https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68212
--- Comment #10 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> --- I had a try for GCC11, https://gcc.gnu.org/pipermail/gcc-patches/2021-July/574421.html. The patches could mitigate the BB-count mismatch issue for loops. In theory, this patch would make sense. But it also raises the mismatch BB's count out of the loop for some cases. With tests on spec2017, this patch could help performance on some bmks, while it also introduces recession on some bmks. So, I did not pursue pushing that patch.
