https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67305
--- Comment #3 from Jiong Wang <jiwang at gcc dot gnu.org> --- >From the tree dump .pre, I understand the tree shape is improved as we deleted one redundant Phi, but we also noticed there is one regression, we are turning _6 = bl_20 >> 6 into something like: _5 = c_16 / 64; While for signed division, we need to generate extra check instruction sequences, although rtl passes should handle this, but seems to me this is still a regression, Richard, is it because we have lost some range info after your patch? the division was turned into right shift after vrp pass. Anyway, we also need to figure out why after this division change, the rtl pass crash.