Gluster 3.2.5 compile options default are -O0, is it Ok?

[arm2arm at googlemail.com (Arman Khalatyan)]

Hello,
in configure.ac the variable GF_CFLAGS is with -O0 overridden, so all
compilations are unoptimized.
Are there reason to use -O0 instead of -O2?
What about performance penalty if compilation goes with -O0 option?

Thanks.
Arman.

PS
I was testing to compile with -O2, it seems it is working.