These options enable and disable automatic inlining of functions.

The compiler automatically inlines functions at the higher optimization levels where it is sensible to do so. The -Ospace and -Otime options, together with some other factors such as function size, influence how the compiler automatically inlines functions.

Selecting -Otime, in combination with various other factors, increases the likelihood that functions are inlined.

In general, when automatic inlining is enabled, the compiler inlines any function that is sensible to inline. When automatic inlining is disabled, only functions marked as __inline are candidates for inlining.