[Bug tree-optimization/43233] `&1` not being sunk to the use of if from the beginging of the function

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=43233

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
That is take:
```
int g1,g2,g3;
int f2(int a, int b)
{
    a &= 1;
    if (b)
        g3++;
    if (a) return g1;
    return g2;
}
int f2_(int a, int b)
{
    if (b)
        g3++;
    a &= 1;
    if (a) return g1;
    return g2;
}
```

f2 and f2_ should produce the same code generation.