Re: PR other/51165: add new adress_escapes predicate

[Patrick Marlier <patrick dot marlier at gmail dot com>]

On 01/17/2012 08:20 AM, Aldy Hernandez wrote:
> On 01/17/12 03:09, Richard Guenther wrote:
> > On Mon, Jan 16, 2012 at 4:58 PM, Aldy Hernandez<aldyh@redhat.com> wrote:
> > > > Not really - you handle both ptr and *ptr in the same predicate and
> > > > call both "address escaped". What I suggested was sth like
> > >
> > >
> > > I think I confused myself and you by asking the wrong question in the
> > > first
> > > place.
> > >
> > > Actually, what I want is to handle VAR_DECL correctly, and your original
> > > suggestion of using may_be_aliased() fits the bill. The other calls to
> > > ptr_deref_may_alias_global_p() were fine because we have an SSA_NAME.
> > >
> > > We're now down to a one-liner :).
> > >
> > > How about this? All TM memory optimization tests fixed, and no
> > > regressions.
> >
> > Ok. Note that may_be_aliased (x) is also true if x is an automatic
> > variable
> > that has its address taken. You can use is_global_var (x) instead if you
> > only want to test for "global memory".
> >
> > Richard.
>
> is_global_var is fine. Thanks.
>
> Committed.

I disagree. is_global_var is already tested just above:

      if (is_global_var (x))
        return !TREE_READONLY (x);

Which make sense since we don't want to log if it is read-only.

So you can do probably the following:

Index: trans-mem.c
===================================================================
--- trans-mem.c (revision 183253)
+++ trans-mem.c (working copy)
@@ -1497,8 +1497,6 @@ requires_barrier (basic_block entry_block, tree x,
             to needs_to_live_in_memory until we eliminate
             lower_sequence_tm altogether.  */
          needs_to_live_in_memory (x)
-         /* X escapes.  */
-         || is_global_var (x))
        return true;
       else
        {

Thanks.

Patrick Marlier.