Re: [PATCH] x86: Disable XCHG to MOV optimization
Jan Beulich <[email protected]>
| Newsgroups | gmane.comp.gnu.binutils |
|---|---|
| Message-ID | <[email protected]> |
On 13.07.2026 17:10, H.J. Lu wrote: > On Mon, Jul 13, 2026 at 11:03 PM Jan Beulich <[email protected]> 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. That's your position. I continue to fail to see why -O needs to work on anything (valgrind or not) that depends on getting to see specific encodings for certain insns. Such uses of -O are simply wrong. Undoing the change on the branch is, as previously indicated, merely to give them some time to adjust their machinery. Jan