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From: "cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug libstdc++/104719] Use of `std::move` in libstdc++ leads to worsened debug performance Date: Wed, 04 May 2022 15:34:43 +0000 [thread overview] Message-ID: <bug-104719-4-4TkRVPqnsJ@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-104719-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104719 --- Comment #15 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>: https://gcc.gnu.org/g:ef8d5ac08b5e60f35c52087d88c0235c8ce6b65b commit r13-113-gef8d5ac08b5e60f35c52087d88c0235c8ce6b65b Author: Jonathan Wakely <jwakely@redhat.com> Date: Fri Mar 25 10:28:28 2022 +0000 libstdc++: Simplify std::array accessors [PR104719] This removes the __array_traits::_S_ref and __array_traits::_S_ptr accessors, which only exist to make the special case of std::array<T, 0> syntactically well-formed. By changing the empty type used as the std::array<T, 0>::_M_elems data member to support operator[] and conversion to a pointer, we can write code using the natural syntax. The indirection through _S_ref and _S_ptr is removed for the common case, and a function call is only used for the special case of zero-size arrays. The invalid member access for zero-sized arrays is changed to use __builtin_trap() instead of a null dereference. This guarantees a runtime error if it ever gets called, instead of undefined behaviour that is likely to get optimized out as unreachable. libstdc++-v3/ChangeLog: PR libstdc++/104719 * include/std/array (__array_traits::_S_ref): Remove. (__array_traits::_S_ptr): Remove. (__array_traits<T, 0>::_Type): Define operator[] and operator T* to provide an array-like API. (array::_AT_Type): Remove public typeef. (array::operator[], array::at, array::front, array::back): Use index operator to access _M_elems instead of _S_ref. (array::data): Use implicit conversion from _M_elems to pointer. (swap(array&, array&)): Use __enable_if_t helper. (get<I>): Use index operator to access _M_elems. * testsuite/23_containers/array/tuple_interface/get_neg.cc: Adjust dg-error line numbers.
next prev parent reply other threads:[~2022-05-04 15:34 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-02-28 16:20 [Bug libstdc++/104719] New: " vittorio.romeo at outlook dot com 2022-02-28 16:46 ` [Bug libstdc++/104719] " redi at gcc dot gnu.org 2022-02-28 16:50 ` redi at gcc dot gnu.org 2022-02-28 16:56 ` egallager at gcc dot gnu.org 2022-02-28 17:00 ` vittorio.romeo at outlook dot com 2022-02-28 17:16 ` redi at gcc dot gnu.org 2022-02-28 17:20 ` vittorio.romeo at outlook dot com 2022-02-28 17:24 ` redi at gcc dot gnu.org 2022-02-28 17:37 ` redi at gcc dot gnu.org 2022-03-01 2:23 ` vittorio.romeo at outlook dot com 2022-03-01 20:12 ` redi at gcc dot gnu.org 2022-03-01 20:14 ` redi at gcc dot gnu.org 2022-03-10 23:04 ` jason at gcc dot gnu.org 2022-03-26 23:37 ` jason at gcc dot gnu.org 2022-03-27 7:35 ` redi at gcc dot gnu.org 2022-05-04 15:34 ` cvs-commit at gcc dot gnu.org [this message] 2022-05-04 15:34 ` cvs-commit at gcc dot gnu.org 2022-05-04 15:49 ` unlvsur at live dot com 2022-05-04 15:55 ` redi at gcc dot gnu.org
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