The -Og compiler optimization flag for the GNU Compiler Collection would be similar to -O1 and be more about enhancing the debug-ability of binaries as opposed to performing optimizations for speed. "This adds a new optimization level, -Og, as previously discussed. It aims at providing fast compilation, a superior debugging experience and reasonable runtime performance...It's a first cut, highlighting that our fixed pass pipeline and simply enabling/disabling individual passes (but not pass copies for example) doesn't scale to properly differentiate between -Og and -O. -O1 should get similar treatment, eventually just building on -Og but not focusing on debugging experience."
While this optimization level was previously discussed amongst developers previously, no GCC developers have yet to comment on the -Og "RFC" that went out last month, so Guenther may end up shelving the idea for GCC 4.8 rather than pushing it into trunk.
The mailing list message concerning GCC -Og can be found on gcc-patches.