# Re: \[RFC PATCH\] LKMM: Add ctrl\_dep() macro for control dependency

- From: Linus Torvalds \<torvalds@linux-foundation.org\>
- Date: 2021-09-29 14:54:43 
- List: linux-toolchains
- Page: https://ratatoskr.run/linux-toolchains/2021/09/1525914
- Thread: https://ratatoskr.run/linux-toolchains/2021/09/1525080/t.md

```text
On Wed, Sep 29, 2021 at 7:47 AM Linus Torvalds
[ref] wrote:
>
> And if there *is* need ("look, we have that same store in both the if-
> and the else-statement" or whatever), then say so, and state that
> thing.

Side note: I'd also like the commit that introduces this to talk very
explicitly about the particular case that it is used doe and that it
fixes. No "this can happen". A "this happened, here's the _actual_
wrong code generation, and look how this new ctrl_dep() macro fixes
it".

When it's this subtle, I don't want theoretical arguments. I want
actual outstanding and real bugs.

Because I get the feeling that there were very few actual realistic
examples of this, only made-up theoretical cases that wouldn't ever
really be found in real code.

                Linus
```