Hi,
On Fri, Apr 13, 2012 at 04:13:13PM +0200, Richard Guenther wrote:
> On Fri, 13 Apr 2012, Martin Jambor wrote:
>
> > Hi,
> >
> > currently we ICE when attempting to devirtualize a call to a virtual
> > method introduced in a descendant but with a base which is an ancestor
> > which does not have it. This is because fold_ctor_reference returns
> > constant zero when it cannot find the particular value in the provided
> > constructor which is something gimple_get_virt_method_for_binfo cannot
> > cope with. The patch below avoids it by simply testing for that
> > value and bailing out.
> >
> > Bootstrapped and tested on x86_64-linux, OK for trunk?
>
> Ok.
I forgot to ask permission also to commit it to the 4.7 branch but I
suppose that I can do that too and will go ahead with the same patch
soon (after bootstrap and testing on the branch).
Thanks,
Martin
>
> Thanks,
> Richard.
>
> > Thanks,
> >
> > Martin
> >
> >
> > 2012-04-12 Martin Jambor <mjam...@suse.cz>
> >
> > PR middle-end/52939
> > * gimple-fold.c (gimple_get_virt_method_for_binfo): Bail out if
> > fold_ctor_reference returns a zero constant.
> >
> > * testsuite/g++.dg/ipa/pr52939.C: New test.
> >
> > Index: src/gcc/gimple-fold.c
> > ===================================================================
> > --- src.orig/gcc/gimple-fold.c
> > +++ src/gcc/gimple-fold.c
> > @@ -3087,7 +3087,7 @@ gimple_get_virt_method_for_binfo (HOST_W
> > offset += token * size;
> > fn = fold_ctor_reference (TREE_TYPE (TREE_TYPE (v)), DECL_INITIAL (v),
> > offset, size);
> > - if (!fn)
> > + if (!fn || integer_zerop (fn))
> > return NULL_TREE;
> > gcc_assert (TREE_CODE (fn) == ADDR_EXPR
> > || TREE_CODE (fn) == FDESC_EXPR);
> > Index: src/gcc/testsuite/g++.dg/ipa/pr52939.C
> > ===================================================================
> > --- /dev/null
> > +++ src/gcc/testsuite/g++.dg/ipa/pr52939.C
> > @@ -0,0 +1,58 @@
> > +/* Verify that we do not ICE on invalid devirtualizations (which might
> > + be OK at run-time because never executed). */
> > +/* { dg-do run } */
> > +/* { dg-options "-O3 -fno-early-inlining -fno-inline" } */
> > +
> > +extern "C" void abort (void);
> > +
> > +class A
> > +{
> > +public:
> > + int data;
> > + virtual int foo (int i);
> > +};
> > +
> > +class B : public A
> > +{
> > +public:
> > + virtual int foo (int i);
> > + virtual int bar (int i);
> > +};
> > +
> > +int A::foo (int i)
> > +{
> > + return i + 1;
> > +}
> > +
> > +int B::foo (int i)
> > +{
> > + return i + 2;
> > +}
> > +
> > +int B::bar (int i)
> > +{
> > + return i + 3;
> > +}
> > +
> > +static int middleman (class A *obj, int i)
> > +{
> > + class B *b = (class B *) obj;
> > +
> > + if (i != 1)
> > + return b->bar (i);
> > + else
> > + return i;
> > +}
> > +
> > +int __attribute__ ((noinline,noclone)) get_input(void)
> > +{
> > + return 1;
> > +}
> > +
> > +int main (int argc, char *argv[])
> > +{
> > + class A o;
> > + if (middleman (&o, get_input ()) != 1)
> > + abort ();
> > + return 0;
> > +}
> >
> >
>
> --
> Richard Guenther <rguent...@suse.de>
> SUSE / SUSE Labs
> SUSE LINUX Products GmbH - Nuernberg - AG Nuernberg - HRB 16746
> GF: Jeff Hawn, Jennifer Guild, Felix Imendörffer
