On 10/23/24 10:15, Dave Hansen wrote:
On 10/22/24 16:24, Christoph Lameter (Ampere) wrote:
On Tue, 22 Oct 2024, Dave Hansen wrote:
So I think Peter's version was the best. It shuts up clang and also
preserves the existing (good) gcc 'sub' behavior. I'll send it out for
real in a bit, but I'm thinking of something like the attached patch.
The desired behavior is a "dec". "sub" has a longer op code AFAICT.
Gah, yes, of course. I misspoke.
We want "inc" and "dec" for +1 and -1. "add" and "sub" are heftier and
get used for everything else.
Do we really? I don't know if there are any microarchitectures where the
partial register update still matters. It is only one byte difference.
-hpa
