https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111739
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |INVALID
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The code is undefined for alias reasons:
union {
int f;
short g
} h;
*j = &h;
...
a = n(h.f++);
*j = 0;
...
for (; i < 2; i++)
d = k(h.g || 0, 59376);
short *b = &h;
*b ^= e;
printf("%d\n", h);
```
In the case of profiling, we are able to optimize away the short load from h
in:
*b ^= e;
and point it back to the store from `h.f++` and miss the store via *j.
Once you add -fno-strict-aliasing the testcase starts to work.
