On Tue, 9 Sept 2025 at 18:11, Jakub Jelinek <ja...@redhat.com> wrote: > > On Tue, Sep 09, 2025 at 06:08:12PM +0300, Ville Voutilainen wrote: > > The fail() can fall through when the contracts are evaluated in the > > "observe" evaluation mode. > > In that case it's not an actual "fail", it will call the contract > > violation handler and return from that. > > > > And then the concern is that that call may be completely elided > > because what follows is > > UB in the form of the pointer dereference. > > IMHO a correct compiler can't do that. > Because the contract violation handler could have validly exit (0) > or for (;;) ; etc. in it, so the UB wouldn't encountered in the program and > so it would be valid.
The violation handler may be defined in the same translation unit, and its definition may be completely visible to the middle-end.
