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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++/91427] Implement P1825R0, Merged wording for P0527R1 and P1155R3 Date: Wed, 29 Jul 2020 18:25:28 +0000 [thread overview] Message-ID: <bug-91427-4-zBdnBOJvi9@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-91427-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91427 --- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <jason@gcc.gnu.org>: https://gcc.gnu.org/g:1722e2013f05f1f1f99379dbaa0c0df356da731f commit r11-2412-g1722e2013f05f1f1f99379dbaa0c0df356da731f Author: Jason Merrill <jason@redhat.com> Date: Tue Jul 21 00:19:49 2020 -0400 c++: Implement C++20 implicit move changes. [PR91427] P1825R0 extends the C++11 implicit move on return by removing the constraints on the called constructor: previously, it needed to take an rvalue reference to the type of the returned variable. The paper also allows move on throw of parameters and implicit move of rvalue references. Discussion on the CWG reflector about how to avoid breaking the PR91212 test in the new model settled on the model of doing only a single overload resolution, with the variable treated as an xvalue that can bind to non-const lvalue references. So this patch implements that approach. The implementation does not use the existing LOOKUP_PREFER_RVALUE flag, but instead sets a flag on the representation of the static_cast turning the variable into an xvalue. For the time being I'm limiting the new semantics to C++20 mode; since it was moved as a DR, we will probably want to apply the change to other standard modes as well once we have a better sense of the impact on existing code, probably in GCC 12. gcc/cp/ChangeLog: PR c++/91427 * cp-tree.h (IMPLICIT_RVALUE_P): New. (enum cp_lvalue_kind_flags): Add clk_implicit_rval. (implicit_rvalue_p, set_implicit_rvalue_p): New. * call.c (reference_binding): Check clk_implicit_rval. (build_over_call): Adjust C++20 implicit move. * coroutines.cc (finish_co_return_stmt): Simplify implicit move. * except.c (build_throw): Adjust C++20 implicit move. * pt.c (tsubst_copy_and_build) [STATIC_CAST_EXPR]: Propagate IMPLICIT_RVALUE_P. * tree.c (lvalue_kind): Set clk_implicit_rval. * typeck.c (treat_lvalue_as_rvalue_p): Overhaul. (maybe_warn_pessimizing_move): Adjust. (check_return_expr): Adjust C++20 implicit move. gcc/testsuite/ChangeLog: PR c++/91427 * g++.dg/coroutines/co-return-syntax-10-movable.C: Extend. * g++.dg/cpp0x/Wredundant-move1.C: Adjust for C++20. * g++.dg/cpp0x/Wredundant-move7.C: Adjust for C++20. * g++.dg/cpp0x/Wredundant-move9.C: Adjust for C++20. * g++.dg/cpp0x/elision_neg.C: Adjust for C++20. * g++.dg/cpp0x/move-return2.C: Adjust for C++20. * g++.dg/cpp0x/ref-qual20.C: Adjust for C++20. * g++.dg/cpp2a/implicit-move1.C: New test. * g++.dg/cpp2a/implicit-move2.C: New test. * g++.dg/cpp2a/implicit-move3.C: New test.
next parent reply other threads:[~2020-07-29 18:25 UTC|newest] Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <bug-91427-4@http.gcc.gnu.org/bugzilla/> 2020-07-29 18:25 ` cvs-commit at gcc dot gnu.org [this message] 2020-09-09 22:06 ` jason at gcc dot gnu.org
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