[libcxx-commits] [libcxx] Speed up legacy (non-builtin) std::invoke() compile times by ~45% for plain function calls (PR #213403)
via libcxx-commits
libcxx-commits at lists.llvm.org
Fri Jul 31 23:51:51 PDT 2026
https://github.com/higher-performance updated https://github.com/llvm/llvm-project/pull/213403
>From 2fa765f18e6d0609cc082678d7b90390aabb9c5d Mon Sep 17 00:00:00 2001
From: higher-performance <higher.performance.github at gmail.com>
Date: Sat, 1 Aug 2026 00:40:29 -0400
Subject: [PATCH] Speed up legacy implementation of std::invoke() by 50%
---
libcxx/include/__functional/invoke.h | 4 +-
libcxx/include/__type_traits/invoke.h | 180 +++++++++++---------------
2 files changed, 78 insertions(+), 106 deletions(-)
diff --git a/libcxx/include/__functional/invoke.h b/libcxx/include/__functional/invoke.h
index f7d6a23a4e520..823c5c1532800 100644
--- a/libcxx/include/__functional/invoke.h
+++ b/libcxx/include/__functional/invoke.h
@@ -24,8 +24,8 @@
_LIBCPP_BEGIN_NAMESPACE_STD
template <class _Fn, class... _Args>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 invoke_result_t<_Fn, _Args...>
-invoke(_Fn&& __f, _Args&&... __args) noexcept(is_nothrow_invocable_v<_Fn, _Args...>) {
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __sfinae_invoke_result_t<_Fn, _Args...>
+invoke(_Fn&& __f, _Args&&... __args) noexcept(__is_nothrow_invocable_v<_Fn, _Args...>) {
return std::__invoke(std::forward<_Fn>(__f), std::forward<_Args>(__args)...);
}
diff --git a/libcxx/include/__type_traits/invoke.h b/libcxx/include/__type_traits/invoke.h
index ba8202576593e..419b40bb7e8df 100644
--- a/libcxx/include/__type_traits/invoke.h
+++ b/libcxx/include/__type_traits/invoke.h
@@ -21,7 +21,8 @@
#include <__type_traits/is_reference_wrapper.h>
#include <__type_traits/is_same.h>
#include <__type_traits/is_void.h>
-#include <__type_traits/nat.h>
+#include <__type_traits/remove_cvref.h>
+#include <__type_traits/type_identity.h>
#include <__type_traits/void_t.h>
#include <__utility/declval.h>
#include <__utility/forward.h>
@@ -68,24 +69,21 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-#if __has_builtin(__builtin_invoke)
-
-template <class, class... _Args>
+template <class _Void, class _Fp, class... _Args>
struct __invoke_result_impl {};
-template <class... _Args>
-struct __invoke_result_impl<__void_t<decltype(__builtin_invoke(std::declval<_Args>()...))>, _Args...> {
- using type _LIBCPP_NODEBUG = decltype(__builtin_invoke(std::declval<_Args>()...));
-};
+#if __has_builtin(__builtin_invoke)
template <class... _Args>
-using __invoke_result _LIBCPP_NODEBUG = __invoke_result_impl<void, _Args...>;
+using __sfinae_invoke_result_t = decltype(__builtin_invoke(std::declval<_Args>()...));
-template <class... _Args>
-using __invoke_result_t _LIBCPP_NODEBUG = typename __invoke_result<_Args...>::type;
+template <class _Fp, class... _Args>
+struct __invoke_result_impl<__void_t<__sfinae_invoke_result_t<_Fp, _Args...> >, _Fp, _Args...> {
+ using type _LIBCPP_NODEBUG = __sfinae_invoke_result_t<_Fp, _Args...>;
+};
template <class... _Args>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __invoke_result_t<_Args...> __invoke(_Args&&... __args)
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR __sfinae_invoke_result_t<_Args...> __invoke(_Args&&... __args)
_NOEXCEPT_(noexcept(__builtin_invoke(std::forward<_Args>(__args)...))) {
return __builtin_invoke(std::forward<_Args>(__args)...);
}
@@ -94,7 +92,7 @@ template <class _Void, class... _Args>
inline const bool __is_invocable_impl = false;
template <class... _Args>
-inline const bool __is_invocable_impl<__void_t<__invoke_result_t<_Args...> >, _Args...> = true;
+inline const bool __is_invocable_impl<__void_t<__sfinae_invoke_result_t<_Args...> >, _Args...> = true;
template <class... _Args>
inline const bool __is_invocable_v = __is_invocable_impl<void, _Args...>;
@@ -107,7 +105,7 @@ inline const bool __is_invocable_r_impl = false;
