CStr eq acts as an optimization barrier

[SUPERCILEX]

I tried this code:

use std::ffi::CStr;

pub fn bytes(a: &CStr) -> bool {
    a.to_bytes() == b".."
}

pub fn cstr(a: &CStr) -> bool {
    a == unsafe { CStr::from_bytes_with_nul_unchecked(b"..\0") }
}

Godbolt: https://rust.godbolt.org/z/nh6nGjPMP

The explicit conversion to bytes lets the compiler figure out that it can compare two integers, but directly comparing CStrs seems to block that.