[Bug tree-optimization/62171] restrict pointer to struct with restrict pointers parm doesn't prevent aliases

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62171

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
And maybe set DECL_BY_REFERENCE, a mere REFERENCE_TYPE doesn't prevent
you from doing (&param)[2] which we'd miscompile.  Not sure who added
that REFERENCE_TYPE code.