Stance on -cross-module-optimization

[MahdiBM (Mahdi Bahrami)]

@dimi mentioned this nice response from @Erik_Eckstein in another post to me:

Brave new world: best practices for cross-module optimization

In general, CMO is a significant performance win. But (as with most optimizations) there can be corner cases where you see a degradation. The critical problem with CMO is code size. Therefore the CMO which is enabled by default is much more conservative than the "aggressive" CMO, which must be explicitly enabled with -cross-module-optimization. impact on compilation times We didn't see any significant impact on compilation times. Especially with the default CMO which has only a relatively s…

So ... It appears the flag does still have some usage, and while CMO (cross-module-optimization) is enabled by default, explicitly enabling it will make it more aggressive?

And if code size doesn't matter much, one should enable that setting?