[Bug tree-optimization/80738] dead first stmt in a=0;a=b;b=0 whatever the aliasing

[david at doublewise dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80738

--- Comment #2 from David Stone <david at doublewise dot net> ---
*** Bug 90888 has been marked as a duplicate of this bug. ***