[htfy96]

It depends. O0 turns off a few trimming optimizations and could potentially causes more information (code or DWARF) to be included in the objects, which may eventually slow down the compilation. In our large code base, we found that -O1 works best in terms of compilation speed.

[ahartmetz]

Yeah, -O1 is usually a good choice. I get the occasional <value optimized out> while debugging, well I add another logging statement and rerun.