[Bug other/110260] New: Multiple applications misbehave when compiled with -march=znver4

["chiitoo at gentoo dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110260

            Bug ID: 110260
           Summary: Multiple applications misbehave when compiled with
                    -march=znver4
           Product: gcc
           Version: 13.1.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: chiitoo at gentoo dot org
  Target Milestone: ---

While hunting for the cause for a stack alignment issue in Wine [1], it started
to look more and more that '-march=znver4' is at least related to the issue.

I had compiled a few hundred other packages mistakingly with certain testing
flags in between building Wine and the mingw-toolchain, and noticed a certain
issue related to KWin disappear [2].

The issue came back the next day, after resting X11, and it took me a while to
realise what had happened.  I saw from my build logs that KWin was one of those
packages that I had compiled with the testing C{XX}FLAGS (-march=x86-64 -O2
-g), and I had then later compiled it again with the usual flags (-march=znver4
-O2 -fomit-frame-pointer -pipe -mindirect-branch=thunk), and so I did some test
builds with -march=x86-64 and -march=znver3 and the problem goes away.

There's at least one more recent issue with my LXQt panel task manager widget,
but I'm not sure yet if this will make that go away as well.

Let me know if I can help pinpoint the issue more, or/and confirm this to be a
GCC issue or not.

Next I'm thinking of trying to see if I can spot one or more of the
instructions do it that is not included with znver3 per the x86-Options
documentation [3].

(By the by, is ADCX a typo of ADX?  I see -madx as an option but only one use
of it otherwise, and no -adcx as an option and lots of mentions of it... but
perhaps I'm not reading them correct-like.)

Thank you!


1. https://bugs.winehq.org/show_bug.cgi?id=55007
2. https://bugs.kde.org/show_bug.cgi?id=469426
3. https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html