REQUIRE(co_await expr) unexpectedly repeats execution in GCC

[Hackerl]

Describe the bug
REQUIRE(co_await expr) unexpectedly repeats execution in GCC.

Expected behavior
The co_await expression should only be executed once

Reproduction steps
https://godbolt.org/z/h6jshrYs8

#include <iostream>
#include <coroutine>
#include <https://raw.githubusercontent.com/catchorg/Catch2/refs/tags/v3.7.1/extras/catch_amalgamated.hpp>
#include <https://raw.githubusercontent.com/catchorg/Catch2/refs/tags/v3.7.1/extras/catch_amalgamated.cpp>

struct promise;

struct coroutine : std::coroutine_handle<promise> {
    using promise_type = ::promise;
};

struct promise {
    coroutine get_return_object() { return {coroutine::from_promise(*this)}; }
    std::suspend_never initial_suspend() noexcept { return {}; }
    std::suspend_never final_suspend() noexcept { return {}; }

    void return_void() {
    }

    void unhandled_exception() {
    }
};

struct Awaitable {
    bool await_ready() {
        static int counter{};
        std::cout << ++counter << std::endl;
        return true;
    }

    void await_suspend(std::coroutine_handle<>) {
    }

    bool await_resume() {
        return true;
    }
};

coroutine test() {
    REQUIRE(co_await Awaitable{});
}

TEST_CASE("test") {
    test();
}

Platform information:

• OS: Any
• Compiler+version: GCC v14.x.x
• Catch version: v3.7.1

Additional context
In GCC, __builtin_constant_p(co_await expr) is executed unexpectedly.
while ((void) 0, (false) && static_cast<const bool &>(!!(co_await expr))) is also.
I believe this is a compiler bug, but is there a way to avoid it with catch?

[horenmar]

Well, that's not the funniest bug with __builtin_constant_p I've seen*, but this is the first time GCC has one. Currently there isn't a configuration option to disable this, but seeing this, I think that it is either time to add one, or to remove that check completely.

Have you reported this to GCC bugzilla?

* That goes to IBM XL, which would generate a call to the destructor of a temporary, without generating the constructor 😃

[horenmar]

GCC already has two bugs for this upstream

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116775 and https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101027