optimizations for non-polymorphic types

CMakeLists.txt

@@ -24,4 +24,7 @@ target_include_directories(small_unique_ptr SYSTEM INTERFACE "${CMAKE_CURRENT_SO
 target_compile_features(small_unique_ptr INTERFACE "cxx_std_20")
 target_compile_options(small_unique_ptr INTERFACE "$<$<CXX_COMPILER_ID:MSVC>:-Zc:preprocessor>" "$<$<CXX_COMPILER_ID:MSVC>:-Zc:__cplusplus>")
 
+include(CTest)
+
+enable_testing()
 add_subdirectory("${CMAKE_CURRENT_SOURCE_DIR}/test")

src/small_unique_ptr.hpp

@@ -119,7 +119,7 @@ namespace detail
         constexpr bool is_stack_allocated() const noexcept { return static_cast<bool>(this->move_); }
 
         alignas(buffer_alignment_v<T>)
-        mutable buffer_t buffer_;
+        mutable buffer_t buffer_ = {};
         T* data_      = nullptr;
         move_fn move_ = nullptr;
     };
@@ -153,7 +153,7 @@ namespace detail
         constexpr bool is_stack_allocated() const noexcept { return !std::is_constant_evaluated() && (data_ == buffer()); }
 
         alignas(buffer_alignment_v<T>)
-        mutable buffer_t buffer_;
+        mutable buffer_t buffer_ = {};
         T* data_ = nullptr;
     };
 
@@ -168,6 +168,7 @@ namespace detail
 
 } // namespace detail
 
+
 template<typename T>
 class small_unique_ptr : private detail::small_unique_ptr_base<T>
 {
@@ -299,7 +300,7 @@ class small_unique_ptr : private detail::small_unique_ptr_base<T>
     [[nodiscard]]
     constexpr bool is_stack_allocated() const noexcept
     {
-        return small_unique_ptr_base::is_stack_allocated();
+        return small_unique_ptr::small_unique_ptr_base::is_stack_allocated();
     }
 
     [[nodiscard]]
@@ -357,13 +358,13 @@ class small_unique_ptr : private detail::small_unique_ptr_base<T>
     }
 
 private:
-    template<typename B = T>
+    template<typename Base = T>
     constexpr std::ptrdiff_t offsetof_base() const noexcept
     {
         if (!is_stack_allocated()) return 0;
 
         const auto derived_ptr = reinterpret_cast<const volatile unsigned char*>(this->buffer());
-        const auto base_ptr    = reinterpret_cast<const volatile unsigned char*>(static_cast<const volatile B*>(this->data_));
+        const auto base_ptr    = reinterpret_cast<const volatile unsigned char*>(static_cast<const volatile Base*>(this->data_));
 
         return base_ptr - derived_ptr;
     }
@@ -372,8 +373,7 @@ class small_unique_ptr : private detail::small_unique_ptr_base<T>
     friend class small_unique_ptr;
 
     template<typename U, typename... Args>
-    friend constexpr small_unique_ptr<U> make_unique_small(Args&&...)
-    noexcept(!detail::always_heap_allocated_v<U> && std::is_nothrow_constructible_v<U, Args...>);
+    friend constexpr small_unique_ptr<U> make_unique_small(Args&&...);
 };
 
 template<typename T>
@@ -397,7 +397,6 @@ namespace std
 
 template<typename T, typename... Args>
 [[nodiscard]] constexpr small_unique_ptr<T> make_unique_small(Args&&... args)
-noexcept(!detail::always_heap_allocated_v<T> && std::is_nothrow_constructible_v<T, Args...>)
 {
     small_unique_ptr<T> ptr;
 

test/CMakeLists.txt

@@ -1,8 +1,6 @@
 find_package(Catch2 3 REQUIRED)
 
 include(Catch)
-include(CTest)
-enable_testing()
 
 add_executable(small_unique_ptr_test "${CMAKE_CURRENT_SOURCE_DIR}/small_unique_ptr.cpp")
 target_link_libraries(small_unique_ptr_test PRIVATE Catch2::Catch2WithMain small_unique_ptr)

test/small_unique_ptr.cpp

@@ -457,12 +457,3 @@ TEST_CASE("const_unique_ptr", "[small_unique_ptr]")
 
     REQUIRE(*p == 2);
 }
-
-TEST_CASE("noexcept_construct", "[small_unique_ptr]")
-{
-    STATIC_REQUIRE(noexcept(make_unique_small<SmallPOD>()));
-    STATIC_REQUIRE(!noexcept(make_unique_small<LargePOD>()));
-
-    STATIC_REQUIRE(noexcept(make_unique_small<SmallDerived>()));
-    STATIC_REQUIRE(!noexcept(make_unique_small<LargeDerived>()));
-}