cmpnd_a<1, !test.smpla, [5, 6]>
+
 //===----------------------------------------------------------------------===//
 // Format custom directives
 //===----------------------------------------------------------------------===//
diff --git a/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel b/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel
--- a/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel
+++ b/utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel
@@ -155,7 +155,7 @@
         ),
     ],
     tblgen = "//mlir:mlir-tblgen",
-    td_file = "lib/Dialect/Test/TestAttrDefs.td",
+    td_file = "lib/Dialect/Test/TestOps.td",
     test = True,
     deps = [
         ":TestOpTdFiles",