https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82004
--- Comment #45 from john henning <mailboxnotfound at yahoo dot com> --- I had promised to do some more testing. There were miscompares during the training run (thus causing the build to fail) using -Ofast -flto -fprofile-generate/-fprofile-use on aarch64 with GCC 8.2, 9.3, and 10.1 and on x86_64 with GCC 8.3, 9.3, and 10.1. The above succeeded with GCC 7.3 on both aarch64 and x86_64. The attachment 628.pop2.moretests.7aug2020.txt digs into 10.1 a bit deeper (posted as an attachment to reduce the chances of unwanted line wraps or white space mangling for the tables)