https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82735
--- Comment #3 from Marc Glisse <glisse at gcc dot gnu.org> --- Actually, what CSE1 does might be fine, and it is LRA that should have noticed that the register it assigned was clobbered, so it should have spilled (or better rematerialized). Assuming the i386 backend does say that this unspec clobbers the registers, which I am not seeing right now (but I may not be looking in the right place).
