https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84732
--- Comment #8 from Martin Liška <marxin at gcc dot gnu.org> --- (In reply to Jakub Jelinek from comment #4) > (In reply to Martin Liška from comment #2) > > I guess it somehow confuses VRP, Martin can you please take a look? Note > > that __builtin___sanitizer_cov_trace_pc is pure function, can't modify > > memory in original program. > > No, __builtin___sanitizer_cov_trace_pc is certainly not pure and can't > really be, otherwise would optimize them all away (nothing uses their void > return value), > so the problem is that it invalidates all recorded string lengths, at least > those that escape (but in this testcase it is a global variable). > As __sanitizer_cov_trace_pc is a user-supplied function, I don't really > think we can assume anything on it (e.g. that it will not change any global > or escaped local variables, it can change them and most likely will do at > least some of them, otherwise it would be useless). I see, I was probably too eager :)
