[Bug tree-optimization/92932] Optimizers generate wrong code due to aggressive data optimization.

[gjl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92932

--- Comment #2 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #1)
> Dup of at least PR92294 and  PR54666;


These PRs are different because no target hook is needed to see that the code
is wrong. This is different with PR92606 because a target attribute is
involved. 

Hence this PR for a new target hook that can tell whether such transformation
might not be legitimate {apart from generic reasons}.