[Bug libfortran/78379] Processor-specific versions for matmul

[jvdelisle at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78379

--- Comment #10 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> ---
(In reply to Thomas Koenig from comment #9)
> Next question - what happens if you add
> 
> -mvzeroupper -mavx
> 
> to the line in the Makefile?  Does that make a difference in speed?

-mvzeroupper slows all way down with or without -mprefer-avx128