https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106434
--- Comment #11 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:4ba94abf147fe7778a7541849ce27cafee74df9b commit r13-4525-g4ba94abf147fe7778a7541849ce27cafee74df9b Author: Jonathan Wakely <jwak...@redhat.com> Date: Mon Dec 5 12:53:42 2022 +0000 libstdc++: Add hint to compiler about vector invariants [PR106434] The PR shows a bogus warning where jump threading generates code for the undefined case that the insertion point is a value-initialized iterator but _M_finish and _M_end_of_storage are unequal (so at least one must be non-null). Using __builtin_unreachable() removes the bogus warning. Also add an assertion to diagnose undefined misuses of a null iterator here, so we don't just silently optimize that undefined code to something unsafe. libstdc++-v3/ChangeLog: PR c++/106434 * include/bits/vector.tcc (insert(const_iterator, const T&)): Add assertion and optimization hint that the iterator for the insertion point must be non-null.
