diff --git a/include/luisa/xir/builder.h b/include/luisa/xir/builder.h
index b3bce07a6..a5eec4b47 100644
--- a/include/luisa/xir/builder.h
+++ b/include/luisa/xir/builder.h
@@ -39,15 +39,8 @@ class LC_XIR_API Builder {
     Instruction *_insertion_point = nullptr;
 
 private:
-    void _check_valid_insertion_point() const noexcept;
-
     template<typename T, typename... Args>
-    [[nodiscard]] auto _create_and_append_instruction(Args &&...args) noexcept {
-        _check_valid_insertion_point();
-        auto inst = _pool->create<T>(std::forward<Args>(args)...);
-        append(inst);
-        return inst;
-    }
+    [[nodiscard]] auto _create_and_append_instruction(Args &&...args) noexcept -> T *;
 
 public:
     Builder() noexcept;
diff --git a/src/xir/builder.cpp b/src/xir/builder.cpp
index 5fecd805f..610aa08c1 100644
--- a/src/xir/builder.cpp
+++ b/src/xir/builder.cpp
@@ -4,13 +4,17 @@
 
 namespace luisa::compute::xir {
 
-void Builder::_check_valid_insertion_point() const noexcept {
+Builder::Builder() noexcept = default;
+
+template<typename T, typename... Args>
+auto Builder::_create_and_append_instruction(Args &&...args) noexcept -> T * {
     LUISA_DEBUG_ASSERT(_insertion_point != nullptr, "Invalid insertion point.");
     LUISA_DEBUG_ASSERT(_pool != nullptr, "Invalid pool.");
+    auto inst = _pool->create<T>(std::forward<Args>(args)...);
+    append(inst);
+    return inst;
 }
 
-Builder::Builder() noexcept = default;
-
 void Builder::append(Instruction *inst) noexcept {
     _insertion_point->insert_after_self(inst);
     set_insertion_point(inst);