template <class _Ret, class... _Args>
inline const bool __is_invocable_r_impl<_Ret, true, _Args...> =
- __is_core_convertible<__invoke_result_t<_Args...>, _Ret>::value || is_void<_Ret>::value;
+ __is_core_convertible<__sfinae_invoke_result_t<_Args...>, _Ret>::value || is_void<_Ret>::value;
template <class _Ret, class... _Args>
inline const bool __is_invocable_r_v = __is_invocable_r_impl<_Ret, __is_invocable_v<_Args...>, _Args...>;
@@ -128,7 +126,7 @@ inline const bool __is_nothrow_invocable_r_impl = false;
template <class _Ret, class... _Args>
inline const bool __is_nothrow_invocable_r_impl<true, _Ret, _Args...> =
- __is_nothrow_core_convertible_v<__invoke_result_t<_Args...>, _Ret> || is_void<_Ret>::value;
+ __is_nothrow_core_convertible_v<__sfinae_invoke_result_t<_Args...>, _Ret> || is_void<_Ret>::value;
template <class _Ret, class... _Args>
inline const bool __is_nothrow_invocable_r_v =
@@ -192,32 +190,27 @@ using __enable_if_bullet6 _LIBCPP_NODEBUG =
// __invoke forward declarations
-// fall back - none of the bullets
-
-template <class... _Args>
-__nat __invoke(_Args&&... __args);
-
// bullets 1, 2 and 3
// clang-format off
template <class _Fp, class _A0, class... _Args, class = __enable_if_bullet1<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype((std::declval<_A0>().*std::declval<_Fp>())(std::declval<_Args>()...))
-__invoke(_Fp&& __f, _A0&& __a0, _Args&&... __args)
+__invoke_member(_Fp&& __f, _A0&& __a0, _Args&&... __args)
_NOEXCEPT_(noexcept((static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...)))
{ return (static_cast<_A0&&>(__a0).*__f)(static_cast<_Args&&>(__args)...); }
template <class _Fp, class _A0, class... _Args, class = __enable_if_bullet2<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype((std::declval<_A0>().get().*std::declval<_Fp>())(std::declval<_Args>()...))
-__invoke(_Fp&& __f, _A0&& __a0, _Args&&... __args)
+__invoke_member(_Fp&& __f, _A0&& __a0, _Args&&... __args)
_NOEXCEPT_(noexcept((__a0.get().*__f)(static_cast<_Args&&>(__args)...)))
{ return (__a0.get().*__f)(static_cast<_Args&&>(__args)...); }
template <class _Fp, class _A0, class... _Args, class = __enable_if_bullet3<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype(((*std::declval<_A0>()).*std::declval<_Fp>())(std::declval<_Args>()...))
-__invoke(_Fp&& __f, _A0&& __a0, _Args&&... __args)
+__invoke_member(_Fp&& __f, _A0&& __a0, _Args&&... __args)
_NOEXCEPT_(noexcept(((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...)))
{ return ((*static_cast<_A0&&>(__a0)).*__f)(static_cast<_Args&&>(__args)...); }
@@ -226,24 +219,33 @@ __invoke(_Fp&& __f, _A0&& __a0, _Args&&... __args)
template <class _Fp, class _A0, class = __enable_if_bullet4<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype(std::declval<_A0>().*std::declval<_Fp>())
-__invoke(_Fp&& __f, _A0&& __a0)
+__invoke_member(_Fp&& __f, _A0&& __a0)
_NOEXCEPT_(noexcept(static_cast<_A0&&>(__a0).*__f))
{ return static_cast<_A0&&>(__a0).*__f; }
template <class _Fp, class _A0, class = __enable_if_bullet5<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype(std::declval<_A0>().get().*std::declval<_Fp>())
-__invoke(_Fp&& __f, _A0&& __a0)
+__invoke_member(_Fp&& __f, _A0&& __a0)
_NOEXCEPT_(noexcept(__a0.get().*__f))
{ return __a0.get().*__f; }
template <class _Fp, class _A0, class = __enable_if_bullet6<_Fp, _A0> >
inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
decltype((*std::declval<_A0>()).*std::declval<_Fp>())
-__invoke(_Fp&& __f, _A0&& __a0)
+__invoke_member(_Fp&& __f, _A0&& __a0)
_NOEXCEPT_(noexcept((*static_cast<_A0&&>(__a0)).*__f))
{ return (*static_cast<_A0&&>(__a0)).*__f; }
+// bullets < 7
+
+template <class _Fp, class... _Args>
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR
+decltype(std::__invoke_member(std::declval<__enable_if_t<is_member_pointer<__remove_cvref_t<_Fp> >::value, _Fp>&&>(), std::declval<_Args&&>()...))
