Problem with evaluation order in assignment expression after c++17

Problem with evaluation order in assignment expression after c++17

[cyb_yorkin]

Hi all,

After c++17, the standard in section [expr.ass] guarantees "right operand is sequenced before the left operand".
I wrote this code, tested in gcc 12.1.

```
#include<iostream>
using namespace std;
int a = 1, b = 1;
int *ptr = &a;

int f(){
    ptr = &b;
    return 9;
}

int main(){
    *ptr = f();
    cout<<a<<','<<b<<endl;
}
```
I assume the program will evaluate function f first (it changed the ptr), and then get address of b from the pointer. After that, store returned value into b.
The output should be "1,9", like clang. but gcc give me "9,1".
You can check this here: https://godbolt.org/z/9P3cj7nYs

I wonder is that a gcc's bug or am I miss something else in c++ standard.

Thanks.