https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118661
--- Comment #10 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-13 branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:eb3e7de323a67e5a92f1c2224f3251cb47b49c0b commit r13-9588-geb3e7de323a67e5a92f1c2224f3251cb47b49c0b Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Feb 7 14:27:18 2025 +0100 c++: Allow constexpr reads from volatile std::nullptr_t objects [PR118661] As mentioned in the PR, https://eel.is/c++draft/conv.lval#note-1 says that even volatile reads from std::nullptr_t typed objects actually don't read anything and https://eel.is/c++draft/expr.const#10.9 says that even those are ok in constant expressions. So, the following patch adjusts the r9-4793 changes to have an exception for NULLPTR_TYPE. As [conv.lval]/3 also talks about accessing to inactive member, I've added testcase to cover that as well. 2025-02-07 Jakub Jelinek <ja...@redhat.com> PR c++/118661 * constexpr.cc (potential_constant_expression_1): Don't diagnose lvalue-to-rvalue conversion of volatile lvalue if it has NULLPTR_TYPE. * decl2.cc (decl_maybe_constant_var_p): Return true for constexpr decls with NULLPTR_TYPE even if they are volatile. * g++.dg/cpp0x/constexpr-volatile4.C: New test. * g++.dg/cpp0x/constexpr-union9.C: New test. (cherry picked from commit 6c8e6d6febaed3c167ca9534935c2cb18045528e)
