[Bug middle-end/71741] The program works 3 times slower compiled with g++ 5.3.1 than the same program compiled with g++ 4.8.4 with the same command (i7-5820 Haswell)

pinskia at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Sun Jul 24 07:22:00 GMT 2016


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71741

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING
   Last reconfirmed|                            |2016-07-24
     Ever confirmed|0                           |1

--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Have you tried the binary you created with GCC 4.8.x and used it on the newer
distro?  If it is slower there, then this is a glibc issue.  It has been known
that glibc has slowed down sin/cos to make it more accurate in some corner
cases which might be what you are seeing.


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