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// Test for PR59221. Tests the compiler wouldn't misoptimize the final result.
//
// REQUIRES: x86-registered-target
//
// RUN: %clang_cc1 -triple x86_64-unknown-linux-gnu -std=c++20 %s -O1 -emit-llvm -o - | FileCheck %s
#include "Inputs/coroutine.h"
template <typename T> struct task {
struct promise_type {
T value{123};
std::coroutine_handle<> caller{std::noop_coroutine()};
struct final_awaiter: std::suspend_always {
auto await_suspend(std::coroutine_handle<promise_type> me) const noexcept {
return me.promise().caller;
}
};
constexpr auto initial_suspend() const noexcept {
return std::suspend_always();
}
constexpr auto final_suspend() const noexcept {
return final_awaiter{};
}
auto unhandled_exception() noexcept {
// ignore
}
constexpr void return_value(T v) noexcept {
value = v;
}
constexpr auto & get_return_object() noexcept {
return *this;
}
};
using coroutine_handle = std::coroutine_handle<promise_type>;
promise_type & promise{nullptr};
task(promise_type & p) noexcept: promise{p} { }
~task() noexcept {
coroutine_handle::from_promise(promise).destroy();
}
auto await_ready() noexcept {
return false;
}
auto await_suspend(std::coroutine_handle<> caller) noexcept {
promise.caller = caller;
return coroutine_handle::from_promise(promise);
}
constexpr auto await_resume() const noexcept {
return promise.value;
}
// non-coroutine access to result
auto get() noexcept {
const auto handle = coroutine_handle::from_promise(promise);
if (!handle.done()) {
handle.resume();
}
return promise.value;
}
};
static inline auto a() noexcept -> task<int> {
co_return 42;
}
static inline auto test() noexcept -> task<int> {
co_return co_await a();
}
int foo() {
return test().get();
}
// Checks that the store for the result value 42 is not misoptimized out.
// CHECK: define{{.*}}_Z3foov(
// CHECK: store i32 42, ptr %{{.*}}
// CHECK: }
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