[Bug tree-optimization/64601] Missed PRE on std::vector move assignment

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64601

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
It's indeed that GCC only sees int accesses based on w and v and thus has to
consider they might alias.

Maybe it's time to try that "trick" with the same clobbering value...

TBAA cannot be strengthened easily here because the stores change the
dynamic type of the memory.