When using switch "-O2" all is fine, but

...using -O3 I get this:

+===========================GNAT BUG DETECTED==============================+
| Community 2018 (20180524-73) (x86_64-pc-linux-gnu) GCC error:            |
| in vectorizable_reduction, at tree-vect-loop.c:5935                      |
| Error detected around gameutils-updategamestate.adb:5:1                  |
| Please submit a bug report by email to report@adacore.com.               |
| GAP members can alternatively use GNAT Tracker:                          |
| http://www.adacore.com/ section 'send a report'.                         |
| See gnatinfo.txt for full info on procedure for submitting bugs.         |
| Use a subject line meaningful to you and us to track the bug.            |
| Include the entire contents of this bug box in the report.               |
| Include the exact command that you entered.                              |
| Also include sources listed below.                                       |
| Use plain ASCII or MIME attachment(s).                                   |
+==========================================================================+

Please include these source files with error report
Note that list may not be accurate in some cases,
so please double check that the problem can still
be reproduced with the set of files listed.
Consider also -gnatd.n switch (see debug.adb).
