I haven't bothered to use -Os much (outside of places where performance decidedly does not matter); it seems fairly clear to me that code with like any amount of hot spots (i.e. most code) would greatly suffer.
I wonder how different would things be if it was more common to select optimization level per function, instead of for the whole project (gcc allows it, clang has only a thing to disable all optimizations on a function).
I wonder how different would things be if it was more common to select optimization level per function, instead of for the whole project (gcc allows it, clang has only a thing to disable all optimizations on a function).