On Mon, Jan 26, 2009 at 5:29 PM, Hariharan <harihar...@picochip.com> wrote: > Hi, > I ran into some code-size/stack size bloat using -Os for a piece of code. > This seemed to happen only when certain single call-site functions are > defined "static" and not otherwise. On investigating further on this, i see > that the inline_functions_called_once seems to rely only on > "cgraph_check_inline_limits", whereas other inlining code go through more > rigorous cost-benefit analysis to decide on inlining (especially with > INLINE_SIZE). > > I have been looking at re-setting some of the parameters used in > "cgraph_check_inline_limits" for inlining for picochip. I could not > understand the way PARAM_LARGE_FUNCTION_GROWTH and PARAM_STACK_FRAME_GROWTH > are used in this function. Both of these parameters are used as a fraction > of the bigger (or to) function. > > I want to be able to say, if the inlining would increase the code size or > stack frame size, dont inline. Otherwise, go ahead an inline. Of course, i > am compiling this code at -Os, so this condition is probably obvious. Can > you advice me on how to use these parameters to do that?
For -Os it should be enough to set PARAM_STACK_FRAME_GROWTH to zero. Inlining at -Os should already only happen if it decreases (overall!) code-size. Thus, inlining a function that is called once and that does not need to be emitted will always be an overall code-size win. > A side question... Are 'static' single call-site functions always inlined? I > would hope not (under -Os), but just checking. Yes. This is always a code-size win. Richard. > Thanks > Hari > > PS: If this were to be considered a "bug", i will file a report with a > testcase. > >
