https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119616
--- Comment #17 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:d060d7a3ddc1c782e2800b1f68a2eb8f0de1fc32 commit r15-9208-gd060d7a3ddc1c782e2800b1f68a2eb8f0de1fc32 Author: Jakub Jelinek <ja...@redhat.com> Date: Fri Apr 4 20:52:41 2025 +0200 tailc: Don't reject all tail calls if param has addr taken [PR119616] Before my PR119376 r15-9145 changes, suitable_for_tail_call_opt_p would return the same value in the same caller, regardless of the calls in it. If it fails, the caller clears opt_tailcalls which is a reference and therefore shared by all calls in the caller and we only do tail recursion, all non-recursive or tail recursion non-optimizable calls are not tail call optimized. For musttail calls we want to allow address taken parameters, but the r15-9145 change effectively resulted in the behavior where if there are just musttail calls considered, they will be tail call optimized, and if there are also other tail call candidates (without musttail), we clear opt_tailcall and then error out on all the musttail calls. The following patch fixes that by moving the address taken parameter discovery from suitable_for_tail_call_opt_p to its single caller. If there are addressable parameters, if !cfun->has_musttail it will work as before, disable all tail calls in the caller but possibly allow tail recursions. If cfun->has_musttail, it will set a new bool automatic flag and reject non-tail recursions. This way musttail calls can be still accepted and normal tail call candidates rejected (and tail recursions accepted). 2025-04-04 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/119616 * tree-tailcall.cc (suitable_for_tail_call_opt_p): Move checking for addressable parameters from here ... (find_tail_calls): ... here. If cfun->has_musttail, don't clear opt_tailcalls for it, instead set a local flag and punt if we can't tail recurse optimize it. * c-c++-common/pr119616.c: New test.
