17 Regression: over optimization at -O2 #123347
Description
godbolt: https://godbolt.org/z/4xEEz6fsY
#include <iostream>
#include <coroutine>
#include <utility>
#include <vector>
struct Promise {
std::vector<int> obj;
~Promise() {
std::cout << "~Promise: " << obj.data() << std::endl;
}
auto get_return_object() { return std::coroutine_handle<Promise>::from_promise(*this); };
std::suspend_never initial_suspend() noexcept { return {}; }
std::suspend_never final_suspend() noexcept { return {}; }
std::suspend_always yield_value(std::vector<int> b) noexcept {
obj = std::move(b);
return {};
}
void return_void() noexcept {}
void unhandled_exception() {}
};
struct coro {
using promise_type = Promise;
std::vector<int> arr;
std::coroutine_handle<Promise> handle;
coro(std::coroutine_handle<Promise> handle_) noexcept {
handle = handle_;
arr = std::move(handle_.promise().obj);
}
};
coro fn() {
co_yield std::vector<int>(1);
}
int main(int argc, char** argv) {
coro cr = fn();
std::cout << "main: " << cr.arr.data() << std::endl;
cr.handle.resume();
return 0;
}
The code works fine using clang 16, but it breaks using 17 ~ trunk.
Possible wrong result(-O2):
main: 0x61c7ada362f0
~Promise: 0x61c7ada362f0
Expected result(-O0):
main: 0x61c7ada362f0
~Promise: 0