diff --git a/mlir/test/Target/llvmir.mlir b/mlir/test/Target/llvmir.mlir
--- a/mlir/test/Target/llvmir.mlir
+++ b/mlir/test/Target/llvmir.mlir
@@ -1350,7 +1350,7 @@
   %3 = llvm.inline_asm is_align_stack "foo", "=r,r,r" %arg0, %arg0 : (!llvm.i32, !llvm.i32) -> !llvm.i8
 
   // CHECK-NEXT:  call i8 asm inteldialect "foo", "=r,r,r"(i32 {{.*}}, i32 {{.*}}), !dbg !13
-  %4 = llvm.inline_asm asm_dialect = 1 "foo", "=r,r,r" %arg0, %arg0 : (!llvm.i32, !llvm.i32) -> !llvm.i8
+  %4 = llvm.inline_asm asm_dialect = "intel" "foo", "=r,r,r" %arg0, %arg0 : (!llvm.i32, !llvm.i32) -> !llvm.i8
 
   // CHECK-NEXT:  call { i8, i8 } asm "foo", "=r,=r,r"(i32 {{.*}}), !dbg !14
   %5 = llvm.inline_asm "foo", "=r,=r,r" %arg0 : (!llvm.i32) -> !llvm.struct<(i8, i8)>
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
@@ -1592,6 +1592,11 @@
   let assemblyFormat = "($is_optional^)? attr-dict";
 }
 
+def FormatOptionalEnumAttr : TEST_Op<"format_optional_enum_attr"> {
+  let arguments = (ins OptionalAttr<SomeI64Enum>:$attr);
+  let assemblyFormat = "($attr^)? attr-dict";
+}
+
 //===----------------------------------------------------------------------===//
 // 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
@@ -185,6 +185,13 @@
 // CHECK: test.format_optional_unit_attribute_no_elide unit
 test.format_optional_unit_attribute_no_elide unit
 
+// CHECK: test.format_optional_enum_attr "case5"
+test.format_optional_enum_attr "case5"
+
+// CHECK: test.format_optional_enum_attr
+// CHECK-NOT: "case5"
+test.format_optional_enum_attr
+
 //===----------------------------------------------------------------------===//
 // Format optional operands and results
 //===----------------------------------------------------------------------===//
diff --git a/mlir/tools/mlir-tblgen/OpFormatGen.cpp b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
--- a/mlir/tools/mlir-tblgen/OpFormatGen.cpp
+++ b/mlir/tools/mlir-tblgen/OpFormatGen.cpp
@@ -462,7 +462,8 @@
 /// Returns true if we can format the given attribute as an EnumAttr in the
 /// parser format.
 static bool canFormatEnumAttr(const NamedAttribute *attr) {
-  const EnumAttr *enumAttr = dyn_cast<EnumAttr>(&attr->attr);
+  Attribute baseAttr = attr->attr.getBaseAttr();
+  const EnumAttr *enumAttr = dyn_cast<EnumAttr>(&baseAttr);
   if (!enumAttr)
     return false;
 
@@ -1104,7 +1105,8 @@
 
     // Check to see if we can parse this as an enum attribute.
     if (canFormatEnumAttr(var)) {
-      const EnumAttr &enumAttr = cast<EnumAttr>(var->attr);
+      Attribute baseAttr = var->attr.getBaseAttr();
+      const EnumAttr &enumAttr = cast<EnumAttr>(baseAttr);
 
       // Generate the code for building an attribute for this enum.
       std::string attrBuilderStr;
@@ -1679,9 +1681,11 @@
 
     // If we are formatting as an enum, symbolize the attribute as a string.
     if (canFormatEnumAttr(var)) {
-      const EnumAttr &enumAttr = cast<EnumAttr>(var->attr);
+      Attribute baseAttr = var->attr.getBaseAttr();
+      const EnumAttr &enumAttr = cast<EnumAttr>(baseAttr);
       body << "  p << '\"' << " << enumAttr.getSymbolToStringFnName() << "("
-           << var->name << "()) << '\"';\n";
+           << (var->attr.isOptional() ? "*" : "") << var->name
+           << "()) << '\"';\n";
       return;
     }