[Bug tree-optimization/78386] Powerpc64le: optimization -O2 and higher cause math inconsistency

[brenohl at br dot ibm.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78386

--- Comment #2 from Breno Leitao <brenohl at br dot ibm.com> ---
I did further tests with older versions, and the problem is also reproducible,
so, this is not a regression.

These are the versions I tested also:

  * gcc-5 (Debian 5.4.1-3) 5.4.1 20161019
  * gcc-4 (Debian 4.9.4-2) 4.9.4