[committed] libstdc++: Skip tag dispatching for _S_relocate in C++17
Commit Message
Tested x86_64-linux, pushed to trunk.
In C++17 mode all callers of _S_relocate have already done:
if constexpr (_S_use_relocate())
so we don't need to repeat that check and use tag dispatching to avoid
ill-formed instantiations.
libstdc++-v3/ChangeLog:
* include/bits/stl_vector.h (vector::_S_do_relocate): Remove
C++20 constexpr specifier.
(vector::_S_relocate) [__cpp_if_constexpr]: Call __relocate_a
directly without tag dispatching.
---
libstdc++-v3/include/bits/stl_vector.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
@@ -481,14 +481,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
return _S_nothrow_relocate(__is_move_insertable<_Tp_alloc_type>{});
}
- static _GLIBCXX20_CONSTEXPR pointer
+ static pointer
_S_do_relocate(pointer __first, pointer __last, pointer __result,
_Tp_alloc_type& __alloc, true_type) noexcept
{
return std::__relocate_a(__first, __last, __result, __alloc);
}
- static _GLIBCXX20_CONSTEXPR pointer
+ static pointer
_S_do_relocate(pointer, pointer, pointer __result,
_Tp_alloc_type&, false_type) noexcept
{ return __result; }
@@ -497,8 +497,13 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
_S_relocate(pointer __first, pointer __last, pointer __result,
_Tp_alloc_type& __alloc) noexcept
{
+#if __cpp_if_constexpr
+ // All callers have already checked _S_use_relocate() so just do it.
+ return std::__relocate_a(__first, __last, __result, __alloc);
+#else
using __do_it = __bool_constant<_S_use_relocate()>;
return _S_do_relocate(__first, __last, __result, __alloc, __do_it{});
+#endif
}
#endif // C++11