https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125366

--- Comment #19 from Sam James <sjames at gcc dot gnu.org> ---
(In reply to Michal Kowalewski from comment #18)
> (In reply to Sam James from comment #14)
> > (In reply to Michal Kowalewski from comment #12)
> > > compare-lto still fails, and the files seem identical (since I've already
> > > built them with stripped with -s). I also tried bootstrapping with the 
> > > same
> > > flags on another machine with AMD 7950X where -march=native expands to
> > > znver4, and surprisingly, more objects failed the comparison:
> > > 
> > > ...
> > >
> > > So the -march switch does affect this bug. I am including gimple-match-5
> > > objects from the zen 4 build.
> > 
> > Could you please pick the smallest of the relevant objects, then for the
> > matching command lines, share those, then run one of them with -save-temps,
> > and upload xyz.ii for preprocessed source?
> > 
> > You can then try whittle down which flag causes a difference too when both
> > are built with the same flags.
> 
> I rebuilt everything with -g0 on both alderlake and zen 4, and the results
> are rather surprising.

Thanks (though I wasn't saying to rebuild everything).

> All but gimple-match-6 diffs have disappeared. I have
> included stage2 and stage3 objects, with preprocessed sources as split 7z
> archive (due to size). All artifacts are from my znver4 build. So disabling
> debug info does indeed affect this bug, however gimple-match-6.o still
> remains. All sources were compiled with "-O3 -march=znver4 -flto
> -flto-partition=none -ftrivial-auto-var-init=uninitialized
> -fgraphite-identity -floop-nest-optimize -fno-semantic-interposition
> -fno-plt -s -fno-ident -fno-asynchronous-unwind-tables -g0"

Can you narrow down which of the flags for stage2 and stage3 (changing them
both at the same time) causes a difference when rebuilding just gimple-match-6?

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