diff --git a/mlir/test/mlir-tblgen/attrdefs.td b/mlir/test/mlir-tblgen/attrdefs.td
--- a/mlir/test/mlir-tblgen/attrdefs.td
+++ b/mlir/test/mlir-tblgen/attrdefs.td
@@ -141,3 +141,13 @@
 // DEF: ParamWithAccessorTypeAttrStorage
 // DEF: ParamWithAccessorTypeAttrStorage(std::string param)
 // DEF: StringRef ParamWithAccessorTypeAttr::getParam()
+
+
+def G_OptionalAndDefaultValuedParams
+    : TestAttr<"OptionalAndDefaultValuedParams"> {
+  let parameters = (ins OptionalParameter<"int *">:$a,
+                        DefaultValuedParameter<"int", "5">:$b);
+}
+
+// DECL-LABEL: class OptionalAndDefaultValuedParamsAttr
+// DECL: get(::mlir::MLIRContext *context, int *a = {}, int b = 5);
diff --git a/mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp b/mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp
--- a/mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp
+++ b/mlir/tools/mlir-tblgen/AttrOrTypeDefGen.cpp
@@ -319,8 +319,22 @@
 DefGen::getBuilderParams(std::initializer_list<MethodParameter> prefix) const {
   SmallVector<MethodParameter> builderParams;
   builderParams.append(prefix.begin(), prefix.end());
-  for (auto &param : params)
+  // Optional/default-valued parameters at the end of the parameter list can be
+  // given default arguments in C++.
+  auto paramsReverse = llvm::reverse(params);
+  auto lastOptional =
+      llvm::find_if(paramsReverse, [](const AttrOrTypeParameter &param) {
+        return !param.isOptional();
+      });
+  for (const AttrOrTypeParameter &param :
+       llvm::reverse(llvm::make_range(lastOptional, paramsReverse.end())))
     builderParams.emplace_back(param.getCppType(), param.getName());
+  for (const AttrOrTypeParameter &param :
+       llvm::reverse(llvm::make_range(paramsReverse.begin(), lastOptional))) {
+    Optional<StringRef> defaultValue = param.getDefaultValue();
+    builderParams.emplace_back(param.getCppType(), param.getName(),
+                               defaultValue ? *defaultValue : "{}");
+  }
   return builderParams;
 }