[ThinLTO] Attempt to recommit r365040 after caching fix
It's possible that some function can load and store the same
variable using the same constant expression:
store %Derived* @foo, %Derived bitcast (%Base @bar to %Derived)
%42 = load %Derived*, %Derived bitcast (%Base @bar to %Derived)
The bitcast expression was mistakenly cached while processing loads,
and never examined later when processing store. This caused @bar to
be mistakenly treated as read-only variable. See load-store-caching.ll.