> On Fri, Oct 9, 2015 at 9:27 PM, Jan Hubicka <hubi...@ucw.cz> wrote:
> >> >Of course it also depends what you inline into function. You can have
> >> >
> >> >bar() target(-mavx) {fancy avx code}
> >> >foobar() { ...... if (avx) bar();}
> >> >foo() ctarget(-mavx,-mno-avx) {....foobar();....}
>
> "no-" targets are not supported
Why not? I suppose I can use -march=x86_64 in a file compiled with
-march=core-avx2 or something like that, too.
>
> >> >
> >> >Now if you compile with -mavx and because ctarget takes effect only after
> >> >inlining,
> >> >at inlining time the target attributes will match and we can edn up
> >> >inline bar->foobar->foo.
> >> >After that we multiversion foo and drop AVX flag we will likely get ICE
> >> >at expansion
> >> >time.
> >> But isn't that avoided by fixing up the call graph so that all calls
> >> to the affected function are going through the dispatcher? Or is
> >> that happening too late?
> >
> > There is dispatcher only for foo that is the root of the callgarph tree.
> > When inlining we compare target attributes for match (in can_inline_edge_p).
> > We do not compare ctarget attributes. Expanding ctarget to target early
> > would
> > avoid need for ctarget handling.
> Currently inlining is disabled for functions with target_clone attribute:
Do you also disable inlining into functions with target_clone?
What I am concerned about is early inliner inlining (say) AVX code into ctarget
function because at early inlining time the target is not applied, yet.
Honza
