[Bug c/59984] OpenMP and Cilk Plus SIMD pragma makes loop incorrect

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59984

--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
Ok, so SCCVN only can forward constant addresses (because variable ones
wouldn't fit in the same refs vector without "inserting" ops).  See
vn_reference_maybe_forwprop_address.  It's also required so that we can
re-materialize the expression in PRE for example and not wind up with
invalid access paths there (similar to the reason why forwprop doesn't do
this transform).

I think it might be possible to teach SCCVN to do this, but it might be
not trivial.