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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 c++/89074] valid pointer equality constexpr comparison rejected Date: Thu, 18 Nov 2021 16:14:21 +0000 [thread overview] Message-ID: <bug-89074-4-x2lVoyBk5O@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-89074-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89074 --- Comment #6 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:ca243ada71656651a8753e88164a1f0f019be1c3 commit r12-5376-gca243ada71656651a8753e88164a1f0f019be1c3 Author: Jonathan Wakely <jwakely@redhat.com> Date: Thu Nov 18 12:39:20 2021 +0000 libstdc++: Fix std::char_traits<C>::move for constexpr The constexpr branch in __gnu_cxx::char_traits::move compares the string arguments to see if they overlap, but relational comparisons between unrelated pointers are not core constant expressions. I want to replace the comparisons with a loop using pointer equality to determine whether the end of the source string is in the destination string. However, that doesn't work with GCC, due to PR c++/89074 so allocate a temporary buffer instead and copy out into that first, so that overlapping source and destination don't matter. The allocation isn't supported by the current Intel icc so use the loop as a fallback. libstdc++-v3/ChangeLog: * include/bits/char_traits.h (__gnu_cxx::char_traits::move): Do not compare unrelated pointers during constant evaluation. * testsuite/21_strings/char_traits/requirements/constexpr_functions_c++20.cc: Improve tests for char_traits::move.
next prev parent reply other threads:[~2021-11-18 16:14 UTC|newest] Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-89074-4@http.gcc.gnu.org/bugzilla/> 2021-07-27 9:30 ` pinskia at gcc dot gnu.org 2021-11-18 14:18 ` redi at gcc dot gnu.org 2021-11-18 16:14 ` cvs-commit at gcc dot gnu.org [this message] 2022-01-05 16:38 ` ppalka at gcc dot gnu.org 2022-01-05 16:56 ` jakub at gcc dot gnu.org 2022-01-05 17:07 ` ppalka at gcc dot gnu.org 2022-01-05 19:45 ` jakub at gcc dot gnu.org 2022-01-05 19:56 ` jakub at gcc dot gnu.org 2022-01-05 22:07 ` cvs-commit at gcc dot gnu.org 2022-01-05 22:07 ` cvs-commit at gcc dot gnu.org 2022-01-06 20:01 ` jakub at gcc dot gnu.org 2022-01-08 8:54 ` cvs-commit at gcc dot gnu.org 2022-01-14 11:08 ` cvs-commit at gcc dot gnu.org 2022-01-19 8:26 ` cvs-commit at gcc dot gnu.org 2022-02-06 10:21 ` cvs-commit at gcc dot gnu.org 2022-07-07 16:38 ` cvs-commit at gcc dot gnu.org 2022-11-07 14:16 ` ppalka at gcc dot gnu.org
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