> On Sat, 24 Oct 2015, Jan Hubicka wrote:
> 
> > Hi, as discussed earlier, the types_compatible_p in operand_equal_p 
> > seems redundant. (it is callers work to figure out how much of type 
> > matching it wants.  If not, we probably want to treat most of other 
> > references and casts simlar way).
> > 
> > Bootstrapped/regtested x86_64-linux. OK?
> 
> Ok.
> 
> Btw, you need to audit tree hashing for required changes with respect
> to your ones to operand_equal_p.  operand_equal_p is the equality
> function for it.

Yep, I am aware that tree hasing must match.  I think my changes are safe so
far:
 - ctors are already hashed resonably
 - types are not hashed so the changes strenghtening OEP_ADDRESS_OF are safe
 - OEP_ADDRESS_OF (so far) still boils down to syntactic matching. 

Looking at this I noticed that simple_cst_equal in tree.c seems to reimplement
OEP_CONSTANT part of operand_equal_p and it seems to have bugs - i.e. not
comparing index for CONSTRUCTOR ELTs.

Also I was always bit unsure how the path through operand_equal_p that allows
different tree codes to match (stripping MEM_REF) and use of STRIP_NOPS combine
with add_expr that doesn't do these.  Do we have some mechanism that will
prevent this from corrupting hashtables?

Honza
> 
> Thanks,
> Richard.
> 
> >     * fold-const.c (operand_equal_p): Drop types_compatible_p when
> >     comparing references.
> > 
> > Index: fold-const.c
> > ===================================================================
> > --- fold-const.c    (revision 229278)
> > +++ fold-const.c    (working copy)
> > @@ -2982,9 +2982,6 @@ operand_equal_p (const_tree arg0, const_
> >                                        TYPE_SIZE (TREE_TYPE (arg1)),
> >                                        flags)))
> >             return 0;
> > -         /* Verify that access happens in similar types.  */
> > -         if (!types_compatible_p (TREE_TYPE (arg0), TREE_TYPE (arg1)))
> > -           return 0;
> >           /* Verify that accesses are TBAA compatible.  */
> >           if (flag_strict_aliasing
> >               && (!alias_ptr_types_compatible_p
> > 
> > 
> 
> -- 
> Richard Biener <rguent...@suse.de>
> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 
> 21284 (AG Nuernberg)

Reply via email to