https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123343
--- Comment #5 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to Zhongyao Chen from comment #4) > Yes. Without unrolling, inner loop vectorization produces better asm. Could > .cunrolli be made vectorization-aware to avoid unrolling when beneficial? > Once unrolled, SLP has no way to recover the loop; what we want is inner > loop vectorization only, not SLP. cunrolli first and foremost job is to remove abstraction, it's difficult to anticipate further optimization on the unrolled body, so - not easily I'd say. BB SLP should work on this though (but as you said we first vectorize the loop containing the code in an awkward way).
