[Bug tree-optimization/120268] Missed removing loop of setting zero when dereference pointer (memset) at -O3 -fallow-store-data-races

[kaelfandrew at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120268

--- Comment #4 from Kael Franco <kaelfandrew at gmail dot com> ---
(In reply to Andrew Pinski from comment #1)
> This is only valid with -fallow-store-data-races. Otherwise you can
> introduce a race condition according to the C/C++11 memory model.

I don't think -fallow-store-data-races is needed if the pointer was restrict or
TYPE_QUAL_RESTRICT in GCC's tree:

```
void f0(int * restrict arg0){
    if(arg0[0])
        arg0[0] = 0;
}
```