https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103299
Bug ID: 103299
Summary: accessing incorrect storage for union at constexpr
context
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: unlvsur at live dot com
Target Milestone: ---
struct compile_time_fp
{
void* ct_fp{};
};
struct foo
{
union
{
void* fp{};
compile_time_fp ct_fp;
};
};
inline constexpr foo foo_factory()
{
if (__builtin_is_constant_evaluated())
{
return {.ct_fp={}};
}
else
{
return {};
}
}
constexpr bool test_direct_construction()
{
foo f{.ct_fp={}};
f.ct_fp;
return true;
}
constexpr bool test_factory_construction()
{
foo_factory().ct_fp;
return true;
}
static_assert(test_direct_construction());
static_assert(test_factory_construction());//should not fail
GCC fails for the 2nd one while msvc and clang all accept the code here.
