libstdc++: Use _GLIBCXX_USE_BUILTIN_TRAIT

This patch uses _GLIBCXX_USE_BUILTIN_TRAIT macro instead of __has_builtin
in the type_traits header for traits that have a corresponding fallback
non-built-in implementation.  This macro supports to toggle the use of
built-in traits in the type_traits header through
_GLIBCXX_DO_NOT_USE_BUILTIN_TRAITS macro, without needing to modify the
source code.

libstdc++-v3/ChangeLog:

	* include/std/type_traits: Use _GLIBCXX_USE_BUILTIN_TRAIT.

Signed-off-by: Ken Matsui <kmatsui@gcc.gnu.org>
Reviewed-by: Patrick Palka <ppalka@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
This commit is contained in:
Ken Matsui 2023-09-11 08:21:50 -07:00
parent 3ab4c3816b
commit f151db0f0e
No known key found for this signature in database

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@ -1481,7 +1481,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
: public __bool_constant<__is_base_of(_Base, _Derived)>
{ };
#if __has_builtin(__is_convertible)
#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_convertible)
template<typename _From, typename _To>
struct is_convertible
: public __bool_constant<__is_convertible(_From, _To)>
@ -1531,7 +1531,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#ifdef __cpp_lib_is_nothrow_convertible // C++ >= 20
#if __has_builtin(__is_nothrow_convertible)
#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_nothrow_convertible)
/// is_nothrow_convertible_v
template<typename _From, typename _To>
inline constexpr bool is_nothrow_convertible_v
@ -1606,7 +1606,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{ using type = _Tp; };
/// remove_cv
#if __has_builtin(__remove_cv)
#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cv)
template<typename _Tp>
struct remove_cv
{ using type = __remove_cv(_Tp); };
@ -1672,7 +1672,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
// Reference transformations.
/// remove_reference
#if __has_builtin(__remove_reference)
#if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_reference)
template<typename _Tp>
struct remove_reference
{ using type = __remove_reference(_Tp); };
@ -3537,7 +3537,7 @@ template<typename _Ret, typename _Fn, typename... _Args>
* @{
*/
#ifdef __cpp_lib_remove_cvref // C++ >= 20
# if __has_builtin(__remove_cvref)
# if _GLIBCXX_USE_BUILTIN_TRAIT(__remove_cvref)
template<typename _Tp>
struct remove_cvref
{ using type = __remove_cvref(_Tp); };