> Date: Tue, 29 Aug 2023 15:42:27 -0400 > From: Marek Polacek via Gcc-patches <gcc-patches@gcc.gnu.org>
> Surely, there must be no ABI impact, the option cannot cause > severe performance issues, > Currently, -fhardened enables: ... > -ftrivial-auto-var-init=zero > Thoughts? Regarding -ftrivial-auto-var-init=zero, I was consulted when colleagues investigating a performance regression pint-pointed it as *causing severe performance issues*; cf. https://github.com/systemd/systemd.git commit 1a4e392760 (TL;DR: adds "-ftrivial-auto-var-init=zero" to the systemd build). The situation was described as "we noticed that some test suites takes 35% percent longer time to finish. After further investigation it was noticed that running systemctl unmask x takes around 5s more time on [version including patch vs. before that patch]" (timing out some tests). Reverting that patch fixed the drop in performance. Just a data point, but I believe also exactly your intended use. IMO including -ftrivial-auto-var-init is worth extra consideration. Alternatively, strike the while "cannot cause severe performance issues". brgds, H-P
