[PATCH] x86: Disable XCHG to MOV optimization

[H.J. Lu]

On Mon, Jul 13, 2026 at 11:03 PM Jan Beulich <jbeulich@suse.com> wrote:
>
> On 13.07.2026 14:08, H.J. Lu wrote:
> > I am going to check this patch into master as well as 2.47 branch.
> > I added optimize_for_unsafe, which is 0, and moved XCHG to MOV
> > optimization under it.  We can add something like -Ounsafe later.
>
> But this is wrong, the optimization itself isn't unsafe. Please can we

You can change it to a different name.  But -O on master must work with
today's valgrind.

> not rush things for master, and go the easy (revert) route for 2.47?
>

For 2.47, there should be tests to verify that -O doesn't change
XCHG to MOV.


-- 
H.J.