Hacker News new | ask | show | jobs
by BoingBoomTschak 463 days ago
-O3 itself isn't "buggy", but since it uses more optimizations, it can reveal issues in them. Other Gentoo users know: e.g. https://bugs.gentoo.org/show_bug.cgi?id=941208 https://bugs.gentoo.org/show_bug.cgi?id=940923 (search O3 in the bugzilla).
1 comments
kllrnohj 463 days ago
strict-aliasing, which is what caused that bug to manifest, is enabled at O2.
link
BoingBoomTschak 463 days ago
Yep, it's what caused the bug to manifest, but who knows if that UB would have caused -O2 optimizations to mangle the result as well.

EDIT: first one is -funswitch-loops, though

link
kllrnohj 463 days ago
Probably would have. There's no shortage of UB bugs revealed by O2 after all, including major security issues.
link