[Bug c++/84824] DCE fails to remove dead code of std::function constructor

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824 --- Comment #5 from linzj --- Change the function call to printf to asm like: int main() { // printf("%d", getFunc(1)(1, 1)); asm volatile("" : : "r"(getFunc(1)(1, 1))); return 0; } Will generate the concise code. I think # USE

[Bug c++/84824] DCE fails to remove dead code of std::function constructor

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824 --- Comment #4 from Marc Glisse --- Probably related to PR59948, PR81000, etc. (I didn't look closely)

[Bug c++/84824] DCE fails to remove dead code of std::function constructor

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824 --- Comment #3 from linzj --- From the function destructor ~_Function_base() { if (_M_manager) _M_manager(_M_functor, _M_functor, __destroy_functor); }

[Bug c++/84824] DCE fails to remove dead code of std::function constructor

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824 --- Comment #2 from linzj --- Okay， it's std::_Function_base::_Base_manager >::_M_manager(std::_Any_data &, const std::_Any_data &, std::_Manager_operation) (__dest=..., __source=..., __op=std::__destroy_functor)

[Bug c++/84824] DCE fails to remove dead code of std::function constructor

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84824 --- Comment #1 from linzj --- According to the tree generated, the problem is sourced from fail to remove the lambda function call. But the constant value is deduced and propagated. In case of the side effect?