https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78130
--- Comment #7 from Marc Glisse <glisse at gcc dot gnu.org> ---
Reduced a bit more:
struct B {
B();
void m_fn2(int p1) {
if (p1 <= storage_)
throw;
}
int storage_;
};
void f() {
B span_;
int b = span_.storage_;
span_.m_fn2(b - 1);
}
The warning seems correct to me (assuming the reduction didn't change things
too much). We have a comparison storage_ - 1 <= storage_, the compiler
optimizes it to true, and the warning tells you about it (maybe in the full
code the compiler would have a chance to prove that storage_ is never 0 and
thus storage_ - 1 can never overflow, but that's hard).
A warning doesn't necessary say that something is wrong with your code, here it
just informs you about an optimization. How useful that is is a different
question...
