[Bug c/71538] Obvious optimization related to arrays aren't performed.

[sasho648 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71538

--- Comment #1 from sasho648 at gmail dot com ---
The exact command used to compile this code was "gcc -O3 test.c" (as test.c
containing the snippet above).