Rust

You probably could implement some workarounds in the compiler, though the linked Oodle blog-post does a good job of explaining why that isn't feasible in this particular case:

The bug is not a flaw in the CPU logic as such, but rather the result of the CPU physically degrading due to design flaws. And for whatever reason, that degradation most frequently manifested as the mov instruction occasionally doing the wrong thing. Though the blog-post also makes it clear that this is not the only issue resulting from this degradation.

Moreover, the mov instruction is a very common instruction, so a general workaround for this problem would affect large parts of the resulting programs. For example, the 1-line function that Godbolt uses as its example code results in 3 mov instructions when compiled without optimizations:

int square(int num) {
    return num * num;
}

becomes

"square(int)":
        push    rbp
        mov     rbp, rsp
        mov     DWORD PTR [rbp-4], edi
        mov     eax, DWORD PTR [rbp-4]
        imul    eax, eax
        pop     rbp
        ret

I was kinda surprised as well that you couldn't annotate the function or something. But then again, an attribute like "please don't use this instruction" sounds like something that's pretty hard to integrate in the code generation. What kind of flag would you use? I don't think you want to apply that flag to everything, just to that particular function.