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[Bug middle-end/35545] virtual call specialization not happening with FDO
- From: "rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 17 Dec 2013 18:05:53 +0000
- Subject: [Bug middle-end/35545] virtual call specialization not happening with FDO
- Auto-submitted: auto-generated
- References: <bug-35545-4 at http dot gcc dot gnu dot org/bugzilla/>
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35545
--- Comment #4 from rguenther at suse dot de <rguenther at suse dot de> ---
"hubicka at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> wrote:
>http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35545
>
>Jan Hubicka <hubicka at gcc dot gnu.org> changed:
>
> What |Removed |Added
>----------------------------------------------------------------------------
> Status|UNCONFIRMED |NEW
> Last reconfirmed| |2013-12-17
> CC| |hubicka at gcc dot gnu.org,
> | |mjambor at suse dot cz,
> | |rguenther at suse dot de
> Ever confirmed|0 |1
>
>--- Comment #2 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
>Couple years later we finally devirtualize here:
> <bb 5>:
> ap_8 = operator new (16);
> ap_8->i = 0;
> ap_8->_vptr.A = &MEM[(void *)&_ZTV1A + 16B];
> _19 = foo;
> PROF_26 = [obj_type_ref] OBJ_TYPE_REF(_19;(struct A)ap_8->0);
> if (PROF_26 == foo)
> goto <bb 8>;
> else
> goto <bb 7>;
>
> <bb 6>:
> ap_13 = operator new (16);
> MEM[(struct B *)ap_13].D.2237.i = 0;
> MEM[(struct B *)ap_13].b = 0;
> MEM[(struct B *)ap_13].D.2237._vptr.A = &MEM[(void *)&_ZTV1B + 16B];
> _1 = foo;
> PROF_30 = [obj_type_ref] OBJ_TYPE_REF(_1;(struct A)ap_13->0);
> if (PROF_30 == foo)
> goto <bb 8>;
> else
> goto <bb 7>;
>
>however the code ends up super sily after tracer.
>for some reason we do not manage to fold away the virtual table lookup.
>Why?
This is probably doms fault. Does it even handle function pointers?
Tracer runs way too late and with no cleanups behind it.