https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121773
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> --- The patch was done under the assumption written in the commit message: "The following patch replaces the modified_between_p tests with reg_used_between_p, my understanding is that modified_between_p is a subset of reg_used_between_p, so one doesn't need both." To my surprise that is not the case, reg_used_between_p ignores the cases where SET_DEST of some insn in between is the same (or SUBREG_REG), and similarly reg_overlap_mentioned_p does etc.
