ilya-biryukov added a comment. Reverting the RVO breaks some coroutine code we have. The short repro is https://gcc.godbolt.org/z/1543qc8Ee (code at the end of the post, very similar to the deleted constructor in `warn-throw-out-noexcept-coro.cpp`): The RVO seems to be mandated by the standard and D145641 <https://reviews.llvm.org/D145641> is in the works to fix this.
Could we revert this change and wait for D145641 <https://reviews.llvm.org/D145641> to land before reverting existing RVO behavior? This would unblock our compiler releases (we live at head). This looks like the right trade-off given that previous behavior was in Clang for more than a year after D117087 <https://reviews.llvm.org/D117087> landed. Reproducer <https://gcc.godbolt.org/z/1543qc8Ee> (works in Clang 15 and GCC, fails in trunk): #include <coroutine> struct MyTask{ struct promise_type { MyTask get_return_object() { return MyTask{std::coroutine_handle<promise_type>::from_promise(*this)}; } std::suspend_always initial_suspend() { return {}; } void unhandled_exception(); void return_void() {} auto await_transform(MyTask task) { struct Awaiter { bool await_ready() { return false; } std::coroutine_handle<promise_type> await_suspend(std::coroutine_handle<promise_type> h); std::nullptr_t await_resume(); promise_type& caller; promise_type& callee; }; return Awaiter{*this, task.handle.promise()}; } auto final_suspend() noexcept { struct Awaiter { bool await_ready() noexcept { return false; } std::coroutine_handle<promise_type> await_suspend(std::coroutine_handle<promise_type> h) noexcept; void await_resume() noexcept; std::coroutine_handle<promise_type> to_resume; }; return Awaiter{resume_when_done}; } // The coroutine to resume when we're done. std::coroutine_handle<promise_type> resume_when_done; }; explicit MyTask(std::coroutine_handle<promise_type>); MyTask(MyTask&&) = delete; // A handle for the coroutine that returned this task. std::coroutine_handle<promise_type> handle; }; MyTask DoNothing() { co_return; } Repository: rG LLVM Github Monorepo CHANGES SINCE LAST ACTION https://reviews.llvm.org/D145639/new/ https://reviews.llvm.org/D145639 _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
