https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123343
--- Comment #12 from Zhongyao Chen <chenzhongyao.hit at gmail dot com> --- (In reply to Richard Biener from comment #10) Dump shows multi-lane SLP failed, but size-1 subgroup analysis "succeeded" with poor code generation. Shouldn't subgroups also require size > 1? I added a check and now size-1 cases fall back to single-lane reduction, which gives the expected asm.
