[FFmpeg-devel] MPEG-2 Acceleration Refactor

Michael Niedermayer michaelni
Fri Jun 22 13:30:39 CEST 2007


On Fri, Jun 22, 2007 at 02:02:20AM -0700, Trent Piepho wrote:
> On Fri, 22 Jun 2007, Michael Niedermayer wrote:
> > if yes then this is a new gcc bug, that is gcc inlines fewer functions
> > with av_always_inline but there is not a single function it inlines in the
> > av_always_inline case which wasnt already inlined wthout it
> >
> > if no and the normal inline case looks different then this is still a
> > gcc bug just not a new one, av_always_inline should IMO inline the function
> > without changing the inlining of the other code (if av_inline behaves
> > different, which it does sadly, then its not usefull for anything and
> > another attribute which does force the inlining of a function without
> > code slowification sideeffectes would be needed)
> gcc will do a lot of inlining without any kind of inline keywords or
> attributes at all.  There are a number of parameters that control this.
> Imagine three functions, A which calls B which calls C.  One could inline B
> into A, but not inline C into A+B.  Or inline C into B, but not inline B+C
> into A.  Or inline all three.
> Suppose functions A and B are small, but C is big.
> In one inline directives are used, gcc might decide to inline B into A, but
> not inline C.  If you now add an inline directive to C, gcc will inline C into
> B, and the new big B+C function won't be inlined into A.

makes sense iam fully agreeing with you here but this has nothing to do with
this thread

gcc stops inlining unrelated funtions if inlining of a function is forced
which was already inlined without the always_inline

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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