[Bug c++/82229] New: GCC7's LTO underperforms compared to GCC6

[krzysio.kurek at wp dot pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82229

            Bug ID: 82229
           Summary: GCC7's LTO underperforms compared to GCC6
           Product: gcc
           Version: 7.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: krzysio.kurek at wp dot pl
  Target Milestone: ---

A small SFML project on github:
https://github.com/Hopson97/Empire
Takes huge advantage of -flto flag on GCC6, but after upgrading to GCC7, the
difference is negligible.
Here are some of my test results:
gcc6.3 no flto: 24-25 fps
gcc7.2 no flto: 24 fps
gcc6.3 with flto: 40-42fps
gcc7.2 with flto: 26-27fps