https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87871
--- Comment #28 from Peter Bergner <bergner at gcc dot gnu.org> --- Vlad, in looking at add_insn_allocno_copies(), it looks like it relies on seeing REG_DEAD notes on whether to record a copy/shuffle that should be handled. Shouldn't we instead be looking at whether the source and destination regs conflict or not? Ie, there might not be a REG_DEAD note, but that doesn't mean the two regs/pseudos conflict. And conversely, if there is a REG_DEAD note on the copy/shuffle, the two regs/pseudos still could conflict.
