https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111399
--- Comment #2 from David Brown <david at westcontrol dot com> ---
Would it be possible to have the "-Wreturn-type" warning pass not issue a
warning immediately, but inject a warning into the code that could then be
removed later by optimisation?
What I mean, is to have something roughly like this :
void __attribute__((warning("Reached return in non-void function")))
__ReturnNonVoid(void);
int sign(int x) {
if (x < 0) return -1;
if (x == 0) return 0;
if (x > 0) return 1;
__ReturnNonVoid();
}
Instead of issuing a warning straight away, if the compiler had added a call to
a non-existent "__ReturnNonVoid" function (just like the sanitizer adds a call
to "__ubsan_handle_missing_return"), this would be optimised away in functions
like this sample and the false positive warning would not be issued. (Ideally,
of course, it would be suitable GIMPLE, or appropriate internal representation
for that pass, rather than a call to a non-existent function.)
