[CUDA][HIP] file-scope device variable not allowed with trivial ctor

[yxsamliu]

`struct A {
A() {}
~A() {}
int x;
};

device A x;`

the above code is allowed with nvcc but not cuda-clang.

https://godbolt.org/z/jjMG3zTd3

https://godbolt.org/z/74Ed1WvGn

nvcc allows it not because it makes the ctor A::A() implicitly host device (this can be seen by defining A x in device function), but because it does not check host/device availability for file-scope device var.

I think it makes sense to make trivial ctor/dtor implicitly host device.

@Artem-B

[Artem-B]

I think it makes sense to make trivial ctor/dtor implicitly host device.
SGTM.

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: Yaxun (Sam) Liu (yxsamliu)

`struct A { A() {} ~A() {} int x; };

device A x;`

the above code is allowed with nvcc but not cuda-clang.

https://godbolt.org/z/jjMG3zTd3

https://godbolt.org/z/74Ed1WvGn

nvcc allows it not because it makes the ctor A::A() implicitly host device (this can be seen by defining A x in device function), but because it does not check host/device availability for file-scope device var.

I think it makes sense to make trivial ctor/dtor implicitly host device.

@Artem-B

[Artem-B]

@yxsamliu The patch is causing compilation issues: #72394 (comment)