https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101944
--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> --- On x86 we even have Vector cost: 136 Scalar cost: 196 note that we seem to vectorize the reduction but that only happens with -ffast-math, not -O2 -ftree-slp-vectorize? One issue is the association of (diffa * vdw_d * (1 / 6.) + vdw_c * (1 / 4.)) * diffa + vdw_b * (1 / 2.)) * diffa + vdw_a which we fail to reduce as diffa*diffa*diffa*(1/6.)*vdw_d + diffa*diffa*(1/4.)*vdw_c + diffa*(1/2.)*vdw_b + 1.0*vdw_a
