[Bug tree-optimization/112307] Segmentation fault with -O1 -fcode-hoisting

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112307

--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Ironically, writing a user-provided (and so non-trivial) copy constructor which
fixes up the self-referential pointer (or iterator, in your case) will restore
guaranteed elision, and that copy constructor isn't actually used.

But with a trivial copy constructor, your object gets copied, and the
self-referential pointer gets invalidated because it points to a temporary that
has gone out of scope, not to the final object after the copies are done.