https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122219
--- Comment #17 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Here is a simplified example without memcpy but an union instead of scalars
rather than vectors since vectors still run into PR 107916:
```
struct s1
{
int t;
};
union s2
{
long long tt;
struct s1 t[2];
};
inline long long s1_to_s2(struct s1 a)
{
s2 t={};
t.t[0] = a;
return t.tt;
}
inline
long long insert_s1_to_s2 (long long c1, struct s1 b, int a)
{
s2 c;
c.tt = c1;
c.t[a] = b;
return c.tt;
}
void foo(long long& v, unsigned int n) {
s1 f0 = {1};
s1 f1 = {2};
for (int i = 0; i < n; i++) {
f0.t = f0.t + f0.t;
f1.t = f1.t + f1.t;
v = s1_to_s2(f0);
v = insert_s1_to_s2(v, f1, 1);
}
}
```
