https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113458
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The loop based vectorizer is able to do a decent job at:
```
int f(short *a, signed char *b, int n)
{
int sum = 0;
n = 8;
for(int i = 0;i < n; i++)
sum += a[i]*b[i];
return sum;
}
```
But if we reduce n to 4, the loop based vectorizer is not able to handle it
either.
