https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65961
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- Hmpf, so we have an operand that is both part of a regular SLP node _and_ is part of a SLP node that gets its operand built up from scalars. So obviously looking at STMT_VINFO_VECTORIZABLE (def-of-op) isn't giving the correct answer (it depends on context). I tried to avoid passing down the SLP node to vect_is_simple_use[_1], but that is what it would take to fix this (well, or reject the SLP build while we compute STMT_VINFO_VECTORIZABLE ()). I have to think more about what refactoring would make sense here.
