https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100676
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jonathan Wakely <r...@gcc.gnu.org>: https://gcc.gnu.org/g:6b42b5a8a207de5e021a2916281f46bcd60b20d2 commit r12-952-g6b42b5a8a207de5e021a2916281f46bcd60b20d2 Author: Jonathan Wakely <jwak...@redhat.com> Date: Thu May 20 16:39:06 2021 +0100 libstdc++: Use __builtin_unreachable for constexpr assertions [PR 100676] The current implementation of compile-time precondition checks causes compilation to fail by calling a non-constexpr function declared at block scope. This breaks the CUDA compiler, which wraps some libstdc++ headers in a pragma that declares everything as a __host__ __device__ function, but others are not wrapped and so everything is a __host__ function. The local declaration thus gets redeclared as two different types of function, which doesn't work. Just use __builtin_unreachable to make constant evaluation fail, instead of the local function declaration. Also simplify the assertion macros, which has the side effect of giving simpler compilation errors when using Clang. libstdc++-v3/ChangeLog: PR libstdc++/100676 * include/bits/c++config (__glibcxx_assert_1): Rename to ... (__glibcxx_constexpr_assert): ... this. (__glibcxx_assert_impl): Use __glibcxx_constexpr_assert. (__glibcxx_assert): Define as either __glibcxx_constexpr_assert or __glibcxx_assert_impl. (__glibcxx_assert_2): Remove * include/debug/macros.h (_GLIBCXX_DEBUG_VERIFY_AT_F): Use __glibcxx_constexpr_assert instead of __glibcxx_assert_1. * testsuite/21_strings/basic_string_view/element_access/char/back_constexpr_neg.cc: Adjust expected error. * testsuite/21_strings/basic_string_view/element_access/char/constexpr_neg.cc: Likewise. * testsuite/21_strings/basic_string_view/element_access/char/front_constexpr_neg.cc: Likewise. Likewise. * testsuite/21_strings/basic_string_view/element_access/wchar_t/back_constexpr_neg.cc: Likewise. * testsuite/21_strings/basic_string_view/element_access/wchar_t/constexpr_neg.cc: Likewise. * testsuite/21_strings/basic_string_view/element_access/wchar_t/front_constexpr_neg.cc: Likewise. * testsuite/23_containers/span/back_neg.cc: Likewise. * testsuite/23_containers/span/front_neg.cc: Likewise. * testsuite/23_containers/span/index_op_neg.cc: Likewise.
