[Bug middle-end/71690] absence of integer conversion defeats memcpy optimizaton

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71690

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Martin Sebor from comment #1)
> See also C++ bug 71654 for the "inverse" of the problem where VRP
> successfully provides range information in the absence of a conversion but
> fails with it.

That is a totally different issue.
The issue here is that range information has to be correct for all places where
the name is used.  Without a cast the name is used in both the comparison and
in the memcpy so the range needs to be empty so the comparison is not removed.