https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77478
--- Comment #6 from Alexander Monakov <amonakov at gcc dot gnu.org> --- Thanks, seeing alignment info in dumps helps (I think you meant -vops rather than -alias?). This doesn't seem to reproduce on trunk. On gcc-5 branch, I see alignment increasing in dom2 pass. Specifically, the 147t.slsr dump prior to dom2 has: <bb 23>: ... vectp.10_4 = vectp.22_88; ... # rhs access alignment 32+0 vect__22.11_163 = MEM[(float *)vectp.10_4]; and then 149.dom2 has: <bb 23>: ... vectp.10_4 = vectp.22_88; ... # rhs access alignment 128+0 vect__22.11_163 = MEM[(float *)vectp.22_88];