+__invoke(_Fp&& __f, _Args&&... __args)
+ _NOEXCEPT_(noexcept(std::__invoke_member(static_cast<_Fp&&>(__f), static_cast<_Args&&>(__args)...)))
+ { return std::__invoke_member(static_cast<_Fp&&>(__f), static_cast<_Args&&>(__args)...); }
+
// bullet 7
template <class _Fp, class... _Args>
@@ -254,106 +256,76 @@ __invoke(_Fp&& __f, _Args&&... __args)
{ return static_cast<_Fp&&>(__f)(static_cast<_Args&&>(__args)...); }
// clang-format on
-// __invokable
-template <class _Ret, class _Fp, class... _Args>
-struct __invokable_r {
- template <class _XFp, class... _XArgs>
- static decltype(std::__invoke(std::declval<_XFp>(), std::declval<_XArgs>()...)) __try_call(int);
- template <class _XFp, class... _XArgs>
- static __nat __try_call(...);
-
- // FIXME: Check that _Ret, _Fp, and _Args... are all complete types, cv void,
- // or incomplete array types as required by the standard.
- using _Result _LIBCPP_NODEBUG = decltype(__try_call<_Fp, _Args...>(0));
-
- using type = __conditional_t<_IsNotSame<_Result, __nat>::value,
- __conditional_t<is_void<_Ret>::value, true_type, __is_core_convertible<_Result, _Ret> >,
- false_type>;
- static const bool value = type::value;
-};
-template <class _Fp, class... _Args>
-using __is_invocable _LIBCPP_NODEBUG = __invokable_r<void, _Fp, _Args...>;
+// This is cheaper to compute than the non-SFINAE version, so prefer it when possible.
+template <class _XFp, class... _XArgs>
+using __sfinae_invoke_result_t = decltype(std::__invoke(std::declval<_XFp>(), std::declval<_XArgs>()...));
-template <bool _IsInvokable, bool _IsCVVoid, class _Ret, class _Fp, class... _Args>
-struct __nothrow_invokable_r_imp {
- static const bool value = false;
+template <class _Fp, class... _Args>
+struct __invoke_result_impl<__void_t<__sfinae_invoke_result_t<_Fp, _Args...> >, _Fp, _Args...> {
+ using type _LIBCPP_NODEBUG = __sfinae_invoke_result_t<_Fp, _Args...>;
};
-template <class _Ret, class _Fp, class... _Args>
-struct __nothrow_invokable_r_imp<true, false, _Ret, _Fp, _Args...> {
- typedef __nothrow_invokable_r_imp _ThisT;
-
- template <class _Tp>
- static void __test_noexcept(_Tp) _NOEXCEPT;
-
-# ifdef _LIBCPP_CXX03_LANG
- static const bool value = false;
-# else
- static const bool value =
- noexcept(_ThisT::__test_noexcept<_Ret>(std::__invoke(std::declval<_Fp>(), std::declval<_Args>()...)));
-# endif
-};
+// __invokable
+template <class, class _Ret, class _Fp, class... _Args>
+inline const bool __is_invocable_r_impl = false;
template <class _Ret, class _Fp, class... _Args>
-struct __nothrow_invokable_r_imp<true, true, _Ret, _Fp, _Args...> {
-# ifdef _LIBCPP_CXX03_LANG
- static const bool value = false;
-# else
- static const bool value = noexcept(std::__invoke(std::declval<_Fp>(), std::declval<_Args>()...));
-# endif
-};
+inline const bool __is_invocable_r_impl<decltype(void(std::__invoke(std::declval<_Fp>(), std::declval<_Args>()...))),
+ _Ret,
+ _Fp,
+ _Args...> =
+ is_void<_Ret>::value || __is_core_convertible<__sfinae_invoke_result_t<_Fp, _Args...>, _Ret>::value;
template <class _Ret, class _Fp, class... _Args>
-using __nothrow_invokable_r _LIBCPP_NODEBUG =
- __nothrow_invokable_r_imp<__invokable_r<_Ret, _Fp, _Args...>::value, is_void<_Ret>::value, _Ret, _Fp, _Args...>;
+inline const bool __is_invocable_r_v = __is_invocable_r_impl<void, _Ret, _Fp, _Args...>;
+
+template <class _Func, class... _Args>
+inline const bool __is_invocable_v = __is_invocable_r_v<void, _Func, _Args...>;
template <class _Fp, class... _Args>
-using __nothrow_invokable _LIBCPP_NODEBUG =
- __nothrow_invokable_r_imp<__is_invocable<_Fp, _Args...>::value, true, void, _Fp, _Args...>;
+using __is_invocable _LIBCPP_NODEBUG = bool_constant<__is_invocable_v<_Fp, _Args...> >;
template <class _Func, class... _Args>
-inline const bool __is_invocable_v = __is_invocable<_Func, _Args...>::value;
+inline const bool __is_nothrow_invocable_v = noexcept(std::__invoke(std::declval<_Func>(), std::declval<_Args>()...));
