[Bug tree-optimization/65752] Too strong optimizations int -> pointer casts

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65752

--- Comment #53 from Jeffrey A. Law <law at redhat dot com> ---
And presumably walking forward/backward from the equivalency point to determine
if an object is derived from or is used to derive a pointer is insufficient
because the equivalency point and casting to/from pointer types might be in
different functions?

Is this the final straw and do we just stop recording these conditional
equivalences when both sides are SSA_NAMEs and declare the fallout unavoidable?

And note I believe we do similar stuff in the RTL optimizers too.