[Bug tree-optimization/92860] [9/10/11/12 regression] Global flags affected by -O settings are clobbered by optimize attribute

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92860

--- Comment #76 from rguenther at suse dot de <rguenther at suse dot de> ---
On Tue, 14 Dec 2021, marxin at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92860
> 
> --- Comment #75 from Martin Liška <marxin at gcc dot gnu.org> ---
> (In reply to David Binderman from comment #74)
> > (In reply to Martin Liška from comment #72)
> > > You will manage, it's not rocket science.
> > > 
> > > So please, add break point at the place it triggers the ICE and do:
> > > 
> > > (gdb) p &ptr1->x_help_flag
> > > (gdb) p &ptr2->x_help_flag
> > 
> > For this to work, I had to replace the options-save.o with a version
> > compiled by -O0 and that made the problem go away ;-<
> 
> Or you would have to print &ptr1->x_help_flag with a printf and then
> use gdb for the memory.
> 
> > 
> > I am still happy to walk away from this bug report. It is known
> > to occur on only one variant of one architecture and it is hard
> > to reproduce. I can think of better things to work on in gcc.
> 
> Ok...
> 
> > 
> > As far as finding a machine with a bdver2 architecture, I suspect
> > any more recent AMD machine would be fine. 
> > 
> > Has no one checked the compile farm ?
> 
> No, there's not a bdver2 machine.

Maybe the issue reproduces with only -mtune=bdver2 or with -march=bdver2 
-mno-xop (XOP is what's removed from znver2 for example, not 100% sure
that's all, but ...).  It does sound like eventually options-save.c
is miscompiled somehow ...