-template <class _Ret, class _Func, class... _Args>
-inline const bool __is_invocable_r_v = __invokable_r<_Ret, _Func, _Args...>::value;
+template <bool _IsInvokable, class _Ret, class _Fp, class... _Args>
+inline const bool __is_nothrow_invocable_r_v_imp = false;
-template <class _Func, class... _Args>
-inline const bool __is_nothrow_invocable_v = __nothrow_invokable<_Func, _Args...>::value;
+template <class _Ret, class _Fp, class... _Args>
+inline const bool __is_nothrow_invocable_r_v_imp<true, _Ret, _Fp, _Args...> =
+ noexcept(static_cast<void (*)(_Ret)>(0)(std::__invoke(std::declval<_Fp>(), std::declval<_Args>()...)));
-template <class _Ret, class _Func, class... _Args>
-inline const bool __is_nothrow_invocable_r_v = __nothrow_invokable_r<_Ret, _Func, _Args...>::value;
+template <class _Fp, class... _Args>
+inline const bool __is_nothrow_invocable_r_v_imp<true, void, _Fp, _Args...> = __is_nothrow_invocable_v<_Fp, _Args...>;
-template <class _Func, class... _Args>
-struct __invoke_result
- : enable_if<__is_invocable_v<_Func, _Args...>, typename __invokable_r<void, _Func, _Args...>::_Result> {};
+template <class _Ret, class _Fp, class... _Args>
+inline const bool __is_nothrow_invocable_r_v _LIBCPP_NODEBUG =
+ __is_nothrow_invocable_r_v_imp<__is_invocable_r_v<_Ret, _Fp, _Args...>,
+ __conditional_t<is_void<_Ret>::value, void, _Ret>,
+ _Fp,
+ _Args...>;
+
+#endif // __has_builtin(__builtin_invoke)
template <class _Func, class... _Args>
-using __invoke_result_t _LIBCPP_NODEBUG = typename __invoke_result<_Func, _Args...>::type;
+using __invoke_result = __invoke_result_impl<void, _Func, _Args...>;
-#endif // __has_builtin(__builtin_invoke_r)
+template <class _Func, class... _Args>
+using __invoke_result_t _LIBCPP_NODEBUG = typename __invoke_result_impl<void, _Func, _Args...>::type;
template <class _Ret, class _Func, class... _Args>
struct __is_invocable_r : integral_constant<bool, __is_invocable_r_v<_Ret, _Func, _Args...> > {};
-template <class _Ret, bool = is_void<_Ret>::value>
-struct __invoke_void_return_wrapper {
- template <class... _Args>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static _Ret __call(_Args&&... __args) {
- return std::__invoke(std::forward<_Args>(__args)...);
- }
-};
-
-template <class _Ret>
-struct __invoke_void_return_wrapper<_Ret, true> {
- template <class... _Args>
- _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 static void __call(_Args&&... __args) {
- std::__invoke(std::forward<_Args>(__args)...);
- }
-};
+template <class _Ret, class... _Args>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<is_void<_Ret>::value, _Ret>
+__invoke_r(_Args&&... __args) _NOEXCEPT_(noexcept(std::__invoke(std::forward<_Args>(__args)...))) {
+ std::__invoke(std::forward<_Args>(__args)...);
+}
template <class _Ret, class... _Args>
-_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _Ret __invoke_r(_Args&&... __args) {
- return __invoke_void_return_wrapper<_Ret>::__call(std::forward<_Args>(__args)...);
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 __enable_if_t<!is_void<_Ret>::value, _Ret>
+__invoke_r(_Args&&... __args) _NOEXCEPT_(noexcept(std::__invoke(std::forward<_Args>(__args)...))) {
+ return std::__invoke(std::forward<_Args>(__args)...);
}
#if _LIBCPP_STD_VER >= 17
@@ -389,10 +361,10 @@ _LIBCPP_NO_SPECIALIZATIONS inline constexpr bool is_nothrow_invocable_r_v =
__is_nothrow_invocable_r_v<_Ret, _Fn, _Args...>;
template <class _Fn, class... _Args>
-struct _LIBCPP_NO_SPECIALIZATIONS invoke_result : __invoke_result<_Fn, _Args...> {};
+using invoke_result_t = __invoke_result_t<_Fn, _Args...>;
template <class _Fn, class... _Args>
-using invoke_result_t = __invoke_result_t<_Fn, _Args...>;
+struct _LIBCPP_NO_SPECIALIZATIONS invoke_result : __type_identity<invoke_result_t<_Fn, _Args...> > {};
#endif
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