[PATCH] D51741: [coro]Pass rvalue reference for named local variable to return_value
Brian Gesiak via Phabricator via cfe-commits
cfe-commits at lists.llvm.org
Sun Oct 7 20:10:30 PDT 2018
This revision was automatically updated to reflect the committed changes.
Closed by commit rL343949: [coro]Pass rvalue reference for named local variable to return_value (authored by modocache, committed by ).
Herald added a subscriber: llvm-commits.
Repository:
rL LLVM
https://reviews.llvm.org/D51741
Files:
cfe/trunk/lib/Sema/SemaCoroutine.cpp
cfe/trunk/test/SemaCXX/coroutine-rvo.cpp
Index: cfe/trunk/lib/Sema/SemaCoroutine.cpp
===================================================================
--- cfe/trunk/lib/Sema/SemaCoroutine.cpp
+++ cfe/trunk/lib/Sema/SemaCoroutine.cpp
@@ -841,6 +841,19 @@
E = R.get();
}
+ // Move the return value if we can
+ if (E) {
+ auto NRVOCandidate = this->getCopyElisionCandidate(E->getType(), E, CES_AsIfByStdMove);
+ if (NRVOCandidate) {
+ InitializedEntity Entity =
+ InitializedEntity::InitializeResult(Loc, E->getType(), NRVOCandidate);
+ ExprResult MoveResult = this->PerformMoveOrCopyInitialization(
+ Entity, NRVOCandidate, E->getType(), E);
+ if (MoveResult.get())
+ E = MoveResult.get();
+ }
+ }
+
// FIXME: If the operand is a reference to a variable that's about to go out
// of scope, we should treat the operand as an xvalue for this overload
// resolution.
Index: cfe/trunk/test/SemaCXX/coroutine-rvo.cpp
===================================================================
--- cfe/trunk/test/SemaCXX/coroutine-rvo.cpp
+++ cfe/trunk/test/SemaCXX/coroutine-rvo.cpp
@@ -0,0 +1,69 @@
+// RUN: %clang_cc1 -triple x86_64-apple-darwin9 %s -stdlib=libc++ -std=c++1z -fcoroutines-ts -fsyntax-only
+
+namespace std::experimental {
+template <class Promise = void> struct coroutine_handle {
+ coroutine_handle() = default;
+ static coroutine_handle from_address(void *) noexcept;
+};
+
+template <> struct coroutine_handle<void> {
+ static coroutine_handle from_address(void *) noexcept;
+ coroutine_handle() = default;
+ template <class PromiseType>
+ coroutine_handle(coroutine_handle<PromiseType>) noexcept;
+};
+
+template <class... Args>
+struct void_t_imp {
+ using type = void;
+};
+template <class... Args>
+using void_t = typename void_t_imp<Args...>::type;
+
+template <class T, class = void>
+struct traits_sfinae_base {};
+
+template <class T>
+struct traits_sfinae_base<T, void_t<typename T::promise_type>> {
+ using promise_type = typename T::promise_type;
+};
+
+template <class Ret, class... Args>
+struct coroutine_traits : public traits_sfinae_base<Ret> {};
+}
+
+struct suspend_never {
+ bool await_ready() noexcept;
+ void await_suspend(std::experimental::coroutine_handle<>) noexcept;
+ void await_resume() noexcept;
+};
+
+struct MoveOnly {
+ MoveOnly() {};
+ MoveOnly(const MoveOnly&) = delete;
+ MoveOnly(MoveOnly&&) noexcept {};
+ ~MoveOnly() {};
+};
+
+template <typename T>
+struct task {
+ struct promise_type {
+ auto initial_suspend() { return suspend_never{}; }
+ auto final_suspend() { return suspend_never{}; }
+ auto get_return_object() { return task{}; }
+ static void unhandled_exception() {}
+ void return_value(T&& value) {}
+ };
+};
+
+task<MoveOnly> f() {
+ MoveOnly value;
+ co_return value;
+}
+
+int main() {
+ f();
+ return 0;
+}
+
+// expected-no-diagnostics
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