llvm/clang/test/SemaCXX/PR19955.cpp

// RUN: %clang_cc1 -triple i686-win32 -verify -std=c++11 %s
// RUN: %clang_cc1 -triple i686-mingw32 -verify -std=c++11 %s

extern int __attribute__((dllimport)) var;
constexpr int *varp = &var; // expected-error {{must be initialized by a constant expression}}

extern __attribute__((dllimport)) void fun();
constexpr void (*funp)(void) = &fun; // expected-error {{must be initialized by a constant expression}}

template <void (*)()>
struct S {};
S<&fun> x;

template <int *>
struct U {};
U<&var> y;