Re: [PATCH] inline: improve internal function costs

[Richard Biener <rguenther@suse.de>]

On Mon, 12 Jun 2023, Andre Vieira (lists) wrote:

> 
> 
> On 05/06/2023 04:04, Jan Hubicka wrote:
> >> On Thu, 1 Jun 2023, Andre Vieira (lists) wrote:
> >>
> >>> Hi,
> >>>
> >>> This is a follow-up of the internal function patch to add widening and
> >>> narrowing patterns.  This patch improves the inliner cost estimation for
> >>> internal functions.
> >>
> >> I have no idea why calls are special in IPA analyze_function_body
> >> and so I cannot say whether treating all internal fn calls as
> >> non-calls is correct there.  Honza?
> > 
> > The reason is that normal statements are acconted as part of the
> > function body, while calls have their costs attached to call edges
> > (so it can be adjusted when call is inlined to otherwise optimized).
> > 
> > However since internal functions have no cgraph edges, this looks like
> > a bug that we do not test it.  (the code was written before internal
> > calls was introduced).
> >
> 
> This sounds to me like you agree with my approach to treat internal calls
> different to regular calls.
> 
> > I wonder if we don't want to have is_noninternal_gimple_call that could
> > be used by IPA code to test whether cgraph edge should exist for
> > the statement.
> 
> I'm happy to add such a helper function @richi,rsandifo: you ok with that?

It's a bit of an ugly name, if we want something that keys on calls
that have an edge it should be obvious it does this.  I wouldn't
add is_noninternal_gimple_call.  With LTO and libgcc and internal
optab fns it's also less obvious in cases we want to have say
.DIVMODDI3 (...) which in the end maps to a LTOed libcall from libgcc.a 
...

Richard.