https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104800
--- Comment #25 from Richard Biener <rguenth at gcc dot gnu.org> --- (In reply to uecker from comment #24) > For C++ a builtin was added that acts as a barrier for std::observable. This > could potentially be emitted by the C frontend after each volatile access. That would work, on the GIMPLE side at least. > https://gcc.gnu.org/cgit/gcc/commit/ > ?id=9056b5faa87df59fb8eb2f92096a8e6e7d246757 > > I do not understand the test case though, as the addition is not volatile, > so it may have stronger semantics than what is needed here. It depends on what is considered "observable", here the global variable write is supposedly so. > (IIRC, in C the function without return would also not have UB as long as > the return value is not used.).
