[Bug middle-end/81914] [7/8 Regression] gcc 7.1 generates branch for code which was branchless in earlier gcc version

[bugzilla@poradnik-webmastera.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81914

--- Comment #3 from Daniel Fruzynski <bugzilla@poradnik-webmastera.com> ---
Yes, branchless version is faster. Here are results for code compiled with gcc
4.8.5:

Benchmark            Time           CPU Iterations
--------------------------------------------------
BM_memcmp            6 ns          6 ns  111001949
BM_int64cmp          4 ns          4 ns  183761752

And here for gcc 7.1.0:

Benchmark            Time           CPU Iterations
--------------------------------------------------
BM_memcmp            6 ns          6 ns  113198940
BM_int64cmp          8 ns          8 ns   82036754

Note: Code tested accepted values passed via pointer instead of value, to
better compare it with memcmp function. Functions were comparing random values,
generated before tests and stored in arrays. srand was called with constant
value to get repeatable results.