[Bug tree-optimization/68654] [6 Regression] CoreMark Pro performance degradation

[law at redhat dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68654

--- Comment #9 from Jeffrey A. Law <law at redhat dot com> ---
Without looking at the dumps or the code we generate, the only thing that makes
any sense would be the different SSA_NAME_VERSIONs resulting in different
coalescing.

If that is indeed the case, then that's an indication that performance is
likely to randomly bounce around due to seemingly innocuous changes.  Whether
or not there's something we ought to do, both to stabilize the resulting code
and hopefully get consistently good performance would require some deep
investigation of the coalescing heuristics.