GCC 5+ generates invalid code due to UB

[mikedld]

GCC 4 (tested with 4.4.7, 4.8.5, 4.9.4) generates working code even with optimizations enabled. GCC 5+ (tested with 5.4.0, 6.3.0) OTOH generates invalid (aborting, segfaulting, infinitely looping) code even with -O1. I guess it's worth mentioning on the wiki page that optimizations bring trouble not only in the case of MSVC.

Out of curiosity,

1. Is it possible to enable optimizations but still get working code (with some compiler attributes or other magic)? We're currently building both binaries for release (so, with optimizations enabled) and their unit tests in one go.
2. Is it possible to implement HippoMocks in non-UB way with current C++ standards (up to C++17)?

P.S. Clang (tested with Apple Clang 8.1.0 from Xcode 8.3) currently generates working code regardless of optimization level.

P.P.S. Sample code used in tests:

#include "hippomocks.h"

struct A { virtual ~A() {} };

int main()
{
    HippoMocks::MockRepository mocks;

    A* a = mocks.Mock<A>();
    mocks.ExpectCallDestructor(a);
    delete a;

    return 0;
}