https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83252
--- Comment #6 from Dmitry Babokin <babokin at gmail dot com> --- (In reply to Jakub Jelinek from comment #1) > Option bisection is rarely useful for GCC, debugging issues with -Ox -fthat > -fno-this -fwhatever is usually not beneficial over just -Ox or whatever > minimal options you need it. Bisecting to what GCC version introduced the > bug or changed behavior is usually much better. Bisecting optimizations is orthogonal to bisecting of revision the bug started with. In my experience it's extremely useful (with icc and clang) for understanding the root cause of the bug (just compare two assemblers or IRs with and without the guilty optimization). It's also very useful for distinguishing bugs in automatic way - in case of multiple failing test cases I can sort them in different buckets corresponding to guilty optmizations. This analysis is not 100% accurate, but is very useful. And the third useful feature of such bisection - finding an optimization for initial bug assignment. I'm not insisting on such functionality, as my bugs were always analysed and fixed in timely manner (unlike with other compilers). But I still think gcc would benefit from such mechanism a lot.
