https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120608
--- Comment #13 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:35a26f2ec55d20d524464c33b68b23328a7f6bbe commit r16-1626-g35a26f2ec55d20d524464c33b68b23328a7f6bbe Author: Jakub Jelinek <ja...@redhat.com> Date: Mon Jun 23 16:08:34 2025 +0200 tailc: Allow musttail tail calls with -fsanitize=address [PR120608] These testcases show another problem with -fsanitize=address vs. musttail tail calls. In particular, there can be .ASAN_MARK (POISON, &a, 4); etc. calls after a tail call and those just prevent the tailc pass to mark the musttail calls as [tail call]. Normally, the sanopt pass (which comes after tailc) will optimize those away, the optimization is if there are no .ASAN_CHECK calls or normal function calls dominated by those .ASAN_MARK (POSION, ...) calls, the poison is not needed, because in the epilog sequence (the one dealt with in the patch posted earlier today) all the stack slots are unpoisoned anyway (or poisoned for use-after-return). Unlike __builtin_tsan_exit_function, .ASAN_MARK is not a real function and is always expanded inline, so can be never tail called successfully, so the patch just ignores those for the cfun->has_musttail && diag_musttail cases. If there is a non-musttail call, it will fail worst case during expansion because there is the epilog asan sequence. 2025-06-12 Jakub Jelinek <ja...@redhat.com> PR middle-end/120608 * tree-tailcall.cc (empty_eh_cleanup): Ignore .ASAN_MARK (POISON) internal calls for the cfun->has_musttail case and diag_musttail. (find_tail_calls): Likewise. * c-c++-common/asan/pr120608-1.c: New test. * c-c++-common/asan/pr120608-2.c: New test.
