https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93264
--- Comment #5 from Roman Zhuykov <zhroma at gcc dot gnu.org> --- Created attachment 47820 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47820&action=edit Considered "moving sms earlier" patch I haven't tested "moving sms earlier" patch since 2011. But I remember there were some testsuite items where it makes difference, not sure whether it was arm or ia64 platform. I decided those passes between substantially change the loop code and DDG. I'll run some cross-testing to check how it works for now. > In general it's a bad idea to try go "back" to CFG layout mode and the fix is > to not do that. Also qouting https://gcc.gnu.org/ml/gcc-patches/2020-02/msg00714.html: > I think the expectation that you can go back to CFG layout mode > and then work with CFG layout tools after we've lowered to CFG RTL > is simply bogus. Yeah, you can probably do analysis things but > I wouldn't be surprised if a CFG RTL -> CFG layout -> CFG RTL cycle > can wreck things. Undoubtedly doing CFG manipulations is not going > to work since CFG layout does not respect CFG RTL restrictions. > Partitioning simply uncovered latent bugs, there's nothing wrong > with it IMHO. There are two more passes re-entering cfg layout: pass_reorder_blocks and pass_machine_reorg.
