https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112760
--- Comment #6 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:e44ed92dbbe9d4e5c23f486cd2f77a6f9ee513c5 commit r14-6210-ge44ed92dbbe9d4e5c23f486cd2f77a6f9ee513c5 Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Dec 6 09:59:12 2023 +0100 i386: Move vzeroupper pass from after reload pass to after postreload_cse [PR112760] Regardless of the outcome of the REG_UNUSED discussions, I think it is a good idea to move the vzeroupper pass one pass later. As can be seen in the multiple PRs and as postreload.cc documents, reload/LRA is known to create dead statements quite often, which is the reason why we have postreload_cse pass at all. Doing vzeroupper pass before such cleanup means the pass including df_analyze for it needs to process more instructions than needed and because mode switching adds note problem, also higher chance of having stale REG_UNUSED notes. And, I really don't see why vzeroupper can't wait until those cleanups are done. 2023-12-06 Jakub Jelinek <ja...@redhat.com> PR rtl-optimization/112760 * config/i386/i386-passes.def (pass_insert_vzeroupper): Insert after pass_postreload_cse rather than pass_reload. * config/i386/i386-features.cc (rest_of_handle_insert_vzeroupper): Adjust comment for it. * gcc.dg/pr112760.c: New test.
