https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67364
--- Comment #13 from Louis Dionne <ldionne.2 at gmail dot com> ---
Actually, the problem is much worse than I thought. It turns out that with -O1,
the following code does not pass the assertion:
#include <cassert>
template <typename Xn>
struct tuple {
Xn storage_;
constexpr tuple(Xn const& xn)
: storage_(xn)
{ }
template <typename ...dummy>
constexpr tuple(tuple const& other)
: storage_(other.storage_)
{ }
template <typename ...dummy>
constexpr tuple(tuple& other)
: tuple(const_cast<tuple const&>(other))
{ }
};
template <typename T>
struct wrapper { T value; };
template <typename T>
constexpr wrapper<T> wrap(T t) { return {t}; }
int main() {
wrapper<tuple<int>> t = wrap(tuple<int>{2});
assert(t.value.storage_ == 2);
}
Live example: http://melpon.org/wandbox/permlink/nRGrPcbvqYWhzCDt
This is the same code as above, except the `t` variable is not constexpr
anymore.
This seems like a case of invalid codegen. If I make the `wrap` function
non-constexpr,
the problem goes away. Should I create a separate bug report for this?
