https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124173
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <[email protected]>: https://gcc.gnu.org/g:37738f0422aa4d70ac5a71bd82b6c257a9309bde commit r16-7630-g37738f0422aa4d70ac5a71bd82b6c257a9309bde Author: Jakub Jelinek <[email protected]> Date: Sun Feb 22 22:09:13 2026 +0100 c++: Fix up recent regression in convert_nontype_argument for C++1[14] [PR124173] The following testcase is rejected since my recent convert_nontype_argument change, but only in C++11/14 modes. The problem is that C++17 says that all NTTPs should be converted constant expressions, but C++11 only said that for integral and enumeration ones and something that applied to the decltype(nullptr) case was - a constant expression that evaluates to a null pointer value The problem is that for NULLPTR_TYPE_P for C++11/14, we just never called maybe_constant_value, so obviously just making sure it is integer_zerop and without tf_error returning NULL_TREE otherwise changes behavior on valid programs, we really need to constant evaluate it first. The following patch fixes that. I'm afraid I actually don't know what exactly C++14 specifies, whether I've grabbed a pre-C++14 or post-C++14 draft, which looked like the C++17 wording. So, if C++14 needs something different, we'll need a further change, but this at least fixes the regression. 2026-02-22 Jakub Jelinek <[email protected]> PR c++/124173 * pt.cc (convert_nontype_argument): For C++11/C++14 handle NULLPTR_TYPE_P non-type arguments like TYPE_PTR_P. * g++.dg/cpp0x/pr124173.C: New test.
