[Bug tree-optimization/69489] missed vectorization for boolean loop, missed if-conversion

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69489

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
And in the end it is also related to PR23286, the inability to hoist the v[i]
load out of

  if (u[i])
    ... = v[i];
  else
    ... = v[i];

which would also enable the if-conversion.