[jleahy]

It’s a shame that Osize can sometimes produce truly awful code. There are a few optimisations in there that trade a byte for a massive slowdown.

[userbinator]

You asked for minimum size, and that's what you got. I'd say that's working as it should.

A more granular control over optimisation would be good, however.

[jleahy]

Probably just some tweaks to O2 would be enough, after all people are selecting Os over O2 because they see better performance, and that should not be happening.

[kevin_thibedeau]

You can enable/disable individual optimizations. How much more granular do you need?

[jhgb]

Surely a profile-guided build should be able to only apply -Os to those functions where it doesn't cause a lot of problems.

[pclmulqdq]

In the application I referred to, PGO was also used. However, that only applies -Os to cold code, and if what you're doing is very branchy, it can help even in the hot path.