https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126312
--- Comment #3 from Guillaume Racicot <dev at gracicot dot com> ---
I was able to reproduce this failure in x86-64 too.
Seems like with those change the frontend think there's a dangling reference
both in ARM64 and x86, and GCC generate bad code for both architectures:
#include <print>
struct val_ref {
int val = 42;
int& ref = val;
};
struct wrapper {
constexpr wrapper(): impl{} {}
// wrapper(wrapper&&) = delete; // uncomment to fix issue
val_ref impl{};
};
constexpr auto make_s() {
return wrapper{};
}
constexpr int test() {
auto s = make_s();
std::println("{}", s.impl.ref); // prints garbage
return s.impl.ref;
}
//static_assert(test()); // uncomment for constexpr evaluator error
int main() {
return test() == 42 ? 0 : 1;
}
Uncommenting the deleted move constructor fixes the code generation.
Compiler explorer link: https://godbolt.org/z/n57b1rbx1
