[Bug target/86448] GCC 9 compiler generates slower code for spec 2006 milc on a power9 using -mcpu=power9 than using -mcpu=power8

[kelvin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86448

kelvin at gcc dot gnu.org changed:

           What    |Removed                     |Added
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                 CC|                            |kelvin at gcc dot gnu.org

--- Comment #1 from kelvin at gcc dot gnu.org ---
Using trunk on a dedicated DD2.2 power9, I get the following performance
comparisons:

         -mcpu=power8    -mcpu=power9           
             28.92      28.97           
             28.37      28.99           
             28.13      28.26           
             29.06      28.12           
             28.8       28.23           
             28.9       28.69           
             28.37      28.48           
             28.3       28.08           
                                delta   Percent
average 28.60625        28.4775 0.12875 0.45%