[Bug tree-optimization/48031] [4.4/4.5 Regression] gcc.c-torture/compile/pr42956.c ICEs gcc on m68k-linux, ivopts related?

["rguenther at suse dot de" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48031

--- Comment #9 from rguenther at suse dot de <rguenther at suse dot de> 2011-03-10 12:36:33 UTC ---
On Thu, 10 Mar 2011, ebotcazou at gcc dot gnu.org wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48031
> 
> --- Comment #8 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2011-03-10 12:34:57 UTC ---
> > It's mixing VLA unaware foldings into the mids of GIMPLE which is the
> > root of the issue though.  The issue is latent on trunk.
> > 
> > Patch for the first (and safe) idea:
> > 
> > Index: gcc/fold-const.c
> > ===================================================================
> > --- gcc/fold-const.c    (revision 170818)
> > +++ gcc/fold-const.c    (working copy)
> > @@ -15554,7 +15560,8 @@ fold_indirect_ref_1 (location_t loc, tre
> >         }
> >        /* *(foo *)&fooarray => fooarray[0] */
> >        else if (TREE_CODE (optype) == ARRAY_TYPE
> > -              && type == TREE_TYPE (optype))
> > +              && type == TREE_TYPE (optype)
> > +              && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
> >         {
> >           tree type_domain = TYPE_DOMAIN (optype);
> >           tree min_val = size_zero_node;
> > @@ -15633,7 +15640,8 @@ fold_indirect_ref_1 (location_t loc, tre
> > 
> >    /* *(foo *)fooarrptr => (*fooarrptr)[0] */
> >    if (TREE_CODE (TREE_TYPE (subtype)) == ARRAY_TYPE
> > -      && type == TREE_TYPE (TREE_TYPE (subtype)))
> > +      && type == TREE_TYPE (TREE_TYPE (subtype))
> > +      && TREE_CODE (TYPE_SIZE (type)) == INTEGER_CST)
> >      {
> >        tree type_domain;
> >        tree min_val = size_zero_node;
> > 
> > Eric, can you see any issues with that and Ada?
> 
> If this is limited to the in_gimple_form case, probably none.

No it isn't.  But given that fold at this place doesn't even
fill in the array-ref element-size slot but provides NULL_TREE
it is probably a fix for the better anyway?

Richard.